avcodec/alac: Fix integer overflow with 24/20bps samples

Fixes: signed integer overflow: 1020048 * 4096 cannot be represented in type 'int'
Fixes: 20492/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_ALAC_fuzzer-5753877751660544
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index c8c04223a0616d8be0b9f9d7924cb0534954b35b..82689da02a2f12f2ffdd005a3521a49447c3cd37 100644 (file)
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -397,13 +397,13 @@ static int decode_element(AVCodecContext *avctx, AVFrame *frame, int ch_index,
     case 20: {
         for (ch = 0; ch < channels; ch++) {
             for (i = 0; i < alac->nb_samples; i++)
-                alac->output_samples_buffer[ch][i] *= 1 << 12;
+                alac->output_samples_buffer[ch][i] *= 1U << 12;
         }}
         break;
     case 24: {
         for (ch = 0; ch < channels; ch++) {
             for (i = 0; i < alac->nb_samples; i++)
-                alac->output_samples_buffer[ch][i] *= 1 << 8;
+                alac->output_samples_buffer[ch][i] *= 1U << 8;
         }}
         break;
     }