Fix buffer overflow vulernability in thumbnail file reading.
[blender.git] / source / blender / blenloader / intern / readfile.c
index 40b53d4c684b2b02da04e55a264936df3545bc26..51b77938dea5ef14b959ca2bbcffdc81806f9cc0 100644 (file)
@@ -982,7 +982,13 @@ static int *read_file_thumbnail(FileData *fd)
                                BLI_endian_switch_int32(&data[1]);
                        }
 
-                       if (bhead->len < BLEN_THUMB_MEMSIZE_FILE(data[0], data[1])) {
+                       int width = data[0];
+                       int height = data[1];
+
+                       if (!BLEN_THUMB_SAFE_MEMSIZE(width, height)) {
+                               break;
+                       }
+                       if (bhead->len < BLEN_THUMB_MEMSIZE_FILE(width, height)) {
                                break;
                        }
 
@@ -1421,23 +1427,28 @@ bool BLO_library_path_explode(const char *path, char *r_dir, char **r_group, cha
 BlendThumbnail *BLO_thumbnail_from_file(const char *filepath)
 {
        FileData *fd;
-       BlendThumbnail *data;
+       BlendThumbnail *data = NULL;
        int *fd_data;
 
        fd = blo_openblenderfile_minimal(filepath);
        fd_data = fd ? read_file_thumbnail(fd) : NULL;
 
        if (fd_data) {
-               const size_t sz = BLEN_THUMB_MEMSIZE(fd_data[0], fd_data[1]);
-               data = MEM_mallocN(sz, __func__);
+               int width = fd_data[0];
+               int height = fd_data[1];
 
-               BLI_assert((sz - sizeof(*data)) == (BLEN_THUMB_MEMSIZE_FILE(fd_data[0], fd_data[1]) - (sizeof(*fd_data) * 2)));
-               data->width = fd_data[0];
-               data->height = fd_data[1];
-               memcpy(data->rect, &fd_data[2], sz - sizeof(*data));
-       }
-       else {
-               data = NULL;
+               /* Protect against buffer overflow vulnerability. */
+               if (BLEN_THUMB_SAFE_MEMSIZE(width, height)) {
+                       const size_t sz = BLEN_THUMB_MEMSIZE(width, height);
+                       data = MEM_mallocN(sz, __func__);
+
+                       if (data) {
+                               BLI_assert((sz - sizeof(*data)) == (BLEN_THUMB_MEMSIZE_FILE(width, height) - (sizeof(*fd_data) * 2)));
+                               data->width = width;
+                               data->height = height;
+                               memcpy(data->rect, &fd_data[2], sz - sizeof(*data));
+                       }
+               }
        }
 
        blo_freefiledata(fd);
@@ -8624,14 +8635,20 @@ BlendFileData *blo_read_file_internal(FileData *fd, const char *filepath)
                const int *data = read_file_thumbnail(fd);
 
                if (data) {
-                       const size_t sz = BLEN_THUMB_MEMSIZE(data[0], data[1]);
-                       bfd->main->blen_thumb = MEM_mallocN(sz, __func__);
-
-                       BLI_assert((sz - sizeof(*bfd->main->blen_thumb)) ==
-                                  (BLEN_THUMB_MEMSIZE_FILE(data[0], data[1]) - (sizeof(*data) * 2)));
-                       bfd->main->blen_thumb->width = data[0];
-                       bfd->main->blen_thumb->height = data[1];
-                       memcpy(bfd->main->blen_thumb->rect, &data[2], sz - sizeof(*bfd->main->blen_thumb));
+                       int width = data[0];
+                       int height = data[1];
+
+                       /* Protect against buffer overflow vulnerability. */
+                       if (BLEN_THUMB_SAFE_MEMSIZE(width, height)) {
+                               const size_t sz = BLEN_THUMB_MEMSIZE(width, height);
+                               bfd->main->blen_thumb = MEM_mallocN(sz, __func__);
+
+                               BLI_assert((sz - sizeof(*bfd->main->blen_thumb)) ==
+                                          (BLEN_THUMB_MEMSIZE_FILE(width, height) - (sizeof(*data) * 2)));
+                               bfd->main->blen_thumb->width = width;
+                               bfd->main->blen_thumb->height = height;
+                               memcpy(bfd->main->blen_thumb->rect, &data[2], sz - sizeof(*bfd->main->blen_thumb));
+                       }
                }
        }