git-for-windows/git
1
0
Fork 0
mirror of https://github.com/git-for-windows/git.git synced 2026-06-21 10:29:16 -05:00
Code Issues Packages Projects Releases 335 Wiki Activity

zlib: properly clamp to uLong

Browse Source 
On platforms where `unsigned long` and `size_t` differ in bit size, we
want to clamp the buffers we pass to zlib to the former's size, as per
d05d666977 (git-zlib: handle data streams larger than 4GB, 2026-05-08).

The logic introduced in that commit performs a clamping to the bits,
though, which fails to do what is needed here: If too many bytes are
available in the buffers, we need to clamp to the maximum value of an
`unsigned long`. Otherwise, we ask zlib to use too small buffers, in the
worst case using 0 as the size (think: a value whose 32 lowest bits are
all zero).

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Johannes Schindelin
2026-06-18 13:50:18 +00:00
committed by Junio C Hamano
parent 7a094d68a2
commit ab3810eb6f
1 changed files with 9 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

13
git-zlib.c
View File

@@ -38,12 +38,17 @@ static inline uInt zlib_buf_cap(unsigned long len)
return (ZLIB_BUF_MAX < len) ? ZLIB_BUF_MAX : len;
}
static inline uLong zlib_uLong_cap(size_t s)
{
return s < ULONG_MAX_VALUE ? (uLong)s : ULONG_MAX_VALUE;
}
static void zlib_pre_call(git_zstream *s)
{
s->z.next_in = s->next_in;
s->z.next_out = s->next_out;
s->z.total_in = (uLong)(s->total_in & ULONG_MAX_VALUE);
s->z.total_out = (uLong)(s->total_out & ULONG_MAX_VALUE);
s->z.total_in = zlib_uLong_cap(s->total_in);
s->z.total_out = zlib_uLong_cap(s->total_out);
s->z.avail_in = zlib_buf_cap(s->avail_in);
s->z.avail_out = zlib_buf_cap(s->avail_out);
}
@@ -60,7 +65,7 @@ static void zlib_post_call(git_zstream *s, int status)
* We track our own totals and verify only the low bits match.
*/
if ((s->z.total_out & ULONG_MAX_VALUE) !=
((s->total_out + bytes_produced) & ULONG_MAX_VALUE))
((zlib_uLong_cap(s->total_out) + bytes_produced) & ULONG_MAX_VALUE))
BUG("total_out mismatch");
/*
* zlib does not update total_in when it returns Z_NEED_DICT,
@@ -68,7 +73,7 @@ static void zlib_post_call(git_zstream *s, int status)
*/
if (status != Z_NEED_DICT &&
(s->z.total_in & ULONG_MAX_VALUE) !=
((s->total_in + bytes_consumed) & ULONG_MAX_VALUE))
((zlib_uLong_cap(s->total_in) + bytes_consumed) & ULONG_MAX_VALUE))
BUG("total_in mismatch");
s->total_out += bytes_produced;