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Commit c6d738a3 authored by Victor Hsieh's avatar Victor Hsieh
Browse files

installd: implement measureFsverityRootHash 

Test: Observed to ioctl, will soon integrate with the actual ioctl
Bug: 30972906

Change-Id: I30729abbdc540093d2b33d0451a29c5bbf0fb83d
parent 57188c67

cmds/installd/InstalldNativeService.cpp

+40 −0
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 


#define ATRACE_TAG ATRACE_TAG_PACKAGE_MANAGER



#include <algorithm>

#include <errno.h>

#include <fstream>

#include <fts.h>
@@ -90,6 +91,7 @@ static constexpr const char* IDMAP_SUFFIX = "@idmap"; 
// fsverity assumes the page size is always 4096. If not, the feature can not be

// enabled.

static constexpr int kVerityPageSize = 4096;

static constexpr size_t kSha256Size = 32;

static constexpr const char* kPropApkVerityMode = "ro.apk_verity.mode";



// NOTE: keep in sync with Installer
@@ -2357,6 +2359,14 @@ struct fsverity_set { 
    __u64 flags;

};



struct fsverity_root_hash {

    short root_hash_algorithm;

    short flags;

    __u8 reserved[4];

    __u8 root_hash[64];

};



#define FS_IOC_MEASURE_FSVERITY        _IOW('f', 2733, struct fsverity_root_hash)

#define FS_IOC_SET_FSVERITY            _IOW('f', 2734, struct fsverity_set)



#define FSVERITY_FLAG_ENABLED          0x0001
@@ -2423,6 +2433,36 @@ binder::Status InstalldNativeService::installApkVerity(const std::string& filePa 
    return ok();

}



binder::Status InstalldNativeService::assertFsverityRootHashMatches(const std::string& filePath,

        const std::vector<uint8_t>& expectedHash) {

    ENFORCE_UID(AID_SYSTEM);

    if (!android::base::GetBoolProperty(kPropApkVerityMode, false)) {

        return ok();

    }

    // TODO: also check fsverity support in the current file system if compiled with DEBUG.

    if (expectedHash.size() != kSha256Size) {

        return error("verity hash size should be " + std::to_string(kSha256Size) + " but is " +

                     std::to_string(expectedHash.size()));

    }



    // TODO(71871109): Validate filePath.

    ::android::base::unique_fd fd(open(filePath.c_str(), O_RDONLY));

    if (fd.get() < 0) {

        return error("Failed to open " + filePath + ": " + strerror(errno));

    }



    struct fsverity_root_hash config;

    memset(&config, 0, sizeof(config));

    config.root_hash_algorithm = 0;  // SHA256

    memcpy(config.root_hash, expectedHash.data(), std::min(sizeof(config.root_hash), kSha256Size));

    if (ioctl(fd.get(), FS_IOC_MEASURE_FSVERITY, &config) < 0) {

        // This includes an expected failure case with no FSVerity setup. It normally happens when

        // the apk does not contains the Merkle tree root hash.

        return error("Failed to measure fsverity on " + filePath + ": " + strerror(errno));

    }

    return ok();  // hashes match

}



binder::Status InstalldNativeService::reconcileSecondaryDexFile(

        const std::string& dexPath, const std::string& packageName, int32_t uid,

        const std::vector<std::string>& isas, const std::unique_ptr<std::string>& volumeUuid,

cmds/installd/InstalldNativeService.h

+2 −0
Original line number Diff line number Diff line
@@ -120,6 +120,8 @@ public: 
            const std::unique_ptr<std::string>& outputPath);

    binder::Status installApkVerity(const std::string& filePath,

            const ::android::base::unique_fd& verityInput);

    binder::Status assertFsverityRootHashMatches(const std::string& filePath,

            const std::vector<uint8_t>& expectedHash);

    binder::Status reconcileSecondaryDexFile(const std::string& dexPath,

        const std::string& packageName, int32_t uid, const std::vector<std::string>& isa,

        const std::unique_ptr<std::string>& volumeUuid, int32_t storage_flag, bool* _aidl_return);

cmds/installd/binder/android/os/IInstalld.aidl

+1 −0
Original line number Diff line number Diff line
@@ -82,6 +82,7 @@ interface IInstalld { 
    void deleteOdex(@utf8InCpp String apkPath, @utf8InCpp String instructionSet,

            @nullable @utf8InCpp String outputPath);

    void installApkVerity(@utf8InCpp String filePath, in FileDescriptor verityInput);

    void assertFsverityRootHashMatches(@utf8InCpp String filePath, in byte[] expectedHash);



    boolean reconcileSecondaryDexFile(@utf8InCpp String dexPath, @utf8InCpp String pkgName,

        int uid, in @utf8InCpp String[] isas, @nullable @utf8InCpp String volume_uuid,