From abec6549ae1e86fdf89dbab8a8abca8eb7205c6e Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Sun, 22 Apr 2012 13:56:07 +0200 Subject: [PATCH] ffv1dec: Require a valid keyframe for decoding non keyframes. Before this the context could become inconsistent, this lead to a null ptr dereference. Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind Signed-off-by: Michael Niedermayer --- libavcodec/ffv1.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/libavcodec/ffv1.c b/libavcodec/ffv1.c index 491b3f5d32..ac37216c7d 100644 --- a/libavcodec/ffv1.c +++ b/libavcodec/ffv1.c @@ -193,6 +193,7 @@ typedef struct FFV1Context{ int gob_count; int packed_at_lsb; int ec; + int key_frame_ok; int quant_table_count; @@ -1945,11 +1946,17 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPac p->pict_type= AV_PICTURE_TYPE_I; //FIXME I vs. P if(get_rac(c, &keystate)){ p->key_frame= 1; + f->key_frame_ok = 0; if(read_header(f) < 0) return -1; if(init_slices_state(f) < 0) return -1; + f->key_frame_ok = 1; }else{ + if (!f->key_frame_ok) { + av_log(avctx, AV_LOG_ERROR, "Cant decode non keyframe without valid keyframe\n"); + return AVERROR_INVALIDDATA; + } p->key_frame= 0; } if(f->ac>1){