avcodec/hevc_ps: Fix integer overflow with num_tile_rows and num_tile_columns

Fixes: signed integer overflow: -2147483648 - 1 cannot be represented in type 'int'
Fixes: 14880/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_HEVC_fuzzer-5130977304641536

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

libavcodec/hevc_ps.c

@@ -1584,22 +1584,25 @@ int ff_hevc_decode_nal_pps(GetBitContext *gb, AVCodecContext *avctx,
     pps->entropy_coding_sync_enabled_flag = get_bits1(gb);
 
     if (pps->tiles_enabled_flag) {
-        pps->num_tile_columns = get_ue_golomb_long(gb) + 1;
-        pps->num_tile_rows    = get_ue_golomb_long(gb) + 1;
-        if (pps->num_tile_columns <= 0 ||
-            pps->num_tile_columns >= sps->width) {
+        int num_tile_columns_minus1 = get_ue_golomb(gb);
+        int num_tile_rows_minus1    = get_ue_golomb(gb);
+
+        if (num_tile_columns_minus1 < 0 ||
+            num_tile_columns_minus1 >= sps->width - 1) {
             av_log(avctx, AV_LOG_ERROR, "num_tile_columns_minus1 out of range: %d\n",
-                   pps->num_tile_columns - 1);
-            ret = AVERROR_INVALIDDATA;
+                   num_tile_columns_minus1);
+            ret = num_tile_columns_minus1 < 0 ? num_tile_columns_minus1 : AVERROR_INVALIDDATA;
             goto err;
         }
-        if (pps->num_tile_rows <= 0 ||
-            pps->num_tile_rows >= sps->height) {
+        if (num_tile_rows_minus1 < 0 ||
+            num_tile_rows_minus1 >= sps->height - 1) {
             av_log(avctx, AV_LOG_ERROR, "num_tile_rows_minus1 out of range: %d\n",
-                   pps->num_tile_rows - 1);
-            ret = AVERROR_INVALIDDATA;
+                   num_tile_rows_minus1);
+            ret = num_tile_rows_minus1 < 0 ? num_tile_rows_minus1 : AVERROR_INVALIDDATA;
             goto err;
         }
+        pps->num_tile_columns = num_tile_columns_minus1 + 1;
+        pps->num_tile_rows    = num_tile_rows_minus1    + 1;
 
         pps->column_width = av_malloc_array(pps->num_tile_columns, sizeof(*pps->column_width));
         pps->row_height   = av_malloc_array(pps->num_tile_rows,    sizeof(*pps->row_height));

libavcodec/hevc_ps.h

@@ -347,8 +347,8 @@ typedef struct HEVCPPS {
     uint8_t tiles_enabled_flag;
     uint8_t entropy_coding_sync_enabled_flag;
 
-    int num_tile_columns;   ///< num_tile_columns_minus1 + 1
-    int num_tile_rows;      ///< num_tile_rows_minus1 + 1
+    uint16_t num_tile_columns;   ///< num_tile_columns_minus1 + 1
+    uint16_t num_tile_rows;      ///< num_tile_rows_minus1 + 1
     uint8_t uniform_spacing_flag;
     uint8_t loop_filter_across_tiles_enabled_flag;