https://github.com/git/git
Revision 34ace8bad02bb14ecc5b631f7e3daaa7a9bba7d9 authored by Patrick Steinhardt on 01 December 2022, 14:45:27 UTC, committed by Junio C Hamano on 05 December 2022, 06:14:16 UTC
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>
1 parent 2455720
Tip revision: 34ace8bad02bb14ecc5b631f7e3daaa7a9bba7d9 authored by Patrick Steinhardt on 01 December 2022, 14:45:27 UTC
attr: fix out-of-bounds write when parsing huge number of attributes
attr: fix out-of-bounds write when parsing huge number of attributes
Tip revision: 34ace8b
path.h
#ifndef PATH_H
#define PATH_H
struct repository;
struct strbuf;
/*
* The result to all functions which return statically allocated memory may be
* overwritten by another call to _any_ one of these functions. Consider using
* the safer variants which operate on strbufs or return allocated memory.
*/
/*
* Return a statically allocated path.
*/
const char *mkpath(const char *fmt, ...)
__attribute__((format (printf, 1, 2)));
/*
* Return a path.
*/
char *mkpathdup(const char *fmt, ...)
__attribute__((format (printf, 1, 2)));
/*
* Construct a path and place the result in the provided buffer `buf`.
*/
char *mksnpath(char *buf, size_t n, const char *fmt, ...)
__attribute__((format (printf, 3, 4)));
/*
* The `git_common_path` family of functions will construct a path into a
* repository's common git directory, which is shared by all worktrees.
*/
/*
* Constructs a path into the common git directory of repository `repo` and
* append it in the provided buffer `sb`.
*/
void strbuf_git_common_path(struct strbuf *sb,
const struct repository *repo,
const char *fmt, ...)
__attribute__((format (printf, 3, 4)));
/*
* Return a statically allocated path into the main repository's
* (the_repository) common git directory.
*/
const char *git_common_path(const char *fmt, ...)
__attribute__((format (printf, 1, 2)));
/*
* The `git_path` family of functions will construct a path into a repository's
* git directory.
*
* These functions will perform adjustments to the resultant path to account
* for special paths which are either considered common among worktrees (e.g.
* paths into the object directory) or have been explicitly set via an
* environment variable or config (e.g. path to the index file).
*
* For an exhaustive list of the adjustments made look at `common_list` and
* `adjust_git_path` in path.c.
*/
/*
* Return a path into the git directory of repository `repo`.
*/
char *repo_git_path(const struct repository *repo,
const char *fmt, ...)
__attribute__((format (printf, 2, 3)));
/*
* Construct a path into the git directory of repository `repo` and append it
* to the provided buffer `sb`.
*/
void strbuf_repo_git_path(struct strbuf *sb,
const struct repository *repo,
const char *fmt, ...)
__attribute__((format (printf, 3, 4)));
/*
* Return a statically allocated path into the main repository's
* (the_repository) git directory.
*/
const char *git_path(const char *fmt, ...)
__attribute__((format (printf, 1, 2)));
/*
* Return a path into the main repository's (the_repository) git directory.
*/
char *git_pathdup(const char *fmt, ...)
__attribute__((format (printf, 1, 2)));
/*
* Construct a path into the main repository's (the_repository) git directory
* and place it in the provided buffer `buf`, the contents of the buffer will
* be overridden.
*/
char *git_path_buf(struct strbuf *buf, const char *fmt, ...)
__attribute__((format (printf, 2, 3)));
/*
* Construct a path into the main repository's (the_repository) git directory
* and append it to the provided buffer `sb`.
*/
void strbuf_git_path(struct strbuf *sb, const char *fmt, ...)
__attribute__((format (printf, 2, 3)));
/*
* Return a path into the worktree of repository `repo`.
*
* If the repository doesn't have a worktree NULL is returned.
*/
char *repo_worktree_path(const struct repository *repo,
const char *fmt, ...)
__attribute__((format (printf, 2, 3)));
/*
* Construct a path into the worktree of repository `repo` and append it
* to the provided buffer `sb`.
*
* If the repository doesn't have a worktree nothing will be appended to `sb`.
*/
void strbuf_repo_worktree_path(struct strbuf *sb,
const struct repository *repo,
const char *fmt, ...)
__attribute__((format (printf, 3, 4)));
/*
* Return a path into a submodule's git directory located at `path`. `path`
* must only reference a submodule of the main repository (the_repository).
*/
char *git_pathdup_submodule(const char *path, const char *fmt, ...)
__attribute__((format (printf, 2, 3)));
/*
* Construct a path into a submodule's git directory located at `path` and
* append it to the provided buffer `sb`. `path` must only reference a
* submodule of the main repository (the_repository).
*/
int strbuf_git_path_submodule(struct strbuf *sb, const char *path,
const char *fmt, ...)
__attribute__((format (printf, 3, 4)));
void report_linked_checkout_garbage(void);
/*
* You can define a static memoized git path like:
*
* static GIT_PATH_FUNC(git_path_foo, "FOO")
*
* or use one of the global ones below.
*/
#define GIT_PATH_FUNC(func, filename) \
const char *func(void) \
{ \
static char *ret; \
if (!ret) \
ret = git_pathdup(filename); \
return ret; \
}
#define REPO_GIT_PATH_FUNC(var, filename) \
const char *git_path_##var(struct repository *r) \
{ \
if (!r->cached_paths.var) \
r->cached_paths.var = repo_git_path(r, filename); \
return r->cached_paths.var; \
}
struct path_cache {
const char *squash_msg;
const char *merge_msg;
const char *merge_rr;
const char *merge_mode;
const char *merge_head;
const char *merge_autostash;
const char *fetch_head;
const char *shallow;
};
#define PATH_CACHE_INIT \
{ \
NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL \
}
const char *git_path_squash_msg(struct repository *r);
const char *git_path_merge_msg(struct repository *r);
const char *git_path_merge_rr(struct repository *r);
const char *git_path_merge_mode(struct repository *r);
const char *git_path_merge_head(struct repository *r);
const char *git_path_merge_autostash(struct repository *r);
const char *git_path_fetch_head(struct repository *r);
const char *git_path_shallow(struct repository *r);
int ends_with_path_components(const char *path, const char *components);
#endif /* PATH_H */
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