diff options
author | Patrick Steinhardt <ps@pks.im> | 2022-12-01 17:46:49 +0300 |
---|---|---|
committer | Junio C Hamano <gitster@pobox.com> | 2022-12-09 08:26:21 +0300 |
commit | 48050c42c73c28b0c001d63d11dffac7e116847b (patch) | |
tree | fbea2ce85a3b749345fd987b13277e8f7ab26e00 | |
parent | 1de69c0cdd388b0a5b7bdde0bfa0bda514a354b0 (diff) |
pretty: fix integer overflow in wrapping format
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>
-rw-r--r-- | git-compat-util.h | 8 | ||||
-rw-r--r-- | pretty.c | 4 | ||||
-rwxr-xr-x | t/t4205-log-pretty-formats.sh | 12 |
3 files changed, 23 insertions, 1 deletions
diff --git a/git-compat-util.h b/git-compat-util.h index f505f817d5..0ac1b7f560 100644 --- a/git-compat-util.h +++ b/git-compat-util.h @@ -918,6 +918,14 @@ static inline size_t st_sub(size_t a, size_t b) return a - b; } +static inline int cast_size_t_to_int(size_t a) +{ + if (a > INT_MAX) + die("number too large to represent as int on this platform: %"PRIuMAX, + (uintmax_t)a); + return (int)a; +} + #ifdef HAVE_ALLOCA_H # include <alloca.h> # define xalloca(size) (alloca(size)) @@ -915,7 +915,9 @@ static void strbuf_wrap(struct strbuf *sb, size_t pos, if (pos) strbuf_add(&tmp, sb->buf, pos); strbuf_add_wrapped_text(&tmp, sb->buf + pos, - (int) indent1, (int) indent2, (int) width); + cast_size_t_to_int(indent1), + cast_size_t_to_int(indent2), + cast_size_t_to_int(width)); strbuf_swap(&tmp, sb); strbuf_release(&tmp); } diff --git a/t/t4205-log-pretty-formats.sh b/t/t4205-log-pretty-formats.sh index 1d768f7244..c88b64d08b 100755 --- a/t/t4205-log-pretty-formats.sh +++ b/t/t4205-log-pretty-formats.sh @@ -887,6 +887,18 @@ test_expect_success 'log --pretty with magical wrapping directives' ' test_cmp expect actual ' +test_expect_success SIZE_T_IS_64BIT 'log --pretty with overflowing wrapping directive' ' + cat >expect <<-EOF && + fatal: number too large to represent as int on this platform: 2147483649 + EOF + test_must_fail git log -1 --pretty="format:%w(2147483649,1,1)%d" 2>error && + test_cmp expect error && + test_must_fail git log -1 --pretty="format:%w(1,2147483649,1)%d" 2>error && + test_cmp expect error && + test_must_fail git log -1 --pretty="format:%w(1,1,2147483649)%d" 2>error && + test_cmp expect error +' + test_expect_success EXPENSIVE,SIZE_T_IS_64BIT 'log --pretty with huge commit message' ' # We only assert that this command does not crash. This needs to be # executed with the address sanitizer to demonstrate failure. |