Merge "Fix a rare failure for imgdiff when random data equals gzip header" (8542502f) · Commits · e / tools / etwrp

applypatch/imgdiff.cpp

+14 −11

Original line number	Diff line number	Diff line
		@@ -693,6 +693,20 @@ static bool ReadImage(const char* filename, std::vector<ImageChunk>* chunks,
		continue;
		}

		// The footer contains the size of the uncompressed data. Double-check to make sure that it
		// matches the size of the data we got when we actually did the decompression.
		size_t footer_index = pos + raw_data_len + GZIP_FOOTER_LEN - 4;
		if (sz - footer_index < 4) {
		printf("Warning: invalid footer position; treating as a nomal chunk\n");
		continue;
		}
		size_t footer_size = get_unaligned<uint32_t>(img->data() + footer_index);
		if (footer_size != uncompressed_len) {
		printf("Warning: footer size %zu != decompressed size %zu; treating as a nomal chunk\n",
		footer_size, uncompressed_len);
		continue;
		}

		ImageChunk body(CHUNK_DEFLATE, pos, img, raw_data_len);
		uncompressed_data.resize(uncompressed_len);
		body.SetUncompressedData(std::move(uncompressed_data));
		@@ -704,17 +718,6 @@ static bool ReadImage(const char* filename, std::vector<ImageChunk>* chunks,
		chunks->emplace_back(CHUNK_NORMAL, pos, img, GZIP_FOOTER_LEN);

		pos += GZIP_FOOTER_LEN;

		// The footer (that we just skipped over) contains the size of
		// the uncompressed data. Double-check to make sure that it
		// matches the size of the data we got when we actually did
		// the decompression.
		size_t footer_size = get_unaligned<uint32_t>(img->data() + pos - 4);
		if (footer_size != body.DataLengthForPatch()) {
		printf("Error: footer size %zu != decompressed size %zu\n", footer_size,
		body.GetRawDataLength());
		return false;
		}
		} else {
		// Use a normal chunk to take all the contents until the next gzip chunk (or EOF); we expect
		// the number of chunks to be small (5 for typical boot and recovery images).

tests/component/imgdiff_test.cpp

+33 −0

Original line number	Diff line number	Diff line
		@@ -328,6 +328,39 @@ TEST(ImgdiffTest, image_mode_simple) {
		verify_patched_image(src, patch, tgt);
		}

		TEST(ImgdiffTest, image_mode_bad_gzip) {
		// Modify the uncompressed length in the gzip footer.
		const std::vector<char> src_data = { 'a', 'b', 'c', 'd', 'e', 'f', 'g',
		'h', '\x1f', '\x8b', '\x08', '\x00', '\xc4', '\x1e',
		'\x53', '\x58', '\x00', '\x03', '\xab', '\xa8', '\xac',
		'\x02', '\x00', '\x67', '\xba', '\x8e', '\xeb', '\x03',
		'\xff', '\xff', '\xff' };
		const std::string src(src_data.cbegin(), src_data.cend());
		TemporaryFile src_file;
		ASSERT_TRUE(android::base::WriteStringToFile(src, src_file.path));

		// Modify the uncompressed length in the gzip footer.
		const std::vector<char> tgt_data = {
		'a', 'b', 'c', 'd', 'e', 'f', 'g', 'x', 'y', 'z', '\x1f', '\x8b',
		'\x08', '\x00', '\x62', '\x1f', '\x53', '\x58', '\x00', '\x03', '\xab', '\xa8', '\xa8', '\xac',
		'\xac', '\xaa', '\x02', '\x00', '\x96', '\x30', '\x06', '\xb7', '\x06', '\xff', '\xff', '\xff'
		};
		const std::string tgt(tgt_data.cbegin(), tgt_data.cend());
		TemporaryFile tgt_file;
		ASSERT_TRUE(android::base::WriteStringToFile(tgt, tgt_file.path));

		TemporaryFile patch_file;
		std::vector<const char*> args = {
		"imgdiff", src_file.path, tgt_file.path, patch_file.path,
		};
		ASSERT_EQ(0, imgdiff(args.size(), args.data()));

		// Verify.
		std::string patch;
		ASSERT_TRUE(android::base::ReadFileToString(patch_file.path, &patch));
		verify_patched_image(src, patch, tgt);
		}

		TEST(ImgdiffTest, image_mode_different_num_chunks) {
		// src: "abcdefgh" + gzipped "xyz" (echo -n "xyz" \| gzip -f \| hd) + gzipped "test".
		const std::vector<char> src_data = {