malloc padding to avoid reading past the malloc()ed area.

Credits to Mikulas Patocka (mikulas at artax karlin mff cuni cz)

Originally committed as revision 4748 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/ogg.c

@@ -216,6 +216,7 @@ static int ogg_read_header(AVFormatContext *avfcontext, AVFormatParameters *ap)
             return -1;
         codec->extradata_size+= 2 + op.bytes;
         codec->extradata= av_realloc(codec->extradata, codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);
+        memset(codec->extradata + codec->extradata_size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
         p= codec->extradata + codec->extradata_size - 2 - op.bytes;
         *(p++)= op.bytes>>8;
         *(p++)= op.bytes&0xFF;

libavformat/rm.c

@@ -557,7 +557,7 @@ static void rm_read_audio_stream_info(AVFormatContext *s, AVStream *st,
             codecdata_length = get_be32(pb);
             st->codec->codec_id = CODEC_ID_COOK;
             st->codec->extradata_size= codecdata_length;
-            st->codec->extradata= av_mallocz(st->codec->extradata_size);
+            st->codec->extradata= av_mallocz(st->codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);
             for(i = 0; i < codecdata_length; i++)
                 ((uint8_t*)st->codec->extradata)[i] = get_byte(pb);
             rm->audio_framesize = st->codec->block_align;
@@ -708,7 +708,7 @@ static int rm_read_header(AVFormatContext *s, AVFormatParameters *ap)
                 get_be16(pb);
                 
                 st->codec->extradata_size= codec_data_size - (url_ftell(pb) - codec_pos);
-                st->codec->extradata= av_malloc(st->codec->extradata_size);
+                st->codec->extradata= av_mallocz(st->codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);
                 get_buffer(pb, st->codec->extradata, st->codec->extradata_size);
                 
 //                av_log(NULL, AV_LOG_DEBUG, "fps= %d fps2= %d\n", fps, fps2);

libavformat/sierravmd.c

@@ -137,7 +137,7 @@ static int vmd_read_header(AVFormatContext *s,
     st->codec->width = LE_16(&vmd->vmd_header[12]);
     st->codec->height = LE_16(&vmd->vmd_header[14]);
     st->codec->extradata_size = VMD_HEADER_SIZE;
-    st->codec->extradata = av_malloc(VMD_HEADER_SIZE);
+    st->codec->extradata = av_mallocz(VMD_HEADER_SIZE + FF_INPUT_BUFFER_PADDING_SIZE);
     memcpy(st->codec->extradata, vmd->vmd_header, VMD_HEADER_SIZE);
 
     /* if sample rate is 0, assume no audio */

libavformat/westwood.c

@@ -231,7 +231,7 @@ static int wsvqa_read_header(AVFormatContext *s,
 
     /* the VQA header needs to go to the decoder */
     st->codec->extradata_size = VQA_HEADER_SIZE;
-    st->codec->extradata = av_malloc(VQA_HEADER_SIZE);
+    st->codec->extradata = av_mallocz(VQA_HEADER_SIZE + FF_INPUT_BUFFER_PADDING_SIZE);
     header = (unsigned char *)st->codec->extradata;
     if (get_buffer(pb, st->codec->extradata, VQA_HEADER_SIZE) !=
         VQA_HEADER_SIZE) {