The code tries to decode a number of channels at the
offset given by the ff_alac_channel_layout_offsets table.
Even if the number of channels decoded so far doesn't
exceed the total number of channels, we need to check that
we actually can decode that number of channels at this offset
as well.

Reported-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: [email protected]
---
 libavcodec/alac.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index d643dd3..41d1f77 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -418,7 +418,8 @@ static int alac_decode_frame(AVCodecContext *avctx, void 
*data,
         }
 
         channels = (element == TYPE_CPE) ? 2 : 1;
-        if (ch + channels > alac->channels) {
+        if (ch + channels > alac->channels ||
+            ff_alac_channel_layout_offsets[alac->channels - 1][ch] + channels 
> alac->channels) {
             av_log(avctx, AV_LOG_ERROR, "invalid element channel count\n");
             return AVERROR_INVALIDDATA;
         }
-- 
1.7.9.4

_______________________________________________
libav-devel mailing list
[email protected]
https://lists.libav.org/mailman/listinfo/libav-devel

Reply via email to