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zip_archive: reject files that don't start with an LFH signature.

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Bug: 64211847
Test: zip_archive_test

Merged-In: I275e7c4da05ceeb20401b560c72294f29ef63642
Change-Id: I38705f4e9688326a140aa59a1333b0878ed39c14
This commit is contained in:
Narayan Kamath 2017-08-09 18:32:09 +01:00
parent f0a43dede9
commit dbacd826a1
2 changed files with 67 additions and 0 deletions
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18
libziparchive/zip_archive.cc
View file

@ -552,6 +552,8 @@ static int32_t MapCentralDirectory(int fd, const char* debug_file_name,
return result;
}
static inline ssize_t ReadAtOffset(int fd, uint8_t* buf, size_t len, off64_t off);
/*
* Parses the Zip archive's Central Directory. Allocates and populates the
* hash table.
@ -630,6 +632,22 @@ static int32_t ParseZipArchive(ZipArchive* archive) {
return -1;
}
}
uint32_t lfh_start_bytes;
if (ReadAtOffset(archive->fd, reinterpret_cast<uint8_t*>(&lfh_start_bytes),
sizeof(uint32_t), 0) != sizeof(uint32_t)) {
ALOGW("Zip: Unable to read header for entry at offset == 0.");
return -1;
}
if (lfh_start_bytes != LocalFileHeader::kSignature) {
ALOGW("Zip: Entry at offset zero has invalid LFH signature %" PRIx32, lfh_start_bytes);
#if defined(__ANDROID__)
android_errorWriteLog(0x534e4554, "64211847");
#endif
return -1;
}
ALOGV("+++ zip good scan %" PRIu16 " entries", num_entries);
return 0;

49
libziparchive/zip_archive_test.cc
View file

@ -530,6 +530,55 @@ TEST(ziparchive, ExtractToFile) {
close(fd);
}
// A zip file whose local file header at offset zero is corrupted.
//
// ---------------
// cat foo > a.txt
// zip a.zip a.txt
// cat a.zip | xxd -i
//
// Manual changes :
// [2] = 0xff // Corrupt the LFH signature of entry 0.
// [3] = 0xff // Corrupt the LFH signature of entry 0.
static const std::vector<uint8_t> kZipFileWithBrokenLfhSignature{
//[lfh-sig-----------], [lfh contents---------------------------------
0x50, 0x4b, 0xff, 0xff, 0x0a, 0x00, 0x00, 0x00, 0x00, 0x00, 0x77, 0x80,
//--------------------------------------------------------------------
0x09, 0x4b, 0xa8, 0x65, 0x32, 0x7e, 0x04, 0x00, 0x00, 0x00, 0x04, 0x00,
//-------------------------------] [file-name-----------------], [---
0x00, 0x00, 0x05, 0x00, 0x1c, 0x00, 0x61, 0x2e, 0x74, 0x78, 0x74, 0x55,
// entry-contents------------------------------------------------------
0x54, 0x09, 0x00, 0x03, 0x51, 0x24, 0x8b, 0x59, 0x51, 0x24, 0x8b, 0x59,
//--------------------------------------------------------------------
0x75, 0x78, 0x0b, 0x00, 0x01, 0x04, 0x89, 0x42, 0x00, 0x00, 0x04, 0x88,
//-------------------------------------], [cd-record-sig-------], [---
0x13, 0x00, 0x00, 0x66, 0x6f, 0x6f, 0x0a, 0x50, 0x4b, 0x01, 0x02, 0x1e,
// cd-record-----------------------------------------------------------
0x03, 0x0a, 0x00, 0x00, 0x00, 0x00, 0x00, 0x77, 0x80, 0x09, 0x4b, 0xa8,
//--------------------------------------------------------------------
0x65, 0x32, 0x7e, 0x04, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00, 0x05,
//--------------------------------------------------------------------
0x00, 0x18, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0xa0,
//-] [lfh-file-header-off-], [file-name-----------------], [extra----
0x81, 0x00, 0x00, 0x00, 0x00, 0x61, 0x2e, 0x74, 0x78, 0x74, 0x55, 0x54,
//--------------------------------------------------------------------
0x05, 0x00, 0x03, 0x51, 0x24, 0x8b, 0x59, 0x75, 0x78, 0x0b, 0x00, 0x01,
//-------------------------------------------------------], [eocd-sig-
0x04, 0x89, 0x42, 0x00, 0x00, 0x04, 0x88, 0x13, 0x00, 0x00, 0x50, 0x4b,
//-------], [---------------------------------------------------------
0x05, 0x06, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x01, 0x00, 0x4b, 0x00,
//-------------------------------------------]
0x00, 0x00, 0x43, 0x00, 0x00, 0x00, 0x00, 0x00};
TEST(ziparchive, BrokenLfhSignature) {
TemporaryFile tmp_file;
ASSERT_NE(-1, tmp_file.fd);
ASSERT_TRUE(android::base::WriteFully(tmp_file.fd, &kZipFileWithBrokenLfhSignature[0],
kZipFileWithBrokenLfhSignature.size()));
ZipArchiveHandle handle;
ASSERT_EQ(-1, OpenArchiveFd(tmp_file.fd, "LeadingNonZipBytes", &handle));
}
int main(int argc, char** argv) {
::testing::InitGoogleTest(&argc, argv);