From 4b96f43fe169bb29a9b45cbb116cd8a81cebfebe Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Reimar=20D=C3=B6ffinger?= Date: Fri, 17 Apr 2009 18:03:00 +0000 Subject: [PATCH] Change buffer size checks to avoid the very unlikely overflow case. Originally committed as revision 18576 to svn://svn.ffmpeg.org/ffmpeg/trunk --- libavcodec/xan.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/libavcodec/xan.c b/libavcodec/xan.c index 9a311eae6c..5c99e9848d 100644 --- a/libavcodec/xan.c +++ b/libavcodec/xan.c @@ -140,12 +140,12 @@ static void xan_unpack(unsigned char *dest, const unsigned char *src, int dest_l offset = *src++; size = opcode & 3; - if (dest + size > dest_end) + if (size > dest_end - dest) return; memcpy(dest, src, size); dest += size; src += size; size = ((opcode & 0x1c) >> 2) + 3; - if (dest + size > dest_end) + if (size > dest_end - dest) return; av_memcpy_backptr(dest, ((opcode & 0x60) << 3) + offset + 1, size); dest += size; @@ -156,12 +156,12 @@ static void xan_unpack(unsigned char *dest, const unsigned char *src, int dest_l byte2 = *src++; size = byte1 >> 6; - if (dest + size > dest_end) + if (size > dest_end - dest) return; memcpy(dest, src, size); dest += size; src += size; size = (opcode & 0x3f) + 4; - if (dest + size > dest_end) + if (size > dest_end - dest) return; av_memcpy_backptr(dest, ((byte1 & 0x3f) << 8) + byte2 + 1, size); dest += size; @@ -173,12 +173,12 @@ static void xan_unpack(unsigned char *dest, const unsigned char *src, int dest_l byte3 = *src++; size = opcode & 3; - if (dest + size > dest_end) + if (size > dest_end - dest) return; memcpy(dest, src, size); dest += size; src += size; size = byte3 + 5 + ((opcode & 0xc) << 6); - if (dest + size > dest_end) + if (size > dest_end - dest) return; av_memcpy_backptr(dest, ((opcode & 0x10) << 12) + 1 + (byte1 << 8) + byte2, @@ -190,7 +190,7 @@ static void xan_unpack(unsigned char *dest, const unsigned char *src, int dest_l if (size > 0x70) break; - if (dest + size > dest_end) + if (size > dest_end - dest) return; memcpy(dest, src, size); dest += size; src += size; }