Author: glebius
Date: Mon Oct 15 20:20:57 2018
New Revision: 339370
URL: https://svnweb.freebsd.org/changeset/base/339370
Log:
Avoid OOB reads in memmem(3).
commit 51bdcdc424bd7169c8cccdc2de7cad17f5ea0f70
Author: Alexander Monakov <amona...@ispras.ru>
Date: Fri Jun 30 00:35:33 2017 +0300
fix OOB reads in Xbyte_memmem
Reported by Leah Neukirchen.
Reviewed by: emaste
Approved by: re (kib)
Modified:
head/lib/libc/string/memmem.c
Modified: head/lib/libc/string/memmem.c
==============================================================================
--- head/lib/libc/string/memmem.c Mon Oct 15 20:11:53 2018
(r339369)
+++ head/lib/libc/string/memmem.c Mon Oct 15 20:20:57 2018
(r339370)
@@ -31,27 +31,27 @@ __FBSDID("$FreeBSD$");
static char *twobyte_memmem(const unsigned char *h, size_t k, const unsigned
char *n)
{
uint16_t nw = n[0]<<8 | n[1], hw = h[0]<<8 | h[1];
- for (h++, k--; k; k--, hw = hw<<8 | *++h)
- if (hw == nw) return (char *)h-1;
- return 0;
+ for (h+=2, k-=2; k; k--, hw = hw<<8 | *h++)
+ if (hw == nw) return (char *)h-2;
+ return hw == nw ? (char *)h-2 : 0;
}
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;
- for (h+=2, k-=2; k; k--, hw = (hw|*++h)<<8)
- if (hw == nw) return (char *)h-2;
- return 0;
+ for (h+=3, k-=3; k; k--, hw = (hw|*h++)<<8)
+ if (hw == nw) return (char *)h-3;
+ return hw == nw ? (char *)h-3 : 0;
}
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];
- for (h+=3, k-=3; k; k--, hw = hw<<8 | *++h)
- if (hw == nw) return (char *)h-3;
- return 0;
+ for (h+=4, k-=4; k; k--, hw = hw<<8 | *h++)
+ if (hw == nw) return (char *)h-4;
+ return hw == nw ? (char *)h-4 : 0;
}
#define MAX(a,b) ((a)>(b)?(a):(b))
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