zkey: Add 'convert' command to convert keys from one type to another

Add a new 'convert' command. It allows to convert a secure key from
one key type to another. Currently only keys of type CCA-AESDATA can be
converted to CCA-AESCIPHER.

Signed-off-by: Ingo Franzki <ifranzki@linux.ibm.com>
Reviewed-by: Harald Freudenberger <freude@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>

zkey/keystore.c

@@ -3946,6 +3946,218 @@ int keystore_crypttab(struct keystore *keystore, const char *volume_filter,
 	return rc;
 }
 
+/**
+ * Converts a secure keys in the keystore
+ *
+ * @param[in] keystore the key store
+ * @param[in] name         the name of the key to convert
+ * @param[in] key_type     the type of the key to convert it to
+ * @param[in] noapqncheck  if true, the specified APQN(s) are not checked for
+ *                         existence and type.
+ * @param[in] pkey_fd      the file descriptor of /dev/pkey
+ * @param[in] cca          the CCA library struct
+ *
+ * @returns 0 for success or a negative errno in case of an error
+ */
+int keystore_convert_key(struct keystore *keystore, const char *name,
+			 const char *key_type, bool noapqncheck, bool quiet,
+			 int pkey_fd, struct cca_lib *cca)
+{
+	struct key_filenames file_names = { NULL, NULL, NULL };
+	u8 output_key[2 * MAX_SECURE_KEY_SIZE];
+	struct properties *properties = NULL;
+	int rc, min_level, selected = 1;
+	unsigned int output_key_size;
+	char *cur_key_type = NULL;
+	char **apqn_list = NULL;
+	size_t secure_key_size;
+	u8 *secure_key = NULL;
+	char *apqns = NULL;
+	char *temp;
+	u64 mkvp;
+
+	util_assert(keystore != NULL, "Internal error: keystore is NULL");
+	util_assert(name != NULL, "Internal error: name is NULL");
+
+	rc = _keystore_get_key_filenames(keystore, name, &file_names);
+	if (rc != 0)
+		goto out;
+
+	rc = _keystore_ensure_keyfiles_exist(&file_names, name);
+	if (rc != 0)
+		goto out;
+
+	properties = properties_new();
+	rc = properties_load(properties, file_names.info_filename, 1);
+	if (rc != 0) {
+		warnx("Key '%s' does not exist or is invalid", name);
+		goto out;
+	}
+
+	cur_key_type = _keystore_get_key_type(properties);
+	if (strcasecmp(cur_key_type, key_type) == 0) {
+		warnx("The secure key '%s' is already of type %s", name,
+		      cur_key_type);
+		rc = 0;
+		goto out;
+	}
+	if (strcasecmp(cur_key_type, KEY_TYPE_CCA_AESDATA) != 0) {
+		warnx("Only secure keys of type %s can "
+		      "be converted. The secure key '%s' is of type %s",
+		      KEY_TYPE_CCA_AESDATA, name, cur_key_type);
+		rc = 0;
+		goto out;
+	}
+
+	secure_key = read_secure_key(file_names.skey_filename,
+				     &secure_key_size, keystore->verbose);
+	if (secure_key == NULL) {
+		rc = -ENOENT;
+		goto out;
+	}
+
+	min_level = get_min_card_level_for_keytype(key_type);
+	if (min_level < 0) {
+		warnx("Invalid key-type specified: %s", key_type);
+		rc = -EINVAL;
+		goto out;
+	}
+
+	apqns = properties_get(properties, PROP_NAME_APQNS);
+	if (apqns != NULL)
+		apqn_list = str_list_split(apqns);
+
+	rc = cross_check_apqns(apqns, 0, min_level, true, keystore->verbose);
+	if (rc == -EINVAL)
+		goto out;
+	if (rc != 0 && rc != -ENOTSUP && !noapqncheck) {
+		warnx("Your master key setup is improper for converting key "
+		      "'%s'", name);
+		goto out;
+	}
+
+	rc = validate_secure_key(pkey_fd, secure_key, secure_key_size,
+				 NULL, NULL, (const char **)apqn_list,
+				 keystore->verbose);
+	if (rc != 0)
+		goto out;
+
+	rc = get_master_key_verification_pattern(secure_key, secure_key_size,
+						 &mkvp, keystore->verbose);
+	if (rc)
+		goto out;
+
+	rc = select_cca_adapter_by_mkvp(cca, mkvp, NULL,
+					FLAG_SEL_CCA_MATCH_CUR_MKVP,
+					keystore->verbose);
+	if (rc == -ENOTSUP) {
+		rc = 0;
+		selected = 0;
+	}
+	if (rc != 0) {
+		warnx("No APQN found that is suitable for "
+		      "converting the secure AES key '%s'", name);
+		goto out;
+	}
+
+	if (!quiet) {
+		util_print_indented("ATTENTION: Converting a secure key is "
+				    "irreversible, and might have an effect "
+				    "on the volumes encrypted with it!", 0);
+		_keystore_msg_for_volumes("The following volumes are encrypted "
+					  "with this key:", properties, NULL);
+		printf("%s: Convert key '%s [y/N]'? ",
+		       program_invocation_short_name, name);
+		if (!prompt_for_yes(keystore->verbose)) {
+			warnx("Operation aborted");
+			rc = -ECANCELED;
+			goto out;
+		}
+	}
+
+	memset(output_key, 0, sizeof(output_key));
+	output_key_size = sizeof(output_key);
+	rc = convert_aes_data_to_cipher_key(cca, secure_key,
+					    secure_key_size, output_key,
+					    &output_key_size,
+					    keystore->verbose);
+	if (rc != 0) {
+		warnx("Converting the secure key '%s' from %s to %s has failed",
+		      name, KEY_TYPE_CCA_AESDATA, key_type);
+		if (!selected)
+			print_msg_for_cca_envvars("secure AES key");
+		goto out;
+	}
+
+	rc = restrict_key_export(cca, output_key, output_key_size,
+				 keystore->verbose);
+	if (rc != 0) {
+		warnx("Export restricting the converted secure key '%s' has "
+		      "failed", name);
+		if (!selected)
+			print_msg_for_cca_envvars("secure AES key");
+		goto out;
+	}
+
+	rc = properties_set2(properties, PROP_NAME_KEY_TYPE, key_type, true);
+	if (rc != 0) {
+		warnx("Invalid characters in key-type");
+		goto out;
+	}
+
+	rc = properties_save(properties, file_names.info_filename, 1);
+	if (rc != 0) {
+		pr_verbose(keystore,
+			   "Failed to write key info file '%s': %s",
+			   file_names.info_filename, strerror(-rc));
+		goto out;
+	}
+
+	rc = write_secure_key(file_names.skey_filename, output_key,
+			      output_key_size, keystore->verbose);
+	if (rc != 0)
+		goto out;
+
+	pr_verbose(keystore, "Secure key '%s' was converted successfully",
+		   name);
+
+	util_asprintf(&temp, "The following LUKS2 volumes are "
+		      "encrypted with key '%s'. These volumes still contain "
+		      "the secure AES volume key of type CCA-AESDATA. To "
+		      "change the secure AES volume key in the LUKS2 header, "
+		      "run command 'zkey-cryptsetup setkey <device> "
+		      "--master-key-file %s':", name,
+		      file_names.skey_filename);
+	_keystore_msg_for_volumes(temp, properties, VOLUME_TYPE_LUKS2);
+	free(temp);
+	util_asprintf(&temp, "The following plain mode volumes are "
+		      "encrypted with key '%s'. You must adapt the crypttab "
+		      "entries for this volumes and change the key size "
+		      "parameter to 'size=%u' or run command 'zkey crypttab "
+		      "--volumes <device>' for each volume to re-generate the "
+		      "crypttab entries:", name, output_key_size * 8, name);
+	_keystore_msg_for_volumes(temp, properties, VOLUME_TYPE_PLAIN);
+	free(temp);
+
+out:
+	_keystore_free_key_filenames(&file_names);
+	if (properties != NULL)
+		properties_free(properties);
+	if (secure_key != NULL)
+		free(secure_key);
+	if (apqns != NULL)
+		free(apqns);
+	if (apqn_list != NULL)
+		str_list_free_string_array(apqn_list);
+	if (cur_key_type != NULL)
+		free(cur_key_type);
+
+	if (rc != 0)
+		pr_verbose(keystore, "Failed to convert key '%s': %s",
+			   name, strerror(-rc));
+	return rc;
+}
+
 /**
  * Frees a keystore object
  *

zkey/keystore.h

@@ -81,6 +81,10 @@ int keystore_crypttab(struct keystore *keystore, const char *volume_filter,
 		      const char *volume_type, const char *keyfile,
 		      size_t keyfile_offset, size_t keyfile_size, size_t tries);
 
+int keystore_convert_key(struct keystore *keystore, const char *name,
+			 const char *key_type, bool noapqncheck, bool quiet,
+			 int pkey_fd, struct cca_lib *cca);
+
 void keystore_free(struct keystore *keystore);
 
 

zkey/zkey.1

@@ -62,7 +62,8 @@ in size.
 The \fBzkey\fP tool can operate in two modes. When argument
 .I secure\-key\-file
 is specified then it operates on the secure key contained in the specified file.
-This applies to commands \fBgenerate\fP, \fBvalidate\fP, and \fBreencipher\fP.
+This applies to commands \fBgenerate\fP, \fBvalidate\fP, \fBreencipher\fP, and
+\fBconvert\fP.
 When the
 .B \-\-name
 option is specified then it operates on a secure key contained in the secure
@@ -680,6 +681,72 @@ questions, you can specify the
 option. These options are passed to the generated command(s) and behave in the
 same way as with \fBcryptsetup\fP.
 .
+.SS "Convert existing AES secure keys from one key type to another type"
+.
+.B zkey
+.BR convert | con
+.I secure\-key\-file
+.RB \-\-key-type | \-K
+.IR type
+.RB [ \-\-no\-apqn\-check ]
+.RB [ \-\-force | \-F ]
+.RB [ \-\-verbose | \-V ]
+.
+.PP
+.B zkey
+.BR convert | con
+.B \-\-name | \-N
+.IR key-name
+.RB \-\-key-type | \-K
+.IR type
+.RB [ \-\-no\-apqn\-check ]
+.RB [ \-\-force | \-F ]
+.RB [ \-\-verbose | \-V ]
+.
+.PP
+Use the
+.B convert
+command to convert an existing secure key from one key type to another type.
+You can convert secure keys of type CCA-AESDATA to type CCA-AESCIPHER only.
+
+.B Note:
+Secure keys converted to type \fBCCA-AESCIPHER\fP require an IBM cryptographic
+adapter in CCA coprocessor mode of version 6 or later, e.g. a CEX6C.
+
+The secure key can either be contained in a file in the file system, or in a
+secure key repository. To convert a secure key contained in a file, specify
+the file name with option \fIsecure\-key\-file\fP. To convert a secure key
+contained in the secure key repository, specify the name of the key
+that is to be converted using the
+.B \-\-name
+option. You cannot use wildcards. The convert command prompts for
+a confirmation, unless you specify the
+.B \-\-force
+option.
+.PP
+.B Note:
+Converting a secure key is irreversible!
+When converting a secure key that is associated with one or multiple volumes,
+a message informs you about the associated volumes. When the secure key is
+converted, this might have an effect on these volumes.
+.P
+For volumes with volume type \fBplain\fP, you must adapt the crypttab entries
+and change the key size parameter to \fBsize=<new-key-size-in-bits>\fP or run
+command \fBzkey crypttab --volumes <device>\fP for each associated volume to
+re-generate the crypttab entries.
+.P
+Associated volumes of type \fLUKS2\fP still contain the secure AES volume key of
+the original type. To change the secure AES volume key in the LUKS2 header,
+run command \fBzkey-cryptsetup setkey <device> --master-key-file
+<converted-key>\fP for each associated volume.
+.
+.P
+.B Note:
+The \fBconvert\fP command requires the CCA host library (libcsulcca.so)
+to be installed. The required CCA IBM cryptographic adapter firmware version
+is 6.3.27 or later. For the supported environments and downloads, see:
+\fIhttp://www.ibm.com/security/cryptocards\fP
+.
 .
 .
 .
@@ -1203,6 +1270,30 @@ cryptsetup command(s).
 .
 .
 .
+.SS "Options for the convert command"
+.TP
+.BR \-N ", " \-\-name\~\fIkey-name\fP
+Specifies the name of the secure key in the secure key repository. You cannot
+use wildcards.
+This option is only used for secure keys contained in the secure key repository.
+.TP
+.BR \-K ", " \-\-key-type\~\fItype\fP
+Specifies the key type to which the secure key shall be converted to.
+Possible values are \fBCCA-AESCIPHER\fP. Secure keys of type \fBCCA-AESCIPHER\fP
+require an IBM cryptographic adapter in CCA coprocessor mode of version 6 or
+later, e.g. a CEX6C.
+.TP
+.BR \-\-no\-apqn\-check
+Do not check if the associated APQNs are available and capable of converting
+the secure key to type CCA-AESCIPHER.
+This option is only used for secure keys contained in the secure key repository.
+.TP
+.BR \-F ", " \-\-force\fP
+The user is prompted to confirm the convertion of a secure key. Use this option
+to convert a secure key without prompting for a confirmation.
+.
+.
+.
 .SS "General options"
 .TP
 .BR \-V ", " \-\-verbose

zkey/zkey.c

@@ -106,6 +106,7 @@ static struct zkey_globals {
 #define COMMAND_COPY		"copy  "
 #define COMMAND_CRYPTTAB	"crypttab"
 #define COMMAND_CRYPTSETUP	"cryptsetup"
+#define COMMAND_CONVERT		"convert"
 
 #define ZKEY_COMMAND_MAX_LEN	10
 
@@ -764,6 +765,38 @@ static struct util_opt opt_vec[] = {
 		.flags = UTIL_OPT_FLAG_NOSHORT,
 	},
 #endif
+	/***********************************************************/
+	{
+		.flags = UTIL_OPT_FLAG_SECTION,
+		.desc = "OPTIONS",
+		.command = COMMAND_CONVERT,
+	},
+	{
+		.option = { "name", required_argument, NULL, 'N'},
+		.argument = "NAME",
+		.desc = "Name of the secure AES key in the repository that is "
+			"to be converted",
+		.command = COMMAND_CONVERT,
+	},
+	{
+		.option = { "key-type", required_argument, NULL, 'K'},
+		.argument = "type",
+		.desc = "The type of the key to convert the secure key to. "
+			"Possible values are '"KEY_TYPE_CCA_AESCIPHER"'. ",
+		.command = COMMAND_CONVERT,
+	},
+	{
+		.option = {"no-apqn-check", 0, NULL, OPT_NO_APQN_CHECK},
+		.desc = "Do not check if the associated APQN(s) are available",
+		.command = COMMAND_CONVERT,
+		.flags = UTIL_OPT_FLAG_NOSHORT,
+	},
+	{
+		.option = {"force", 0, NULL, 'F'},
+		.desc = "Do not prompt for a confirmation when converting a "
+			"key",
+		.command = COMMAND_CONVERT,
+	},
 	/***********************************************************/
 	{
 		.flags = UTIL_OPT_FLAG_SECTION,
@@ -812,6 +845,7 @@ static int command_rename(void);
 static int command_copy(void);
 static int command_crypttab(void);
 static int command_cryptsetup(void);
+static int command_convert(void);
 
 static struct zkey_command zkey_commands[] = {
 	{
@@ -946,6 +980,21 @@ static struct zkey_command zkey_commands[] = {
 		.has_options = 1,
 		.need_keystore = 1,
 	},
+	{
+		.command = COMMAND_CONVERT,
+		.abbrev_len = 3,
+		.function = command_convert,
+		.need_cca_library = 1,
+		.need_pkey_device = 1,
+		.short_desc = "Convert a secure AES key",
+		.long_desc = "Convert an existing secure AES key that is "
+			     "either contained in SECURE-KEY-FILE or is stored "
+			     "in the repository from one key type to another "
+			     "type.",
+		.has_options = 1,
+		.pos_arg = "[SECURE-KEY-FILE]",
+		.pos_arg_optional = 1,
+	},
 	{ .command = NULL }
 };
 
@@ -1691,6 +1740,206 @@ static int command_cryptsetup(void)
 	return rc != 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 }
 
+/*
+ * Command handler for 'convert'.
+ *
+ * Converts secure keys from one key type to another
+ */
+static int command_convert_file(void)
+{
+	u8 output_key[2 * MAX_SECURE_KEY_SIZE];
+	unsigned int output_key_size;
+	size_t secure_key_size;
+	int rc, is_old_mk;
+	int selected = 1;
+	u8 *secure_key;
+	int min_level;
+	u64 mkvp;
+
+	if (g.name != NULL) {
+		warnx("Option '--name|-N' is not valid for "
+		      "re-enciphering a key outside of the repository");
+		util_prg_print_parse_error();
+		return EXIT_FAILURE;
+	}
+	if (g.noapqncheck) {
+		warnx("Option '--no-apqn-check' is not valid for "
+		      "converting a key outside of the repository");
+		util_prg_print_parse_error();
+		return EXIT_FAILURE;
+	}
+
+	min_level = get_min_card_level_for_keytype(g.key_type);
+	if (min_level < 0) {
+		warnx("Invalid key-type specified: %s", g.key_type);
+		return EXIT_FAILURE;
+	}
+
+	rc = cross_check_apqns(NULL, 0, min_level, true, g.verbose);
+	if (rc == -EINVAL)
+		return EXIT_FAILURE;
+	if (rc != 0 && rc != -ENOTSUP) {
+		warnx("Your master key setup is improper");
+		return EXIT_FAILURE;
+	}
+
+	/* Read the secure key to be re-enciphered */
+	secure_key = read_secure_key(g.pos_arg, &secure_key_size, g.verbose);
+	if (secure_key == NULL)
+		return EXIT_FAILURE;
+
+	rc = validate_secure_key(g.pkey_fd, secure_key, secure_key_size, NULL,
+				 &is_old_mk, NULL, g.verbose);
+	if (rc != 0) {
+		warnx("The secure key in file '%s' is not valid", g.pos_arg);
+		rc = EXIT_FAILURE;
+		goto out;
+	}
+
+	rc = get_master_key_verification_pattern(secure_key, secure_key_size,
+						 &mkvp, g.verbose);
+	if (rc != 0) {
+		warnx("Failed to get the master key verification pattern: %s",
+		      strerror(-rc));
+		rc = EXIT_FAILURE;
+		goto out;
+	}
+
+	if (strcasecmp(get_key_type(secure_key, secure_key_size),
+		       g.key_type) == 0) {
+		warnx("The secure key in file '%s' is already of type %s",
+		      g.pos_arg, get_key_type(secure_key, secure_key_size));
+		rc = EXIT_FAILURE;
+		goto out;
+	}
+
+	if (is_cca_aes_data_key(secure_key, secure_key_size)) {
+		if (strcasecmp(g.key_type, KEY_TYPE_CCA_AESCIPHER) != 0) {
+			warnx("The secure key in file '%s' can not be "
+			      "converted into type %s", g.pos_arg, g.key_type);
+			rc = EXIT_FAILURE;
+			goto out;
+		}
+	} else if (is_cca_aes_cipher_key(secure_key, secure_key_size)) {
+		warnx("The secure key in file '%s' is already of type %s",
+		      g.pos_arg, KEY_TYPE_CCA_AESCIPHER);
+		rc = EXIT_FAILURE;
+		goto out;
+	} else {
+		warnx("The secure key in file '%s' has an unsupported key type",
+		      g.pos_arg);
+		rc = EXIT_FAILURE;
+		goto out;
+	}
+
+	rc = select_cca_adapter_by_mkvp(&g.cca, mkvp, NULL,
+					FLAG_SEL_CCA_MATCH_CUR_MKVP,
+					g.verbose);
+	if (rc == -ENOTSUP) {
+		rc = 0;
+		selected = 0;
+	}
+	if (rc != 0) {
+		warnx("No APQN found that is suitable for "
+		      "converting the secure AES key in file '%s'", g.pos_arg);
+		rc = EXIT_FAILURE;
+		goto out;
+	}
+
+	if (!g.force) {
+		util_print_indented("ATTENTION: Converting a secure key is "
+				    "irreversible, and might have an effect "
+				    "on the volumes encrypted with it!", 0);
+		printf("%s: Convert key in file '%s' [y/N]? ",
+		       program_invocation_short_name, g.pos_arg);
+		if (!prompt_for_yes(g.verbose)) {
+			warnx("Operation aborted");
+			rc = EXIT_FAILURE;
+			goto out;
+		}
+	}
+
+	memset(output_key, 0, sizeof(output_key));
+	output_key_size = sizeof(output_key);
+	rc = convert_aes_data_to_cipher_key(&g.cca, secure_key, secure_key_size,
+					    output_key, &output_key_size,
+					    g.verbose);
+	if (rc != 0) {
+		warnx("Converting the secure key from %s to %s has failed",
+		      get_key_type(secure_key, secure_key_size), g.key_type);
+		if (!selected)
+			print_msg_for_cca_envvars("secure AES key");
+		rc = EXIT_FAILURE;
+		goto out;
+	}
+
+	rc = restrict_key_export(&g.cca, output_key, output_key_size,
+				 g.verbose);
+	if (rc != 0) {
+		warnx("Export restricting the converted secure key has failed");
+		if (!selected)
+			print_msg_for_cca_envvars("secure AES key");
+		rc = EXIT_FAILURE;
+		goto out;
+	}
+
+	pr_verbose("Secure key was converted successfully");
+
+	/* Write the converted secure key */
+	rc = write_secure_key(g.outputfile ? g.outputfile : g.pos_arg,
+			      output_key, output_key_size, g.verbose);
+	if (rc != 0)
+		rc = EXIT_FAILURE;
+out:
+	free(secure_key);
+	return rc;
+}
+
+/*
+ * Command handler for 'convert in repository'.
+ *
+ * Converts secure keys from one key type to another
+ */
+static int command_convert_repository(void)
+{
+	int rc;
+
+	if (g.name == NULL) {
+		misc_print_required_parm("--name/-N");
+		return EXIT_FAILURE;
+	}
+
+	rc = keystore_convert_key(g.keystore, g.name, g.key_type, g.noapqncheck,
+				  g.force, g.pkey_fd, &g.cca);
+
+	return rc != 0 ? EXIT_FAILURE : EXIT_SUCCESS;
+}
+
+/*
+ * Command handler for 'convert'.
+ *
+ * Converts secure keys from one key type to another
+ */
+static int command_convert(void)
+{
+	if (g.key_type == NULL) {
+		misc_print_required_parm("--key-type/-K");
+		return EXIT_FAILURE;
+	}
+	if (strcasecmp(g.key_type, KEY_TYPE_CCA_AESCIPHER) != 0) {
+		warnx("Secure keys can only be converted into key type %s",
+		      KEY_TYPE_CCA_AESCIPHER);
+		return EXIT_FAILURE;
+	}
+
+	if (g.pos_arg != NULL)
+		return command_convert_file();
+	else
+		return command_convert_repository();
+
+	return EXIT_SUCCESS;
+}
+
 /**
  * Opens the keystore. The keystore directory is either the
  * default directory or as specified in an environment variable