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Fail idmap parsing earlier if version differs

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Variable length strings are now in the idmap format. Idmap attempts to
parse the old idmap files using the new format and can interpret old
data as the length of a variable length string.

Fail parsing idmap header early if the idmap magic or version differs
from what is expected.

Bug: 177295273
Test: boot, apply change, reboot
Change-Id: I2914f11547424457fdb78de0ad03976e1fc81084
This commit is contained in:
Ryan Mitchell
2021-01-13 17:21:29 -08:00
parent fb4d09cadd
commit 9289a04315
2 changed files with 35 additions and 18 deletions
Download Patch File Download Diff File Expand all files Collapse all files

13
cmds/idmap2/libidmap2/Idmap.cpp
View File

@@ -103,9 +103,18 @@ Result<uint32_t> GetPackageCrc(const ZipFile& zip) {
std::unique_ptr<const IdmapHeader> IdmapHeader::FromBinaryStream(std::istream& stream) {
std::unique_ptr<IdmapHeader> idmap_header(new IdmapHeader());
if (!Read32(stream, &idmap_header->magic_) || !Read32(stream, &idmap_header->version_)) {
return nullptr;
}
if (idmap_header->magic_ != kIdmapMagic ||
idmap_header->version_ != kIdmapCurrentVersion) {
// Do not continue parsing if the file is not a current version idmap.
return nullptr;
}
uint32_t enforce_overlayable;
if (!Read32(stream, &idmap_header->magic_) || !Read32(stream, &idmap_header->version_) ||
!Read32(stream, &idmap_header->target_crc_) || !Read32(stream, &idmap_header->overlay_crc_) ||
if (!Read32(stream, &idmap_header->target_crc_) || !Read32(stream, &idmap_header->overlay_crc_) ||
!Read32(stream, &idmap_header->fulfilled_policies_) ||
!Read32(stream, &enforce_overlayable) || !ReadString(stream, &idmap_header->target_path_) ||
!ReadString(stream, &idmap_header->overlay_path_) ||

40
cmds/idmap2/tests/IdmapTests.cpp
View File

@@ -76,6 +76,24 @@ TEST(IdmapTests, CreateIdmapHeaderFromBinaryStream) {
ASSERT_EQ(header->GetDebugInfo(), "debug");
}
TEST(IdmapTests, IdmapFailParsingDifferentVersion) {
constexpr size_t kJunkSize = 2000;
std::stringstream stream;
stream << android::kIdmapMagic;
stream << 0xffffffffU;
stream << std::string(kJunkSize, (char) 0xffU);
ASSERT_FALSE(Idmap::FromBinaryStream(stream));
}
TEST(IdmapTests, IdmapFailParsingDifferentMagic) {
constexpr size_t kJunkSize = 2000;
std::stringstream stream;
stream << 0xffffffffU;
stream << android::kIdmapCurrentVersion;
stream << std::string(kJunkSize, (char) 0xffU);
ASSERT_FALSE(Idmap::FromBinaryStream(stream));
}
TEST(IdmapTests, CreateIdmapDataHeaderFromBinaryStream) {
const size_t offset = kIdmapRawDataOffset;
std::string raw(reinterpret_cast<const char*>(idmap_raw_data + offset),
@@ -425,11 +443,7 @@ TEST(IdmapTests, IdmapHeaderIsUpToDate) {
std::stringstream bad_magic_stream(bad_magic_string);
std::unique_ptr<const IdmapHeader> bad_magic_header =
IdmapHeader::FromBinaryStream(bad_magic_stream);
ASSERT_THAT(bad_magic_header, NotNull());
ASSERT_NE(header->GetMagic(), bad_magic_header->GetMagic());
ASSERT_FALSE(bad_magic_header->IsUpToDate(target_apk_path, overlay_apk_path, overlay_name,
target_crc, overlay_crc, policies,
/* enforce_overlayable */ true));
ASSERT_EQ(nullptr, bad_magic_header);
// version: bytes (0x4, 0x07)
std::string bad_version_string(stream.str());
@@ -440,11 +454,7 @@ TEST(IdmapTests, IdmapHeaderIsUpToDate) {
std::stringstream bad_version_stream(bad_version_string);
std::unique_ptr<const IdmapHeader> bad_version_header =
IdmapHeader::FromBinaryStream(bad_version_stream);
ASSERT_THAT(bad_version_header, NotNull());
ASSERT_NE(header->GetVersion(), bad_version_header->GetVersion());
ASSERT_FALSE(bad_magic_header->IsUpToDate(target_apk_path, overlay_apk_path, overlay_name,
target_crc, overlay_crc, policies,
/* enforce_overlayable */ true));
ASSERT_EQ(nullptr, bad_version_header);
// target crc: bytes (0x8, 0xb)
std::string bad_target_crc_string(stream.str());
@@ -457,7 +467,7 @@ TEST(IdmapTests, IdmapHeaderIsUpToDate) {
IdmapHeader::FromBinaryStream(bad_target_crc_stream);
ASSERT_THAT(bad_target_crc_header, NotNull());
ASSERT_NE(header->GetTargetCrc(), bad_target_crc_header->GetTargetCrc());
ASSERT_FALSE(bad_magic_header->IsUpToDate(target_apk_path, overlay_apk_path, overlay_name,
ASSERT_FALSE(bad_target_crc_header->IsUpToDate(target_apk_path, overlay_apk_path, overlay_name,
target_crc, overlay_crc, policies,
/* enforce_overlayable */ true));
@@ -472,7 +482,7 @@ TEST(IdmapTests, IdmapHeaderIsUpToDate) {
IdmapHeader::FromBinaryStream(bad_overlay_crc_stream);
ASSERT_THAT(bad_overlay_crc_header, NotNull());
ASSERT_NE(header->GetOverlayCrc(), bad_overlay_crc_header->GetOverlayCrc());
ASSERT_FALSE(bad_magic_header->IsUpToDate(target_apk_path, overlay_apk_path, overlay_name,
ASSERT_FALSE(bad_overlay_crc_header->IsUpToDate(target_apk_path, overlay_apk_path, overlay_name,
target_crc, overlay_crc, policies,
/* enforce_overlayable */ true));
@@ -511,7 +521,7 @@ TEST(IdmapTests, IdmapHeaderIsUpToDate) {
IdmapHeader::FromBinaryStream(bad_target_path_stream);
ASSERT_THAT(bad_target_path_header, NotNull());
ASSERT_NE(header->GetTargetPath(), bad_target_path_header->GetTargetPath());
ASSERT_FALSE(bad_magic_header->IsUpToDate(target_apk_path, overlay_apk_path, overlay_name,
ASSERT_FALSE(bad_target_path_header->IsUpToDate(target_apk_path, overlay_apk_path, overlay_name,
target_crc, overlay_crc, policies,
/* enforce_overlayable */ true));
@@ -527,7 +537,7 @@ TEST(IdmapTests, IdmapHeaderIsUpToDate) {
target_crc, overlay_crc, policies,
/* enforce_overlayable */ true));
// overlay path: bytes (0x3c, 0x47)
// overlay name: bytes (0x3c, 0x47)
std::string bad_overlay_name_string(stream.str());
bad_overlay_name_string[0x3c] = '\0';
std::stringstream bad_overlay_name_stream(bad_overlay_name_string);
@@ -538,8 +548,6 @@ TEST(IdmapTests, IdmapHeaderIsUpToDate) {
ASSERT_FALSE(bad_overlay_name_header->IsUpToDate(target_apk_path, overlay_apk_path, overlay_name,
target_crc, overlay_crc, policies,
/* enforce_overlayable */ true));
// overlay name: bytes (0x2c, 0x37)
}
class TestVisitor : public Visitor {