mjpegdec: Properly fail on malloc failure

Signed-off-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>
Signed-off-by: Anton Khirnov <anton@khirnov.net>

libavcodec/mjpegdec.c

@@ -1327,9 +1327,11 @@ static int mjpeg_decode_com(MJpegDecodeContext *s)
 {
     int len = get_bits(&s->gb, 16);
     if (len >= 2 && 8 * len - 16 <= get_bits_left(&s->gb)) {
-        char *cbuf = av_malloc(len - 1);
-        if (cbuf) {
         int i;
+        char *cbuf = av_malloc(len - 1);
+        if (!cbuf)
+            return AVERROR(ENOMEM);
+
         for (i = 0; i < len - 2; i++)
             cbuf[i] = get_bits(&s->gb, 8);
         if (i > 0 && cbuf[i - 1] == '\n')
@@ -1351,7 +1353,6 @@ static int mjpeg_decode_com(MJpegDecodeContext *s)
 
         av_free(cbuf);
     }
-    }
 
     return 0;
 }
@@ -1525,8 +1526,11 @@ int ff_mjpeg_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
         else if (start_code >= APP0 && start_code <= APP15)
             mjpeg_decode_app(s);
             /* Comment */
-        else if (start_code == COM)
-            mjpeg_decode_com(s);
+        else if (start_code == COM) {
+            ret = mjpeg_decode_com(s);
+            if (ret < 0)
+                return ret;
+        }
 
         if (!CONFIG_JPEGLS_DECODER &&
             (start_code == SOF48 || start_code == LSE)) {