Date: Mon, 15 Oct 2018 20:20:58 +0000 (UTC) From: Gleb Smirnoff <glebius@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r339370 - head/lib/libc/string Message-ID: <201810152020.w9FKKwbL072717@repo.freebsd.org>
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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 <amonakov@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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