From 51bdcdc424bd7169c8cccdc2de7cad17f5ea0f70 Mon Sep 17 00:00:00 2001 From: Alexander Monakov Date: Fri, 30 Jun 2017 00:35:33 +0300 Subject: [PATCH] fix OOB reads in Xbyte_memmem Reported by Leah Neukirchen. --- src/string/memmem.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/src/string/memmem.c b/src/string/memmem.c index 4be6a310..54a66e46 100644 --- a/src/string/memmem.c +++ b/src/string/memmem.c @@ -5,27 +5,27 @@ 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)) -- 2.25.1