* maint-2.33:
Git 2.33.7
Git 2.32.6
Git 2.31.7
Git 2.30.8
apply: fix writing behind newly created symbolic links
dir-iterator: prevent top-level symlinks without FOLLOW_SYMLINKS
clone: delay picking a transport until after get_repo_path()
t5619: demonstrate clone_local() with ambiguous transport
Deal with a few deprecation warning from cURL library.
* jk/curl-avoid-deprecated-api:
http: support CURLOPT_PROTOCOLS_STR
http: prefer CURLOPT_SEEKFUNCTION to CURLOPT_IOCTLFUNCTION
http-push: prefer CURLOPT_UPLOAD to CURLOPT_PUT
The CURLOPT_PROTOCOLS (and matching CURLOPT_REDIR_PROTOCOLS) flag was
deprecated in curl 7.85.0, and using it generate compiler warnings as of
curl 7.87.0. The path forward is to use CURLOPT_PROTOCOLS_STR, but we
can't just do so unilaterally, as it was only introduced less than a
year ago in 7.85.0.
Until that version becomes ubiquitous, we have to either disable the
deprecation warning or conditionally use the "STR" variant on newer
versions of libcurl. This patch switches to the new variant, which is
nice for two reasons:
- we don't have to worry that silencing curl's deprecation warnings
might cause us to miss other more useful ones
- we'd eventually want to move to the new variant anyway, so this gets
us set up (albeit with some extra ugly boilerplate for the
conditional)
There are a lot of ways to split up the two cases. One way would be to
abstract the storage type (strbuf versus a long), how to append
(strbuf_addstr vs bitwise OR), how to initialize, which CURLOPT to use,
and so on. But the resulting code looks pretty magical:
GIT_CURL_PROTOCOL_TYPE allowed = GIT_CURL_PROTOCOL_TYPE_INIT;
if (...http is allowed...)
GIT_CURL_PROTOCOL_APPEND(&allowed, "http", CURLOPT_HTTP);
and you end up with more "#define GIT_CURL_PROTOCOL_TYPE" macros than
actual code.
On the other end of the spectrum, we could just implement two separate
functions, one that handles a string list and one that handles bits. But
then we end up repeating our list of protocols (http, https, ftp, ftp).
This patch takes the middle ground. The run-time code is always there to
handle both types, and we just choose which one to feed to curl.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
The IOCTLFUNCTION option has been deprecated, and generates a compiler
warning in recent versions of curl. We can switch to using SEEKFUNCTION
instead. It was added in 2008 via curl 7.18.0; our INSTALL file already
indicates we require at least curl 7.19.4.
But there's one catch: curl says we should use CURL_SEEKFUNC_{OK,FAIL},
and those didn't arrive until 7.19.5. One workaround would be to use a
bare 0/1 here (or define our own macros). But let's just bump the
minimum required version to 7.19.5. That version is only a minor version
bump from our existing requirement, and is only a 2 month time bump for
versions that are almost 13 years old. So it's not likely that anybody
cares about the distinction.
Switching means we have to rewrite the ioctl functions into seek
functions. In some ways they are simpler (seeking is the only
operation), but in some ways more complex (the ioctl allowed only a full
rewind, but now we can seek to arbitrary offsets).
Curl will only ever use SEEK_SET (per their documentation), so I didn't
bother implementing anything else, since it would naturally be
completely untested. This seems unlikely to change, but I added an
assertion just in case.
Likewise, I doubt curl will ever try to seek outside of the buffer sizes
we've told it, but I erred on the defensive side here, rather than do an
out-of-bounds read.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
The two options do exactly the same thing, but the latter has been
deprecated and in recent versions of curl may produce a compiler
warning. Since the UPLOAD form is available everywhere (it was
introduced in the year 2000 by curl 7.1), we can just switch to it.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
* maint-2.32:
Git 2.32.6
Git 2.31.7
Git 2.30.8
apply: fix writing behind newly created symbolic links
dir-iterator: prevent top-level symlinks without FOLLOW_SYMLINKS
clone: delay picking a transport until after get_repo_path()
t5619: demonstrate clone_local() with ambiguous transport
* maint-2.31:
Git 2.31.7
Git 2.30.8
apply: fix writing behind newly created symbolic links
dir-iterator: prevent top-level symlinks without FOLLOW_SYMLINKS
clone: delay picking a transport until after get_repo_path()
t5619: demonstrate clone_local() with ambiguous transport
* maint-2.30:
Git 2.30.8
apply: fix writing behind newly created symbolic links
dir-iterator: prevent top-level symlinks without FOLLOW_SYMLINKS
clone: delay picking a transport until after get_repo_path()
t5619: demonstrate clone_local() with ambiguous transport
Fix a vulnerability (CVE-2023-23946) that allows crafted input to trick
`git apply` into writing files outside of the working tree.
* ps/apply-beyond-symlink:
dir-iterator: prevent top-level symlinks without FOLLOW_SYMLINKS
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Resolve a security vulnerability (CVE-2023-22490) where `clone_local()`
is used in conjunction with non-local transports, leading to arbitrary
path exfiltration.
* tb/clone-local-symlinks:
dir-iterator: prevent top-level symlinks without FOLLOW_SYMLINKS
clone: delay picking a transport until after get_repo_path()
t5619: demonstrate clone_local() with ambiguous transport
When writing files git-apply(1) initially makes sure that none of the
files it is about to create are behind a symlink:
```
$ git init repo
Initialized empty Git repository in /tmp/repo/.git/
$ cd repo/
$ ln -s dir symlink
$ git apply - <<EOF
diff --git a/symlink/file b/symlink/file
new file mode 100644
index 0000000..e69de29
EOF
error: affected file 'symlink/file' is beyond a symbolic link
```
This safety mechanism is crucial to ensure that we don't write outside
of the repository's working directory. It can be fooled though when the
patch that is being applied creates the symbolic link in the first
place, which can lead to writing files in arbitrary locations.
Fix this by checking whether the path we're about to create is
beyond a symlink or not. Tightening these checks like this should be
fine as we already have these precautions in Git as explained
above. Ideally, we should update the check we do up-front before
starting to reflect the computed changes to the working tree so that
we catch this case as well, but as part of embargoed security work,
adding an equivalent check just before we try to write out a file
should serve us well as a reasonable first step.
Digging back into history shows that this vulnerability has existed
since at least Git v2.9.0. As Git v2.8.0 and older don't build on my
system anymore I cannot tell whether older versions are affected, as
well.
Reported-by: Joern Schneeweisz <jschneeweisz@gitlab.com>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When using the dir_iterator API, we first stat(2) the base path, and
then use that as a starting point to enumerate the directory's contents.
If the directory contains symbolic links, we will immediately die() upon
encountering them without the `FOLLOW_SYMLINKS` flag. The same is not
true when resolving the top-level directory, though.
As explained in a previous commit, this oversight in 6f054f9fb3
(builtin/clone.c: disallow `--local` clones with symlinks, 2022-07-28)
can be used as an attack vector to include arbitrary files on a victim's
filesystem from outside of the repository.
Prevent resolving top-level symlinks unless the FOLLOW_SYMLINKS flag is
given, which will cause clones of a repository with a symlink'd
"$GIT_DIR/objects" directory to fail.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In the previous commit, t5619 demonstrates an issue where two calls to
`get_repo_path()` could trick Git into using its local clone mechanism
in conjunction with a non-local transport.
That sequence is:
- the starting state is that the local path https:/example.com/foo is a
symlink that points to ../../../.git/modules/foo. So it's dangling.
- get_repo_path() sees that no such path exists (because it's
dangling), and thus we do not canonicalize it into an absolute path
- because we're using --separate-git-dir, we create .git/modules/foo.
Now our symlink is no longer dangling!
- we pass the url to transport_get(), which sees it as an https URL.
- we call get_repo_path() again, on the url. This second call was
introduced by f38aa83f9a (use local cloning if insteadOf makes a
local URL, 2014-07-17). The idea is that we want to pull the url
fresh from the remote.c API, because it will apply any aliases.
And of course now it sees that there is a local file, which is a
mismatch with the transport we already selected.
The issue in the above sequence is calling `transport_get()` before
deciding whether or not the repository is indeed local, and not passing
in an absolute path if it is local.
This is reminiscent of a similar bug report in [1], where it was
suggested to perform the `insteadOf` lookup earlier. Taking that
approach may not be as straightforward, since the intent is to store the
original URL in the config, but to actually fetch from the insteadOf
one, so conflating the two early on is a non-starter.
Note: we pass the path returned by `get_repo_path(remote->url[0])`,
which should be the same as `repo_name` (aside from any `insteadOf`
rewrites).
We *could* pass `absolute_pathdup()` of the same argument, which
86521acaca (Bring local clone's origin URL in line with that of a remote
clone, 2008-09-01) indicates may differ depending on the presence of
".git/" for a non-bare repo. That matters for forming relative submodule
paths, but doesn't matter for the second call, since we're just feeding
it to the transport code, which is fine either way.
[1]: https://lore.kernel.org/git/CAMoD=Bi41mB3QRn3JdZL-FGHs4w3C2jGpnJB-CqSndO7FMtfzA@mail.gmail.com/
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When cloning a repository, Git must determine (a) what transport
mechanism to use, and (b) whether or not the clone is local.
Since f38aa83f9a (use local cloning if insteadOf makes a local URL,
2014-07-17), the latter check happens after the remote has been
initialized, and references the remote's URL instead of the local path.
This is done to make it possible for a `url.<base>.insteadOf` rule to
convert a remote URL into a local one, in which case the `clone_local()`
mechanism should be used.
However, with a specially crafted repository, Git can be tricked into
using a non-local transport while still setting `is_local` to "1" and
using the `clone_local()` optimization. The below test case
demonstrates such an instance, and shows that it can be used to include
arbitrary (known) paths in the working copy of a cloned repository on a
victim's machine[^1], even if local file clones are forbidden by
`protocol.file.allow`.
This happens in a few parts:
1. We first call `get_repo_path()` to see if the remote is a local
path. If it is, we replace the repo name with its absolute path.
2. We then call `transport_get()` on the repo name and decide how to
access it. If it was turned into an absolute path in the previous
step, then we should always treat it like a file.
3. We use `get_repo_path()` again, and set `is_local` as appropriate.
But it's already too late to rewrite the repo name as an absolute
path, since we've already fed it to the transport code.
The attack works by including a submodule whose URL corresponds to a
path on disk. In the below example, the repository "sub" is reachable
via the dumb HTTP protocol at (something like):
http://127.0.0.1:NNNN/dumb/sub.git
However, the path "http:/127.0.0.1:NNNN/dumb" (that is, a top-level
directory called "http:", then nested directories "127.0.0.1:NNNN", and
"dumb") exists within the repository, too.
To determine this, it first picks the appropriate transport, which is
dumb HTTP. It then uses the remote's URL in order to determine whether
the repository exists locally on disk. However, the malicious repository
also contains an embedded stub repository which is the target of a
symbolic link at the local path corresponding to the "sub" repository on
disk (i.e., there is a symbolic link at "http:/127.0.0.1/dumb/sub.git",
pointing to the stub repository via ".git/modules/sub/../../../repo").
This stub repository fools Git into thinking that a local repository
exists at that URL and thus can be cloned locally. The affected call is
in `get_repo_path()`, which in turn calls `get_repo_path_1()`, which
locates a valid repository at that target.
This then causes Git to set the `is_local` variable to "1", and in turn
instructs Git to clone the repository using its local clone optimization
via the `clone_local()` function.
The exploit comes into play because the stub repository's top-level
"$GIT_DIR/objects" directory is a symbolic link which can point to an
arbitrary path on the victim's machine. `clone_local()` resolves the
top-level "objects" directory through a `stat(2)` call, meaning that we
read through the symbolic link and copy or hardlink the directory
contents at the destination of the link.
In other words, we can get steps (1) and (3) to disagree by leveraging
the dangling symlink to pick a non-local transport in the first step,
and then set is_local to "1" in the third step when cloning with
`--separate-git-dir`, which makes the symlink non-dangling.
This can result in data-exfiltration on the victim's machine when
sensitive data is at a known path (e.g., "/home/$USER/.ssh").
The appropriate fix is two-fold:
- Resolve the transport later on (to avoid using the local
clone optimization with a non-local transport).
- Avoid reading through the top-level "objects" directory when
(correctly) using the clone_local() optimization.
This patch merely demonstrates the issue. The following two patches will
implement each part of the above fix, respectively.
[^1]: Provided that any target directory does not contain symbolic
links, in which case the changes from 6f054f9fb3 (builtin/clone.c:
disallow `--local` clones with symlinks, 2022-07-28) will abort the
clone.
Reported-by: yvvdwf <yvvdwf@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
On platforms where `size_t` does not have the same width as `unsigned
long`, passing a pointer to the former when a pointer to the latter is
expected can lead to problems.
Windows and 32-bit Linux are among the affected platforms.
In this instance, we want to store the size of the blob that was read in
that variable. However, `read_blob_data_from_index()` passes that
pointer to `read_object_file()` which expects an `unsigned long *`.
Which means that on affected platforms, the variable is not fully
populated and part of its value is left uninitialized. (On Big-Endian
platforms, this problem would be even worse.)
The consequence is that depending on the uninitialized memory's
contents, we may erroneously reject perfectly fine attributes.
Let's address this by passing a pointer to a variable of the expected
data type.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Recently, a vulnerability was reported that can lead to an out-of-bounds
write when reading an unreasonably large gitattributes file. The root
cause of this error are multiple integer overflows in different parts of
the code when there are either too many lines, when paths are too long,
when attribute names are too long, or when there are too many attributes
declared for a pattern.
As all of these are related to size, it seems reasonable to restrict the
size of the gitattributes file via git-fsck(1). This allows us to both
stop distributing known-vulnerable objects via common hosting platforms
that have fsck enabled, and users to protect themselves by enabling the
`fetch.fsckObjects` config.
There are basically two checks:
1. We verify that size of the gitattributes file is smaller than
100MB.
2. We verify that the maximum line length does not exceed 2048
bytes.
With the preceding commits, both of these conditions would cause us to
either ignore the complete gitattributes file or blob in the first case,
or the specific line in the second case. Now with these consistency
checks added, we also grow the ability to stop distributing such files
in the first place when `receive.fsckObjects` is enabled.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Move the checks for gitattributes so that they can be extended more
readily.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In `fsck_finish()` we check all blobs for consistency that we have found
during the tree walk, but that haven't yet been checked. This is only
required for gitmodules right now, but will also be required for a new
check for gitattributes.
Pull out a function `fsck_blobs()` that allows the caller to check a set
of blobs for consistency.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In general, we don't need to validate blob contents as they are opaque
blobs about whose content Git doesn't need to care about. There are some
exceptions though when blobs are linked into trees so that they would be
interpreted by Git. We only have a single such check right now though,
which is the one for gitmodules that has been added in the context of
CVE-2018-11235.
Now we have found another vulnerability with gitattributes that can lead
to out-of-bounds writes and reads. So let's refactor `fsck_blob()` so
that it is more extensible and can check different types of blobs.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Both the padding and wrapping formatting directives allow the caller to
specify an integer that ultimately leads to us adding this many chars to
the result buffer. As a consequence, it is trivial to e.g. allocate 2GB
of RAM via a single formatting directive and cause resource exhaustion
on the machine executing this logic. Furthermore, it is debatable
whether there are any sane usecases that require the user to pad data to
2GB boundaries or to indent wrapped data by 2GB.
Restrict the input sizes to 16 kilobytes at a maximum to limit the
amount of bytes that can be requested by the user. This is not meant
as a fix because there are ways to trivially amplify the amount of
data we generate via formatting directives; the real protection is
achieved by the changes in previous steps to catch and avoid integer
wraparound that causes us to under-allocate and access beyond the
end of allocated memory reagions. But having such a limit
significantly helps fuzzing the pretty format, because the fuzzer is
otherwise quite fast to run out-of-memory as it discovers these
formatters.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In `strbuf_utf8_replace`, we preallocate the destination buffer and then
use `memcpy` to copy bytes into it at computed offsets. This feels
rather fragile and is hard to understand at times. Refactor the code to
instead use `strbuf_add` and `strbuf_addstr` so that we can be sure that
there is no possibility to perform an out-of-bounds write.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In `strbuf_utf8_replace()`, we call `utf8_width()` to compute the width
of the current glyph. If the glyph is a control character though it can
be that `utf8_width()` returns `-1`, but because we assign this value to
a `size_t` the conversion will cause us to underflow. This bug can
easily be triggered with the following command:
$ git log --pretty='format:xxx%<|(1,trunc)%x10'
>From all I can see though this seems to be a benign underflow that has
no security-related consequences.
Fix the bug by using an `int` instead. When we see a control character,
we now copy it into the target buffer but don't advance the current
width of the string.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The return type of both `utf8_strwidth()` and `utf8_strnwidth()` is
`int`, but we operate on string lengths which are typically of type
`size_t`. This means that when the string is longer than `INT_MAX`, we
will overflow and thus return a negative result.
This can lead to an out-of-bounds write with `--pretty=format:%<1)%B`
and a commit message that is 2^31+1 bytes long:
=================================================================
==26009==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x603000001168 at pc 0x7f95c4e5f427 bp 0x7ffd8541c900 sp 0x7ffd8541c0a8
WRITE of size 2147483649 at 0x603000001168 thread T0
#0 0x7f95c4e5f426 in __interceptor_memcpy /usr/src/debug/gcc/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:827
#1 0x5612bbb1068c in format_and_pad_commit pretty.c:1763
#2 0x5612bbb1087a in format_commit_item pretty.c:1801
#3 0x5612bbc33bab in strbuf_expand strbuf.c:429
#4 0x5612bbb110e7 in repo_format_commit_message pretty.c:1869
#5 0x5612bbb12d96 in pretty_print_commit pretty.c:2161
#6 0x5612bba0a4d5 in show_log log-tree.c:781
#7 0x5612bba0d6c7 in log_tree_commit log-tree.c:1117
#8 0x5612bb691ed5 in cmd_log_walk_no_free builtin/log.c:508
#9 0x5612bb69235b in cmd_log_walk builtin/log.c:549
#10 0x5612bb6951a2 in cmd_log builtin/log.c:883
#11 0x5612bb56c993 in run_builtin git.c:466
#12 0x5612bb56d397 in handle_builtin git.c:721
#13 0x5612bb56db07 in run_argv git.c:788
#14 0x5612bb56e8a7 in cmd_main git.c:923
#15 0x5612bb803682 in main common-main.c:57
#16 0x7f95c4c3c28f (/usr/lib/libc.so.6+0x2328f)
#17 0x7f95c4c3c349 in __libc_start_main (/usr/lib/libc.so.6+0x23349)
#18 0x5612bb5680e4 in _start ../sysdeps/x86_64/start.S:115
0x603000001168 is located 0 bytes to the right of 24-byte region [0x603000001150,0x603000001168)
allocated by thread T0 here:
#0 0x7f95c4ebe7ea in __interceptor_realloc /usr/src/debug/gcc/libsanitizer/asan/asan_malloc_linux.cpp:85
#1 0x5612bbcdd556 in xrealloc wrapper.c:136
#2 0x5612bbc310a3 in strbuf_grow strbuf.c:99
#3 0x5612bbc32acd in strbuf_add strbuf.c:298
#4 0x5612bbc33aec in strbuf_expand strbuf.c:418
#5 0x5612bbb110e7 in repo_format_commit_message pretty.c:1869
#6 0x5612bbb12d96 in pretty_print_commit pretty.c:2161
#7 0x5612bba0a4d5 in show_log log-tree.c:781
#8 0x5612bba0d6c7 in log_tree_commit log-tree.c:1117
#9 0x5612bb691ed5 in cmd_log_walk_no_free builtin/log.c:508
#10 0x5612bb69235b in cmd_log_walk builtin/log.c:549
#11 0x5612bb6951a2 in cmd_log builtin/log.c:883
#12 0x5612bb56c993 in run_builtin git.c:466
#13 0x5612bb56d397 in handle_builtin git.c:721
#14 0x5612bb56db07 in run_argv git.c:788
#15 0x5612bb56e8a7 in cmd_main git.c:923
#16 0x5612bb803682 in main common-main.c:57
#17 0x7f95c4c3c28f (/usr/lib/libc.so.6+0x2328f)
SUMMARY: AddressSanitizer: heap-buffer-overflow /usr/src/debug/gcc/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:827 in __interceptor_memcpy
Shadow bytes around the buggy address:
0x0c067fff81d0: fd fd fd fa fa fa fd fd fd fa fa fa fd fd fd fa
0x0c067fff81e0: fa fa fd fd fd fd fa fa fd fd fd fd fa fa fd fd
0x0c067fff81f0: fd fa fa fa fd fd fd fa fa fa fd fd fd fa fa fa
0x0c067fff8200: fd fd fd fa fa fa fd fd fd fd fa fa 00 00 00 fa
0x0c067fff8210: fa fa fd fd fd fa fa fa fd fd fd fa fa fa fd fd
=>0x0c067fff8220: fd fa fa fa fd fd fd fa fa fa 00 00 00[fa]fa fa
0x0c067fff8230: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c067fff8240: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c067fff8250: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c067fff8260: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c067fff8270: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
Addressable: 00
Partially addressable: 01 02 03 04 05 06 07
Heap left redzone: fa
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
Stack after return: f5
Stack use after scope: f8
Global redzone: f9
Global init order: f6
Poisoned by user: f7
Container overflow: fc
Array cookie: ac
Intra object redzone: bb
ASan internal: fe
Left alloca redzone: ca
Right alloca redzone: cb
==26009==ABORTING
Now the proper fix for this would be to convert both functions to return
an `size_t` instead of an `int`. But given that this commit may be part
of a security release, let's instead do the minimal viable fix and die
in case we see an overflow.
Add a test that would have previously caused us to crash.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The `utf8_strnwidth()` function calls `utf8_width()` in a loop and adds
its returned width to the end result. `utf8_width()` can return `-1`
though in case it reads a control character, which means that the
computed string width is going to be wrong. In the worst case where
there are more control characters than non-control characters, we may
even return a negative string width.
Fix this bug by treating control characters as having zero width.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The `utf8_strnwidth()` function accepts an optional string length as
input parameter. This parameter can either be set to `-1`, in which case
we call `strlen()` on the input. Or it can be set to a positive integer
that indicates a precomputed length, which callers typically compute by
calling `strlen()` at some point themselves.
The input parameter is an `int` though, whereas `strlen()` returns a
`size_t`. This can lead to implementation-defined behaviour though when
the `size_t` cannot be represented by the `int`. In the general case
though this leads to wrap-around and thus to negative string sizes,
which is sure enough to not lead to well-defined behaviour.
Fix this by accepting a `size_t` instead of an `int` as string length.
While this takes away the ability of callers to simply pass in `-1` as
string length, it really is trivial enough to convert them to instead
pass in `strlen()` instead.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The `%w(width,indent1,indent2)` formatting directive can be used to
rewrap text to a specific width and is designed after git-shortlog(1)'s
`-w` parameter. While the three parameters are all stored as `size_t`
internally, `strbuf_add_wrapped_text()` accepts integers as input. As a
result, the casted integers may overflow. As these now-negative integers
are later on passed to `strbuf_addchars()`, we will ultimately run into
implementation-defined behaviour due to casting a negative number back
to `size_t` again. On my platform, this results in trying to allocate
9000 petabyte of memory.
Fix this overflow by using `cast_size_t_to_int()` so that we reject
inputs that cannot be represented as an integer.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When a formatting directive has a `+` or ` ` after the `%`, then we add
either a line feed or space if the placeholder expands to a non-empty
string. In specific cases though this logic doesn't work as expected,
and we try to add the character even in the case where the formatting
directive is empty.
One such pattern is `%w(1)%+d%+w(2)`. `%+d` expands to reference names
pointing to a certain commit, like in `git log --decorate`. For a tagged
commit this would for example expand to `\n (tag: v1.0.0)`, which has a
leading newline due to the `+` modifier and a space added by `%d`. Now
the second wrapping directive will cause us to rewrap the text to
`\n(tag:\nv1.0.0)`, which is one byte shorter due to the missing leading
space. The code that handles the `+` magic now notices that the length
has changed and will thus try to insert a leading line feed at the
original posititon. But as the string was shortened, the original
position is past the buffer's boundary and thus we die with an error.
Now there are two issues here:
1. We check whether the buffer length has changed, not whether it
has been extended. This causes us to try and add the character
past the string boundary.
2. The current logic does not make any sense whatsoever. When the
string got expanded due to the rewrap, putting the separator into
the original position is likely to put it somewhere into the
middle of the rewrapped contents.
It is debatable whether `%+w()` makes any sense in the first place.
Strictly speaking, the placeholder never expands to a non-empty string,
and consequentially we shouldn't ever accept this combination. We thus
fix the bug by simply refusing `%+w()`.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
An out-of-bounds read can be triggered when parsing an incomplete
padding format string passed via `--pretty=format` or in Git archives
when files are marked with the `export-subst` gitattribute.
This bug exists since we have introduced support for truncating output
via the `trunc` keyword a7f01c6b4d (pretty: support truncating in %>, %<
and %><, 2013-04-19). Before this commit, we used to find the end of the
formatting string by using strchr(3P). This function returns a `NULL`
pointer in case the character in question wasn't found. The subsequent
check whether any character was found thus simply checked the returned
pointer. After the commit we switched to strcspn(3P) though, which only
returns the offset to the first found character or to the trailing NUL
byte. As the end pointer is now computed by adding the offset to the
start pointer it won't be `NULL` anymore, and as a consequence the check
doesn't do anything anymore.
The out-of-bounds data that is being read can in fact end up in the
formatted string. As a consequence, it is possible to leak memory
contents either by calling git-log(1) or via git-archive(1) when any of
the archived files is marked with the `export-subst` gitattribute.
==10888==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x602000000398 at pc 0x7f0356047cb2 bp 0x7fff3ffb95d0 sp 0x7fff3ffb8d78
READ of size 1 at 0x602000000398 thread T0
#0 0x7f0356047cb1 in __interceptor_strchrnul /usr/src/debug/gcc/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:725
#1 0x563b7cec9a43 in strbuf_expand strbuf.c:417
#2 0x563b7cda7060 in repo_format_commit_message pretty.c:1869
#3 0x563b7cda8d0f in pretty_print_commit pretty.c:2161
#4 0x563b7cca04c8 in show_log log-tree.c:781
#5 0x563b7cca36ba in log_tree_commit log-tree.c:1117
#6 0x563b7c927ed5 in cmd_log_walk_no_free builtin/log.c:508
#7 0x563b7c92835b in cmd_log_walk builtin/log.c:549
#8 0x563b7c92b1a2 in cmd_log builtin/log.c:883
#9 0x563b7c802993 in run_builtin git.c:466
#10 0x563b7c803397 in handle_builtin git.c:721
#11 0x563b7c803b07 in run_argv git.c:788
#12 0x563b7c8048a7 in cmd_main git.c:923
#13 0x563b7ca99682 in main common-main.c:57
#14 0x7f0355e3c28f (/usr/lib/libc.so.6+0x2328f)
#15 0x7f0355e3c349 in __libc_start_main (/usr/lib/libc.so.6+0x23349)
#16 0x563b7c7fe0e4 in _start ../sysdeps/x86_64/start.S:115
0x602000000398 is located 0 bytes to the right of 8-byte region [0x602000000390,0x602000000398)
allocated by thread T0 here:
#0 0x7f0356072faa in __interceptor_strdup /usr/src/debug/gcc/libsanitizer/asan/asan_interceptors.cpp:439
#1 0x563b7cf7317c in xstrdup wrapper.c:39
#2 0x563b7cd9a06a in save_user_format pretty.c:40
#3 0x563b7cd9b3e5 in get_commit_format pretty.c:173
#4 0x563b7ce54ea0 in handle_revision_opt revision.c:2456
#5 0x563b7ce597c9 in setup_revisions revision.c:2850
#6 0x563b7c9269e0 in cmd_log_init_finish builtin/log.c:269
#7 0x563b7c927362 in cmd_log_init builtin/log.c:348
#8 0x563b7c92b193 in cmd_log builtin/log.c:882
#9 0x563b7c802993 in run_builtin git.c:466
#10 0x563b7c803397 in handle_builtin git.c:721
#11 0x563b7c803b07 in run_argv git.c:788
#12 0x563b7c8048a7 in cmd_main git.c:923
#13 0x563b7ca99682 in main common-main.c:57
#14 0x7f0355e3c28f (/usr/lib/libc.so.6+0x2328f)
#15 0x7f0355e3c349 in __libc_start_main (/usr/lib/libc.so.6+0x23349)
#16 0x563b7c7fe0e4 in _start ../sysdeps/x86_64/start.S:115
SUMMARY: AddressSanitizer: heap-buffer-overflow /usr/src/debug/gcc/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:725 in __interceptor_strchrnul
Shadow bytes around the buggy address:
0x0c047fff8020: fa fa fd fd fa fa 00 06 fa fa 05 fa fa fa fd fd
0x0c047fff8030: fa fa 00 02 fa fa 06 fa fa fa 05 fa fa fa fd fd
0x0c047fff8040: fa fa 00 07 fa fa 03 fa fa fa fd fd fa fa 00 00
0x0c047fff8050: fa fa 00 01 fa fa fd fd fa fa 00 00 fa fa 00 01
0x0c047fff8060: fa fa 00 06 fa fa 00 06 fa fa 05 fa fa fa 05 fa
=>0x0c047fff8070: fa fa 00[fa]fa fa fd fa fa fa fd fd fa fa fd fd
0x0c047fff8080: fa fa fd fd fa fa 00 00 fa fa 00 fa fa fa fd fa
0x0c047fff8090: fa fa fd fd fa fa 00 00 fa fa fa fa fa fa fa fa
0x0c047fff80a0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff80b0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff80c0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
Addressable: 00
Partially addressable: 01 02 03 04 05 06 07
Heap left redzone: fa
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
Stack after return: f5
Stack use after scope: f8
Global redzone: f9
Global init order: f6
Poisoned by user: f7
Container overflow: fc
Array cookie: ac
Intra object redzone: bb
ASan internal: fe
Left alloca redzone: ca
Right alloca redzone: cb
==10888==ABORTING
Fix this bug by checking whether `end` points at the trailing NUL byte.
Add a test which catches this out-of-bounds read and which demonstrates
that we used to write out-of-bounds data into the formatted message.
Reported-by: Markus Vervier <markus.vervier@x41-dsec.de>
Original-patch-by: Markus Vervier <markus.vervier@x41-dsec.de>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
With the `%>>(<N>)` pretty formatter, you can ask git-log(1) et al to
steal spaces. To do so we need to look ahead of the next token to see
whether there are spaces there. This loop takes into account ANSI
sequences that end with an `m`, and if it finds any it will skip them
until it finds the first space. While doing so it does not take into
account the buffer's limits though and easily does an out-of-bounds
read.
Add a test that hits this behaviour. While we don't have an easy way to
verify this, the test causes the following failure when run with
`SANITIZE=address`:
==37941==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x603000000baf at pc 0x55ba6f88e0d0 bp 0x7ffc84c50d20 sp 0x7ffc84c50d10
READ of size 1 at 0x603000000baf thread T0
#0 0x55ba6f88e0cf in format_and_pad_commit pretty.c:1712
#1 0x55ba6f88e7b4 in format_commit_item pretty.c:1801
#2 0x55ba6f9b1ae4 in strbuf_expand strbuf.c:429
#3 0x55ba6f88f020 in repo_format_commit_message pretty.c:1869
#4 0x55ba6f890ccf in pretty_print_commit pretty.c:2161
#5 0x55ba6f7884c8 in show_log log-tree.c:781
#6 0x55ba6f78b6ba in log_tree_commit log-tree.c:1117
#7 0x55ba6f40fed5 in cmd_log_walk_no_free builtin/log.c:508
#8 0x55ba6f41035b in cmd_log_walk builtin/log.c:549
#9 0x55ba6f4131a2 in cmd_log builtin/log.c:883
#10 0x55ba6f2ea993 in run_builtin git.c:466
#11 0x55ba6f2eb397 in handle_builtin git.c:721
#12 0x55ba6f2ebb07 in run_argv git.c:788
#13 0x55ba6f2ec8a7 in cmd_main git.c:923
#14 0x55ba6f581682 in main common-main.c:57
#15 0x7f2d08c3c28f (/usr/lib/libc.so.6+0x2328f)
#16 0x7f2d08c3c349 in __libc_start_main (/usr/lib/libc.so.6+0x23349)
#17 0x55ba6f2e60e4 in _start ../sysdeps/x86_64/start.S:115
0x603000000baf is located 1 bytes to the left of 24-byte region [0x603000000bb0,0x603000000bc8)
allocated by thread T0 here:
#0 0x7f2d08ebe7ea in __interceptor_realloc /usr/src/debug/gcc/libsanitizer/asan/asan_malloc_linux.cpp:85
#1 0x55ba6fa5b494 in xrealloc wrapper.c:136
#2 0x55ba6f9aefdc in strbuf_grow strbuf.c:99
#3 0x55ba6f9b0a06 in strbuf_add strbuf.c:298
#4 0x55ba6f9b1a25 in strbuf_expand strbuf.c:418
#5 0x55ba6f88f020 in repo_format_commit_message pretty.c:1869
#6 0x55ba6f890ccf in pretty_print_commit pretty.c:2161
#7 0x55ba6f7884c8 in show_log log-tree.c:781
#8 0x55ba6f78b6ba in log_tree_commit log-tree.c:1117
#9 0x55ba6f40fed5 in cmd_log_walk_no_free builtin/log.c:508
#10 0x55ba6f41035b in cmd_log_walk builtin/log.c:549
#11 0x55ba6f4131a2 in cmd_log builtin/log.c:883
#12 0x55ba6f2ea993 in run_builtin git.c:466
#13 0x55ba6f2eb397 in handle_builtin git.c:721
#14 0x55ba6f2ebb07 in run_argv git.c:788
#15 0x55ba6f2ec8a7 in cmd_main git.c:923
#16 0x55ba6f581682 in main common-main.c:57
#17 0x7f2d08c3c28f (/usr/lib/libc.so.6+0x2328f)
#18 0x7f2d08c3c349 in __libc_start_main (/usr/lib/libc.so.6+0x23349)
#19 0x55ba6f2e60e4 in _start ../sysdeps/x86_64/start.S:115
SUMMARY: AddressSanitizer: heap-buffer-overflow pretty.c:1712 in format_and_pad_commit
Shadow bytes around the buggy address:
0x0c067fff8120: fa fa fd fd fd fa fa fa fd fd fd fa fa fa fd fd
0x0c067fff8130: fd fd fa fa fd fd fd fd fa fa fd fd fd fa fa fa
0x0c067fff8140: fd fd fd fa fa fa fd fd fd fa fa fa fd fd fd fa
0x0c067fff8150: fa fa fd fd fd fd fa fa 00 00 00 fa fa fa fd fd
0x0c067fff8160: fd fa fa fa fd fd fd fa fa fa fd fd fd fa fa fa
=>0x0c067fff8170: fd fd fd fa fa[fa]00 00 00 fa fa fa 00 00 00 fa
0x0c067fff8180: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c067fff8190: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c067fff81a0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c067fff81b0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c067fff81c0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
Addressable: 00
Partially addressable: 01 02 03 04 05 06 07
Heap left redzone: fa
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
Stack after return: f5
Stack use after scope: f8
Global redzone: f9
Global init order: f6
Poisoned by user: f7
Container overflow: fc
Array cookie: ac
Intra object redzone: bb
ASan internal: fe
Left alloca redzone: ca
Right alloca redzone: cb
Luckily enough, this would only cause us to copy the out-of-bounds data
into the formatted commit in case we really had an ANSI sequence
preceding our buffer. So this bug likely has no security consequences.
Fix it regardless by not traversing past the buffer's start.
Reported-by: Patrick Steinhardt <ps@pks.im>
Reported-by: Eric Sesterhenn <eric.sesterhenn@x41-dsec.de>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When using a padding specifier in the pretty format passed to git-log(1)
we need to calculate the string length in several places. These string
lengths are stored in `int`s though, which means that these can easily
overflow when the input lengths exceeds 2GB. This can ultimately lead to
an out-of-bounds write when these are used in a call to memcpy(3P):
==8340==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7f1ec62f97fe at pc 0x7f2127e5f427 bp 0x7ffd3bd63de0 sp 0x7ffd3bd63588
WRITE of size 1 at 0x7f1ec62f97fe thread T0
#0 0x7f2127e5f426 in __interceptor_memcpy /usr/src/debug/gcc/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:827
#1 0x5628e96aa605 in format_and_pad_commit pretty.c:1762
#2 0x5628e96aa7f4 in format_commit_item pretty.c:1801
#3 0x5628e97cdb24 in strbuf_expand strbuf.c:429
#4 0x5628e96ab060 in repo_format_commit_message pretty.c:1869
#5 0x5628e96acd0f in pretty_print_commit pretty.c:2161
#6 0x5628e95a44c8 in show_log log-tree.c:781
#7 0x5628e95a76ba in log_tree_commit log-tree.c:1117
#8 0x5628e922bed5 in cmd_log_walk_no_free builtin/log.c:508
#9 0x5628e922c35b in cmd_log_walk builtin/log.c:549
#10 0x5628e922f1a2 in cmd_log builtin/log.c:883
#11 0x5628e9106993 in run_builtin git.c:466
#12 0x5628e9107397 in handle_builtin git.c:721
#13 0x5628e9107b07 in run_argv git.c:788
#14 0x5628e91088a7 in cmd_main git.c:923
#15 0x5628e939d682 in main common-main.c:57
#16 0x7f2127c3c28f (/usr/lib/libc.so.6+0x2328f)
#17 0x7f2127c3c349 in __libc_start_main (/usr/lib/libc.so.6+0x23349)
#18 0x5628e91020e4 in _start ../sysdeps/x86_64/start.S:115
0x7f1ec62f97fe is located 2 bytes to the left of 4831838265-byte region [0x7f1ec62f9800,0x7f1fe62f9839)
allocated by thread T0 here:
#0 0x7f2127ebe7ea in __interceptor_realloc /usr/src/debug/gcc/libsanitizer/asan/asan_malloc_linux.cpp:85
#1 0x5628e98774d4 in xrealloc wrapper.c:136
#2 0x5628e97cb01c in strbuf_grow strbuf.c:99
#3 0x5628e97ccd42 in strbuf_addchars strbuf.c:327
#4 0x5628e96aa55c in format_and_pad_commit pretty.c:1761
#5 0x5628e96aa7f4 in format_commit_item pretty.c:1801
#6 0x5628e97cdb24 in strbuf_expand strbuf.c:429
#7 0x5628e96ab060 in repo_format_commit_message pretty.c:1869
#8 0x5628e96acd0f in pretty_print_commit pretty.c:2161
#9 0x5628e95a44c8 in show_log log-tree.c:781
#10 0x5628e95a76ba in log_tree_commit log-tree.c:1117
#11 0x5628e922bed5 in cmd_log_walk_no_free builtin/log.c:508
#12 0x5628e922c35b in cmd_log_walk builtin/log.c:549
#13 0x5628e922f1a2 in cmd_log builtin/log.c:883
#14 0x5628e9106993 in run_builtin git.c:466
#15 0x5628e9107397 in handle_builtin git.c:721
#16 0x5628e9107b07 in run_argv git.c:788
#17 0x5628e91088a7 in cmd_main git.c:923
#18 0x5628e939d682 in main common-main.c:57
#19 0x7f2127c3c28f (/usr/lib/libc.so.6+0x2328f)
#20 0x7f2127c3c349 in __libc_start_main (/usr/lib/libc.so.6+0x23349)
#21 0x5628e91020e4 in _start ../sysdeps/x86_64/start.S:115
SUMMARY: AddressSanitizer: heap-buffer-overflow /usr/src/debug/gcc/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:827 in __interceptor_memcpy
Shadow bytes around the buggy address:
0x0fe458c572a0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0fe458c572b0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0fe458c572c0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0fe458c572d0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0fe458c572e0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
=>0x0fe458c572f0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa[fa]
0x0fe458c57300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0fe458c57310: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0fe458c57320: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0fe458c57330: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0fe458c57340: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Shadow byte legend (one shadow byte represents 8 application bytes):
Addressable: 00
Partially addressable: 01 02 03 04 05 06 07
Heap left redzone: fa
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
Stack after return: f5
Stack use after scope: f8
Global redzone: f9
Global init order: f6
Poisoned by user: f7
Container overflow: fc
Array cookie: ac
Intra object redzone: bb
ASan internal: fe
Left alloca redzone: ca
Right alloca redzone: cb
==8340==ABORTING
The pretty format can also be used in `git archive` operations via the
`export-subst` attribute. So this is what in our opinion makes this a
critical issue in the context of Git forges which allow to download an
archive of user supplied Git repositories.
Fix this vulnerability by using `size_t` instead of `int` to track the
string lengths. Add tests which detect this vulnerability when Git is
compiled with the address sanitizer.
Reported-by: Joern Schneeweisz <jschneeweisz@gitlab.com>
Original-patch-by: Joern Schneeweisz <jschneeweisz@gitlab.com>
Modified-by: Taylor Blau <me@ttalorr.com>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Allow tests that assume a 64-bit `size_t` to be skipped in 32-bit
platforms and regardless of the size of `long`.
This imitates the `LONG_IS_64BIT` prerequisite.
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Similar as with the preceding commit, start ignoring gitattributes files
that are overly large to protect us against out-of-bounds reads and
writes caused by integer overflows. Unfortunately, we cannot just define
"overly large" in terms of any preexisting limits in the codebase.
Instead, we choose a very conservative limit of 100MB. This is plenty of
room for specifying gitattributes, and incidentally it is also the limit
for blob sizes for GitHub. While we don't want GitHub to dictate limits
here, it is still sensible to use this fact for an informed decision
given that it is hosting a huge set of repositories. Furthermore, over
at GitLab we scanned a subset of repositories for their root-level
attribute files. We found that 80% of them have a gitattributes file
smaller than 100kB, 99.99% have one smaller than 1MB, and only a single
repository had one that was almost 3MB in size. So enforcing a limit of
100MB seems to give us ample of headroom.
With this limit in place we can be reasonably sure that there is no easy
way to exploit the gitattributes file via integer overflows anymore.
Furthermore, it protects us against resource exhaustion caused by
allocating the in-memory data structures required to represent the
parsed attributes.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There are two different code paths to read gitattributes: once via a
file, and once via the index. These two paths used to behave differently
because when reading attributes from a file, we used fgets(3P) with a
buffer size of 2kB. Consequentially, we silently truncate line lengths
when lines are longer than that and will then parse the remainder of the
line as a new pattern. It goes without saying that this is entirely
unexpected, but it's even worse that the behaviour depends on how the
gitattributes are parsed.
While this is simply wrong, the silent truncation saves us with the
recently discovered vulnerabilities that can cause out-of-bound writes
or reads with unreasonably long lines due to integer overflows. As the
common path is to read gitattributes via the worktree file instead of
via the index, we can assume that any gitattributes file that had lines
longer than that is already broken anyway. So instead of lifting the
limit here, we can double down on it to fix the vulnerabilities.
Introduce an explicit line length limit of 2kB that is shared across all
paths that read attributes and ignore any line that hits this limit
while printing a warning.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When reading attributes from a file we use fgets(3P) with a buffer size
of 2048 bytes. This means that as soon as a line exceeds the buffer size
we split it up into multiple parts and parse each of them as a separate
pattern line. This is of course not what the user intended, and even
worse the behaviour is inconsistent with how we read attributes from the
index.
Fix this bug by converting the code to use `strbuf_getline()` instead.
This will indeed read in the whole line, which may theoretically lead to
an out-of-memory situation when the gitattributes file is huge. We're
about to reject any gitattributes files larger than 100MB in the next
commit though, which makes this less of a concern.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When parsing an attributes line, we need to allocate an array that holds
all attributes specified for the given file pattern. The calculation to
determine the number of bytes that need to be allocated was prone to an
overflow though when there was an unreasonable amount of attributes.
Harden the allocation by instead using the `st_` helper functions that
cause us to die when we hit an integer overflow.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Attributes have a field that tracks the position in the `all_attrs`
array they're stored inside. This field gets set via `hashmap_get_size`
when adding the attribute to the global map of attributes. But while the
field is of type `int`, the value returned by `hashmap_get_size` is an
`unsigned int`. It can thus happen that the value overflows, where we
would now dereference teh `all_attrs` array at an out-of-bounds value.
We do have a sanity check for this overflow via an assert that verifies
the index matches the new hashmap's size. But asserts are not a proper
mechanism to detect against any such overflows as they may not in fact
be compiled into production code.
Fix this by using an `unsigned int` to track the index and convert the
assert to a call `die()`.
Reported-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The `struct attr_stack` tracks the stack of all patterns together with
their attributes. When parsing a gitattributes file that has more than
2^31 such patterns though we may trigger multiple out-of-bounds reads on
64 bit platforms. This is because while the `num_matches` variable is an
unsigned integer, we always use a signed integer to iterate over them.
I have not been able to reproduce this issue due to memory constraints
on my systems. But despite the out-of-bounds reads, the worst thing that
can seemingly happen is to call free(3P) with a garbage pointer when
calling `attr_stack_free()`.
Fix this bug by using unsigned integers to iterate over the array. While
this makes the iteration somewhat awkward when iterating in reverse, it
is at least better than knowingly running into an out-of-bounds read.
While at it, convert the call to `ALLOC_GROW` to use `ALLOC_GROW_BY`
instead.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It is possible to trigger an integer overflow when parsing attribute
names when there are more than 2^31 of them for a single pattern. This
can either lead to us dying due to trying to request too many bytes:
blob=$(perl -e 'print "f" . " a=" x 2147483649' | git hash-object -w --stdin)
git update-index --add --cacheinfo 100644,$blob,.gitattributes
git attr-check --all file
=================================================================
==1022==ERROR: AddressSanitizer: requested allocation size 0xfffffff800000032 (0xfffffff800001038 after adjustments for alignment, red zones etc.) exceeds maximum supported size of 0x10000000000 (thread T0)
#0 0x7fd3efabf411 in __interceptor_calloc /usr/src/debug/gcc/libsanitizer/asan/asan_malloc_linux.cpp:77
#1 0x5563a0a1e3d3 in xcalloc wrapper.c:150
#2 0x5563a058d005 in parse_attr_line attr.c:384
#3 0x5563a058e661 in handle_attr_line attr.c:660
#4 0x5563a058eddb in read_attr_from_index attr.c:769
#5 0x5563a058ef12 in read_attr attr.c:797
#6 0x5563a058f24c in bootstrap_attr_stack attr.c:867
#7 0x5563a058f4a3 in prepare_attr_stack attr.c:902
#8 0x5563a05905da in collect_some_attrs attr.c:1097
#9 0x5563a059093d in git_all_attrs attr.c:1128
#10 0x5563a02f636e in check_attr builtin/check-attr.c:67
#11 0x5563a02f6c12 in cmd_check_attr builtin/check-attr.c:183
#12 0x5563a02aa993 in run_builtin git.c:466
#13 0x5563a02ab397 in handle_builtin git.c:721
#14 0x5563a02abb2b in run_argv git.c:788
#15 0x5563a02ac991 in cmd_main git.c:926
#16 0x5563a05432bd in main common-main.c:57
#17 0x7fd3ef82228f (/usr/lib/libc.so.6+0x2328f)
==1022==HINT: if you don't care about these errors you may set allocator_may_return_null=1
SUMMARY: AddressSanitizer: allocation-size-too-big /usr/src/debug/gcc/libsanitizer/asan/asan_malloc_linux.cpp:77 in __interceptor_calloc
==1022==ABORTING
Or, much worse, it can lead to an out-of-bounds write because we
underallocate and then memcpy(3P) into an array:
perl -e '
print "A " . "\rh="x2000000000;
print "\rh="x2000000000;
print "\rh="x294967294 . "\n"
' >.gitattributes
git add .gitattributes
git commit -am "evil attributes"
$ git clone --quiet /path/to/repo
=================================================================
==15062==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x602000002550 at pc 0x5555559884d5 bp 0x7fffffffbc60 sp 0x7fffffffbc58
WRITE of size 8 at 0x602000002550 thread T0
#0 0x5555559884d4 in parse_attr_line attr.c:393
#1 0x5555559884d4 in handle_attr_line attr.c:660
#2 0x555555988902 in read_attr_from_index attr.c:784
#3 0x555555988902 in read_attr_from_index attr.c:747
#4 0x555555988a1d in read_attr attr.c:800
#5 0x555555989b0c in bootstrap_attr_stack attr.c:882
#6 0x555555989b0c in prepare_attr_stack attr.c:917
#7 0x555555989b0c in collect_some_attrs attr.c:1112
#8 0x55555598b141 in git_check_attr attr.c:1126
#9 0x555555a13004 in convert_attrs convert.c:1311
#10 0x555555a95e04 in checkout_entry_ca entry.c:553
#11 0x555555d58bf6 in checkout_entry entry.h:42
#12 0x555555d58bf6 in check_updates unpack-trees.c:480
#13 0x555555d5eb55 in unpack_trees unpack-trees.c:2040
#14 0x555555785ab7 in checkout builtin/clone.c:724
#15 0x555555785ab7 in cmd_clone builtin/clone.c:1384
#16 0x55555572443c in run_builtin git.c:466
#17 0x55555572443c in handle_builtin git.c:721
#18 0x555555727872 in run_argv git.c:788
#19 0x555555727872 in cmd_main git.c:926
#20 0x555555721fa0 in main common-main.c:57
#21 0x7ffff73f1d09 in __libc_start_main ../csu/libc-start.c:308
#22 0x555555723f39 in _start (git+0x1cff39)
0x602000002552 is located 0 bytes to the right of 2-byte region [0x602000002550,0x602000002552) allocated by thread T0 here:
#0 0x7ffff768c037 in __interceptor_calloc ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:154
#1 0x555555d7fff7 in xcalloc wrapper.c:150
#2 0x55555598815f in parse_attr_line attr.c:384
#3 0x55555598815f in handle_attr_line attr.c:660
#4 0x555555988902 in read_attr_from_index attr.c:784
#5 0x555555988902 in read_attr_from_index attr.c:747
#6 0x555555988a1d in read_attr attr.c:800
#7 0x555555989b0c in bootstrap_attr_stack attr.c:882
#8 0x555555989b0c in prepare_attr_stack attr.c:917
#9 0x555555989b0c in collect_some_attrs attr.c:1112
#10 0x55555598b141 in git_check_attr attr.c:1126
#11 0x555555a13004 in convert_attrs convert.c:1311
#12 0x555555a95e04 in checkout_entry_ca entry.c:553
#13 0x555555d58bf6 in checkout_entry entry.h:42
#14 0x555555d58bf6 in check_updates unpack-trees.c:480
#15 0x555555d5eb55 in unpack_trees unpack-trees.c:2040
#16 0x555555785ab7 in checkout builtin/clone.c:724
#17 0x555555785ab7 in cmd_clone builtin/clone.c:1384
#18 0x55555572443c in run_builtin git.c:466
#19 0x55555572443c in handle_builtin git.c:721
#20 0x555555727872 in run_argv git.c:788
#21 0x555555727872 in cmd_main git.c:926
#22 0x555555721fa0 in main common-main.c:57
#23 0x7ffff73f1d09 in __libc_start_main ../csu/libc-start.c:308
SUMMARY: AddressSanitizer: heap-buffer-overflow attr.c:393 in parse_attr_line
Shadow bytes around the buggy address:
0x0c047fff8450: fa fa 00 02 fa fa 00 07 fa fa fd fd fa fa 00 00
0x0c047fff8460: fa fa 02 fa fa fa fd fd fa fa 00 06 fa fa 05 fa
0x0c047fff8470: fa fa fd fd fa fa 00 02 fa fa 06 fa fa fa 05 fa
0x0c047fff8480: fa fa 07 fa fa fa fd fd fa fa 00 01 fa fa 00 02
0x0c047fff8490: fa fa 00 03 fa fa 00 fa fa fa 00 01 fa fa 00 03
=>0x0c047fff84a0: fa fa 00 01 fa fa 00 02 fa fa[02]fa fa fa fa fa
0x0c047fff84b0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff84c0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff84d0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff84e0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff84f0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
Addressable: 00
Partially addressable: 01 02 03 04 05 06 07
Heap left redzone: fa
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
Stack after return: f5
Stack use after scope: f8
Global redzone: f9
Global init order: f6
Poisoned by user: f7
Container overflow: fc
Array cookie: ac
Intra object redzone: bb
ASan internal: fe
Left alloca redzone: ca
Right alloca redzone: cb
Shadow gap: cc
==15062==ABORTING
Fix this bug by using `size_t` instead to count the number of attributes
so that this value cannot reasonably overflow without running out of
memory before already.
Reported-by: Markus Vervier <markus.vervier@x41-dsec.de>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It is possible to trigger an integer overflow when parsing attribute
names that are longer than 2^31 bytes because we assign the result of
strlen(3P) to an `int` instead of to a `size_t`. This can lead to an
abort in vsnprintf(3P) with the following reproducer:
blob=$(perl -e 'print "A " . "B"x2147483648 . "\n"' | git hash-object -w --stdin)
git update-index --add --cacheinfo 100644,$blob,.gitattributes
git check-attr --all path
BUG: strbuf.c:400: your vsnprintf is broken (returned -1)
But furthermore, assuming that the attribute name is even longer than
that, it can cause us to silently truncate the attribute and thus lead
to wrong results.
Fix this integer overflow by using a `size_t` instead. This fixes the
silent truncation of attribute names, but it only partially fixes the
BUG we hit: even though the initial BUG is fixed, we can still hit a BUG
when parsing invalid attribute lines via `report_invalid_attr()`.
This is due to an underlying design issue in vsnprintf(3P) which only
knows to return an `int`, and thus it may always overflow with large
inputs. This issue is benign though: the worst that can happen is that
the error message is misreported to be either truncated or too long, but
due to the buffer being NUL terminated we wouldn't ever do an
out-of-bounds read here.
Reported-by: Markus Vervier <markus.vervier@x41-dsec.de>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There is an out-of-bounds read possible when parsing gitattributes that
have an attribute that is 2^31+1 bytes long. This is caused due to an
integer overflow when we assign the result of strlen(3P) to an `int`,
where we use the wrapped-around value in a subsequent call to
memcpy(3P). The following code reproduces the issue:
blob=$(perl -e 'print "a" x 2147483649 . " attr"' | git hash-object -w --stdin)
git update-index --add --cacheinfo 100644,$blob,.gitattributes
git check-attr --all file
AddressSanitizer:DEADLYSIGNAL
=================================================================
==8451==ERROR: AddressSanitizer: SEGV on unknown address 0x7f93efa00800 (pc 0x7f94f1f8f082 bp 0x7ffddb59b3a0 sp 0x7ffddb59ab28 T0)
==8451==The signal is caused by a READ memory access.
#0 0x7f94f1f8f082 (/usr/lib/libc.so.6+0x176082)
#1 0x7f94f2047d9c in __interceptor_strspn /usr/src/debug/gcc/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:752
#2 0x560e190f7f26 in parse_attr_line attr.c:375
#3 0x560e190f9663 in handle_attr_line attr.c:660
#4 0x560e190f9ddd in read_attr_from_index attr.c:769
#5 0x560e190f9f14 in read_attr attr.c:797
#6 0x560e190fa24e in bootstrap_attr_stack attr.c:867
#7 0x560e190fa4a5 in prepare_attr_stack attr.c:902
#8 0x560e190fb5dc in collect_some_attrs attr.c:1097
#9 0x560e190fb93f in git_all_attrs attr.c:1128
#10 0x560e18e6136e in check_attr builtin/check-attr.c:67
#11 0x560e18e61c12 in cmd_check_attr builtin/check-attr.c:183
#12 0x560e18e15993 in run_builtin git.c:466
#13 0x560e18e16397 in handle_builtin git.c:721
#14 0x560e18e16b2b in run_argv git.c:788
#15 0x560e18e17991 in cmd_main git.c:926
#16 0x560e190ae2bd in main common-main.c:57
#17 0x7f94f1e3c28f (/usr/lib/libc.so.6+0x2328f)
#18 0x7f94f1e3c349 in __libc_start_main (/usr/lib/libc.so.6+0x23349)
#19 0x560e18e110e4 in _start ../sysdeps/x86_64/start.S:115
AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV (/usr/lib/libc.so.6+0x176082)
==8451==ABORTING
Fix this bug by converting the variable to a `size_t` instead.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The function `git_attr_internal()` is called to upsert attributes into
the global map. And while all callers pass a `size_t`, the function
itself accepts an `int` as the attribute name's length. This can lead to
an integer overflow in case the attribute name is longer than `INT_MAX`.
Now this overflow seems harmless as the first thing we do is to call
`attr_name_valid()`, and that function only succeeds in case all chars
in the range of `namelen` match a certain small set of chars. We thus
can't do an out-of-bounds read as NUL is not part of that set and all
strings passed to this function are NUL-terminated. And furthermore, we
wouldn't ever read past the current attribute name anyway due to the
same reason. And if validation fails we will return early.
On the other hand it feels fragile to rely on this behaviour, even more
so given that we pass `namelen` to `FLEX_ALLOC_MEM()`. So let's instead
just do the correct thing here and accept a `size_t` as line length.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Explicitly cloning over the "file://" protocol in t1092 in preparation
for merging a security release which will change the default value of
this configuration to be "user".
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Explicitly cloning over the "file://" protocol in t1092 in preparation
for merging a security release which will change the default value of
this configuration to be "user".
Signed-off-by: Taylor Blau <me@ttaylorr.com>
This function improperly uses an int to represent the number of entries
in the resulting argument array. This allows a malicious actor to
intentionally overflow the return value, leading to arbitrary heap
writes.
Because the resulting argv array is typically passed to execv(), it may
be possible to leverage this attack to gain remote code execution on a
victim machine. This was almost certainly the case for certain
configurations of git-shell until the previous commit limited the size
of input it would accept. Other calls to split_cmdline() are typically
limited by the size of argv the OS is willing to hand us, so are
similarly protected.
So this is not strictly fixing a known vulnerability, but is a hardening
of the function that is worth doing to protect against possible unknown
vulnerabilities.
One approach to fixing this would be modifying the signature of
`split_cmdline()` to look something like:
int split_cmdline(char *cmdline, const char ***argv, size_t *argc);
Where the return value of `split_cmdline()` is negative for errors, and
zero otherwise. If non-NULL, the `*argc` pointer is modified to contain
the size of the `**argv` array.
But this implies an absurdly large `argv` array, which more than likely
larger than the system's argument limit. So even if split_cmdline()
allowed this, it would fail immediately afterwards when we called
execv(). So instead of converting all of `split_cmdline()`'s callers to
work with `size_t` types in this patch, instead pursue the minimal fix
here to prevent ever returning an array with more than INT_MAX entries
in it.
Signed-off-by: Kevin Backhouse <kevinbackhouse@github.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
When git-shell is run in interactive mode (which must be enabled by
creating $HOME/git-shell-commands), it reads commands from stdin, one
per line, and executes them.
We read the commands with git_read_line_interactively(), which uses a
strbuf under the hood. That means we'll accept an input of arbitrary
size (limited only by how much heap we can allocate). That creates two
problems:
- the rest of the code is not prepared to handle large inputs. The
most serious issue here is that split_cmdline() uses "int" for most
of its types, which can lead to integer overflow and out-of-bounds
array reads and writes. But even with that fixed, we assume that we
can feed the command name to snprintf() (via xstrfmt()), which is
stuck for historical reasons using "int", and causes it to fail (and
even trigger a BUG() call).
- since the point of git-shell is to take input from untrusted or
semi-trusted clients, it's a mild denial-of-service. We'll allocate
as many bytes as the client sends us (actually twice as many, since
we immediately duplicate the buffer).
We can fix both by just limiting the amount of per-command input we're
willing to receive.
We should also fix split_cmdline(), of course, which is an accident
waiting to happen, but that can come on top. Most calls to
split_cmdline(), including the other one in git-shell, are OK because
they are reading from an OS-provided argv, which is limited in practice.
This patch should eliminate the immediate vulnerabilities.
I picked 4MB as an arbitrary limit. It's big enough that nobody should
ever run into it in practice (since the point is to run the commands via
exec, we're subject to OS limits which are typically much lower). But
it's small enough that allocating it isn't that big a deal.
The code is mostly just swapping out fgets() for the strbuf call, but we
have to add a few niceties like flushing and trimming line endings. We
could simplify things further by putting the buffer on the stack, but
4MB is probably a bit much there. Note that we'll _always_ allocate 4MB,
which for normal, non-malicious requests is more than we would before
this patch. But on the other hand, other git programs are happy to use
96MB for a delta cache. And since we'd never touch most of those pages,
on a lazy-allocating OS like Linux they won't even get allocated to
actual RAM.
The ideal would be a version of strbuf_getline() that accepted a maximum
value. But for a minimal vulnerability fix, let's keep things localized
and simple. We can always refactor further on top.
The included test fails in an obvious way with ASan or UBSan (which
notice the integer overflow and out-of-bounds reads). Without them, it
fails in a less obvious way: we may segfault, or we may try to xstrfmt()
a long string, leading to a BUG(). Either way, it fails reliably before
this patch, and passes with it. Note that we don't need an EXPENSIVE
prereq on it. It does take 10-15s to fail before this patch, but with
the new limit, we fail almost immediately (and the perl process
generating 2GB of data exits via SIGPIPE).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
We have no tests of even basic functionality of git-shell. Let's add a
couple of obvious ones. This will serve as a framework for adding tests
for new things we fix, as well as making sure we don't screw anything up
too badly while doing so.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
An earlier patch discussed and fixed a scenario where Git could be used
as a vector to exfiltrate sensitive data through a Docker container when
a potential victim clones a suspicious repository with local submodules
that contain symlinks.
That security hole has since been plugged, but a similar one still
exists. Instead of convincing a would-be victim to clone an embedded
submodule via the "file" protocol, an attacker could convince an
individual to clone a repository that has a submodule pointing to a
valid path on the victim's filesystem.
For example, if an individual (with username "foo") has their home
directory ("/home/foo") stored as a Git repository, then an attacker
could exfiltrate data by convincing a victim to clone a malicious
repository containing a submodule pointing at "/home/foo/.git" with
`--recurse-submodules`. Doing so would expose any sensitive contents in
stored in "/home/foo" tracked in Git.
For systems (such as Docker) that consider everything outside of the
immediate top-level working directory containing a Dockerfile as
inaccessible to the container (with the exception of volume mounts, and
so on), this is a violation of trust by exposing unexpected contents in
the working copy.
To mitigate the likelihood of this kind of attack, adjust the "file://"
protocol's default policy to be "user" to prevent commands that execute
without user input (including recursive submodule initialization) from
taking place by default.
Suggested-by: Jeff King <peff@peff.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
To prepare for the default value of `protocol.file.allow` to change to
"user", ensure tests that rely on local submodules can initialize them
over the file protocol.
Tests that interact with submodules a handful of times use
`test_config_global`.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
To prepare for the default value of `protocol.file.allow` to change to
"user", ensure tests that rely on local submodules can initialize them
over the file protocol.
Tests that only need to interact with submodules in a limited capacity
have individual Git commands annotated with the appropriate
configuration via `-c`. Tests that interact with submodules a handful of
times use `test_config_global` instead. Test scripts that rely on
submodules throughout use a `git config --global` during a setup test
towards the beginning of the script.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
To prepare for the default value of `protocol.file.allow` to change to
"user", ensure tests that rely on local submodules can initialize them
over the file protocol.
Tests that only need to interact with submodules in a limited capacity
have individual Git commands annotated with the appropriate
configuration via `-c`.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
To prepare for the default value of `protocol.file.allow` to change to
"user", ensure tests that rely on local submodules can initialize them
over the file protocol.
Tests that only need to interact with submodules in a limited capacity
have individual Git commands annotated with the appropriate
configuration via `-c`. Tests that interact with submodules a handful of
times use `test_config_global` instead. Test scripts that rely on
submodules throughout use a `git config --global` during a setup test
towards the beginning of the script.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
To prepare for the default value of `protocol.file.allow` to change to
"user", ensure tests that rely on local submodules can initialize them
over the file protocol.
Tests that only need to interact with submodules in a limited capacity
have individual Git commands annotated with the appropriate
configuration via `-c`. Tests that interact with submodules a handful of
times use `test_config_global` instead. Test scripts that rely on
submodules throughout use a `git config --global` during a setup test
towards the beginning of the script.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
To prepare for the default value of `protocol.file.allow` to change to
"user", ensure tests that rely on local submodules can initialize them
over the file protocol.
Tests that only need to interact with submodules in a limited capacity
have individual Git commands annotated with the appropriate
configuration via `-c`. Tests that interact with submodules a handful of
times use `test_config_global` instead. Test scripts that rely on
submodules throughout use a `git config --global` during a setup test
towards the beginning of the script.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
To prepare for the default value of `protocol.file.allow` to change to
"user", ensure tests that rely on local submodules can initialize them
over the file protocol.
Tests that only need to interact with submodules in a limited capacity
have individual Git commands annotated with the appropriate
configuration via `-c`. Tests that interact with submodules a handful of
times use `test_config_global` instead. Test scripts that rely on
submodules throughout use a `git config --global` during a setup test
towards the beginning of the script.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
To prepare for the default value of `protocol.file.allow` to change to
"user", ensure tests that rely on local submodules can initialize them
over the file protocol.
Tests that only need to interact with submodules in a limited capacity
have individual Git commands annotated with the appropriate
configuration via `-c`. Tests that interact with submodules a handful of
times use `test_config_global` instead.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
To prepare for changing the default value of `protocol.file.allow` to
"user", update the `prolog()` function in lib-submodule-update to allow
submodules to be cloned over the file protocol.
This is used by a handful of submodule-related test scripts, which
themselves will have to tweak the value of `protocol.file.allow` in
certain locations. Those will be done in subsequent commits.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
When cloning a repository with `--local`, Git relies on either making a
hardlink or copy to every file in the "objects" directory of the source
repository. This is done through the callpath `cmd_clone()` ->
`clone_local()` -> `copy_or_link_directory()`.
The way this optimization works is by enumerating every file and
directory recursively in the source repository's `$GIT_DIR/objects`
directory, and then either making a copy or hardlink of each file. The
only exception to this rule is when copying the "alternates" file, in
which case paths are rewritten to be absolute before writing a new
"alternates" file in the destination repo.
One quirk of this implementation is that it dereferences symlinks when
cloning. This behavior was most recently modified in 36596fd2df (clone:
better handle symlinked files at .git/objects/, 2019-07-10), which
attempted to support `--local` clones of repositories with symlinks in
their objects directory in a platform-independent way.
Unfortunately, this behavior of dereferencing symlinks (that is,
creating a hardlink or copy of the source's link target in the
destination repository) can be used as a component in attacking a
victim by inadvertently exposing the contents of file stored outside of
the repository.
Take, for example, a repository that stores a Dockerfile and is used to
build Docker images. When building an image, Docker copies the directory
contents into the VM, and then instructs the VM to execute the
Dockerfile at the root of the copied directory. This protects against
directory traversal attacks by copying symbolic links as-is without
dereferencing them.
That is, if a user has a symlink pointing at their private key material
(where the symlink is present in the same directory as the Dockerfile,
but the key itself is present outside of that directory), the key is
unreadable to a Docker image, since the link will appear broken from the
container's point of view.
This behavior enables an attack whereby a victim is convinced to clone a
repository containing an embedded submodule (with a URL like
"file:///proc/self/cwd/path/to/submodule") which has a symlink pointing
at a path containing sensitive information on the victim's machine. If a
user is tricked into doing this, the contents at the destination of
those symbolic links are exposed to the Docker image at runtime.
One approach to preventing this behavior is to recreate symlinks in the
destination repository. But this is problematic, since symlinking the
objects directory are not well-supported. (One potential problem is that
when sharing, e.g. a "pack" directory via symlinks, different writers
performing garbage collection may consider different sets of objects to
be reachable, enabling a situation whereby garbage collecting one
repository may remove reachable objects in another repository).
Instead, prohibit the local clone optimization when any symlinks are
present in the `$GIT_DIR/objects` directory of the source repository.
Users may clone the repository again by prepending the "file://" scheme
to their clone URL, or by adding the `--no-local` option to their `git
clone` invocation.
The directory iterator used by `copy_or_link_directory()` must no longer
dereference symlinks (i.e., it *must* call `lstat()` instead of `stat()`
in order to discover whether or not there are symlinks present). This has
no bearing on the overall behavior, since we will immediately `die()` on
encounter a symlink.
Note that t5604.33 suggests that we do support local clones with
symbolic links in the source repository's objects directory, but this
was likely unintentional, or at least did not take into consideration
the problem with sharing parts of the objects directory with symbolic
links at the time. Update this test to reflect which options are and
aren't supported.
Helped-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
* maint-2.33:
Git 2.33.4
Git 2.32.3
Git 2.31.4
Git 2.30.5
setup: tighten ownership checks post CVE-2022-24765
git-compat-util: allow root to access both SUDO_UID and root owned
t0034: add negative tests and allow git init to mostly work under sudo
git-compat-util: avoid failing dir ownership checks if running privileged
t: regression git needs safe.directory when using sudo
* maint-2.32:
Git 2.32.3
Git 2.31.4
Git 2.30.5
setup: tighten ownership checks post CVE-2022-24765
git-compat-util: allow root to access both SUDO_UID and root owned
t0034: add negative tests and allow git init to mostly work under sudo
git-compat-util: avoid failing dir ownership checks if running privileged
t: regression git needs safe.directory when using sudo
* maint-2.31:
Git 2.31.4
Git 2.30.5
setup: tighten ownership checks post CVE-2022-24765
git-compat-util: allow root to access both SUDO_UID and root owned
t0034: add negative tests and allow git init to mostly work under sudo
git-compat-util: avoid failing dir ownership checks if running privileged
t: regression git needs safe.directory when using sudo
* maint-2.30:
Git 2.30.5
setup: tighten ownership checks post CVE-2022-24765
git-compat-util: allow root to access both SUDO_UID and root owned
t0034: add negative tests and allow git init to mostly work under sudo
git-compat-util: avoid failing dir ownership checks if running privileged
t: regression git needs safe.directory when using sudo
8959555cee (setup_git_directory(): add an owner check for the top-level
directory, 2022-03-02), adds a function to check for ownership of
repositories using a directory that is representative of it, and ways to
add exempt a specific repository from said check if needed, but that
check didn't account for owership of the gitdir, or (when used) the
gitfile that points to that gitdir.
An attacker could create a git repository in a directory that they can
write into but that is owned by the victim to work around the fix that
was introduced with CVE-2022-24765 to potentially run code as the
victim.
An example that could result in privilege escalation to root in *NIX would
be to set a repository in a shared tmp directory by doing (for example):
$ git -C /tmp init
To avoid that, extend the ensure_valid_ownership function to be able to
check for all three paths.
This will have the side effect of tripling the number of stat() calls
when a repository is detected, but the effect is expected to be likely
minimal, as it is done only once during the directory walk in which Git
looks for a repository.
Additionally make sure to resolve the gitfile (if one was used) to find
the relevant gitdir for checking.
While at it change the message printed on failure so it is clear we are
referring to the repository by its worktree (or gitdir if it is bare) and
not to a specific directory.
Helped-by: Junio C Hamano <junio@pobox.com>
Helped-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
With a recent update to refuse access to repositories of other
people by default, "sudo make install" and "sudo git describe"
stopped working. This series intends to loosen it while keeping
the safety.
* cb/path-owner-check-with-sudo:
t0034: add negative tests and allow git init to mostly work under sudo
git-compat-util: avoid failing dir ownership checks if running privileged
t: regression git needs safe.directory when using sudo
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Previous changes introduced a regression which will prevent root for
accessing repositories owned by thyself if using sudo because SUDO_UID
takes precedence.
Loosen that restriction by allowing root to access repositories owned
by both uid by default and without having to add a safe.directory
exception.
A previous workaround that was documented in the tests is no longer
needed so it has been removed together with its specially crafted
prerequisite.
Helped-by: Johanness Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a support library that provides one function that can be used
to run a "scriplet" of commands through sudo and that helps invoking
sudo in the slightly awkward way that is required to ensure it doesn't
block the call (if shell was allowed as tested in the prerequisite)
and it doesn't run the command through a different shell than the one
we intended.
Add additional negative tests as suggested by Junio and that use a
new workspace that is owned by root.
Document a regression that was introduced by previous commits where
root won't be able anymore to access directories they own unless
SUDO_UID is removed from their environment.
The tests document additional ways that this new restriction could
be worked around and the documentation explains why it might be instead
considered a feature, but a "fix" is planned for a future change.
Helped-by: Junio C Hamano <gitster@pobox.com>
Helped-by: Phillip Wood <phillip.wood123@gmail.com>
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
bdc77d1d68 (Add a function to determine whether a path is owned by the
current user, 2022-03-02) checks for the effective uid of the running
process using geteuid() but didn't account for cases where that user was
root (because git was invoked through sudo or a compatible tool) and the
original uid that repository trusted for its config was no longer known,
therefore failing the following otherwise safe call:
guy@renard ~/Software/uncrustify $ sudo git describe --always --dirty
[sudo] password for guy:
fatal: unsafe repository ('/home/guy/Software/uncrustify' is owned by someone else)
Attempt to detect those cases by using the environment variables that
those tools create to keep track of the original user id, and do the
ownership check using that instead.
This assumes the environment the user is running on after going
privileged can't be tampered with, and also adds code to restrict that
the new behavior only applies if running as root, therefore keeping the
most common case, which runs unprivileged, from changing, but because of
that, it will miss cases where sudo (or an equivalent) was used to change
to another unprivileged user or where the equivalent tool used to raise
privileges didn't track the original id in a sudo compatible way.
Because of compatibility with sudo, the code assumes that uid_t is an
unsigned integer type (which is not required by the standard) but is used
that way in their codebase to generate SUDO_UID. In systems where uid_t
is signed, sudo might be also patched to NOT be unsigned and that might
be able to trigger an edge case and a bug (as described in the code), but
it is considered unlikely to happen and even if it does, the code would
just mostly fail safely, so there was no attempt either to detect it or
prevent it by the code, which is something that might change in the future,
based on expected user feedback.
Reported-by: Guy Maurel <guy.j@maurel.de>
Helped-by: SZEDER Gábor <szeder.dev@gmail.com>
Helped-by: Randall Becker <rsbecker@nexbridge.com>
Helped-by: Phillip Wood <phillip.wood123@gmail.com>
Suggested-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Originally reported after release of v2.35.2 (and other maint branches)
for CVE-2022-24765 and blocking otherwise harmless commands that were
done using sudo in a repository that was owned by the user.
Add a new test script with very basic support to allow running git
commands through sudo, so a reproduction could be implemented and that
uses only `git status` as a proxy of the issue reported.
Note that because of the way sudo interacts with the system, a much
more complete integration with the test framework will require a lot
more work and that was therefore intentionally punted for now.
The current implementation requires the execution of a special cleanup
function which should always be kept as the last "test" or otherwise
the standard cleanup functions will fail because they can't remove
the root owned directories that are used. This also means that if
failures are found while running, the specifics of the failure might
not be kept for further debugging and if the test was interrupted, it
will be necessary to clean the working directory manually before
restarting by running:
$ sudo rm -rf trash\ directory.t0034-root-safe-directory/
The test file also uses at least one initial "setup" test that creates
a parallel execution directory under the "root" sub directory, which
should be used as top level directory for all repositories that are
used in this test file. Unlike all other tests the repository provided
by the test framework should go unused.
Special care should be taken when invoking commands through sudo, since
the environment is otherwise independent from what the test framework
setup and might have changed the values for HOME, SHELL and dropped
several relevant environment variables for your test. Indeed `git status`
was used as a proxy because it doesn't even require commits in the
repository to work and usually doesn't require much from the environment
to run, but a future patch will add calls to `git init` and that will
fail to honor the default branch name, unless that setting is NOT
provided through an environment variable (which means even a CI run
could fail that test if enabled incorrectly).
A new SUDO prerequisite is provided that does some sanity checking
to make sure the sudo command that will be used allows for passwordless
execution as root without restrictions and doesn't mess with git's
execution path. This matches what is provided by the macOS agents that
are used as part of GitHub actions and probably nowhere else.
Most of those characteristics make this test mostly only suitable for
CI, but it might be executed locally if special care is taken to provide
for all of them in the local configuration and maybe making use of the
sudo credential cache by first invoking sudo, entering your password if
needed, and then invoking the test with:
$ GIT_TEST_ALLOW_SUDO=YES ./t0034-root-safe-directory.sh
If it fails to run, then it means your local setup wouldn't work for the
test because of the configuration sudo has or other system settings, and
things that might help are to comment out sudo's secure_path config, and
make sure that the account you are using has no restrictions on the
commands it can run through sudo, just like is provided for the user in
the CI.
For example (assuming a username of marta for you) something probably
similar to the following entry in your /etc/sudoers (or equivalent) file:
marta ALL=(ALL:ALL) NOPASSWD: ALL
Reported-by: SZEDER Gábor <szeder.dev@gmail.com>
Helped-by: Phillip Wood <phillip.wood123@gmail.com>
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
With the addition of the safe.directory in 8959555ce
(setup_git_directory(): add an owner check for the top-level directory,
2022-03-02) released in v2.35.2, we are receiving feedback from a
variety of users about the feature.
Some users have a very large list of shared repositories and find it
cumbersome to add this config for every one of them.
In a more difficult case, certain workflows involve running Git commands
within containers. The container boundary prevents any global or system
config from communicating `safe.directory` values from the host into the
container. Further, the container almost always runs as a different user
than the owner of the directory in the host.
To simplify the reactions necessary for these users, extend the
definition of the safe.directory config value to include a possible '*'
value. This value implies that all directories are safe, providing a
single setting to opt-out of this protection.
Note that an empty assignment of safe.directory clears all previous
values, and this is already the case with the "if (!value || !*value)"
condition.
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It seems that nothing is ever checking to make sure the safe directories
in the configs actually have the key safe.directory, so some unrelated
config that has a value with a certain directory would also make it a
safe directory.
Signed-off-by: Matheus Valadares <me@m28.io>
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It is difficult to change the ownership on a directory in our test
suite, so insert a new GIT_TEST_ASSUME_DIFFERENT_OWNER environment
variable to trick Git into thinking we are in a differently-owned
directory. This allows us to test that the config is parsed correctly.
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* maint-2.33:
Git 2.33.2
Git 2.32.1
Git 2.31.2
GIT-VERSION-GEN: bump to v2.33.1
Git 2.30.3
setup_git_directory(): add an owner check for the top-level directory
Add a function to determine whether a path is owned by the current user
* maint-2.32:
Git 2.32.1
Git 2.31.2
Git 2.30.3
setup_git_directory(): add an owner check for the top-level directory
Add a function to determine whether a path is owned by the current user
* maint-2.31:
Git 2.31.2
Git 2.30.3
setup_git_directory(): add an owner check for the top-level directory
Add a function to determine whether a path is owned by the current user
* maint-2.30:
Git 2.30.3
setup_git_directory(): add an owner check for the top-level directory
Add a function to determine whether a path is owned by the current user
When determining the length of the longest ancestor of a given path with
respect to to e.g. `GIT_CEILING_DIRECTORIES`, we special-case the root
directory by returning 0 (i.e. we pretend that the path `/` does not end
in a slash by virtually stripping it).
That is the correct behavior because when normalizing paths, the root
directory is special: all other directory paths have their trailing
slash stripped, but not the root directory's path (because it would
become the empty string, which is not a legal path).
However, this special-casing of the root directory in
`longest_ancestor_length()` completely forgets about Windows-style root
directories, e.g. `C:\`. These _also_ get normalized with a trailing
slash (because `C:` would actually refer to the current directory on
that drive, not necessarily to its root directory).
In fc56c7b34b (mingw: accomodate t0060-path-utils for MSYS2,
2016-01-27), we almost got it right. We noticed that
`longest_ancestor_length()` expects a slash _after_ the matched prefix,
and if the prefix already ends in a slash, the normalized path won't
ever match and -1 is returned.
But then that commit went astray: The correct fix is not to adjust the
_tests_ to expect an incorrect -1 when that function is fed a prefix
that ends in a slash, but instead to treat such a prefix as if the
trailing slash had been removed.
Likewise, that function needs to handle the case where it is fed a path
that ends in a slash (not only a prefix that ends in a slash): if it
matches the prefix (plus trailing slash), we still need to verify that
the path does not end there, otherwise the prefix is not actually an
ancestor of the path but identical to it (and we need to return -1 in
that case).
With these two adjustments, we no longer need to play games in t0060
where we only add `$rootoff` if the passed prefix is different from the
MSYS2 pseudo root, instead we also add it for the MSYS2 pseudo root
itself. We do have to be careful to skip that logic entirely for Windows
paths, though, because they do are not subject to that MSYS2 pseudo root
treatment.
This patch fixes the scenario where a user has set
`GIT_CEILING_DIRECTORIES=C:\`, which would be ignored otherwise.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
It poses a security risk to search for a git directory outside of the
directories owned by the current user.
For example, it is common e.g. in computer pools of educational
institutes to have a "scratch" space: a mounted disk with plenty of
space that is regularly swiped where any authenticated user can create
a directory to do their work. Merely navigating to such a space with a
Git-enabled `PS1` when there is a maliciously-crafted `/scratch/.git/`
can lead to a compromised account.
The same holds true in multi-user setups running Windows, as `C:\` is
writable to every authenticated user by default.
To plug this vulnerability, we stop Git from accepting top-level
directories owned by someone other than the current user. We avoid
looking at the ownership of each and every directories between the
current and the top-level one (if there are any between) to avoid
introducing a performance bottleneck.
This new default behavior is obviously incompatible with the concept of
shared repositories, where we expect the top-level directory to be owned
by only one of its legitimate users. To re-enable that use case, we add
support for adding exceptions from the new default behavior via the
config setting `safe.directory`.
The `safe.directory` config setting is only respected in the system and
global configs, not from repository configs or via the command-line, and
can have multiple values to allow for multiple shared repositories.
We are particularly careful to provide a helpful message to any user
trying to use a shared repository.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
This function will be used in the next commit to prevent
`setup_git_directory()` from discovering a repository in a directory
that is owned by someone other than the current user.
Note: We cannot simply use `st.st_uid` on Windows just like we do on
Linux and other Unix-like platforms: according to
https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/stat-functions
this field is always zero on Windows (because Windows' idea of a user ID
does not fit into a single numerical value). Therefore, we have to do
something a little involved to replicate the same functionality there.
Also note: On Windows, a user's home directory is not actually owned by
said user, but by the administrator. For all practical purposes, it is
under the user's control, though, therefore we pretend that it is owned
by the user.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Build fix on Windows.
* cb/mingw-gmtime-r:
mingw: avoid fallback for {local,gm}time_r()
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
mingw-w64's pthread_unistd.h had a bug that mistakenly (because there is
no support for the *lockfile() functions required[1]) defined
_POSIX_THREAD_SAFE_FUNCTIONS and that was being worked around since
3ecd153a3b (compat/mingw: support MSys2-based MinGW build, 2016-01-14).
The bug was fixed in winphtreads, but as a side effect, leaves the
reentrant functions from time.h no longer visible and therefore breaks
the build.
Since the intention all along was to avoid using the fallback functions,
formalize the use of POSIX by setting the corresponding feature flag and
compile out the implementation for the fallback functions.
[1] https://unix.org/whitepapers/reentrant.html
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Acked-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
@ -29,17 +29,17 @@ This is designed to be as compact as possible.
commit <hash>
Author: <author>
<title-line>
<titleline>
* 'medium'
commit <hash>
Author: <author>
Date: <author-date>
Date: <authordate>
<title-line>
<titleline>
<full-commit-message>
<fullcommitmessage>
* 'full'
@ -47,25 +47,25 @@ This is designed to be as compact as possible.
Author: <author>
Commit: <committer>
<title-line>
<titleline>
<full-commit-message>
<fullcommitmessage>
* 'fuller'
commit <hash>
Author: <author>
AuthorDate: <author-date>
AuthorDate: <authordate>
Commit: <committer>
CommitDate: <committer-date>
CommitDate: <committerdate>
<title-line>
<titleline>
<full-commit-message>
<fullcommitmessage>
* 'reference'
<abbrev-hash> (<title-line>, <short-author-date>)
<abbrevhash> (<titleline>, <shortauthordate>)
+
This format is used to refer to another commit in a commit message and
is the same as `--pretty='format:%C(auto)%h (%s, %ad)'`. By default,
@ -78,10 +78,10 @@ placeholders, its output is not affected by other options like
From <hash> <date>
From: <author>
Date: <author-date>
Subject: [PATCH] <title-line>
Date: <authordate>
Subject: [PATCH] <titleline>
<full-commit-message>
<fullcommitmessage>
* 'mboxrd'
+
@ -101,9 +101,9 @@ commits are displayed, but not the way the diff is shown e.g. with
`git log --raw`. To get full object names in a raw diff format,
use `--no-abbrev`.
* 'format:<format-string>'
* 'format:<string>'
+
The 'format:<format-string>' format allows you to specify which information
The 'format:<string>' format allows you to specify which information
you want to show. It works a little bit like printf format,
with the notable exception that you get a newline with '%n'
instead of '\n'.
@ -220,12 +220,6 @@ The placeholders are:
inconsistent when tags are added or removed at
the same time.
+
** 'tags[=<bool-value>]': Instead of only considering annotated tags,
consider lightweight tags as well.
** 'abbrev=<number>': Instead of using the default number of hexadecimal digits
(which will vary according to the number of objects in the repository with a
default of 7) of the abbreviated object name, use <number> digits, or as many
digits as needed to form a unique object name.
** 'match=<pattern>': Only consider tags matching the given
`glob(7)` pattern, excluding the "refs/tags/" prefix.
** 'exclude=<pattern>': Do not consider tags matching the given
@ -279,7 +273,12 @@ endif::git-rev-list[]
If any option is provided multiple times the
last occurrence wins.
+
** 'key=<key>': only show trailers with specified <key>. Matching is done
The boolean options accept an optional value `[=<BOOL>]`. The values
`true`, `false`, `on`, `off` etc. are all accepted. See the "boolean"
sub-section in "EXAMPLES" in linkgit:git-config[1]. If a boolean
option is given with no value, it's enabled.
+
** 'key=<K>': only show trailers with specified key. Matching is done
case-insensitively and trailing colon is optional. If option is
given multiple times trailer lines matching any of the keys are
shown. This option automatically enables the `only` option so that
@ -287,25 +286,25 @@ endif::git-rev-list[]
desired it can be disabled with `only=false`. E.g.,
`%(trailers:key=Reviewed-by)` shows trailer lines with key
`Reviewed-by`.
** 'only[=<bool>]': select whether non-trailer lines from the trailer
** 'only[=<BOOL>]': select whether non-trailer lines from the trailer
block should be included.
** 'separator=<sep>': specify a separator inserted between trailer
** 'separator=<SEP>': specify a separator inserted between trailer
lines. When this option is not given each trailer line is
terminated with a line feed character. The string <sep> may contain
terminated with a line feed character. The string SEP may contain
the literal formatting codes described above. To use comma as
separator one must use `%x2C` as it would otherwise be parsed as
next option. E.g., `%(trailers:key=Ticket,separator=%x2C )`
shows all trailer lines whose key is "Ticket" separated by a comma
and a space.
** 'unfold[=<bool>]': make it behave as if interpret-trailer's `--unfold`
** 'unfold[=<BOOL>]': make it behave as if interpret-trailer's `--unfold`
option was given. E.g.,
`%(trailers:only,unfold=true)` unfolds and shows all trailer lines.
** 'keyonly[=<bool>]': only show the key part of the trailer.
** 'valueonly[=<bool>]': only show the value part of the trailer.
** 'key_value_separator=<sep>': specify a separator inserted between
** 'keyonly[=<BOOL>]': only show the key part of the trailer.
** 'valueonly[=<BOOL>]': only show the value part of the trailer.
** 'key_value_separator=<SEP>': specify a separator inserted between
trailer lines. When this option is not given each trailer key-value
pair is separated by ": ". Otherwise it shares the same semantics
as 'separator=<sep>' above.
as 'separator=<SEP>' above.
NOTE: Some placeholders may depend on other options given to the
revision traversal engine. For example, the `%g*` reflog options will
@ -314,11 +313,6 @@ insert an empty string unless we are traversing reflog entries (e.g., by
decoration format if `--decorate` was not already provided on the command
line.
The boolean options accept an optional value `[=<bool-value>]`. The values
`true`, `false`, `on`, `off` etc. are all accepted. See the "boolean"
sub-section in "EXAMPLES" in linkgit:git-config[1]. If a boolean
option is given with no value, it's enabled.
If you add a `+` (plus sign) after '%' of a placeholder, a line-feed
is inserted immediately before the expansion if and only if the
placeholder expands to a non-empty string.
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