avformat/apngdec: Make sure that extradata is zero-padded

Zeroing the padding has been forgotten. Signed-off-by: Andreas Rheinhardt <[email protected]> Signed-off-by: Michael Niedermayer <[email protected]>
SaschaVasarrhelyi · Dec 12, 2019 · 2e328a8 · 2e328a8
1 parent 56ce2ad
commit 2e328a8
Showing 1 changed file with 5 additions and 5 deletions.
diff --git a/libavformat/apngdec.c b/libavformat/apngdec.c
@@ -127,13 +127,14 @@ static int append_extradata(AVCodecParameters *par, AVIOContext *pb, int len)
     int new_size, ret;
     uint8_t *new_extradata;
 
-    if (previous_size > INT_MAX - len)
+    if (previous_size > INT_MAX - AV_INPUT_BUFFER_PADDING_SIZE - len)
         return AVERROR_INVALIDDATA;
 
     new_size = previous_size + len;
     new_extradata = av_realloc(par->extradata, new_size + AV_INPUT_BUFFER_PADDING_SIZE);
     if (!new_extradata)
         return AVERROR(ENOMEM);
+    memset(new_extradata + new_size, 0, AV_INPUT_BUFFER_PADDING_SIZE);
     par->extradata = new_extradata;
     par->extradata_size = new_size;
 
@@ -177,10 +178,9 @@ static int apng_read_header(AVFormatContext *s)
         return ret;
 
     /* extradata will contain every chunk up to the first fcTL (excluded) */
-    st->codecpar->extradata = av_malloc(len + 12 + AV_INPUT_BUFFER_PADDING_SIZE);
-    if (!st->codecpar->extradata)
-        return AVERROR(ENOMEM);
-    st->codecpar->extradata_size = len + 12;
+    ret = ff_alloc_extradata(st->codecpar, len + 12);
+    if (ret < 0)
+        return ret;
     AV_WB32(st->codecpar->extradata,    len);
     AV_WL32(st->codecpar->extradata+4,  tag);
     AV_WB32(st->codecpar->extradata+8,  st->codecpar->width);