Check mp3 header before calling avpriv_mpegaudio_decode_header().

As indicated in the function documentation, the header MUST be
checked prior to calling it because no consistency check is done
there.

CC:libav-stable@libav.org

1 files changed, 7 insertions, 1 deletions

diff --git a/libavcodec/libmp3lame.c b/libavcodec/libmp3lame.c
index eebc65c44d..dee1909609 100644
--- a/libavcodec/libmp3lame.c
+++ b/libavcodec/libmp3lame.c
@@ -182,6 +182,7 @@ static int mp3lame_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
     MPADecodeHeader hdr;
     int len, ret, ch;
     int lame_result;
+    uint32_t h;
 
     if (frame) {
         switch (avctx->sample_fmt) {
@@ -237,7 +238,12 @@ static int mp3lame_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
        determine the frame size. */
     if (s->buffer_index < 4)
         return 0;
-    if (avpriv_mpegaudio_decode_header(&hdr, AV_RB32(s->buffer))) {
+    h = AV_RB32(s->buffer);
+    if (ff_mpa_check_header(h) < 0) {
+        av_log(avctx, AV_LOG_ERROR, "Invalid mp3 header at start of buffer\n");
+        return AVERROR_BUG;
+    }
+    if (avpriv_mpegaudio_decode_header(&hdr, h)) {
         av_log(avctx, AV_LOG_ERROR, "free format output not supported\n");
         return -1;
     }