Merge "fs_mgr: trigger dm-verity error handling for invalid signatures" (ad2a5a89) · Commits · e / os / android_system_core

fs_mgr/fs_mgr_verity.c

+47 −7

Original line number	Diff line number	Diff line
		@@ -47,6 +47,8 @@

		#define VERITY_METADATA_SIZE 32768
		#define VERITY_TABLE_RSA_KEY "/verity_key"
		#define VERITY_TABLE_HASH_IDX 8
		#define VERITY_TABLE_SALT_IDX 9

		#define METADATA_MAGIC 0x01564c54
		#define METADATA_TAG_MAX_LENGTH 63
		@@ -141,6 +143,33 @@ out:
		return retval;
		}

		static int invalidate_table(char *table, int table_length)
		{
		int n = 0;
		int idx = 0;
		int cleared = 0;

		while (n < table_length) {
		if (table[n++] == ' ') {
		++idx;
		}

		if (idx != VERITY_TABLE_HASH_IDX && idx != VERITY_TABLE_SALT_IDX) {
		continue;
		}

		while (n < table_length && table[n] != ' ') {
		table[n++] = '0';
		}

		if (++cleared == 2) {
		return 0;
		}
		}

		return -1;
		}

		static int squashfs_get_target_device_size(char blk_device, uint64_t device_size)
		{
		struct squashfs_info sq_info;
		@@ -957,6 +986,7 @@ int fs_mgr_setup_verity(struct fstab_rec *fstab) {
		char *verity_blk_name = 0;
		char *verity_table = 0;
		char *verity_table_signature = 0;
		int verity_table_length = 0;
		uint64_t device_size = 0;

		_Alignas(struct dm_ioctl) char buffer[DM_BUF_SIZE];
		@@ -979,6 +1009,7 @@ int fs_mgr_setup_verity(struct fstab_rec *fstab) {
		}

		retval = FS_MGR_SETUP_VERITY_FAIL;
		verity_table_length = strlen(verity_table);

		// get the device mapper fd
		if ((fd = open("/dev/device-mapper", O_RDWR)) < 0) {
		@@ -998,13 +1029,6 @@ int fs_mgr_setup_verity(struct fstab_rec *fstab) {
		goto out;
		}

		// verify the signature on the table
		if (verify_table(verity_table_signature,
		verity_table,
		strlen(verity_table)) < 0) {
		goto out;
		}

		if (load_verity_state(fstab, &mode) < 0) {
		/* if accessing or updating the state failed, switch to the default
		* safe mode. This makes sure the device won't end up in an endless
		@@ -1013,6 +1037,22 @@ int fs_mgr_setup_verity(struct fstab_rec *fstab) {
		mode = VERITY_MODE_EIO;
		}

		// verify the signature on the table
		if (verify_table(verity_table_signature,
		verity_table,
		verity_table_length) < 0) {
		if (mode == VERITY_MODE_LOGGING) {
		// the user has been warned, allow mounting without dm-verity
		retval = FS_MGR_SETUP_VERITY_SUCCESS;
		goto out;
		}

		// invalidate root hash and salt to trigger device-specific recovery
		if (invalidate_table(verity_table, verity_table_length) < 0) {
		goto out;
		}
		}

		INFO("Enabling dm-verity for %s (mode %d)\n", mount_point, mode);

		// load the verity mapping table