From c8e8f107bf82fb56f49101e1098f4c697b16cfeb Mon Sep 17 00:00:00 2001 From: Campbell Barton Date: Fri, 15 Jul 2022 14:47:18 +1000 Subject: [PATCH] Fix T99711: Eternal loop reading blend file thumbnail Account for negative BHead length (already handled by blend file loading). --- source/blender/blendthumb/src/blendthumb_extract.cc | 3 +++ 1 file changed, 3 insertions(+) diff --git a/source/blender/blendthumb/src/blendthumb_extract.cc b/source/blender/blendthumb/src/blendthumb_extract.cc index 369da559fc8..163197c8b67 100644 --- a/source/blender/blendthumb/src/blendthumb_extract.cc +++ b/source/blender/blendthumb/src/blendthumb_extract.cc @@ -121,6 +121,9 @@ static eThumbStatus blendthumb_extract_from_file_impl(FileReader *file, while (file_read(file, bhead_data, bhead_size)) { /* Parse type and size from `BHead`. */ const int32_t block_size = bytes_to_native_i32(&bhead_data[4], endian_switch); + if (UNLIKELY(block_size < 0)) { + return BT_INVALID_THUMB; + } /* We're looking for the thumbnail, so skip any other block. */ switch (*((int32_t *)bhead_data)) {