diff options
Diffstat (limited to 'src/utils.cc')
| -rw-r--r-- | src/utils.cc | 26 |
1 files changed, 17 insertions, 9 deletions
diff --git a/src/utils.cc b/src/utils.cc index d0aece0..b9b06c1 100644 --- a/src/utils.cc +++ b/src/utils.cc @@ -7,6 +7,7 @@ #include <inttypes.h> #include <algorithm> +#include <iterator> #include <set> #include <string> #include <vector> @@ -176,16 +177,24 @@ bool LocateDeflatesInZlibBlocks(const string& file_path, return true; } +namespace { // For more information about gzip format, refer to RFC 1952 located at: // https://www.ietf.org/rfc/rfc1952.txt +bool IsValidGzipHeader(const uint8_t* header, size_t size) { + // Each gzip entry has the following format magic header: + // 0 1 0x1F + // 1 1 0x8B + // 2 1 compression method (8 denotes deflate) + static const uint8_t magic[] = {0x1F, 0x8B, 8}; + return size >= 10 && std::equal(std::begin(magic), std::end(magic), header); +} +} // namespace + bool LocateDeflatesInGzip(const Buffer& data, vector<BitExtent>* deflates) { + TEST_AND_RETURN_FALSE(IsValidGzipHeader(data.data(), data.size())); uint64_t member_start = 0; - while (member_start + 10 <= data.size() && data[member_start + 0] == 0x1F && - data[member_start + 1] == 0x8B && data[member_start + 2] == 8) { - // Each member entry has the following format - // 0 1 0x1F - // 1 1 0x8B - // 2 1 compression method (8 denotes deflate) + do { + // After the magic header, the gzip contains: // 3 1 set of flags // 4 4 modification time // 8 1 extra flags @@ -234,9 +243,8 @@ bool LocateDeflatesInGzip(const Buffer& data, vector<BitExtent>* deflates) { TEST_AND_RETURN_FALSE(offset + 8 <= data.size()); offset += 8; member_start = offset; - } - // Return true if we've successfully parsed at least one gzip. - return member_start != 0; + } while (IsValidGzipHeader(&data[member_start], data.size() - member_start)); + return true; } // For more information about the zip format, refer to |