Module Name: src
Committed By: riastradh
Date: Sat Dec 14 16:48:13 UTC 2024
Modified Files:
src/common/lib/libc/string: memmem.c
Log Message:
memmem(3): Avoid undefined behaviour in shift.
PR lib/58906: memmem.c: sync with musl upstream that fixes UB on
signed overflow
To generate a diff of this commit:
cvs rdiff -u -r1.5 -r1.6 src/common/lib/libc/string/memmem.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/common/lib/libc/string/memmem.c
diff -u src/common/lib/libc/string/memmem.c:1.5 src/common/lib/libc/string/memmem.c:1.6
--- src/common/lib/libc/string/memmem.c:1.5 Sat Dec 14 16:48:05 2024
+++ src/common/lib/libc/string/memmem.c Sat Dec 14 16:48:13 2024
@@ -25,7 +25,7 @@
#if 0
__FBSDID("$FreeBSD: head/lib/libc/string/memmem.c 315468 2017-03-18 00:53:24Z emaste $");
#else
-__RCSID("$NetBSD: memmem.c,v 1.5 2024/12/14 16:48:05 riastradh Exp $");
+__RCSID("$NetBSD: memmem.c,v 1.6 2024/12/14 16:48:13 riastradh Exp $");
#endif
#endif /* LIBC_SCCS and not lint */
@@ -48,8 +48,8 @@ static char *twobyte_memmem(const unsign
static char *threebyte_memmem(const unsigned char *h, size_t k,
const unsigned char *n)
{
- uint32_t nw = n[0] << 24 | n[1] << 16 | n[2] << 8;
- uint32_t hw = h[0] << 24 | h[1] << 16 | h[2] << 8;
+ uint32_t nw = (uint32_t)n[0] << 24 | n[1] << 16 | n[2] << 8;
+ uint32_t hw = (uint32_t)h[0] << 24 | h[1] << 16 | h[2] << 8;
for (h += 3, k -= 3; k; k--, hw = (hw|*h++) << 8)
if (hw == nw) return __UNCONST(h - 3);
return hw == nw ? __UNCONST(h - 3) : 0;
@@ -58,8 +58,8 @@ static char *threebyte_memmem(const unsi
static char *fourbyte_memmem(const unsigned char *h, size_t k,
const unsigned char *n)
{
- uint32_t nw = n[0] << 24 | n[1] << 16 | n[2] << 8 | n[3];
- uint32_t hw = h[0] << 24 | h[1] << 16 | h[2] << 8 | h[3];
+ uint32_t nw = (uint32_t)n[0] << 24 | n[1] << 16 | n[2] << 8 | n[3];
+ uint32_t hw = (uint32_t)h[0] << 24 | h[1] << 16 | h[2] << 8 | h[3];
for (h += 4, k -= 4; k; k--, hw = hw << 8 | *h++)
if (hw == nw) return __UNCONST(h - 4);
return hw == nw ? __UNCONST(h - 4) : 0;
