transport: add protocol policy config option

Previously the `GIT_ALLOW_PROTOCOL` environment variable was used to
specify a whitelist of protocols to be used in clone/fetch/push
commands.  This patch introduces new configuration options for more
fine-grained control for allowing/disallowing protocols.  This also has
the added benefit of allowing easier construction of a protocol
whitelist on systems where setting an environment variable is
non-trivial.

Now users can specify a policy to be used for each type of protocol via
the 'protocol.<name>.allow' config option.  A default policy for all
unconfigured protocols can be set with the 'protocol.allow' config
option.  If no user configured default is made git will allow known-safe
protocols (http, https, git, ssh, file), disallow known-dangerous
protocols (ext), and have a default policy of `user` for all other
protocols.

The supported policies are `always`, `never`, and `user`.  The `user`
policy can be used to configure a protocol to be usable when explicitly
used by a user, while disallowing it for commands which run
clone/fetch/push commands without direct user intervention (e.g.
recursive initialization of submodules).  Commands which can potentially
clone/fetch/push from untrusted repositories without user intervention
can export `GIT_PROTOCOL_FROM_USER` with a value of '0' to prevent
protocols configured to the `user` policy from being used.

Fix remote-ext tests to use the new config to allow the ext
protocol to be tested.

Based on a patch by Jeff King <peff@peff.net>

Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Brandon Williams
2016-12-14 14:39:52 -08:00
committed by Junio C Hamano
parent f962ddf6ed
commit f1762d772e
7 changed files with 263 additions and 38 deletions

View File

@ -22,14 +22,10 @@ require_work_tree
wt_prefix=$(git rev-parse --show-prefix)
cd_to_toplevel
# Restrict ourselves to a vanilla subset of protocols; the URLs
# we get are under control of a remote repository, and we do not
# want them kicking off arbitrary git-remote-* programs.
#
# If the user has already specified a set of allowed protocols,
# we assume they know what they're doing and use that instead.
: ${GIT_ALLOW_PROTOCOL=file:git:http:https:ssh}
export GIT_ALLOW_PROTOCOL
# Tell the rest of git that any URLs we get don't come
# directly from the user, so it can apply policy as appropriate.
GIT_PROTOCOL_FROM_USER=0
export GIT_PROTOCOL_FROM_USER
command=
branch=