Commit both patches in FS#10833 - Protect against division by zero in AAC (mp4) codec by Juliusz Chroboczek. Adds some return value checking so that faad errors don't crash rockbox when decoding broken or unsupported files.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@23983 a1c6a512-1295-4272-9138-f99709370657

2 files changed, 7 insertions, 6 deletions

diff --git a/apps/codecs/aac.c b/apps/codecs/aac.c
index 6046035..7d706f4 100644
--- a/apps/codecs/aac.c
+++ b/apps/codecs/aac.c
@@ -53,6 +53,7 @@ enum codec_status codec_main(void)
     int err;
     uint32_t s = 0;
     unsigned char c = 0;
+    void *ret;
 
     /* Generic codec initialisation */
     ci->configure(DSP_SET_STEREO_MODE, STEREO_NONINTERLEAVED);
@@ -179,11 +180,10 @@ next_track:
         buffer=ci->request_buffer(&n,sample_byte_size);
 
         /* Decode one block - returned samples will be host-endian */
-        NeAACDecDecode(decoder, &frame_info, buffer, n);
-        /* Ignore return value, we access samples in the decoder struct 
-         * directly.
-         */
-        if (frame_info.error > 0) {
+        ret = NeAACDecDecode(decoder, &frame_info, buffer, n);
+
+        /* NeAACDecDecode may sometimes return NULL without setting error. */
+        if (ret == NULL || frame_info.error > 0) {
             LOGF("FAAD: decode error '%s'\n", NeAACDecGetErrorMessage(frame_info.error));
             err = CODEC_ERROR;
             goto done;
diff --git a/apps/codecs/libm4a/m4a.c b/apps/codecs/libm4a/m4a.c
index f066640..92e619d 100644
--- a/apps/codecs/libm4a/m4a.c
+++ b/apps/codecs/libm4a/m4a.c
@@ -194,7 +194,8 @@ unsigned int get_sample_offset(demux_res_t *demux_res, uint32_t sample)
         prev_chunk_samples = demux_res->sample_to_chunk[i].num_samples;
     }
 
-    if (sample >= demux_res->sample_to_chunk[0].num_samples)
+    if (prev_chunk_samples > 0 &&
+        sample >= demux_res->sample_to_chunk[0].num_samples)
     {
         chunk = prev_chunk + (sample - total_samples) / prev_chunk_samples;
     }