4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 only,
8 * as published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License version 2 for more details (a copy is included
14 * in the LICENSE file that accompanied this code).
16 * You should have received a copy of the GNU General Public License
17 * version 2 along with this program; If not, see
18 * http://www.gnu.org/licenses/gpl-2.0.html
23 * Copyright (C) 2015, Trustees of Indiana University
25 * Author: Jeremy Filizetti <jfilizet@iu.edu>
34 #include <openssl/dh.h>
35 #include <openssl/engine.h>
36 #include <openssl/err.h>
37 #include <openssl/hmac.h>
38 #include <sys/types.h>
40 #include <lnet/nidstr.h>
43 #include "write_bytes.h"
45 #define SK_PBKDF2_ITERATIONS 10000
47 static struct sk_crypt_type sk_crypt_types[] = {
48 [SK_CRYPT_AES256_CTR] = {
49 .sct_name = "ctr(aes)",
54 static struct sk_hmac_type sk_hmac_types[] = {
56 .sht_name = "hmac(sha256)",
60 .sht_name = "hmac(sha512)",
66 # include "lgss_utils.h"
68 # include "gss_util.h"
69 # include "gss_oids.h"
70 # include "err_util.h"
76 * \param[in] program Program name to output
77 * \param[in] verbose Verbose flag
78 * \param[in] fg Whether or not to run in foreground
81 void sk_init_logging(char *program, int verbose, int fg)
83 initerr(program, verbose, fg);
88 * Loads the key from \a filename and returns the struct sk_keyfile_config.
89 * It should be freed by the caller.
91 * \param[in] filename Disk or key payload data
93 * \return sk_keyfile_config sucess
94 * \return NULL failure
96 struct sk_keyfile_config *sk_read_file(char *filename)
98 struct sk_keyfile_config *config;
104 config = malloc(sizeof(*config));
106 printerr(0, "Failed to allocate memory for config\n");
110 /* allow standard input override */
111 if (strcmp(filename, "-") == 0)
114 fd = open(filename, O_RDONLY);
117 printerr(0, "Error opening key file '%s': %s\n", filename,
120 } else if (fd != STDIN_FILENO) {
124 if (rc == 0 && (st.st_mode & ~0600))
125 fprintf(stderr, "warning: "
126 "secret key '%s' has insecure file mode %#o\n",
127 filename, st.st_mode);
130 ptr = (char *)config;
131 remain = sizeof(*config);
133 rc = read(fd, ptr, remain);
137 printerr(0, "read() failed on %s: %s\n", filename,
140 } else if (rc == 0) {
141 printerr(0, "File %s does not have a complete key\n",
149 if (fd != STDIN_FILENO)
151 sk_config_disk_to_cpu(config);
162 * Checks if a key matching \a description is found in the keyring for
163 * logging purposes and then attempts to load \a payload of \a psize into a key
164 * with \a description.
166 * \param[in] payload Key payload
167 * \param[in] psize Payload size
168 * \param[in] description Description used for key in keyring
173 static key_serial_t sk_load_key(const struct sk_keyfile_config *skc,
174 const char *description)
176 struct sk_keyfile_config payload;
179 memcpy(&payload, skc, sizeof(*skc));
181 /* In the keyring use the disk layout so keyctl pipe can be used */
182 sk_config_cpu_to_disk(&payload);
184 /* Check to see if a key is already loaded matching description */
185 key = keyctl_search(KEY_SPEC_USER_KEYRING, "user", description, 0);
187 printerr(2, "Key %d found in session keyring, replacing\n",
190 key = add_key("user", description, &payload, sizeof(payload),
191 KEY_SPEC_USER_KEYRING);
193 printerr(2, "Added key %d with description %s\n", key,
196 printerr(0, "Failed to add key with %s\n", description);
202 * Reads the key from \a path, verifies it and loads into the session keyring
203 * using a description determined by the the \a type. Existing keys with the
204 * same description are replaced.
206 * \param[in] path Path to key file
207 * \param[in] type Type of key to load which determines the description
212 int sk_load_keyfile(char *path)
214 struct sk_keyfile_config *config;
215 char description[SK_DESCRIPTION_SIZE + 1];
221 rc = stat(path, &buf);
223 printerr(0, "stat() failed for file %s: %s\n", path,
228 config = sk_read_file(path);
232 /* Similar to ssh, require adequate care of key files */
233 if (buf.st_mode & (S_IRGRP | S_IWGRP | S_IWOTH | S_IXOTH)) {
234 printerr(0, "Shared key files must be read/writeable only by "
239 if (sk_validate_config(config))
242 /* The server side can have multiple key files per file system so
243 * the nodemap name is appended to the key description to uniquely
245 if (config->skc_type & SK_TYPE_MGS) {
246 /* Any key can be an MGS key as long as we are told to use it */
247 rc = snprintf(description, SK_DESCRIPTION_SIZE, "lustre:MGS:%s",
248 config->skc_nodemap);
249 if (rc >= SK_DESCRIPTION_SIZE)
251 if (sk_load_key(config, description) == -1)
254 if (config->skc_type & SK_TYPE_SERVER) {
255 /* Server keys need to have the file system name in the key */
256 if (!config->skc_fsname) {
257 printerr(0, "Key configuration has no file system "
258 "attribute. Can't load as server type\n");
261 rc = snprintf(description, SK_DESCRIPTION_SIZE, "lustre:%s:%s",
262 config->skc_fsname, config->skc_nodemap);
263 if (rc >= SK_DESCRIPTION_SIZE)
265 if (sk_load_key(config, description) == -1)
268 if (config->skc_type & SK_TYPE_CLIENT) {
269 /* Load client file system key */
270 if (config->skc_fsname) {
271 rc = snprintf(description, SK_DESCRIPTION_SIZE,
272 "lustre:%s", config->skc_fsname);
273 if (rc >= SK_DESCRIPTION_SIZE)
275 if (sk_load_key(config, description) == -1)
279 /* Load client MGC keys */
280 for (i = 0; i < MAX_MGSNIDS; i++) {
281 if (config->skc_mgsnids[i] == LNET_NID_ANY)
283 rc = snprintf(description, SK_DESCRIPTION_SIZE,
285 libcfs_nid2str(config->skc_mgsnids[i]));
286 if (rc >= SK_DESCRIPTION_SIZE)
288 if (sk_load_key(config, description) == -1)
301 * Byte swaps config from cpu format to disk
303 * \param[in,out] config sk_keyfile_config to swap
305 void sk_config_cpu_to_disk(struct sk_keyfile_config *config)
312 config->skc_version = htobe32(config->skc_version);
313 config->skc_hmac_alg = htobe16(config->skc_hmac_alg);
314 config->skc_crypt_alg = htobe16(config->skc_crypt_alg);
315 config->skc_expire = htobe32(config->skc_expire);
316 config->skc_shared_keylen = htobe32(config->skc_shared_keylen);
317 config->skc_prime_bits = htobe32(config->skc_prime_bits);
319 for (i = 0; i < MAX_MGSNIDS; i++)
320 config->skc_mgsnids[i] = htobe64(config->skc_mgsnids[i]);
326 * Byte swaps config from disk format to cpu
328 * \param[in,out] config sk_keyfile_config to swap
330 void sk_config_disk_to_cpu(struct sk_keyfile_config *config)
337 config->skc_version = be32toh(config->skc_version);
338 config->skc_hmac_alg = be16toh(config->skc_hmac_alg);
339 config->skc_crypt_alg = be16toh(config->skc_crypt_alg);
340 config->skc_expire = be32toh(config->skc_expire);
341 config->skc_shared_keylen = be32toh(config->skc_shared_keylen);
342 config->skc_prime_bits = be32toh(config->skc_prime_bits);
344 for (i = 0; i < MAX_MGSNIDS; i++)
345 config->skc_mgsnids[i] = be64toh(config->skc_mgsnids[i]);
351 * Verifies the on key payload format is valid
353 * \param[in] config sk_keyfile_config
358 int sk_validate_config(const struct sk_keyfile_config *config)
363 printerr(0, "Null configuration passed\n");
366 if (config->skc_version != SK_CONF_VERSION) {
367 printerr(0, "Invalid version\n");
370 if (config->skc_hmac_alg >= SK_HMAC_MAX) {
371 printerr(0, "Invalid HMAC algorithm\n");
374 if (config->skc_crypt_alg >= SK_CRYPT_MAX) {
375 printerr(0, "Invalid crypt algorithm\n");
378 if (config->skc_expire < 60 || config->skc_expire > INT_MAX) {
379 /* Try to limit key expiration to some reasonable minimum and
380 * also prevent values over INT_MAX because there appears
381 * to be a type conversion issue */
382 printerr(0, "Invalid expiration time should be between %d "
383 "and %d\n", 60, INT_MAX);
386 if (config->skc_prime_bits % 8 != 0 ||
387 config->skc_prime_bits > SK_MAX_P_BYTES * 8) {
388 printerr(0, "Invalid session key length must be a multiple of 8"
389 " and less then %d bits\n",
393 if (config->skc_shared_keylen % 8 != 0 ||
394 config->skc_shared_keylen > SK_MAX_KEYLEN_BYTES * 8){
395 printerr(0, "Invalid shared key max length must be a multiple "
396 "of 8 and less then %d bits\n",
397 SK_MAX_KEYLEN_BYTES * 8);
401 /* Check for terminating nulls on strings */
402 for (i = 0; i < sizeof(config->skc_fsname) &&
403 config->skc_fsname[i] != '\0'; i++)
405 if (i == sizeof(config->skc_fsname)) {
406 printerr(0, "File system name not null terminated\n");
410 for (i = 0; i < sizeof(config->skc_nodemap) &&
411 config->skc_nodemap[i] != '\0'; i++)
413 if (i == sizeof(config->skc_nodemap)) {
414 printerr(0, "Nodemap name not null terminated\n");
418 if (config->skc_type == SK_TYPE_INVALID) {
419 printerr(0, "Invalid key type\n");
427 * Hashes \a string and places the hash in \a hash
430 * \param[in] string Null terminated string to hash
431 * \param[in] hash_alg OpenSSL EVP_MD to use for hash
432 * \param[in,out] hash gss_buffer_desc to hold the result
437 static int sk_hash_string(const char *string, const EVP_MD *hash_alg,
438 gss_buffer_desc *hash)
440 EVP_MD_CTX *ctx = EVP_MD_CTX_create();
441 size_t len = strlen(string);
442 unsigned int hashlen;
444 if (!hash->value || hash->length < EVP_MD_size(hash_alg))
446 if (!EVP_DigestInit_ex(ctx, hash_alg, NULL))
448 if (!EVP_DigestUpdate(ctx, string, len))
450 if (!EVP_DigestFinal_ex(ctx, hash->value, &hashlen))
453 EVP_MD_CTX_destroy(ctx);
454 hash->length = hashlen;
458 EVP_MD_CTX_destroy(ctx);
463 * Hashes \a string and verifies the resulting hash matches the value
466 * \param[in] string Null terminated string to hash
467 * \param[in] hash_alg OpenSSL EVP_MD to use for hash
468 * \param[in,out] current_hash gss_buffer_desc to compare to
470 * \return gss error failure
471 * \return GSS_S_COMPLETE success
473 uint32_t sk_verify_hash(const char *string, const EVP_MD *hash_alg,
474 const gss_buffer_desc *current_hash)
476 gss_buffer_desc hash;
477 unsigned char hashbuf[EVP_MAX_MD_SIZE];
479 hash.value = hashbuf;
480 hash.length = sizeof(hashbuf);
482 if (sk_hash_string(string, hash_alg, &hash))
483 return GSS_S_FAILURE;
484 if (current_hash->length != hash.length)
485 return GSS_S_DEFECTIVE_TOKEN;
486 if (memcmp(current_hash->value, hash.value, hash.length))
487 return GSS_S_BAD_SIG;
489 return GSS_S_COMPLETE;
492 static inline int sk_config_has_mgsnid(struct sk_keyfile_config *config,
498 nid = libcfs_str2nid(mgsnid);
499 if (nid == LNET_NID_ANY)
502 for (i = 0; i < MAX_MGSNIDS; i++)
503 if (config->skc_mgsnids[i] == nid)
509 * Create an sk_cred structure populated with initial configuration info and the
510 * key. \a tgt and \a nodemap are used in determining the expected key
511 * description so the key can be found by searching the keyring.
512 * This is done because there is no easy way to pass keys from the mount command
513 * all the way to the request_key call. In addition any keys can be dynamically
514 * added to the keyrings and still found. The keyring that needs to be used
515 * must be the session keyring.
517 * \param[in] tgt Target file system
518 * \param[in] nodemap Cluster name for the key. This correlates to
519 * the nodemap name and is used by the server side.
520 * For the client this will be NULL.
521 * \param[in] flags Flags for the credentials
523 * \return sk_cred Allocated struct sk_cred on success
524 * \return NULL failure
526 struct sk_cred *sk_create_cred(const char *tgt, const char *nodemap,
527 const uint32_t flags)
529 struct sk_keyfile_config *config;
530 struct sk_kernel_ctx *kctx;
531 struct sk_cred *skc = NULL;
532 char description[SK_DESCRIPTION_SIZE + 1];
533 char fsname[MTI_NAME_MAXLEN + 1];
534 const char *mgsnid = NULL;
541 printerr(2, "Creating credentials for target: %s with nodemap: %s\n",
544 memset(description, 0, sizeof(description));
545 memset(fsname, 0, sizeof(fsname));
547 /* extract the file system name from target */
548 ptr = index(tgt, '-');
552 /* This must be an MGC target */
553 if (strncmp(tgt, "MGC", 3) || len <= 3) {
554 printerr(0, "Invalid target name\n");
562 if (len > MTI_NAME_MAXLEN) {
563 printerr(0, "Invalid target name\n");
566 memcpy(fsname, tgt, len);
570 rc = snprintf(description, SK_DESCRIPTION_SIZE,
571 "lustre:MGS:%s", nodemap);
573 rc = snprintf(description, SK_DESCRIPTION_SIZE,
574 "lustre:%s:%s", fsname, nodemap);
576 rc = snprintf(description, SK_DESCRIPTION_SIZE, "lustre:%s",
580 if (rc >= SK_DESCRIPTION_SIZE) {
581 printerr(0, "Invalid key description\n");
585 /* It may be a good idea to move Lustre keys to the gss_keyring
586 * (lgssc) type so that they expire when Lustre modules are removed.
587 * Unfortunately it can't be done at mount time because the mount
588 * syscall could trigger the Lustre modules to load and until that
589 * point we don't have a lgssc key type.
591 * TODO: Query the community for a consensus here */
592 printerr(2, "Searching for key with description: %s\n", description);
593 sk_key = keyctl_search(KEY_SPEC_USER_KEYRING, "user",
596 printerr(1, "No key found for %s\n", description);
600 keylen = keyctl_read_alloc(sk_key, (void **)&config);
602 printerr(0, "keyctl_read() failed for key %ld: %s\n", sk_key,
605 } else if (keylen != sizeof(*config)) {
606 printerr(0, "Unexpected key size: %d returned for key %ld, "
607 "expected %zu bytes\n",
608 keylen, sk_key, sizeof(*config));
612 sk_config_disk_to_cpu(config);
614 if (sk_validate_config(config)) {
615 printerr(0, "Invalid key configuration for key: %ld\n", sk_key);
619 if (mgsnid && !sk_config_has_mgsnid(config, mgsnid)) {
620 printerr(0, "Target name does not match key's MGS NIDs\n");
624 if (!mgsnid && strcmp(fsname, config->skc_fsname)) {
625 printerr(0, "Target name does not match key's file system\n");
629 skc = malloc(sizeof(*skc));
631 printerr(0, "Failed to allocate memory for sk_cred\n");
635 /* this initializes all gss_buffer_desc to empty as well */
636 memset(skc, 0, sizeof(*skc));
638 skc->sc_flags = flags;
639 skc->sc_tgt.length = strlen(tgt) + 1;
640 skc->sc_tgt.value = malloc(skc->sc_tgt.length);
641 if (!skc->sc_tgt.value) {
642 printerr(0, "Failed to allocate memory for target\n");
645 memcpy(skc->sc_tgt.value, tgt, skc->sc_tgt.length);
647 skc->sc_nodemap_hash.length = EVP_MD_size(EVP_sha256());
648 skc->sc_nodemap_hash.value = malloc(skc->sc_nodemap_hash.length);
649 if (!skc->sc_nodemap_hash.value) {
650 printerr(0, "Failed to allocate memory for nodemap hash\n");
654 if (sk_hash_string(config->skc_nodemap, EVP_sha256(),
655 &skc->sc_nodemap_hash)) {
656 printerr(0, "Failed to generate hash for nodemap name\n");
660 kctx = &skc->sc_kctx;
661 kctx->skc_version = config->skc_version;
662 kctx->skc_hmac_alg = config->skc_hmac_alg;
663 kctx->skc_crypt_alg = config->skc_crypt_alg;
664 kctx->skc_expire = config->skc_expire;
666 /* key payload format is in bits, convert to bytes */
667 kctx->skc_shared_key.length = config->skc_shared_keylen / 8;
668 kctx->skc_shared_key.value = malloc(kctx->skc_shared_key.length);
669 if (!kctx->skc_shared_key.value) {
670 printerr(0, "Failed to allocate memory for shared key\n");
673 memcpy(kctx->skc_shared_key.value, config->skc_shared_key,
674 kctx->skc_shared_key.length);
676 skc->sc_p.length = config->skc_prime_bits / 8;
677 skc->sc_p.value = malloc(skc->sc_p.length);
678 if (!skc->sc_p.value) {
679 printerr(0, "Failed to allocate p\n");
682 memcpy(skc->sc_p.value, config->skc_p, skc->sc_p.length);
696 * Populates the DH parameters for the DHKE
698 * \param[in,out] skc Shared key credentials structure to
699 * populate with DH parameters
701 * \retval GSS_S_COMPLETE success
702 * \retval GSS_S_FAILURE failure
704 uint32_t sk_gen_params(struct sk_cred *skc)
709 /* Random value used by both the request and response as part of the
710 * key binding material. This also should ensure we have unqiue
711 * tokens that are sent to the remote server which is important because
712 * the token is hashed for the sunrpc cache lookups and a failure there
713 * would cause connection attempts to fail indefinitely due to the large
714 * timeout value on the server side */
715 if (RAND_bytes((unsigned char *)&random, sizeof(random)) != 1) {
716 printerr(0, "Failed to get data for random parameter: %s\n",
717 ERR_error_string(ERR_get_error(), NULL));
718 return GSS_S_FAILURE;
721 /* The random value will always be used in byte range operations
722 * so we keep it as big endian from this point on */
723 skc->sc_kctx.skc_host_random = random;
725 /* Populate DH parameters */
726 skc->sc_params = DH_new();
727 if (!skc->sc_params) {
728 printerr(0, "Failed to allocate DH\n");
729 return GSS_S_FAILURE;
732 skc->sc_params->p = BN_bin2bn(skc->sc_p.value, skc->sc_p.length, NULL);
733 if (!skc->sc_params->p) {
734 printerr(0, "Failed to convert binary to BIGNUM\n");
735 return GSS_S_FAILURE;
738 /* We use a static generator for shared key */
739 skc->sc_params->g = BN_new();
740 if (!skc->sc_params->g) {
741 printerr(0, "Failed to allocate new BIGNUM\n");
742 return GSS_S_FAILURE;
744 if (BN_set_word(skc->sc_params->g, SK_GENERATOR) != 1) {
745 printerr(0, "Failed to set g value for DH params\n");
746 return GSS_S_FAILURE;
749 /* Verify that we have a safe prime and valid generator */
750 if (DH_check(skc->sc_params, &rc) != 1) {
751 printerr(0, "DH_check() failed: %d\n", rc);
752 return GSS_S_FAILURE;
754 printerr(0, "DH_check() returned error codes: 0x%x\n", rc);
755 return GSS_S_FAILURE;
758 if (DH_generate_key(skc->sc_params) != 1) {
759 printerr(0, "Failed to generate public DH key: %s\n",
760 ERR_error_string(ERR_get_error(), NULL));
761 return GSS_S_FAILURE;
764 skc->sc_pub_key.length = BN_num_bytes(skc->sc_params->pub_key);
765 skc->sc_pub_key.value = malloc(skc->sc_pub_key.length);
766 if (!skc->sc_pub_key.value) {
767 printerr(0, "Failed to allocate memory for public key\n");
768 return GSS_S_FAILURE;
771 BN_bn2bin(skc->sc_params->pub_key, skc->sc_pub_key.value);
773 return GSS_S_COMPLETE;
777 * Convert SK hash algorithm into openssl message digest
779 * \param[in,out] alg SK hash algorithm
783 static inline const EVP_MD *sk_hash_to_evp_md(enum sk_hmac_alg alg)
791 return EVP_md_null();
796 * Signs (via HMAC) the parameters used only in the key initialization protocol.
798 * \param[in] key Key to use for HMAC
799 * \param[in] bufs Array of gss_buffer_desc to generate
801 * \param[in] numbufs Number of buffers in array
802 * \param[in] hash_alg OpenSSL EVP_MD to use for hash
803 * \param[in,out] hmac HMAC of buffers is allocated and placed
804 * in this gss_buffer_desc. Caller must
810 int sk_sign_bufs(gss_buffer_desc *key, gss_buffer_desc *bufs, const int numbufs,
811 const EVP_MD *hash_alg, gss_buffer_desc *hmac)
814 unsigned int hashlen = EVP_MD_size(hash_alg);
818 if (hash_alg == EVP_md_null()) {
819 printerr(0, "Invalid hash algorithm\n");
823 HMAC_CTX_init(&hctx);
825 hmac->length = hashlen;
826 hmac->value = malloc(hashlen);
828 printerr(0, "Failed to allocate memory for HMAC\n");
832 if (HMAC_Init_ex(&hctx, key->value, key->length, hash_alg, NULL) != 1) {
833 printerr(0, "Failed to init HMAC\n");
837 for (i = 0; i < numbufs; i++) {
838 if (HMAC_Update(&hctx, bufs[i].value, bufs[i].length) != 1) {
839 printerr(0, "Failed to update HMAC\n");
844 /* The result gets populated in hmac */
845 if (HMAC_Final(&hctx, hmac->value, &hashlen) != 1) {
846 printerr(0, "Failed to finalize HMAC\n");
850 if (hmac->length != hashlen) {
851 printerr(0, "HMAC size does not match expected\n");
857 HMAC_CTX_cleanup(&hctx);
862 * Generates an HMAC for gss_buffer_desc array in \a bufs of \a numbufs
863 * and verifies against \a hmac.
865 * \param[in] skc Shared key credentials
866 * \param[in] bufs Array of gss_buffer_desc to generate HMAC for
867 * \param[in] numbufs Number of buffers in array
868 * \param[in] hash_alg OpenSSL EVP_MD to use for hash
869 * \param[in] hmac HMAC to verify against
871 * \retval GSS_S_COMPLETE success (match)
872 * \retval gss error failure
874 uint32_t sk_verify_hmac(struct sk_cred *skc, gss_buffer_desc *bufs,
875 const int numbufs, const EVP_MD *hash_alg,
876 gss_buffer_desc *hmac)
878 gss_buffer_desc bufs_hmac;
881 if (sk_sign_bufs(&skc->sc_kctx.skc_shared_key, bufs, numbufs, hash_alg,
883 printerr(0, "Failed to sign buffers to verify HMAC\n");
885 free(bufs_hmac.value);
886 return GSS_S_FAILURE;
889 if (hmac->length != bufs_hmac.length) {
890 printerr(0, "Invalid HMAC size\n");
891 free(bufs_hmac.value);
892 return GSS_S_BAD_SIG;
895 rc = memcmp(hmac->value, bufs_hmac.value, bufs_hmac.length);
896 free(bufs_hmac.value);
899 return GSS_S_BAD_SIG;
901 return GSS_S_COMPLETE;
905 * Cleanup an sk_cred freeing any resources
907 * \param[in,out] skc Shared key credentials to free
909 void sk_free_cred(struct sk_cred *skc)
915 free(skc->sc_p.value);
916 if (skc->sc_pub_key.value)
917 free(skc->sc_pub_key.value);
918 if (skc->sc_tgt.value)
919 free(skc->sc_tgt.value);
920 if (skc->sc_nodemap_hash.value)
921 free(skc->sc_nodemap_hash.value);
922 if (skc->sc_hmac.value)
923 free(skc->sc_hmac.value);
925 /* Overwrite keys and IV before freeing */
926 if (skc->sc_dh_shared_key.value) {
927 memset(skc->sc_dh_shared_key.value, 0,
928 skc->sc_dh_shared_key.length);
929 free(skc->sc_dh_shared_key.value);
931 if (skc->sc_kctx.skc_hmac_key.value) {
932 memset(skc->sc_kctx.skc_hmac_key.value, 0,
933 skc->sc_kctx.skc_hmac_key.length);
934 free(skc->sc_kctx.skc_hmac_key.value);
936 if (skc->sc_kctx.skc_encrypt_key.value) {
937 memset(skc->sc_kctx.skc_encrypt_key.value, 0,
938 skc->sc_kctx.skc_encrypt_key.length);
939 free(skc->sc_kctx.skc_encrypt_key.value);
941 if (skc->sc_kctx.skc_shared_key.value) {
942 memset(skc->sc_kctx.skc_shared_key.value, 0,
943 skc->sc_kctx.skc_shared_key.length);
944 free(skc->sc_kctx.skc_shared_key.value);
946 if (skc->sc_kctx.skc_session_key.value) {
947 memset(skc->sc_kctx.skc_session_key.value, 0,
948 skc->sc_kctx.skc_session_key.length);
949 free(skc->sc_kctx.skc_session_key.value);
953 DH_free(skc->sc_params);
959 /* This function handles key derivation using the hash algorithm specified in
960 * \a hash_alg, buffers in \a key_binding_bufs, and original key in
961 * \a origin_key to produce a \a derived_key. The first element of the
962 * key_binding_bufs array is reserved for the counter used in the KDF. The
963 * derived key in \a derived_key could differ in size from \a origin_key and
964 * must be populated with the expected size and a valid buffer to hold the
967 * If the derived key size is greater than the HMAC algorithm size it will be
968 * a done using several iterations of a counter and the key binding bufs.
970 * If the size is smaller it will take copy the first N bytes necessary to
971 * fill the derived key. */
972 int sk_kdf(gss_buffer_desc *derived_key , gss_buffer_desc *origin_key,
973 gss_buffer_desc *key_binding_bufs, int numbufs, int hmac_alg)
979 gss_buffer_desc tmp_hash;
986 /* Use a counter as the first buffer followed by the key binding
987 * buffers in the event we need more than one a single cycle to
988 * produced a symmetric key large enough in size */
989 key_binding_bufs[0].value = &counter;
990 key_binding_bufs[0].length = sizeof(counter);
992 remain = derived_key->length;
993 keydata = derived_key->value;
996 counter = htobe32(i++);
997 rc = sk_sign_bufs(origin_key, key_binding_bufs, numbufs,
998 sk_hash_to_evp_md(hmac_alg), &tmp_hash);
1001 free(tmp_hash.value);
1005 LASSERT(sk_hmac_types[hmac_alg].sht_bytes ==
1008 bytes = (remain < tmp_hash.length) ? remain : tmp_hash.length;
1009 memcpy(keydata, tmp_hash.value, bytes);
1010 free(tmp_hash.value);
1018 /* Populates the sk_cred's session_key using the a Key Derviation Function (KDF)
1019 * based on the recommendations in NIST Special Publication SP 800-56B Rev 1
1020 * (Sep 2014) Section 5.5.1
1022 * \param[in,out] skc Shared key credentials structure with
1024 * \return -1 failure
1027 int sk_session_kdf(struct sk_cred *skc, lnet_nid_t client_nid,
1028 gss_buffer_desc *client_token, gss_buffer_desc *server_token)
1030 struct sk_kernel_ctx *kctx = &skc->sc_kctx;
1031 gss_buffer_desc *session_key = &kctx->skc_session_key;
1032 gss_buffer_desc bufs[5];
1035 session_key->length = sk_crypt_types[kctx->skc_crypt_alg].sct_bytes;
1036 session_key->value = malloc(session_key->length);
1037 if (!session_key->value) {
1038 printerr(0, "Failed to allocate memory for session key\n");
1042 /* Key binding info ordering
1043 * 1. Reserved for counter
1047 * 4. Server's token */
1048 bufs[0].value = NULL;
1050 bufs[1] = skc->sc_dh_shared_key;
1051 bufs[2].value = &client_nid;
1052 bufs[2].length = sizeof(client_nid);
1053 bufs[3] = *client_token;
1054 bufs[4] = *server_token;
1056 return sk_kdf(&kctx->skc_session_key, &kctx->skc_shared_key, bufs,
1057 5, kctx->skc_hmac_alg);
1060 /* Uses the session key to create an HMAC key and encryption key. In
1061 * integrity mode the session key used to generate the HMAC key uses
1062 * session information which is available on the wire but by creating
1063 * a session based HMAC key we can prevent potential replay as both the
1064 * client and server have random numbers used as part of the key creation.
1066 * The keys used for integrity and privacy are formulated as below using
1067 * the session key that is the output of the key derivation function. The
1068 * HMAC algorithm is determined by the shared key algorithm selected in the
1072 * Session HMAC Key = PBKDF2("Integrity", KDF derived Session Key)
1075 * Session HMAC Key = PBKDF2("Integrity", KDF derived Session Key)
1076 * Session Encryption Key = PBKDF2("Encrypt", KDF derived Session Key)
1078 * \param[in,out] skc Shared key credentials structure with
1080 * \return -1 failure
1083 int sk_compute_keys(struct sk_cred *skc)
1085 struct sk_kernel_ctx *kctx = &skc->sc_kctx;
1086 gss_buffer_desc *session_key = &kctx->skc_session_key;
1087 gss_buffer_desc *hmac_key = &kctx->skc_hmac_key;
1088 gss_buffer_desc *encrypt_key = &kctx->skc_encrypt_key;
1089 char *encrypt = "Encrypt";
1090 char *integrity = "Integrity";
1093 hmac_key->length = sk_hmac_types[kctx->skc_hmac_alg].sht_bytes;
1094 hmac_key->value = malloc(hmac_key->length);
1095 if (!hmac_key->value)
1098 rc = PKCS5_PBKDF2_HMAC(integrity, -1, session_key->value,
1099 session_key->length, SK_PBKDF2_ITERATIONS,
1100 sk_hash_to_evp_md(kctx->skc_hmac_alg),
1101 hmac_key->length, hmac_key->value);
1105 /* Encryption key is only populated in privacy mode */
1106 if ((skc->sc_flags & LGSS_SVC_PRIV) == 0)
1109 encrypt_key->length = sk_crypt_types[kctx->skc_crypt_alg].sct_bytes;
1110 encrypt_key->value = malloc(encrypt_key->length);
1111 if (!encrypt_key->value)
1114 rc = PKCS5_PBKDF2_HMAC(encrypt, -1, session_key->value,
1115 session_key->length, SK_PBKDF2_ITERATIONS,
1116 sk_hash_to_evp_md(kctx->skc_hmac_alg),
1117 encrypt_key->length, encrypt_key->value);
1125 * Computes a session key based on the DH parameters from the host and its peer
1127 * \param[in,out] skc Shared key credentials structure with
1128 * the session key populated with the
1130 * \param[in] pub_key Public key returned from peer in
1132 * \return gss error failure
1133 * \return GSS_S_COMPLETE success
1135 uint32_t sk_compute_dh_key(struct sk_cred *skc, const gss_buffer_desc *pub_key)
1137 gss_buffer_desc *dh_shared = &skc->sc_dh_shared_key;
1138 BIGNUM *remote_pub_key;
1140 uint32_t rc = GSS_S_FAILURE;
1142 remote_pub_key = BN_bin2bn(pub_key->value, pub_key->length, NULL);
1143 if (!remote_pub_key) {
1144 printerr(0, "Failed to convert binary to BIGNUM\n");
1148 dh_shared->length = DH_size(skc->sc_params);
1149 dh_shared->value = malloc(dh_shared->length);
1150 if (!dh_shared->value) {
1151 printerr(0, "Failed to allocate memory for computed shared "
1156 /* This compute the shared key from the DHKE */
1157 status = DH_compute_key(dh_shared->value, remote_pub_key,
1160 printerr(0, "DH_compute_key() failed: %s\n",
1161 ERR_error_string(ERR_get_error(), NULL));
1163 } else if (status < dh_shared->length) {
1164 printerr(0, "DH_compute_key() returned a short key of %d "
1165 "bytes, expected: %zu\n", status, dh_shared->length);
1166 rc = GSS_S_DEFECTIVE_TOKEN;
1170 rc = GSS_S_COMPLETE;
1173 BN_free(remote_pub_key);
1178 * Creates a serialized buffer for the kernel in the order of struct
1181 * \param[in,out] skc Shared key credentials structure
1182 * \param[in,out] ctx_token Serialized buffer for kernel.
1183 * Caller must free this buffer.
1186 * \return -1 failure
1188 int sk_serialize_kctx(struct sk_cred *skc, gss_buffer_desc *ctx_token)
1190 struct sk_kernel_ctx *kctx = &skc->sc_kctx;
1194 bufsize = sizeof(*kctx) + kctx->skc_hmac_key.length +
1195 kctx->skc_encrypt_key.length;
1197 ctx_token->value = malloc(bufsize);
1198 if (!ctx_token->value)
1200 ctx_token->length = bufsize;
1202 p = ctx_token->value;
1203 end = p + ctx_token->length;
1205 if (WRITE_BYTES(&p, end, kctx->skc_version))
1207 if (WRITE_BYTES(&p, end, kctx->skc_hmac_alg))
1209 if (WRITE_BYTES(&p, end, kctx->skc_crypt_alg))
1211 if (WRITE_BYTES(&p, end, kctx->skc_expire))
1213 if (WRITE_BYTES(&p, end, kctx->skc_host_random))
1215 if (WRITE_BYTES(&p, end, kctx->skc_peer_random))
1217 if (write_buffer(&p, end, &kctx->skc_hmac_key))
1219 if (write_buffer(&p, end, &kctx->skc_encrypt_key))
1222 printerr(2, "Serialized buffer of %zu bytes for kernel\n", bufsize);
1228 * Decodes a netstring \a ns into array of gss_buffer_descs at \a bufs
1229 * up to \a numbufs. Memory is allocated for each value and length
1230 * will be populated with the length
1232 * \param[in,out] bufs Array of gss_buffer_descs
1233 * \param[in,out] numbufs number of gss_buffer_desc in array
1234 * \param[in] ns netstring to decode
1236 * \return buffers populated success
1237 * \return -1 failure
1239 int sk_decode_netstring(gss_buffer_desc *bufs, int numbufs, gss_buffer_desc *ns)
1241 char *ptr = ns->value;
1242 size_t remain = ns->length;
1249 for (i = 0; i < numbufs; i++) {
1250 /* read the size of first buffer */
1251 rc = sscanf(ptr, "%9u", &size);
1254 digits = (size) ? ceil(log10(size + 1)) : 1;
1256 /* sep of current string */
1257 sep = size + digits + 2;
1259 /* check to make sure it's valid */
1260 if (remain < sep || ptr[digits] != ':' ||
1261 ptr[sep - 1] != ',')
1264 bufs[i].length = size;
1266 bufs[i].value = NULL;
1268 bufs[i].value = malloc(size);
1271 memcpy(bufs[i].value, &ptr[digits + 1], size);
1278 printerr(2, "Decoded netstring of %zu bytes\n", ns->length);
1284 free(bufs[i].value);
1291 * Creates a netstring in a gss_buffer_desc that consists of all
1292 * the gss_buffer_desc found in \a bufs. The netstring should be treated
1293 * as binary as it can contain null characters.
1295 * \param[in] bufs Array of gss_buffer_desc to use as input
1296 * \param[in] numbufs Number of buffers in array
1297 * \param[in,out] ns Destination gss_buffer_desc to hold
1300 * \return -1 failure
1303 int sk_encode_netstring(gss_buffer_desc *bufs, int numbufs,
1304 gss_buffer_desc *ns)
1311 /* size of string in decimal, string size, colon, and comma */
1312 for (i = 0; i < numbufs; i++) {
1314 if (bufs[i].length == 0)
1317 size += ceil(log10(bufs[i].length + 1)) +
1322 ns->value = malloc(ns->length);
1329 for (i = 0; i < numbufs; i++) {
1331 rc = snprintf((char *) ptr, size, "%zu:", bufs[i].length);
1335 memcpy(ptr, bufs[i].value, bufs[i].length);
1336 ptr += bufs[i].length;
1341 size -= bufs[i].length + rc + 1;
1343 /* should not happen */
1348 printerr(2, "Encoded netstring of %zu bytes\n", ns->length);