avcodec/targa: Check input size for uncompressed TGA before allocation

Fixes: Timeout
Fixes: 42667/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_TARGA_fuzzer-5619236075077632

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/targa.c

@@ -117,6 +117,7 @@ static int decode_frame(AVCodecContext *avctx,
     int idlen, pal, compr, y, w, h, bpp, flags, ret;
     int first_clr, colors, csize;
     int interleave;
+    size_t img_size;
 
     bytestream2_init(&s->gb, avpkt->data, avpkt->size);
 
@@ -180,6 +181,15 @@ static int decode_frame(AVCodecContext *avctx,
         return avpkt->size;
     }
 
+    if (!(compr & TGA_RLE)) {
+        img_size = w * ((bpp + 1) >> 3);
+        if (bytestream2_get_bytes_left(&s->gb) < img_size * h) {
+            av_log(avctx, AV_LOG_ERROR,
+                    "Not enough data available for image\n");
+            return AVERROR_INVALIDDATA;
+        }
+    }
+
     if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
         return ret;
     p->pict_type = AV_PICTURE_TYPE_I;
@@ -251,7 +261,6 @@ static int decode_frame(AVCodecContext *avctx,
             if (res < 0)
                 return res;
         } else {
-            size_t img_size = w * ((bpp + 1) >> 3);
             uint8_t *line;
             if (bytestream2_get_bytes_left(&s->gb) < img_size * h) {
                 av_log(avctx, AV_LOG_ERROR,