2 * e4crypt.c - ext4 encryption management utility
4 * Copyright (c) 2014 Google, Inc.
5 * SHA512 implementation from libtomcrypt.
7 * Authors: Michael Halcrow <mhalcrow@google.com>,
8 * Ildar Muslukhov <ildarm@google.com>
11 #ifndef _LARGEFILE_SOURCE
12 #define _LARGEFILE_SOURCE
15 #ifndef _LARGEFILE64_SOURCE
16 #define _LARGEFILE64_SOURCE
34 #include <sys/ioctl.h>
36 #include <sys/types.h>
41 #if !defined(HAVE_ADD_KEY) || !defined(HAVE_KEYCTL)
42 #include <sys/syscall.h>
48 #include "ext2fs/ext2_fs.h"
49 #include "ext2fs/ext2fs.h"
50 #include "uuid/uuid.h"
52 /* special process keyring shortcut IDs */
53 #define KEY_SPEC_THREAD_KEYRING -1
54 #define KEY_SPEC_PROCESS_KEYRING -2
55 #define KEY_SPEC_SESSION_KEYRING -3
56 #define KEY_SPEC_USER_KEYRING -4
57 #define KEY_SPEC_USER_SESSION_KEYRING -5
58 #define KEY_SPEC_GROUP_KEYRING -6
60 #define KEYCTL_GET_KEYRING_ID 0
61 #define KEYCTL_JOIN_SESSION_KEYRING 1
62 #define KEYCTL_DESCRIBE 6
63 #define KEYCTL_SEARCH 10
64 #define KEYCTL_SESSION_TO_PARENT 18
66 typedef __s32 key_serial_t;
68 #define EXT4_KEY_REF_STR_BUF_SIZE ((EXT4_KEY_DESCRIPTOR_SIZE * 2) + 1)
70 #ifndef EXT4_IOC_GET_ENCRYPTION_PWSALT
71 #define EXT4_IOC_GET_ENCRYPTION_PWSALT _IOW('f', 20, __u8[16])
74 #define OPT_VERBOSE 0x0001
75 #define OPT_QUIET 0x0002
80 static long keyctl(int cmd, ...)
83 unsigned long arg2, arg3, arg4, arg5;
86 arg2 = va_arg(va, unsigned long);
87 arg3 = va_arg(va, unsigned long);
88 arg4 = va_arg(va, unsigned long);
89 arg5 = va_arg(va, unsigned long);
91 return syscall(__NR_keyctl, cmd, arg2, arg3, arg4, arg5);
96 static key_serial_t add_key(const char *type, const char *description,
97 const void *payload, size_t plen,
100 return syscall(__NR_add_key, type, description, payload,
105 static const unsigned char *hexchars = (const unsigned char *) "0123456789abcdef";
106 static const size_t hexchars_size = 16;
108 #define SHA512_LENGTH 64
109 #define EXT2FS_KEY_TYPE_LOGON "logon"
110 #define EXT2FS_KEY_DESC_PREFIX "ext4:"
111 #define EXT2FS_KEY_DESC_PREFIX_SIZE 5
113 #define EXT4_IOC_SET_ENCRYPTION_POLICY _IOR('f', 19, struct ext4_encryption_policy)
114 #define EXT4_IOC_GET_ENCRYPTION_POLICY _IOW('f', 21, struct ext4_encryption_policy)
116 static int int_log2(int arg)
128 static void validate_paths(int argc, char *argv[], int path_start_index)
134 for (x = path_start_index; x < argc; x++) {
135 int ret = access(argv[x], W_OK);
142 ret = stat(argv[x], &st);
145 if (!S_ISDIR(st.st_mode)) {
146 fprintf(stderr, "%s is not a directory\n", argv[x]);
154 static int hex2byte(const char *hex, size_t hex_size, unsigned char *bytes,
158 unsigned char *h, *l;
162 for (x = 0; x < hex_size; x += 2) {
163 h = memchr(hexchars, hex[x], hexchars_size);
166 l = memchr(hexchars, hex[x + 1], hexchars_size);
169 if ((x >> 1) >= bytes_size)
171 bytes[x >> 1] = (((unsigned char)(h - hexchars) << 4) +
172 (unsigned char)(l - hexchars));
182 char key_ref_str[EXT4_KEY_REF_STR_BUF_SIZE];
183 unsigned char key_desc[EXT4_KEY_DESCRIPTOR_SIZE];
184 unsigned char key[EXT4_MAX_KEY_SIZE];
187 struct salt *salt_list;
190 char in_passphrase[EXT4_MAX_PASSPHRASE_SIZE];
192 static struct salt *find_by_salt(unsigned char *salt, size_t salt_len)
197 for (i = 0, p = salt_list; i < num_salt; i++, p++)
198 if ((p->salt_len == salt_len) &&
199 !memcmp(p->salt, salt, salt_len))
204 static void add_salt(unsigned char *salt, size_t salt_len)
206 if (find_by_salt(salt, salt_len))
208 if (num_salt >= max_salt) {
209 max_salt = num_salt + 10;
210 salt_list = realloc(salt_list, max_salt * sizeof(struct salt));
212 fprintf(stderr, "Couldn't allocate salt list\n");
216 salt_list[num_salt].salt = salt;
217 salt_list[num_salt].salt_len = salt_len;
221 static void clear_secrets(void)
224 memset(salt_list, 0, sizeof(struct salt) * max_salt);
228 memset(in_passphrase, 0, sizeof(in_passphrase));
231 static void die_signal_handler(int signum EXT2FS_ATTR((unused)),
232 siginfo_t *siginfo EXT2FS_ATTR((unused)),
233 void *context EXT2FS_ATTR((unused)))
239 static void sigcatcher_setup(void)
243 memset(&sa, 0, sizeof(struct sigaction));
244 sa.sa_sigaction = die_signal_handler;
245 sa.sa_flags = SA_SIGINFO;
247 sigaction(SIGHUP, &sa, 0);
248 sigaction(SIGINT, &sa, 0);
249 sigaction(SIGQUIT, &sa, 0);
250 sigaction(SIGFPE, &sa, 0);
251 sigaction(SIGILL, &sa, 0);
252 sigaction(SIGBUS, &sa, 0);
253 sigaction(SIGSEGV, &sa, 0);
254 sigaction(SIGABRT, &sa, 0);
255 sigaction(SIGPIPE, &sa, 0);
256 sigaction(SIGALRM, &sa, 0);
257 sigaction(SIGTERM, &sa, 0);
258 sigaction(SIGUSR1, &sa, 0);
259 sigaction(SIGUSR2, &sa, 0);
260 sigaction(SIGPOLL, &sa, 0);
261 sigaction(SIGPROF, &sa, 0);
262 sigaction(SIGSYS, &sa, 0);
263 sigaction(SIGTRAP, &sa, 0);
264 sigaction(SIGVTALRM, &sa, 0);
265 sigaction(SIGXCPU, &sa, 0);
266 sigaction(SIGXFSZ, &sa, 0);
270 #define PARSE_FLAGS_NOTSUPP_OK 0x0001
271 #define PARSE_FLAGS_FORCE_FN 0x0002
273 static void parse_salt(char *salt_str, int flags)
275 unsigned char buf[EXT4_MAX_SALT_SIZE];
277 unsigned char *salt_buf;
278 int fd, ret, salt_len = 0;
280 if (flags & PARSE_FLAGS_FORCE_FN)
281 goto salt_from_filename;
282 if (strncmp(cp, "s:", 2) == 0) {
284 salt_len = strlen(cp);
285 if (salt_len >= EXT4_MAX_SALT_SIZE)
287 strncpy((char *) buf, cp, sizeof(buf));
288 } else if (cp[0] == '/') {
290 fd = open(cp, O_RDONLY | O_DIRECTORY);
291 if (fd == -1 && errno == ENOTDIR)
292 fd = open(cp, O_RDONLY);
297 ret = ioctl(fd, EXT4_IOC_GET_ENCRYPTION_PWSALT, &buf);
300 if (flags & PARSE_FLAGS_NOTSUPP_OK)
302 perror("EXT4_IOC_GET_ENCRYPTION_PWSALT");
305 if (options & OPT_VERBOSE) {
307 uuid_unparse(buf, tmp);
308 printf("%s has pw salt %s\n", cp, tmp);
311 } else if (strncmp(cp, "f:", 2) == 0) {
313 goto salt_from_filename;
314 } else if (strncmp(cp, "0x", 2) == 0) {
315 unsigned char *h, *l;
321 if (salt_len >= EXT4_MAX_SALT_SIZE)
323 h = memchr(hexchars, *cp++, hexchars_size);
324 l = memchr(hexchars, *cp++, hexchars_size);
328 (((unsigned char)(h - hexchars) << 4) +
329 (unsigned char)(l - hexchars));
331 } else if (uuid_parse(cp, buf) == 0) {
335 fprintf(stderr, "Invalid salt: %s\n", salt_str);
338 salt_buf = malloc(salt_len);
340 fprintf(stderr, "Couldn't allocate salt\n");
343 memcpy(salt_buf, buf, salt_len);
344 add_salt(salt_buf, salt_len);
347 static void set_policy(struct salt *set_salt, int pad,
348 int argc, char *argv[], int path_start_index)
351 struct ext4_encryption_policy policy;
357 if ((pad != 4) && (pad != 8) &&
358 (pad != 16) && (pad != 32)) {
359 fprintf(stderr, "Invalid padding %d\n", pad);
363 for (x = path_start_index; x < argc; x++) {
364 fd = open(argv[x], O_DIRECTORY);
372 if (ioctl(fd, EXT4_IOC_GET_ENCRYPTION_PWSALT,
374 perror("EXT4_IOC_GET_ENCRYPTION_PWSALT");
377 salt = find_by_salt(uu, sizeof(uu));
379 fprintf(stderr, "Couldn't find salt!?!\n");
384 policy.contents_encryption_mode =
385 EXT4_ENCRYPTION_MODE_AES_256_XTS;
386 policy.filenames_encryption_mode =
387 EXT4_ENCRYPTION_MODE_AES_256_CTS;
388 policy.flags = int_log2(pad >> 2);
389 memcpy(policy.master_key_descriptor, salt->key_desc,
390 EXT4_KEY_DESCRIPTOR_SIZE);
391 rc = ioctl(fd, EXT4_IOC_SET_ENCRYPTION_POLICY, &policy);
394 printf("Error [%s] setting policy.\nThe key descriptor "
395 "[%s] may not match the existing encryption "
396 "context for directory [%s].\n",
397 strerror(errno), salt->key_ref_str, argv[x]);
400 printf("Key with descriptor [%s] applied to %s.\n",
401 salt->key_ref_str, argv[x]);
405 static void pbkdf2_sha512(const char *passphrase, struct salt *salt,
407 unsigned char derived_key[EXT4_MAX_KEY_SIZE])
409 size_t passphrase_size = strlen(passphrase);
410 unsigned char buf[SHA512_LENGTH + EXT4_MAX_PASSPHRASE_SIZE] = {0};
411 unsigned char tempbuf[SHA512_LENGTH] = {0};
412 char final[SHA512_LENGTH] = {0};
413 unsigned char saltbuf[EXT4_MAX_SALT_SIZE + EXT4_MAX_PASSPHRASE_SIZE] = {0};
414 int actual_buf_len = SHA512_LENGTH + passphrase_size;
415 int actual_saltbuf_len = EXT4_MAX_SALT_SIZE + passphrase_size;
417 __u32 *final_u32 = (__u32 *)final;
418 __u32 *temp_u32 = (__u32 *)tempbuf;
420 if (passphrase_size > EXT4_MAX_PASSPHRASE_SIZE) {
421 printf("Passphrase size is %zd; max is %d.\n", passphrase_size,
422 EXT4_MAX_PASSPHRASE_SIZE);
425 if (salt->salt_len > EXT4_MAX_SALT_SIZE) {
426 printf("Salt size is %zd; max is %d.\n", salt->salt_len,
430 assert(EXT4_MAX_KEY_SIZE <= SHA512_LENGTH);
432 memcpy(saltbuf, salt->salt, salt->salt_len);
433 memcpy(&saltbuf[EXT4_MAX_SALT_SIZE], passphrase, passphrase_size);
435 memcpy(&buf[SHA512_LENGTH], passphrase, passphrase_size);
437 for (x = 0; x < count; ++x) {
439 ext2fs_sha512(saltbuf, actual_saltbuf_len, tempbuf);
442 * buf: [previous hash || passphrase]
444 memcpy(buf, tempbuf, SHA512_LENGTH);
445 ext2fs_sha512(buf, actual_buf_len, tempbuf);
447 for (y = 0; y < (sizeof(final) / sizeof(*final_u32)); ++y)
448 final_u32[y] = final_u32[y] ^ temp_u32[y];
450 memcpy(derived_key, final, EXT4_MAX_KEY_SIZE);
453 static int disable_echo(struct termios *saved_settings)
455 struct termios current_settings;
458 rc = tcgetattr(0, ¤t_settings);
461 *saved_settings = current_settings;
462 current_settings.c_lflag &= ~ECHO;
463 rc = tcsetattr(0, TCSANOW, ¤t_settings);
468 static void get_passphrase(char *passphrase, int len)
471 struct termios current_settings;
474 disable_echo(¤t_settings);
475 p = fgets(passphrase, len, stdin);
476 tcsetattr(0, TCSANOW, ¤t_settings);
479 printf("Aborting.\n");
482 p = strrchr(passphrase, '\n');
484 p = passphrase + len - 1;
494 static const struct keyring_map keyrings[] = {
495 {"@us", 3, KEY_SPEC_USER_SESSION_KEYRING},
496 {"@u", 2, KEY_SPEC_USER_KEYRING},
497 {"@s", 2, KEY_SPEC_SESSION_KEYRING},
498 {"@g", 2, KEY_SPEC_GROUP_KEYRING},
499 {"@p", 2, KEY_SPEC_PROCESS_KEYRING},
500 {"@t", 2, KEY_SPEC_THREAD_KEYRING},
503 static int get_keyring_id(const char *keyring)
509 * If no keyring is specified, by default use either the user
510 * session keyring or the session keyring. Fetching the
511 * session keyring will return the user session keyring if no
512 * session keyring has been set.
515 return KEY_SPEC_SESSION_KEYRING;
516 for (x = 0; x < (sizeof(keyrings) / sizeof(keyrings[0])); ++x) {
517 if (strcmp(keyring, keyrings[x].name) == 0) {
518 return keyrings[x].code;
521 x = strtoul(keyring, &end, 10);
523 if (keyctl(KEYCTL_DESCRIBE, x, NULL, 0) < 0)
530 static void generate_key_ref_str(struct salt *salt)
532 unsigned char key_ref1[SHA512_LENGTH];
533 unsigned char key_ref2[SHA512_LENGTH];
536 ext2fs_sha512(salt->key, EXT4_MAX_KEY_SIZE, key_ref1);
537 ext2fs_sha512(key_ref1, SHA512_LENGTH, key_ref2);
538 memcpy(salt->key_desc, key_ref2, EXT4_KEY_DESCRIPTOR_SIZE);
539 for (x = 0; x < EXT4_KEY_DESCRIPTOR_SIZE; ++x) {
540 sprintf(&salt->key_ref_str[x * 2], "%02x",
543 salt->key_ref_str[EXT4_KEY_REF_STR_BUF_SIZE - 1] = '\0';
546 static void insert_key_into_keyring(const char *keyring, struct salt *salt)
548 int keyring_id = get_keyring_id(keyring);
549 struct ext4_encryption_key key;
550 char key_ref_full[EXT2FS_KEY_DESC_PREFIX_SIZE +
551 EXT4_KEY_REF_STR_BUF_SIZE];
554 if (keyring_id == 0) {
555 printf("Invalid keyring [%s].\n", keyring);
558 sprintf(key_ref_full, "%s%s", EXT2FS_KEY_DESC_PREFIX,
560 rc = keyctl(KEYCTL_SEARCH, keyring_id, EXT2FS_KEY_TYPE_LOGON,
563 if ((options & OPT_QUIET) == 0)
564 printf("Key with descriptor [%s] already exists\n",
567 } else if ((rc == -1) && (errno != ENOKEY)) {
568 printf("keyctl_search failed: %s\n", strerror(errno));
570 printf("Keyring [%s] is not available.\n", keyring);
573 key.mode = EXT4_ENCRYPTION_MODE_AES_256_XTS;
574 memcpy(key.raw, salt->key, EXT4_MAX_KEY_SIZE);
575 key.size = EXT4_MAX_KEY_SIZE;
578 * We need to do this instead of simply adding the key to
579 * KEY_SPEC_SESSION_KEYRING since trying to add a key to a
580 * session keyring that does not yet exist will cause the
581 * kernel to create a session keyring --- which will then get
582 * garbage collected as soon as e4crypt exits.
584 * The fact that the keyctl system call and the add_key system
585 * call treats KEY_SPEC_SESSION_KEYRING differently when a
586 * session keyring does not exist is very unfortunate and
587 * confusing, but so it goes...
589 if (keyring_id == KEY_SPEC_SESSION_KEYRING) {
590 keyring_id = keyctl(KEYCTL_GET_KEYRING_ID, keyring_id, 0);
591 if (keyring_id < 0) {
592 printf("Error getting session keyring ID: %s\n",
597 rc = add_key(EXT2FS_KEY_TYPE_LOGON, key_ref_full, (void *)&key,
598 sizeof(key), keyring_id);
600 if (errno == EDQUOT) {
601 printf("Error adding key to keyring; quota exceeded\n");
603 printf("Error adding key with key descriptor [%s]: "
604 "%s\n", salt->key_ref_str, strerror(errno));
608 if ((options & OPT_QUIET) == 0)
609 printf("Added key with descriptor [%s]\n",
614 static void get_default_salts(void)
616 FILE *f = setmntent("/etc/mtab", "r");
619 while (f && ((mnt = getmntent(f)) != NULL)) {
620 if (strcmp(mnt->mnt_type, "ext4") ||
621 access(mnt->mnt_dir, R_OK))
623 parse_salt(mnt->mnt_dir, PARSE_FLAGS_NOTSUPP_OK);
628 /* Functions which implement user commands */
631 const char *cmd_name;
632 void (*cmd_func)(int, char **, const struct cmd_desc *);
633 const char *cmd_desc;
634 const char *cmd_help;
638 #define CMD_HIDDEN 0x0001
640 static void do_help(int argc, char **argv, const struct cmd_desc *cmd);
642 #define add_key_desc "adds a key to the user's keyring"
643 #define add_key_help \
644 "e4crypt add_key -S salt [ -k keyring ] [-v] [-q] [ -p pad ] [ path ... ]\n\n" \
645 "Prompts the user for a passphrase and inserts it into the specified\n" \
646 "keyring. If no keyring is specified, e4crypt will use the session\n" \
647 "keyring if it exists or the user session keyring if it does not.\n\n" \
648 "If one or more directory paths are specified, e4crypt will try to\n" \
649 "set the policy of those directories to use the key just entered by\n" \
652 static void do_add_key(int argc, char **argv, const struct cmd_desc *cmd)
655 char *keyring = NULL;
659 while ((opt = getopt(argc, argv, "k:S:p:vq")) != -1) {
662 /* Specify a keyring. */
669 /* Salt value for passphrase. */
670 parse_salt(optarg, 0);
673 options |= OPT_VERBOSE;
676 options |= OPT_QUIET;
681 fprintf(stderr, "Unrecognized option: %c\n",
683 fputs("USAGE:\n ", stderr);
684 fputs(cmd->cmd_help, stderr);
691 fprintf(stderr, "No salt values available\n");
694 validate_paths(argc, argv, optind);
695 for (i = optind; i < argc; i++)
696 parse_salt(argv[i], PARSE_FLAGS_FORCE_FN);
697 printf("Enter passphrase (echo disabled): ");
698 get_passphrase(in_passphrase, sizeof(in_passphrase));
699 for (j = 0, salt = salt_list; j < num_salt; j++, salt++) {
700 pbkdf2_sha512(in_passphrase, salt,
701 EXT4_PBKDF2_ITERATIONS, salt->key);
702 generate_key_ref_str(salt);
703 insert_key_into_keyring(keyring, salt);
706 set_policy(NULL, pad, argc, argv, optind);
711 #define set_policy_desc "sets a policy for directories"
712 #define set_policy_help \
713 "e4crypt set_policy [ -p pad ] policy path ... \n\n" \
714 "Sets the policy for the directories specified on the command line.\n" \
715 "All directories must be empty to set the policy; if the directory\n" \
716 "already has a policy established, e4crypt will validate that it the\n" \
717 "policy matches what was specified. A policy is an encryption key\n" \
718 "identifier consisting of 16 hexadecimal characters.\n"
720 static void do_set_policy(int argc, char **argv, const struct cmd_desc *cmd)
725 while ((c = getopt (argc, argv, "p:")) != EOF) {
733 if (argc < optind + 2) {
734 fprintf(stderr, "Missing required argument(s).\n\n");
735 fputs("USAGE:\n ", stderr);
736 fputs(cmd->cmd_help, stderr);
740 if ((strlen(argv[optind]) != (EXT4_KEY_DESCRIPTOR_SIZE * 2)) ||
741 hex2byte(argv[optind], (EXT4_KEY_DESCRIPTOR_SIZE * 2),
742 saltbuf.key_desc, EXT4_KEY_DESCRIPTOR_SIZE)) {
743 printf("Invalid key descriptor [%s]. Valid characters "
744 "are 0-9 and a-f, lower case. "
745 "Length must be %d.\n",
746 argv[optind], (EXT4_KEY_DESCRIPTOR_SIZE * 2));
749 validate_paths(argc, argv, optind+1);
750 strcpy(saltbuf.key_ref_str, argv[optind]);
751 set_policy(&saltbuf, pad, argc, argv, optind+1);
755 #define get_policy_desc "get the encryption for directories"
756 #define get_policy_help \
757 "e4crypt get_policy path ... \n\n" \
758 "Gets the policy for the directories specified on the command line.\n"
760 static void do_get_policy(int argc, char **argv, const struct cmd_desc *cmd)
762 struct ext4_encryption_policy policy;
766 fprintf(stderr, "Missing required argument(s).\n\n");
767 fputs("USAGE:\n ", stderr);
768 fputs(cmd->cmd_help, stderr);
772 for (i = 1; i < argc; i++) {
773 fd = open(argv[i], O_RDONLY);
778 rc = ioctl(fd, EXT4_IOC_GET_ENCRYPTION_POLICY, &policy);
781 printf("Error getting policy for %s: %s\n",
782 argv[i], strerror(errno));
785 printf("%s: ", argv[i]);
786 for (j = 0; j < EXT4_KEY_DESCRIPTOR_SIZE; j++) {
787 printf("%02x", (unsigned char) policy.master_key_descriptor[j]);
794 #define new_session_desc "give the invoking process a new session keyring"
795 #define new_session_help \
796 "e4crypt new_session\n\n" \
797 "Give the invoking process (typically a shell) a new session keyring,\n" \
798 "discarding its old session keyring.\n"
800 static void do_new_session(int argc, char **argv EXT2FS_ATTR((unused)),
801 const struct cmd_desc *cmd)
806 fputs("Excess arguments\n\n", stderr);
807 fputs(cmd->cmd_help, stderr);
810 keyid = keyctl(KEYCTL_JOIN_SESSION_KEYRING, NULL);
812 perror("KEYCTL_JOIN_SESSION_KEYRING");
815 ret = keyctl(KEYCTL_SESSION_TO_PARENT, NULL);
817 perror("KEYCTL_SESSION_TO_PARENT");
820 printf("Switched invoking process to new session keyring %ld\n", keyid);
824 #define CMD(name) { #name, do_##name, name##_desc, name##_help, 0 }
825 #define _CMD(name) { #name, do_##name, NULL, NULL, CMD_HIDDEN }
827 const struct cmd_desc cmd_list[] = {
833 { NULL, NULL, NULL, NULL, 0 }
836 static void do_help(int argc, char **argv,
837 const struct cmd_desc *cmd EXT2FS_ATTR((unused)))
839 const struct cmd_desc *p;
842 for (p = cmd_list; p->cmd_name; p++) {
843 if (p->cmd_flags & CMD_HIDDEN)
845 if (strcmp(p->cmd_name, argv[1]) == 0) {
847 fputs("USAGE:\n ", stdout);
848 fputs(p->cmd_help, stdout);
852 printf("Unknown command: %s\n\n", argv[1]);
855 fputs("Available commands:\n", stdout);
856 for (p = cmd_list; p->cmd_name; p++) {
857 if (p->cmd_flags & CMD_HIDDEN)
859 printf(" %-20s %s\n", p->cmd_name, p->cmd_desc);
861 printf("\nTo get more information on a command, "
862 "type 'e4crypt help cmd'\n");
866 int main(int argc, char *argv[])
868 const struct cmd_desc *cmd;
871 do_help(argc, argv, cmd_list);
874 for (cmd = cmd_list; cmd->cmd_name; cmd++) {
875 if (strcmp(cmd->cmd_name, argv[1]) == 0) {
876 cmd->cmd_func(argc-1, argv+1, cmd);
880 printf("Unknown command: %s\n\n", argv[1]);
881 do_help(1, argv, cmd_list);