diff --git a/services/core/java/com/android/server/pm/PackageManagerService.java b/services/core/java/com/android/server/pm/PackageManagerService.java index 9791ff3e02ba9..7e7822cd978ef 100644 --- a/services/core/java/com/android/server/pm/PackageManagerService.java +++ b/services/core/java/com/android/server/pm/PackageManagerService.java @@ -17474,8 +17474,7 @@ public class PackageManagerService extends IPackageManager.Stub if (new File(signaturePath).exists() && !VerityUtils.hasFsverity(filePath)) { try { VerityUtils.setUpFsverity(filePath, signaturePath); - } catch (IOException | DigestException | NoSuchAlgorithmException - | SecurityException e) { + } catch (IOException e) { throw new PrepareFailure(PackageManager.INSTALL_FAILED_BAD_SIGNATURE, "Failed to enable fs-verity: " + e); } diff --git a/services/core/java/com/android/server/security/VerityUtils.java b/services/core/java/com/android/server/security/VerityUtils.java index b1db46fb3276b..856a40f3ef121 100644 --- a/services/core/java/com/android/server/security/VerityUtils.java +++ b/services/core/java/com/android/server/security/VerityUtils.java @@ -26,27 +26,19 @@ import android.util.Slog; import android.util.apk.ApkSignatureVerifier; import android.util.apk.ByteBufferFactory; import android.util.apk.SignatureNotFoundException; -import android.util.apk.VerityBuilder; import libcore.util.HexEncoding; import java.io.File; import java.io.FileDescriptor; import java.io.IOException; -import java.io.RandomAccessFile; import java.nio.ByteBuffer; -import java.nio.ByteOrder; -import java.nio.channels.FileChannel; import java.nio.file.Files; -import java.nio.file.Path; import java.nio.file.Paths; import java.security.DigestException; -import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; import java.util.Arrays; -import sun.security.pkcs.PKCS7; - /** Provides fsverity related operations. */ abstract public class VerityUtils { private static final String TAG = "VerityUtils"; @@ -60,8 +52,6 @@ abstract public class VerityUtils { /** The maximum size of signature file. This is just to avoid potential abuse. */ private static final int MAX_SIGNATURE_FILE_SIZE_BYTES = 8192; - private static final int COMMON_LINUX_PAGE_SIZE_IN_BYTES = 4096; - private static final boolean DEBUG = false; /** Returns true if the given file looks like containing an fs-verity signature. */ @@ -74,42 +64,15 @@ abstract public class VerityUtils { return filePath + FSVERITY_SIGNATURE_FILE_EXTENSION; } - /** Generates Merkle tree and fs-verity metadata then enables fs-verity. */ - public static void setUpFsverity(@NonNull String filePath, String signaturePath) - throws IOException, DigestException, NoSuchAlgorithmException { - final PKCS7 pkcs7 = new PKCS7(Files.readAllBytes(Paths.get(signaturePath))); - final byte[] expectedMeasurement = pkcs7.getContentInfo().getContentBytes(); - if (DEBUG) { - Slog.d(TAG, "Enabling fs-verity with signed fs-verity measurement " - + bytesToString(expectedMeasurement)); - Slog.d(TAG, "PKCS#7 info: " + pkcs7); + /** Enables fs-verity for the file with a PKCS#7 detached signature file. */ + public static void setUpFsverity(@NonNull String filePath, @NonNull String signaturePath) + throws IOException { + if (Files.size(Paths.get(signaturePath)) > MAX_SIGNATURE_FILE_SIZE_BYTES) { + throw new SecurityException("Signature file is unexpectedly large: " + signaturePath); } - - final TrackedBufferFactory bufferFactory = new TrackedBufferFactory(); - final byte[] actualMeasurement = generateFsverityMetadata(filePath, signaturePath, - bufferFactory); - try (RandomAccessFile raf = new RandomAccessFile(filePath, "rw")) { - FileChannel ch = raf.getChannel(); - ch.position(roundUpToNextMultiple(ch.size(), COMMON_LINUX_PAGE_SIZE_IN_BYTES)); - ByteBuffer buffer = bufferFactory.getBuffer(); - - long offset = buffer.position(); - long size = buffer.limit(); - while (offset < size) { - long s = ch.write(buffer); - offset += s; - size -= s; - } - } - - if (!Arrays.equals(expectedMeasurement, actualMeasurement)) { - throw new SecurityException("fs-verity measurement mismatch: " - + bytesToString(actualMeasurement) + " != " - + bytesToString(expectedMeasurement)); - } - - // This can fail if the public key is not already in .fs-verity kernel keyring. - int errno = enableFsverityNative(filePath); + byte[] pkcs7Signature = Files.readAllBytes(Paths.get(signaturePath)); + // This will fail if the public key is not already in .fs-verity kernel keyring. + int errno = enableFsverityNative(filePath, pkcs7Signature); if (errno != 0) { throw new IOException("Failed to enable fs-verity on " + filePath + ": " + Os.strerror(errno)); @@ -131,12 +94,19 @@ abstract public class VerityUtils { return true; } + private static native int enableFsverityNative(@NonNull String filePath, + @NonNull byte[] pkcs7Signature); + private static native int measureFsverityNative(@NonNull String filePath); + /** * Generates legacy Merkle tree and fs-verity metadata with Signing Block skipped. * + * @deprecated This is only used for previous fs-verity implementation, and should never be used + * on new devices. * @return {@code SetupResult} that contains the result code, and when success, the * {@code FileDescriptor} to read all the data from. */ + @Deprecated public static SetupResult generateApkVeritySetupData(@NonNull String apkPath) { if (DEBUG) { Slog.d(TAG, "Trying to install legacy apk verity to " + apkPath); @@ -173,7 +143,10 @@ abstract public class VerityUtils { /** * {@see ApkSignatureVerifier#generateApkVerityRootHash(String)}. + * @deprecated This is only used for previous fs-verity implementation, and should never be used + * on new devices. */ + @Deprecated public static byte[] generateApkVerityRootHash(@NonNull String apkPath) throws NoSuchAlgorithmException, DigestException, IOException { return ApkSignatureVerifier.generateApkVerityRootHash(apkPath); @@ -181,103 +154,15 @@ abstract public class VerityUtils { /** * {@see ApkSignatureVerifier#getVerityRootHash(String)}. + * @deprecated This is only used for previous fs-verity implementation, and should never be used + * on new devices. */ + @Deprecated public static byte[] getVerityRootHash(@NonNull String apkPath) throws IOException, SignatureNotFoundException { return ApkSignatureVerifier.getVerityRootHash(apkPath); } - /** - * Generates fs-verity metadata for {@code filePath} in the buffer created by {@code - * trackedBufferFactory}. The metadata contains the Merkle tree, fs-verity descriptor and - * extensions, including a PKCS#7 signature provided in {@code signaturePath}. - * - *

It is worthy to note that {@code trackedBufferFactory} generates a "tracked" {@code - * ByteBuffer}. The data will be used outside this method via the factory itself. - * - * @return fs-verity signed data (struct fsverity_digest_disk) of {@code filePath}, which - * includes SHA-256 of fs-verity descriptor and authenticated extensions. - */ - private static byte[] generateFsverityMetadata(String filePath, String signaturePath, - @NonNull ByteBufferFactory trackedBufferFactory) - throws IOException, DigestException, NoSuchAlgorithmException { - try (RandomAccessFile file = new RandomAccessFile(filePath, "r")) { - VerityBuilder.VerityResult result = VerityBuilder.generateFsVerityTree( - file, trackedBufferFactory); - - ByteBuffer buffer = result.verityData; - buffer.position(result.merkleTreeSize); - - final byte[] measurement = generateFsverityDescriptorAndMeasurement(file, - result.rootHash, signaturePath, buffer); - buffer.flip(); - return constructFsveritySignedDataNative(measurement); - } - } - - /** - * Generates fs-verity descriptor including the extensions to the {@code output} and returns the - * fs-verity measurement. - * - * @return fs-verity measurement, which is a SHA-256 of fs-verity descriptor and authenticated - * extensions. - */ - private static byte[] generateFsverityDescriptorAndMeasurement( - @NonNull RandomAccessFile file, @NonNull byte[] rootHash, - @NonNull String pkcs7SignaturePath, @NonNull ByteBuffer output) - throws IOException, NoSuchAlgorithmException, DigestException { - final short kRootHashExtensionId = 1; - final short kPkcs7SignatureExtensionId = 3; - final int origPosition = output.position(); - - // For generating fs-verity file measurement, which consists of the descriptor and - // authenticated extensions (but not unauthenticated extensions and the footer). - MessageDigest md = MessageDigest.getInstance("SHA-256"); - - // 1. Generate fs-verity descriptor. - final byte[] desc = constructFsverityDescriptorNative(file.length()); - output.put(desc); - md.update(desc); - - // 2. Generate authenticated extensions. - final byte[] authExt = - constructFsverityExtensionNative(kRootHashExtensionId, rootHash.length); - output.put(authExt); - output.put(rootHash); - md.update(authExt); - md.update(rootHash); - - // 3. Generate unauthenticated extensions. - ByteBuffer header = ByteBuffer.allocate(8).order(ByteOrder.LITTLE_ENDIAN); - output.putShort((short) 1); // number of unauthenticated extensions below - output.position(output.position() + 6); - - // Generate PKCS#7 extension. NB: We do not verify agaist trusted certificate (should be - // done by the caller if needed). - Path path = Paths.get(pkcs7SignaturePath); - if (Files.size(path) > MAX_SIGNATURE_FILE_SIZE_BYTES) { - throw new IllegalArgumentException("Signature size is unexpectedly large: " - + pkcs7SignaturePath); - } - final byte[] pkcs7Signature = Files.readAllBytes(path); - output.put(constructFsverityExtensionNative(kPkcs7SignatureExtensionId, - pkcs7Signature.length)); - output.put(pkcs7Signature); - - // 4. Generate the footer. - output.put(constructFsverityFooterNative(output.position() - origPosition)); - - return md.digest(); - } - - private static native int enableFsverityNative(@NonNull String filePath); - private static native int measureFsverityNative(@NonNull String filePath); - private static native byte[] constructFsveritySignedDataNative(@NonNull byte[] measurement); - private static native byte[] constructFsverityDescriptorNative(long fileSize); - private static native byte[] constructFsverityExtensionNative(short extensionId, - int extensionDataSize); - private static native byte[] constructFsverityFooterNative(int offsetToDescriptorHead); - /** * Returns a pair of {@code SharedMemory} and {@code Integer}. The {@code SharedMemory} contains * Merkle tree and fsverity headers for the given apk, in the form that can immediately be used @@ -313,6 +198,11 @@ abstract public class VerityUtils { return HexEncoding.encodeToString(bytes); } + /** + * @deprecated This is only used for previous fs-verity implementation, and should never be used + * on new devices. + */ + @Deprecated public static class SetupResult { /** Result code if verity is set up correctly. */ private static final int RESULT_OK = 1; @@ -401,30 +291,4 @@ abstract public class VerityUtils { return mBuffer == null ? -1 : mBuffer.limit(); } } - - /** A {@code ByteBufferFactory} that tracks the {@code ByteBuffer} it creates. */ - private static class TrackedBufferFactory implements ByteBufferFactory { - private ByteBuffer mBuffer; - - @Override - public ByteBuffer create(int capacity) { - if (mBuffer != null) { - throw new IllegalStateException("Multiple instantiation from this factory"); - } - mBuffer = ByteBuffer.allocate(capacity); - return mBuffer; - } - - public ByteBuffer getBuffer() { - return mBuffer; - } - } - - /** Round up the number to the next multiple of the divisor. */ - private static long roundUpToNextMultiple(long number, long divisor) { - if (number > (Long.MAX_VALUE - divisor)) { - throw new IllegalArgumentException("arithmetic overflow"); - } - return ((number + (divisor - 1)) / divisor) * divisor; - } } diff --git a/services/core/jni/com_android_server_security_VerityUtils.cpp b/services/core/jni/com_android_server_security_VerityUtils.cpp index 6cd9f2c718ee8..9ceb7706628ae 100644 --- a/services/core/jni/com_android_server_security_VerityUtils.cpp +++ b/services/core/jni/com_android_server_security_VerityUtils.cpp @@ -36,61 +36,33 @@ #include #else -// Before fs-verity is upstreamed, use the current snapshot for development. -// https://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux.git/tree/include/uapi/linux/fsverity.h?h=fsverity - #include #include #include +#define FS_VERITY_HASH_ALG_SHA256 1 + +struct fsverity_enable_arg { + __u32 version; + __u32 hash_algorithm; + __u32 block_size; + __u32 salt_size; + __u64 salt_ptr; + __u32 sig_size; + __u32 __reserved1; + __u64 sig_ptr; + __u64 __reserved2[11]; +}; + struct fsverity_digest { __u16 digest_algorithm; __u16 digest_size; /* input/output */ __u8 digest[]; }; -#define FS_IOC_ENABLE_VERITY _IO('f', 133) +#define FS_IOC_ENABLE_VERITY _IOW('f', 133, struct fsverity_enable_arg) #define FS_IOC_MEASURE_VERITY _IOWR('f', 134, struct fsverity_digest) -#define FS_VERITY_MAGIC "FSVerity" - -#define FS_VERITY_ALG_SHA256 1 - -struct fsverity_descriptor { - __u8 magic[8]; /* must be FS_VERITY_MAGIC */ - __u8 major_version; /* must be 1 */ - __u8 minor_version; /* must be 0 */ - __u8 log_data_blocksize;/* log2(data-bytes-per-hash), e.g. 12 for 4KB */ - __u8 log_tree_blocksize;/* log2(tree-bytes-per-hash), e.g. 12 for 4KB */ - __le16 data_algorithm; /* hash algorithm for data blocks */ - __le16 tree_algorithm; /* hash algorithm for tree blocks */ - __le32 flags; /* flags */ - __le32 __reserved1; /* must be 0 */ - __le64 orig_file_size; /* size of the original file data */ - __le16 auth_ext_count; /* number of authenticated extensions */ - __u8 __reserved2[30]; /* must be 0 */ -}; - -#define FS_VERITY_EXT_ROOT_HASH 1 -#define FS_VERITY_EXT_PKCS7_SIGNATURE 3 - -struct fsverity_extension { - __le32 length; - __le16 type; /* Type of this extension (see codes above) */ - __le16 __reserved; /* Reserved, must be 0 */ -}; - -struct fsverity_digest_disk { - __le16 digest_algorithm; - __le16 digest_size; - __u8 digest[]; -}; - -struct fsverity_footer { - __le32 desc_reverse_offset; /* distance to fsverity_descriptor */ - __u8 magic[8]; /* FS_VERITY_MAGIC */ -} __packed; - #endif const int kSha256Bytes = 32; @@ -99,52 +71,24 @@ namespace android { namespace { -class JavaByteArrayHolder { - public: - JavaByteArrayHolder(const JavaByteArrayHolder &other) = delete; - JavaByteArrayHolder(JavaByteArrayHolder &&other) - : mEnv(other.mEnv), mBytes(other.mBytes), mElements(other.mElements) { - other.mElements = nullptr; - } - - static JavaByteArrayHolder newArray(JNIEnv* env, jsize size) { - return JavaByteArrayHolder(env, size); - } - - jbyte* getRaw() { - return mElements; - } - - jbyteArray release() { - mEnv->ReleaseByteArrayElements(mBytes, mElements, 0); - mElements = nullptr; - return mBytes; - } - - ~JavaByteArrayHolder() { - LOG_ALWAYS_FATAL_IF(mElements != nullptr, "Elements are not released"); - } - - private: - JavaByteArrayHolder(JNIEnv* env, jsize size) { - mEnv = env; - mBytes = mEnv->NewByteArray(size); - mElements = mEnv->GetByteArrayElements(mBytes, nullptr); - memset(mElements, 0, size); - } - - JNIEnv* mEnv; - jbyteArray mBytes; - jbyte* mElements; -}; - -int enableFsverity(JNIEnv* env, jobject /* clazz */, jstring filePath) { +int enableFsverity(JNIEnv* env, jobject /* clazz */, jstring filePath, jbyteArray signature) { const char* path = env->GetStringUTFChars(filePath, nullptr); ::android::base::unique_fd rfd(open(path, O_RDONLY | O_CLOEXEC)); + env->ReleaseStringUTFChars(filePath, path); if (rfd.get() < 0) { return errno; } - if (ioctl(rfd.get(), FS_IOC_ENABLE_VERITY, nullptr) < 0) { + + fsverity_enable_arg arg = {}; + arg.version = 1; + arg.hash_algorithm = FS_VERITY_HASH_ALG_SHA256; + arg.block_size = 4096; + arg.salt_size = 0; + arg.salt_ptr = reinterpret_cast(nullptr); + arg.sig_size = env->GetArrayLength(signature); + arg.sig_ptr = reinterpret_cast(signature); + + if (ioctl(rfd.get(), FS_IOC_ENABLE_VERITY, &arg) < 0) { return errno; } return 0; @@ -159,6 +103,7 @@ int measureFsverity(JNIEnv* env, jobject /* clazz */, jstring filePath) { const char* path = env->GetStringUTFChars(filePath, nullptr); ::android::base::unique_fd rfd(open(path, O_RDONLY | O_CLOEXEC)); + env->ReleaseStringUTFChars(filePath, path); if (rfd.get() < 0) { return errno; } @@ -168,71 +113,9 @@ int measureFsverity(JNIEnv* env, jobject /* clazz */, jstring filePath) { return 0; } -jbyteArray constructFsveritySignedData(JNIEnv* env, jobject /* clazz */, jbyteArray digest) { - auto raii = JavaByteArrayHolder::newArray(env, sizeof(fsverity_digest_disk) + kSha256Bytes); - fsverity_digest_disk* data = reinterpret_cast(raii.getRaw()); - - data->digest_algorithm = FS_VERITY_ALG_SHA256; - data->digest_size = kSha256Bytes; - if (env->GetArrayLength(digest) != kSha256Bytes) { - jniThrowExceptionFmt(env, "java/lang/IllegalArgumentException", "Invalid hash size of %d", - env->GetArrayLength(digest)); - return 0; - } - const jbyte* src = env->GetByteArrayElements(digest, nullptr); - memcpy(data->digest, src, kSha256Bytes); - - return raii.release(); -} - - -jbyteArray constructFsverityDescriptor(JNIEnv* env, jobject /* clazz */, jlong fileSize) { - auto raii = JavaByteArrayHolder::newArray(env, sizeof(fsverity_descriptor)); - fsverity_descriptor* desc = reinterpret_cast(raii.getRaw()); - - memcpy(desc->magic, FS_VERITY_MAGIC, sizeof(desc->magic)); - desc->major_version = 1; - desc->minor_version = 0; - desc->log_data_blocksize = 12; - desc->log_tree_blocksize = 12; - desc->data_algorithm = FS_VERITY_ALG_SHA256; - desc->tree_algorithm = FS_VERITY_ALG_SHA256; - desc->flags = 0; - desc->orig_file_size = fileSize; - desc->auth_ext_count = 1; - - return raii.release(); -} - -jbyteArray constructFsverityExtension(JNIEnv* env, jobject /* clazz */, jshort extensionId, - jint extensionDataSize) { - auto raii = JavaByteArrayHolder::newArray(env, sizeof(fsverity_extension)); - fsverity_extension* ext = reinterpret_cast(raii.getRaw()); - - ext->length = sizeof(fsverity_extension) + extensionDataSize; - ext->type = extensionId; - - return raii.release(); -} - -jbyteArray constructFsverityFooter(JNIEnv* env, jobject /* clazz */, - jint offsetToDescriptorHead) { - auto raii = JavaByteArrayHolder::newArray(env, sizeof(fsverity_footer)); - fsverity_footer* footer = reinterpret_cast(raii.getRaw()); - - footer->desc_reverse_offset = offsetToDescriptorHead + sizeof(fsverity_footer); - memcpy(footer->magic, FS_VERITY_MAGIC, sizeof(footer->magic)); - - return raii.release(); -} - const JNINativeMethod sMethods[] = { - { "enableFsverityNative", "(Ljava/lang/String;)I", (void *)enableFsverity }, + { "enableFsverityNative", "(Ljava/lang/String;[B)I", (void *)enableFsverity }, { "measureFsverityNative", "(Ljava/lang/String;)I", (void *)measureFsverity }, - { "constructFsveritySignedDataNative", "([B)[B", (void *)constructFsveritySignedData }, - { "constructFsverityDescriptorNative", "(J)[B", (void *)constructFsverityDescriptor }, - { "constructFsverityExtensionNative", "(SI)[B", (void *)constructFsverityExtension }, - { "constructFsverityFooterNative", "(I)[B", (void *)constructFsverityFooter }, }; } // namespace