avcodec/pngdec: Check compression method
method 0 (inflate/deflate) is the only specified in the specification and the only supported
Fixes: Timeout
Fixes: 10976/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_PNG_fuzzer-5729372588736512
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit 1f99674ddddcc33f4c37def0a206e31ad7c4c1af)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
diff --git a/libavcodec/pngdec.c b/libavcodec/pngdec.c
index 67a6e3f..e252397 100644
--- a/libavcodec/pngdec.c
+++ b/libavcodec/pngdec.c
@@ -577,6 +577,10 @@
}
s->color_type = bytestream2_get_byte(&s->gb);
s->compression_type = bytestream2_get_byte(&s->gb);
+ if (s->compression_type) {
+ av_log(avctx, AV_LOG_ERROR, "Invalid compression method %d\n", s->compression_type);
+ goto error;
+ }
s->filter_type = bytestream2_get_byte(&s->gb);
s->interlace_type = bytestream2_get_byte(&s->gb);
bytestream2_skip(&s->gb, 4); /* crc */
