diff mbox series

[FFmpeg-devel,5/6] avformat/flvdec: Check for nesting depth in amf_skip_tag()

Message ID 20210123221056.3366-5-michael@niedermayer.cc
State Accepted
Commit 2ef522c918d48b9f101548b2cadce02003cb3510
Headers show
Series [FFmpeg-devel,1/6] avutil/common: Add FFABSU() for a signed -> unsigned ABS
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Commit Message

Michael Niedermayer Jan. 23, 2021, 10:10 p.m. UTC
Fixes: out of array access
Fixes: 29440/clusterfuzz-testcase-minimized-ffmpeg_dem_KUX_fuzzer-5985279812960256.fuzz

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavformat/flvdec.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

Comments

Michael Niedermayer Jan. 26, 2021, 4:18 p.m. UTC | #1
On Sat, Jan 23, 2021 at 11:10:55PM +0100, Michael Niedermayer wrote:
> Fixes: out of array access
> Fixes: 29440/clusterfuzz-testcase-minimized-ffmpeg_dem_KUX_fuzzer-5985279812960256.fuzz
> 
> Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> ---
>  libavformat/flvdec.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)

will apply

[...]
diff mbox series

Patch

diff --git a/libavformat/flvdec.c b/libavformat/flvdec.c
index e15be0a221..4bc5e15dd2 100644
--- a/libavformat/flvdec.c
+++ b/libavformat/flvdec.c
@@ -842,10 +842,13 @@  static void clear_index_entries(AVFormatContext *s, int64_t pos)
     }
 }
 
-static int amf_skip_tag(AVIOContext *pb, AMFDataType type)
+static int amf_skip_tag(AVIOContext *pb, AMFDataType type, int depth)
 {
     int nb = -1, ret, parse_name = 1;
 
+    if (depth > MAX_DEPTH)
+        return AVERROR_PATCHWELCOME;
+
     switch (type) {
     case AMF_DATA_TYPE_NUMBER:
         avio_skip(pb, 8);
@@ -870,7 +873,7 @@  static int amf_skip_tag(AVIOContext *pb, AMFDataType type)
                 }
                 avio_skip(pb, size);
             }
-            if ((ret = amf_skip_tag(pb, avio_r8(pb))) < 0)
+            if ((ret = amf_skip_tag(pb, avio_r8(pb), depth + 1)) < 0)
                 return ret;
         }
         break;
@@ -914,7 +917,7 @@  static int flv_data_packet(AVFormatContext *s, AVPacket *pkt,
             else
                 break;
         } else {
-            if ((ret = amf_skip_tag(pb, type)) < 0)
+            if ((ret = amf_skip_tag(pb, type, 0)) < 0)
                 goto skip;
         }
     }