From b32d031762bc49d8d076d36c4a8c60fa175a94dc Mon Sep 17 00:00:00 2001 From: Carl Hetherington Date: Mon, 4 Nov 2019 12:04:30 +0100 Subject: Fix out-of-bounds read when cropping JPEG2000 images (#1654). Backported from 25d968fdcf1abada4bd7bbcb8c72eeebda73b134 in v2.15.x. --- src/lib/j2k_image_proxy.cc | 8 +++++++- test/image_test.cc | 9 +++++++++ 2 files changed, 16 insertions(+), 1 deletion(-) diff --git a/src/lib/j2k_image_proxy.cc b/src/lib/j2k_image_proxy.cc index 9893d65a6..d4c7a8716 100644 --- a/src/lib/j2k_image_proxy.cc +++ b/src/lib/j2k_image_proxy.cc @@ -138,7 +138,13 @@ J2KImageProxy::prepare (optional target_size) const shared_ptr decompressed = dcp::decompress_j2k (const_cast (_data.data().get()), _data.size (), reduce); - _image.reset (new Image (_pixel_format, decompressed->size(), true)); + /* When scaling JPEG2000 images (using AV_PIX_FMT_XYZ12LE) ffmpeg will call xyz12ToRgb48 which reads data + from the whole of the image stride. If we are cropping, Image::crop_scale_window munges the + start addresses of each image row (to do the crop) but keeps the stride the same. This means + that under crop we will read over the end of the image by the amount of the crop. To allow this + to happen without invalid memory access we need to overallocate by one whole stride's worth of pixels. + */ + _image.reset (new Image (_pixel_format, decompressed->size(), true, decompressed->size().width)); int const shift = 16 - decompressed->precision (0); diff --git a/test/image_test.cc b/test/image_test.cc index 8a7feb126..40abfda43 100644 --- a/test/image_test.cc +++ b/test/image_test.cc @@ -267,6 +267,15 @@ BOOST_AUTO_TEST_CASE (crop_scale_window_test) check_image("test/data/crop_scale_window_test.png", "build/test/crop_scale_window_test.png"); } +/** Special cases of Image::crop_scale_window which triggered some valgrind warnings */ +BOOST_AUTO_TEST_CASE (crop_scale_window_test2) +{ + /* This 2048 does the same as J2KImageProxy does when it makes an image */ + shared_ptr image (new Image(AV_PIX_FMT_XYZ12LE, dcp::Size(2048, 858), true, 2048)); + image->crop_scale_window (Crop(279, 0, 0, 0), dcp::Size(1069, 448), dcp::Size(1069, 578), dcp::YUV_TO_RGB_REC709, VIDEO_RANGE_FULL, AV_PIX_FMT_RGB24, false, false); + image->crop_scale_window (Crop(2048, 0, 0, 0), dcp::Size(1069, 448), dcp::Size(1069, 578), dcp::YUV_TO_RGB_REC709, VIDEO_RANGE_FULL, AV_PIX_FMT_RGB24, false, false); +} + BOOST_AUTO_TEST_CASE (as_png_test) { shared_ptr proxy(new FFmpegImageProxy("test/data/3d_test/000001.png")); -- cgit v1.2.3