--- /dev/null
+/*
+ * Copyright (c) 2016 Google, Inc. All Rights Reserved.
+ *
+ * Author: Eric Biggers <ebiggers@google.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "platform_defs.h"
+#include "command.h"
+#include "init.h"
+#include "io.h"
+
+#ifndef ARRAY_SIZE
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+#endif
+
+/*
+ * We may have to declare the fscrypt ioctls ourselves because someone may be
+ * compiling xfsprogs with old kernel headers. And since some old versions of
+ * <linux/fs.h> declared the policy struct and ioctl numbers but not the flags
+ * and modes, our declarations must be split into two conditional blocks.
+ */
+
+/* Policy struct and ioctl numbers */
+#ifndef FS_IOC_SET_ENCRYPTION_POLICY
+#define FS_KEY_DESCRIPTOR_SIZE 8
+
+struct fscrypt_policy {
+ __u8 version;
+ __u8 contents_encryption_mode;
+ __u8 filenames_encryption_mode;
+ __u8 flags;
+ __u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE];
+} __attribute__((packed));
+
+#define FS_IOC_SET_ENCRYPTION_POLICY _IOR('f', 19, struct fscrypt_policy)
+#define FS_IOC_GET_ENCRYPTION_PWSALT _IOW('f', 20, __u8[16])
+#define FS_IOC_GET_ENCRYPTION_POLICY _IOW('f', 21, struct fscrypt_policy)
+#endif /* FS_IOC_SET_ENCRYPTION_POLICY */
+
+/* Policy flags and encryption modes */
+#ifndef FS_ENCRYPTION_MODE_AES_256_XTS
+#define FS_POLICY_FLAGS_PAD_4 0x00
+#define FS_POLICY_FLAGS_PAD_8 0x01
+#define FS_POLICY_FLAGS_PAD_16 0x02
+#define FS_POLICY_FLAGS_PAD_32 0x03
+#define FS_POLICY_FLAGS_PAD_MASK 0x03
+#define FS_POLICY_FLAGS_VALID 0x03
+
+#define FS_ENCRYPTION_MODE_INVALID 0
+#define FS_ENCRYPTION_MODE_AES_256_XTS 1
+#define FS_ENCRYPTION_MODE_AES_256_GCM 2
+#define FS_ENCRYPTION_MODE_AES_256_CBC 3
+#define FS_ENCRYPTION_MODE_AES_256_CTS 4
+#endif /* FS_ENCRYPTION_MODE_AES_256_XTS */
+
+static cmdinfo_t get_encpolicy_cmd;
+static cmdinfo_t set_encpolicy_cmd;
+
+static void
+set_encpolicy_help(void)
+{
+ printf(_(
+"\n"
+" assign an encryption policy to the currently open file\n"
+"\n"
+" Examples:\n"
+" 'set_encpolicy' - assign policy with default key [0000000000000000]\n"
+" 'set_encpolicy 0000111122223333' - assign policy with specified key\n"
+"\n"
+" -c MODE -- contents encryption mode\n"
+" -n MODE -- filenames encryption mode\n"
+" -f FLAGS -- policy flags\n"
+" -v VERSION -- version of policy structure\n"
+"\n"
+" MODE can be numeric or one of the following predefined values:\n"
+" AES-256-XTS, AES-256-CTS, AES-256-GCM, AES-256-CBC\n"
+" FLAGS and VERSION must be numeric.\n"
+"\n"
+" Note that it's only possible to set an encryption policy on an empty\n"
+" directory. It's then inherited by new files and subdirectories.\n"
+"\n"));
+}
+
+static const struct {
+ __u8 mode;
+ const char *name;
+} available_modes[] = {
+ {FS_ENCRYPTION_MODE_AES_256_XTS, "AES-256-XTS"},
+ {FS_ENCRYPTION_MODE_AES_256_CTS, "AES-256-CTS"},
+ {FS_ENCRYPTION_MODE_AES_256_GCM, "AES-256-GCM"},
+ {FS_ENCRYPTION_MODE_AES_256_CBC, "AES-256-CBC"},
+};
+
+static bool
+parse_byte_value(const char *arg, __u8 *value_ret)
+{
+ long value;
+ char *tmp;
+
+ value = strtol(arg, &tmp, 0);
+ if (value < 0 || value > 255 || tmp == arg || *tmp != '\0')
+ return false;
+ *value_ret = value;
+ return true;
+}
+
+static bool
+parse_mode(const char *arg, __u8 *mode_ret)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(available_modes); i++) {
+ if (strcmp(arg, available_modes[i].name) == 0) {
+ *mode_ret = available_modes[i].mode;
+ return true;
+ }
+ }
+
+ return parse_byte_value(arg, mode_ret);
+}
+
+static const char *
+mode2str(__u8 mode)
+{
+ static char buf[32];
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(available_modes); i++)
+ if (mode == available_modes[i].mode)
+ return available_modes[i].name;
+
+ sprintf(buf, "0x%02x", mode);
+ return buf;
+}
+
+static const char *
+keydesc2str(__u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE])
+{
+ static char buf[2 * FS_KEY_DESCRIPTOR_SIZE + 1];
+ int i;
+
+ for (i = 0; i < FS_KEY_DESCRIPTOR_SIZE; i++)
+ sprintf(&buf[2 * i], "%02x", master_key_descriptor[i]);
+
+ return buf;
+}
+
+static int
+get_encpolicy_f(int argc, char **argv)
+{
+ struct fscrypt_policy policy;
+
+ if (ioctl(file->fd, FS_IOC_GET_ENCRYPTION_POLICY, &policy) < 0) {
+ fprintf(stderr, "%s: failed to get encryption policy: %s\n",
+ file->name, strerror(errno));
+ exitcode = 1;
+ return 0;
+ }
+
+ printf("Encryption policy for %s:\n", file->name);
+ printf("\tPolicy version: %u\n", policy.version);
+ printf("\tMaster key descriptor: %s\n",
+ keydesc2str(policy.master_key_descriptor));
+ printf("\tContents encryption mode: %u (%s)\n",
+ policy.contents_encryption_mode,
+ mode2str(policy.contents_encryption_mode));
+ printf("\tFilenames encryption mode: %u (%s)\n",
+ policy.filenames_encryption_mode,
+ mode2str(policy.filenames_encryption_mode));
+ printf("\tFlags: 0x%02x\n", policy.flags);
+ return 0;
+}
+
+static int
+set_encpolicy_f(int argc, char **argv)
+{
+ int c;
+ struct fscrypt_policy policy;
+
+ /* Initialize the policy structure with default values */
+ memset(&policy, 0, sizeof(policy));
+ policy.contents_encryption_mode = FS_ENCRYPTION_MODE_AES_256_XTS;
+ policy.filenames_encryption_mode = FS_ENCRYPTION_MODE_AES_256_CTS;
+ policy.flags = FS_POLICY_FLAGS_PAD_16;
+
+ /* Parse options */
+ while ((c = getopt(argc, argv, "c:n:f:v:")) != EOF) {
+ switch (c) {
+ case 'c':
+ if (!parse_mode(optarg,
+ &policy.contents_encryption_mode)) {
+ fprintf(stderr, "invalid contents encryption "
+ "mode: %s\n", optarg);
+ return 0;
+ }
+ break;
+ case 'n':
+ if (!parse_mode(optarg,
+ &policy.filenames_encryption_mode)) {
+ fprintf(stderr, "invalid filenames encryption "
+ "mode: %s\n", optarg);
+ return 0;
+ }
+ break;
+ case 'f':
+ if (!parse_byte_value(optarg, &policy.flags)) {
+ fprintf(stderr, "invalid flags: %s\n", optarg);
+ return 0;
+ }
+ break;
+ case 'v':
+ if (!parse_byte_value(optarg, &policy.version)) {
+ fprintf(stderr, "invalid policy version: %s\n",
+ optarg);
+ return 0;
+ }
+ break;
+ default:
+ return command_usage(&set_encpolicy_cmd);
+ }
+ }
+ argc -= optind;
+ argv += optind;
+
+ if (argc > 1)
+ return command_usage(&set_encpolicy_cmd);
+
+ /* Parse key descriptor if specified */
+ if (argc > 0) {
+ const char *keydesc = argv[0];
+ char *tmp;
+ unsigned long long x;
+ int i;
+
+ if (strlen(keydesc) != FS_KEY_DESCRIPTOR_SIZE * 2) {
+ fprintf(stderr, "invalid key descriptor: %s\n",
+ keydesc);
+ return 0;
+ }
+
+ x = strtoull(keydesc, &tmp, 16);
+ if (tmp == keydesc || *tmp != '\0') {
+ fprintf(stderr, "invalid key descriptor: %s\n",
+ keydesc);
+ return 0;
+ }
+
+ for (i = 0; i < FS_KEY_DESCRIPTOR_SIZE; i++) {
+ policy.master_key_descriptor[i] = x >> 56;
+ x <<= 8;
+ }
+ }
+
+ /* Set the encryption policy */
+ if (ioctl(file->fd, FS_IOC_SET_ENCRYPTION_POLICY, &policy) < 0) {
+ fprintf(stderr, "%s: failed to set encryption policy: %s\n",
+ file->name, strerror(errno));
+ exitcode = 1;
+ return 0;
+ }
+
+ return 0;
+}
+
+void
+encrypt_init(void)
+{
+ get_encpolicy_cmd.name = "get_encpolicy";
+ get_encpolicy_cmd.cfunc = get_encpolicy_f;
+ get_encpolicy_cmd.argmin = 0;
+ get_encpolicy_cmd.argmax = 0;
+ get_encpolicy_cmd.flags = CMD_NOMAP_OK | CMD_FOREIGN_OK;
+ get_encpolicy_cmd.oneline =
+ _("display the encryption policy of the current file");
+
+ set_encpolicy_cmd.name = "set_encpolicy";
+ set_encpolicy_cmd.cfunc = set_encpolicy_f;
+ set_encpolicy_cmd.args =
+ _("[-c mode] [-n mode] [-f flags] [-v version] [keydesc]");
+ set_encpolicy_cmd.argmin = 0;
+ set_encpolicy_cmd.argmax = -1;
+ set_encpolicy_cmd.flags = CMD_NOMAP_OK | CMD_FOREIGN_OK;
+ set_encpolicy_cmd.oneline =
+ _("assign an encryption policy to the current file");
+ set_encpolicy_cmd.help = set_encpolicy_help;
+
+ add_command(&get_encpolicy_cmd);
+ add_command(&set_encpolicy_cmd);
+}
projects / thirdparty / xfsprogs-dev.git / commitdiff
