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| author | Patrick Steinhardt <ps@pks.im> | 2025-01-10 12:26:17 +0100 |
|---|---|---|
| committer | Junio C Hamano <gitster@pobox.com> | 2025-01-10 06:56:54 -0800 |
| commit | 1fbb8d7ecb7bd78ac55d226b6b073372a5ea2c2d (patch) | |
| tree | fbcd303384259bcd2a756f0ab73c030012029f59 | |
| parent | e03d2a9ccb88c7ff42237f5890a05e071497f8ae (diff) | |
| download | git-1fbb8d7ecb7bd78ac55d226b6b073372a5ea2c2d.tar.gz | |
builtin/blame: fix out-of-bounds read with excessive `--abbrev`
In 6411a0a896 (builtin/blame: fix type of `length` variable when
emitting object ID, 2024-12-06) we have fixed the type of the `length`
variable. In order to avoid a cast from `size_t` to `int` in the call to
printf(3p) with the "%.*s" formatter we have converted the code to
instead use fwrite(3p), which accepts the length as a `size_t`.
It was reported though that this makes us read over the end of the OID
array when the provided `--abbrev=` length exceeds the length of the
object ID. This is because fwrite(3p) of course doesn't stop when it
sees a NUL byte, whereas printf(3p) does.
Fix the bug by reverting back to printf(3p) and culling the provided
length to `GIT_MAX_HEXSZ` to keep it from overflowing when cast to an
`int`.
Reported-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
| -rw-r--r-- | builtin/blame.c | 3 | ||||
| -rwxr-xr-x | t/t8002-blame.sh | 8 |
2 files changed, 10 insertions, 1 deletions
diff --git a/builtin/blame.c b/builtin/blame.c index 867032e4c1..d7630ac89c 100644 --- a/builtin/blame.c +++ b/builtin/blame.c @@ -505,7 +505,8 @@ static void emit_other(struct blame_scoreboard *sb, struct blame_entry *ent, int length--; putchar('?'); } - fwrite(hex, 1, length, stdout); + + printf("%.*s", (int)(length < GIT_MAX_HEXSZ ? length : GIT_MAX_HEXSZ), hex); if (opt & OUTPUT_ANNOTATE_COMPAT) { const char *name; if (opt & OUTPUT_SHOW_EMAIL) diff --git a/t/t8002-blame.sh b/t/t8002-blame.sh index 0147de304b..b3f8b63d2e 100755 --- a/t/t8002-blame.sh +++ b/t/t8002-blame.sh @@ -126,6 +126,14 @@ test_expect_success '--no-abbrev works like --abbrev with full length' ' check_abbrev $hexsz --no-abbrev ' +test_expect_success 'blame --abbrev gets truncated' ' + check_abbrev $hexsz --abbrev=9000 HEAD +' + +test_expect_success 'blame --abbrev gets truncated with boundary commit' ' + check_abbrev $hexsz --abbrev=9000 ^HEAD +' + test_expect_success '--exclude-promisor-objects does not BUG-crash' ' test_must_fail git blame --exclude-promisor-objects one ' |