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Make hash-object more robust against malformed objects

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Commits, trees and tags have structure. Don't let users feed git
with malformed ones. Sooner or later git will die() when
encountering them.

Note that this patch does not check semantics. A tree that points
to non-existent objects is perfectly OK (and should be so, users
may choose to add commit first, then its associated tree for example).

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Nguyễn Thái Ngọc Duy
2011-02-05 17:52:21 +07:00
committed by Junio C Hamano
parent cf7b1cad0e
commit c879daa237
5 changed files with 63 additions and 10 deletions
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54
sha1_file.c
View File

@ -13,6 +13,7 @@
#include "commit.h"
#include "tag.h"
#include "tree.h"
#include "tree-walk.h"
#include "refs.h"
#include "pack-revindex.h"
#include "sha1-lookup.h"
@ -2471,8 +2472,37 @@ int has_sha1_file(const unsigned char *sha1)
return has_loose_object(sha1);
}
static void check_tree(const void *buf, size_t size)
{
struct tree_desc desc;
struct name_entry entry;
init_tree_desc(&desc, buf, size);
while (tree_entry(&desc, &entry))
/* do nothing
* tree_entry() will die() on malformed entries */
;
}
static void check_commit(const void *buf, size_t size)
{
struct commit c;
memset(&c, 0, sizeof(c));
if (parse_commit_buffer(&c, buf, size))
die("corrupt commit");
}
static void check_tag(const void *buf, size_t size)
{
struct tag t;
memset(&t, 0, sizeof(t));
if (parse_tag_buffer(&t, buf, size))
die("corrupt tag");
}
static int index_mem(unsigned char *sha1, void *buf, size_t size,
int write_object, enum object_type type, const char *path)
int write_object, enum object_type type,
const char *path, int format_check)
{
int ret, re_allocated = 0;
@ -2490,6 +2520,14 @@ static int index_mem(unsigned char *sha1, void *buf, size_t size,
re_allocated = 1;
}
}
if (format_check) {
if (type == OBJ_TREE)
check_tree(buf, size);
if (type == OBJ_COMMIT)
check_commit(buf, size);
if (type == OBJ_TAG)
check_tag(buf, size);
}
if (write_object)
ret = write_sha1_file(buf, size, typename(type), sha1);
@ -2503,7 +2541,7 @@ static int index_mem(unsigned char *sha1, void *buf, size_t size,
#define SMALL_FILE_SIZE (32*1024)
int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object,
enum object_type type, const char *path)
enum object_type type, const char *path, int format_check)
{
int ret;
size_t size = xsize_t(st->st_size);
@ -2512,23 +2550,25 @@ int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object,
struct strbuf sbuf = STRBUF_INIT;
if (strbuf_read(&sbuf, fd, 4096) >= 0)
ret = index_mem(sha1, sbuf.buf, sbuf.len, write_object,
type, path);
type, path, format_check);
else
ret = -1;
strbuf_release(&sbuf);
} else if (!size) {
ret = index_mem(sha1, NULL, size, write_object, type, path);
ret = index_mem(sha1, NULL, size, write_object, type, path,
format_check);
} else if (size <= SMALL_FILE_SIZE) {
char *buf = xmalloc(size);
if (size == read_in_full(fd, buf, size))
ret = index_mem(sha1, buf, size, write_object, type,
path);
path, format_check);
else
ret = error("short read %s", strerror(errno));
free(buf);
} else {
void *buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
ret = index_mem(sha1, buf, size, write_object, type, path);
ret = index_mem(sha1, buf, size, write_object, type, path,
format_check);
munmap(buf, size);
}
close(fd);
@ -2546,7 +2586,7 @@ int index_path(unsigned char *sha1, const char *path, struct stat *st, int write
if (fd < 0)
return error("open(\"%s\"): %s", path,
strerror(errno));
if (index_fd(sha1, fd, st, write_object, OBJ_BLOB, path) < 0)
if (index_fd(sha1, fd, st, write_object, OBJ_BLOB, path, 0) < 0)
return error("%s: failed to insert into database",
path);
break;