From bbeae2c690f1449bbdcb41eeaf025dd2b9f025f5 Mon Sep 17 00:00:00 2001 From: Andreas Cadhalpun Date: Fri, 6 Nov 2015 21:04:34 +0100 Subject: [PATCH] jvdec: avoid unsigned overflow in comparison The return type of strlen is size_t, i.e. unsigned, so if pd->buf_size is 3, the right side overflows leading to a wrong result of the comparison and subsequently a heap buffer overflow. Reviewed-by: Paul B Mahol Signed-off-by: Andreas Cadhalpun (cherry picked from commit db374790c75fa4ef947abcb5019fcf21d0b2de85) Signed-off-by: Michael Niedermayer --- libavformat/jvdec.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libavformat/jvdec.c b/libavformat/jvdec.c index 64d31e0ee6..103507df4c 100644 --- a/libavformat/jvdec.c +++ b/libavformat/jvdec.c @@ -54,7 +54,7 @@ typedef struct JVDemuxContext { static int read_probe(AVProbeData *pd) { - if (pd->buf[0] == 'J' && pd->buf[1] == 'V' && strlen(MAGIC) <= pd->buf_size - 4 && + if (pd->buf[0] == 'J' && pd->buf[1] == 'V' && strlen(MAGIC) + 4 <= pd->buf_size && !memcmp(pd->buf + 4, MAGIC, strlen(MAGIC))) return AVPROBE_SCORE_MAX; return 0;