From 53a3fdbfc56da54b2c0a44eb1f956ec9d67d1425 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Sat, 26 Jan 2013 02:03:05 +0100 Subject: [PATCH] 4xm: Check available space in read_huffman_tables() Fixes integer overflow and out of array accesses Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind Signed-off-by: Michael Niedermayer --- libavcodec/4xm.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/libavcodec/4xm.c b/libavcodec/4xm.c index 2db3026756..39254f7c07 100644 --- a/libavcodec/4xm.c +++ b/libavcodec/4xm.c @@ -599,8 +599,10 @@ static const uint8_t *read_huffman_tables(FourXContext *f, for (;;) { int i; - if (start <= end && ptr_end - ptr < end - start + 1 + 1) + if (ptr_end - ptr < FFMAX(end - start + 1, 0) + 1) { + av_log(f->avctx, AV_LOG_ERROR, "invalid data in read_huffman_tables\n"); return NULL; + } for (i = start; i <= end; i++) frequency[i] = *ptr++; start = *ptr++; @@ -614,6 +616,11 @@ static const uint8_t *read_huffman_tables(FourXContext *f, while ((ptr - buf) & 3) ptr++; // 4byte align + if (ptr > ptr_end) { + av_log(f->avctx, AV_LOG_ERROR, "ptr overflow in read_huffman_tables\n"); + return NULL; + } + for (j = 257; j < 512; j++) { int min_freq[2] = { 256 * 256, 256 * 256 }; int smallest[2] = { 0, 0 };