[FFmpeg-devel] [PATCH 4/5] avformat/vividas: Check n_sb_blocks against input space
Michael Niedermayer
michael at niedermayer.cc
Wed Sep 4 19:04:57 EEST 2019
Fixes: OOM
Fixes: 16726/clusterfuzz-testcase-minimized-ffmpeg_DEMUXER_fuzzer-5719320750981120
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
---
libavformat/vividas.c | 17 +++++++++++++----
1 file changed, 13 insertions(+), 4 deletions(-)
diff --git a/libavformat/vividas.c b/libavformat/vividas.c
index 645e322b6e..7ccec85761 100644
--- a/libavformat/vividas.c
+++ b/libavformat/vividas.c
@@ -420,7 +420,7 @@ static int track_header(VividasDemuxContext *viv, AVFormatContext *s, uint8_t *
return 0;
}
-static void track_index(VividasDemuxContext *viv, AVFormatContext *s, uint8_t *buf, unsigned size)
+static int track_index(VividasDemuxContext *viv, AVFormatContext *s, uint8_t *buf, unsigned size)
{
int64_t off;
int64_t poff;
@@ -430,16 +430,21 @@ static void track_index(VividasDemuxContext *viv, AVFormatContext *s, uint8_t *b
pb = avio_alloc_context(buf, size, 0, NULL, NULL, NULL, NULL);
if (!pb)
- return;
+ return AVERROR(ENOMEM);
ffio_read_varlen(pb); // track_index_len
avio_r8(pb); // 'c'
viv->n_sb_blocks = ffio_read_varlen(pb);
+ if (viv->n_sb_blocks * 2 > size) {
+ viv->n_sb_blocks = 0;
+ av_free(pb);
+ return AVERROR_INVALIDDATA;
+ }
viv->sb_blocks = av_calloc(viv->n_sb_blocks, sizeof(VIV_SB_block));
if (!viv->sb_blocks) {
viv->n_sb_blocks = 0;
av_free(pb);
- return;
+ return AVERROR(ENOMEM);
}
off = 0;
@@ -462,6 +467,8 @@ static void track_index(VividasDemuxContext *viv, AVFormatContext *s, uint8_t *b
viv->sb_entries = av_calloc(maxnp, sizeof(VIV_SB_entry));
av_free(pb);
+
+ return 0;
}
static void load_sb_block(AVFormatContext *s, VividasDemuxContext *viv, unsigned expected_size)
@@ -587,8 +594,10 @@ static int viv_read_header(AVFormatContext *s)
buf = read_vblock(pb, &v, key, &k2, v);
if (!buf)
return AVERROR(EIO);
- track_index(viv, s, buf, v);
+ ret = track_index(viv, s, buf, v);
av_free(buf);
+ if (ret < 0)
+ return ret;
viv->sb_offset = avio_tell(pb);
if (viv->n_sb_blocks > 0) {
--
2.23.0
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