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imgcodecs: add test to decode a corrupted APNG

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This commit is contained in:
Kumataro 2025-09-13 06:46:53 +09:00
parent 5b1d325530
commit fac647aaeb
1 changed files with 45 additions and 0 deletions
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45
modules/imgcodecs/test/test_png.cpp
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@ -157,6 +157,51 @@ TEST(Imgcodecs_Png, decode_regression27295)
EXPECT_TRUE(img.empty());
}
// The program must not crash even when decoding a corrupted APNG image.
// See https://github.com/opencv/opencv/issues/27744
#if defined(HAVE_PNG) // APNG is supported only with using libpng
TEST(Imgcodecs_Png, decode_regression27744)
{
// Create APNG stream
Animation anim;
for(size_t i = 0 ; i < 3 ; i++) {
Mat frame(120, 120, CV_8UC3, Scalar(0,0,0));
putText(frame, cv::format("%d", static_cast<int>(i)), Point(5, 28), FONT_HERSHEY_SIMPLEX, .5, Scalar(100, 255, 0, 255), 2);
anim.frames.push_back(frame);
anim.durations.push_back(30);
}
bool ret = false;
vector<uchar> buff;
EXPECT_NO_THROW(ret = imencodeanimation(".png", anim, buff));
ASSERT_TRUE(ret) << "imencodeanimation() returns false";
// Find IDAT chunk
const vector<uchar> IDAT = {'I', 'D', 'A', 'T' };
std::vector<uchar>::iterator it = std::search(buff.begin(), buff.end(), IDAT.begin(), IDAT.end());
ASSERT_FALSE(it == buff.end()) << "IDAT chunk not found";
// Determine the range to test
// APNG stream contains as { len0, len1, len2, len3, 'I', 'D', 'A' 'T', ... }
size_t idx = std::distance(buff.begin(), it); // 'I' position
size_t len = (buff[idx-4] << 24) + (buff[idx-3] << 16) +
(buff[idx-2] << 8) + (buff[idx-1]); // IDAT chunk length
idx = idx + 4; // Move to IDAT body
// Test
for(size_t i = 0; i < len; i++, idx++) {
vector<uint8_t> work = buff;
work[idx] = static_cast<uint8_t>((static_cast<uint32_t>(work[idx]) + 1) & 0xff);
Mat dst;
EXPECT_NO_THROW(dst = imdecode(work, cv::IMREAD_COLOR));
if(dst.empty()) {
// libpng detects some error, but the program is not crashed. Test is passed.
break;
}
}
}
#endif
typedef testing::TestWithParam<string> Imgcodecs_Png_PngSuite;
// Parameterized test for decoding PNG files from the PNGSuite test set