Files
opencv-MIRROR/modules/imgcodecs/test/test_sunraster.cpp
pbkx 32080eb949 Merge pull request #29894 from pbkx:fix-sunras-encoding-checks
imgcodecs: fix Sun Raster encoding checks 🤖🤖🤖 - #29894

SunRasterDecoder saves the header's ras_type field in m_encoding but several validation and decoding checks compared RAS_BYTE_ENCODED and RAS_FORMAT_RGB against m_type. This caused valid byte-encoded and RGB-format Sun Raster images to be rejected before their existing decoding paths could be used.

This patch uses the file encoding to make these decisions and limits byte encoding to 8-bit input and RGB-format input to the supported 24- and 32-bit paths. It also selects channel conversion from the file and requested output orders and avoids indexed-palette conversion when decoding truecolor inputs as grayscale.

The regression tests use Sun Raster files written by Netpbm's `pnmtorast -rle` and ImageMagick's SUN encoder. The matching `opencv_extra` PR (opencv/opencv_extra#1408) contains these files and lets them be inspected independently with compatible image viewers. The tests verify exact RLE literal and run values, truncated RLE input, 24- and 32-bit RGB-format input, BGR and RGB output, and grayscale conversion.

The Netpbm file also exposed an existing row-padding error in the RLE path: the decoder consumed a padding byte after even-width rows, although those rows require no padding. The patch now consumes that byte only for odd-width rows.

No public API is changed.

### Pull Request Readiness Checklist

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [x] The PR is proposed to the proper branch
- [ ] There is a reference to the original bug report and related work
- [x] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
      Patch to opencv_extra has the same branch name.
- [ ] The feature is well documented and sample code can be built with the project CMake
2026-09-11 08:56:54 +03:00

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// This file is part of OpenCV project.
// It is subject to the license terms in the LICENSE file found in the top-level directory
// of this distribution and at http://opencv.org/license.html
// Regression tests for the Sun Raster decoder (grfmt_sunras.cpp).
// These tests guard against:
// - UBSan "load of invalid enum value" in SunRasterDecoder::readHeader()
// (see https://github.com/opencv/opencv/issues/29150)
// - Out-of-range SunRasType / SunRasMapType values causing UB via unchecked C-cast
#include "test_precomp.hpp"
#include <fstream>
#include <iterator>
#include <vector>
namespace opencv_test { namespace {
// ---------------------------------------------------------------------------
// Helper: build a minimal Sun Raster byte buffer with caller-supplied fields.
// Sun Raster header layout (all fields big-endian, 32-bit):
// [0] magic = 0x59a66a95
// [4] width
// [8] height
// [12] depth (bits-per-pixel)
// [16] length (image data length, may be 0 for RAS_OLD)
// [20] ras_type (SunRasType)
// [24] maptype (SunRasMapType)
// [28] maplength
// ---------------------------------------------------------------------------
static std::vector<uint8_t> makeSunRasHeader(
uint32_t width, uint32_t height, uint32_t depth,
uint32_t length, uint32_t ras_type, uint32_t maptype, uint32_t maplength)
{
std::vector<uint8_t> buf(32);
auto put32 = [&](size_t off, uint32_t v) {
buf[off+0] = (v >> 24) & 0xff;
buf[off+1] = (v >> 16) & 0xff;
buf[off+2] = (v >> 8) & 0xff;
buf[off+3] = (v ) & 0xff;
};
put32( 0, 0x59a66a95u); // magic
put32( 4, width);
put32( 8, height);
put32(12, depth);
put32(16, length);
put32(20, ras_type);
put32(24, maptype);
put32(28, maplength);
return buf;
}
// ---------------------------------------------------------------------------
// Crash / UBSan regression — issue #29150
// Feeding an invalid maptype value (34077 / 0x851d) must NOT trigger UB;
// imdecode must return an empty Mat gracefully.
// ---------------------------------------------------------------------------
TEST(Imgcodecs_SunRaster, invalid_maptype_returns_empty_29150)
{
// Crafted header from the original bug report:
// magic=0x59a66a95, width=0x10101, height=0x10000, depth=1, length=0x1000000
// ras_type=0 (RAS_OLD, valid), maptype=0x851d (34077, INVALID)
const std::vector<uint8_t> image_data = {
0x59,0xa6,0x6a,0x95, 0x01,0x01,0x00,0x00,
0x00,0x01,0x00,0x00, 0x00,0x00,0x00,0x01,
0x01,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,
0x00,0x00,0x85,0x1d, 0xae,0x5b,0x8d,0xd5,
0x9c,0x25,0x22,0x41, 0x51,0x92,0x13,0x14,0x33
};
cv::Mat result;
ASSERT_NO_THROW(result = cv::imdecode(image_data, cv::IMREAD_REDUCED_GRAYSCALE_2));
EXPECT_TRUE(result.empty()) << "imdecode must return empty Mat for invalid maptype";
}
// Invalid ras_type (value well outside [0,3]) must be rejected cleanly.
TEST(Imgcodecs_SunRaster, invalid_rastype_returns_empty)
{
auto buf = makeSunRasHeader(/*w*/8, /*h*/8, /*depth*/8,
/*len*/0, /*ras_type*/0xFFFF, /*maptype*/0, /*mapllen*/0);
cv::Mat result;
ASSERT_NO_THROW(result = cv::imdecode(buf, cv::IMREAD_GRAYSCALE));
EXPECT_TRUE(result.empty()) << "imdecode must return empty Mat for invalid ras_type";
}
// maptype = 2 is outside [0,1] (only RMT_NONE=0, RMT_EQUAL_RGB=1 are defined).
TEST(Imgcodecs_SunRaster, maptype_2_returns_empty)
{
auto buf = makeSunRasHeader(8, 8, 8, 0, /*ras_type*/0, /*maptype*/2, 0);
cv::Mat result;
ASSERT_NO_THROW(result = cv::imdecode(buf, cv::IMREAD_GRAYSCALE));
EXPECT_TRUE(result.empty()) << "imdecode must return empty Mat for maptype=2";
}
// maptype = UINT32_MAX is also invalid.
TEST(Imgcodecs_SunRaster, maptype_max_returns_empty)
{
auto buf = makeSunRasHeader(8, 8, 8, 0, 0, 0xFFFFFFFFu, 0);
cv::Mat result;
ASSERT_NO_THROW(result = cv::imdecode(buf, cv::IMREAD_GRAYSCALE));
EXPECT_TRUE(result.empty()) << "imdecode must return empty Mat for maptype=UINT_MAX";
}
// A truncated buffer (shorter than the 32-byte header) must not crash.
TEST(Imgcodecs_SunRaster, truncated_header_returns_empty)
{
// Only 16 bytes — header read will run out of data.
const std::vector<uint8_t> buf = {
0x59,0xa6,0x6a,0x95, 0x00,0x00,0x00,0x08,
0x00,0x00,0x00,0x08, 0x00,0x00,0x00,0x08
};
cv::Mat result;
ASSERT_NO_THROW(result = cv::imdecode(buf, cv::IMREAD_GRAYSCALE));
EXPECT_TRUE(result.empty()) << "imdecode must return empty Mat for truncated header";
}
// ---------------------------------------------------------------------------
// Sanity: a well-formed 8-bpp grayscale Sun Raster (RMT_NONE) still decodes.
// We build the full header + pixel data manually so the test has no file I/O.
// ---------------------------------------------------------------------------
TEST(Imgcodecs_SunRaster, valid_8bpp_grayscale_decodes)
{
const int W = 4, H = 4;
// RAS_OLD(0), maptype=RMT_NONE(0), maplength=0
auto buf = makeSunRasHeader(W, H, 8, W*H, 0, 0, 0);
// Sun Raster rows are padded to 16-bit boundary.
// W=4: row_bytes = 4 (already even), no padding needed.
for (int i = 0; i < W * H; ++i)
buf.push_back(static_cast<uint8_t>(i * 16)); // arbitrary gray values
cv::Mat result;
ASSERT_NO_THROW(result = cv::imdecode(buf, cv::IMREAD_GRAYSCALE));
EXPECT_FALSE(result.empty()) << "imdecode must succeed for a valid 8-bpp Sun Raster";
EXPECT_EQ(result.cols, W);
EXPECT_EQ(result.rows, H);
EXPECT_EQ(result.type(), CV_8UC1);
}
TEST(Imgcodecs_SunRaster, byte_encoded_8bpp_decodes)
{
// Generated with Netpbm's pnmtorast -rle.
const String filename = findDataFile("readwrite/sunraster/byte_encoded_8bpp.ras");
uint8_t expected_data[][16] = {
{ 0x11, 0x80, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44,
0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44 },
{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff },
{ 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,
0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff },
{ 0x20, 0x20, 0x40, 0x40, 0x60, 0x60, 0x80, 0x80,
0xa0, 0xa0, 0xc0, 0xc0, 0xe0, 0xe0, 0xff, 0xff },
{ 0x33, 0x33, 0x33, 0x33, 0x33, 0x33, 0x33, 0x33,
0x33, 0x33, 0x33, 0x33, 0x33, 0x33, 0x33, 0x33 },
{ 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66,
0x66, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66 },
{ 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99,
0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99 },
{ 0xcc, 0xcc, 0xcc, 0xcc, 0xcc, 0xcc, 0xcc, 0xcc,
0xcc, 0xcc, 0xcc, 0xcc, 0xcc, 0xcc, 0xcc, 0xcc }
};
const cv::Mat expected(8, 16, CV_8UC1, expected_data);
cv::Mat result;
ASSERT_NO_THROW(result = cv::imread(filename, cv::IMREAD_GRAYSCALE));
ASSERT_FALSE(result.empty());
ASSERT_EQ(expected.size(), result.size());
ASSERT_EQ(expected.type(), result.type());
EXPECT_EQ(0, cv::norm(expected, result, cv::NORM_INF));
}
TEST(Imgcodecs_SunRaster, truncated_byte_encoded_8bpp_returns_empty)
{
const String filename = findDataFile("readwrite/sunraster/byte_encoded_8bpp.ras");
std::ifstream stream(filename.c_str(), std::ios::binary);
ASSERT_TRUE(stream.is_open());
std::vector<uint8_t> buf((std::istreambuf_iterator<char>(stream)),
std::istreambuf_iterator<char>());
const size_t incompleteRleSize = 32 + 3 * 256 + 2;
ASSERT_GT(buf.size(), incompleteRleSize);
buf.resize(incompleteRleSize); // Keep an incomplete RLE escape after the color map.
cv::Mat result;
ASSERT_NO_THROW(result = cv::imdecode(buf, cv::IMREAD_GRAYSCALE));
EXPECT_TRUE(result.empty());
}
typedef tuple<string, int> SunRasterColorParams;
typedef testing::TestWithParam<SunRasterColorParams> Imgcodecs_SunRaster_Color;
TEST_P(Imgcodecs_SunRaster_Color, decodes)
{
const String filename = findDataFile(get<0>(GetParam()));
const int flags = get<1>(GetParam());
uint8_t bgr_data[] = {
30, 20, 10, 60, 50, 40, 0, 0, 255, 0, 255, 0,
255, 0, 0, 0, 255, 255, 255, 0, 255, 255, 255, 0
};
uint8_t rgb_data[] = {
10, 20, 30, 40, 50, 60, 255, 0, 0, 0, 255, 0,
0, 0, 255, 255, 255, 0, 255, 0, 255, 0, 255, 255
};
uint8_t gray_data[] = { 18, 48, 76, 150, 29, 226, 105, 179 };
cv::Mat expected;
if( flags == cv::IMREAD_COLOR )
expected = cv::Mat(2, 4, CV_8UC3, bgr_data);
else if( flags == cv::IMREAD_COLOR_RGB )
expected = cv::Mat(2, 4, CV_8UC3, rgb_data);
else
expected = cv::Mat(2, 4, CV_8UC1, gray_data);
cv::Mat result;
ASSERT_NO_THROW(result = cv::imread(filename, flags));
ASSERT_FALSE(result.empty());
ASSERT_EQ(expected.size(), result.size());
ASSERT_EQ(expected.type(), result.type());
EXPECT_EQ(0, cv::norm(expected, result, cv::NORM_INF));
}
// Generated with ImageMagick's SUN encoder.
INSTANTIATE_TEST_CASE_P(RgbFormat, Imgcodecs_SunRaster_Color,
testing::Combine(
testing::Values(
"readwrite/sunraster/rgb_format_24bpp.ras",
"readwrite/sunraster/rgb_format_32bpp.ras"),
testing::Values(
cv::IMREAD_COLOR,
cv::IMREAD_COLOR_RGB,
cv::IMREAD_GRAYSCALE)));
}} // namespace opencv_test