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 * Copyright (c) 2016, 2017, Intel Corporation.
27 * Author: Jeremy Filizetti <jfilizet@iu.edu>
36 #include <openssl/dh.h>
37 #include <openssl/engine.h>
38 #include <openssl/err.h>
39 #include <openssl/hmac.h>
40 #include <sys/types.h>
42 #include <libcfs/util/string.h>
45 #include "write_bytes.h"
47 #define SK_PBKDF2_ITERATIONS 10000
50 # include "lgss_utils.h"
52 # include "gss_util.h"
53 # include "gss_oids.h"
54 # include "err_util.h"
60 * \param[in] program Program name to output
61 * \param[in] verbose Verbose flag
62 * \param[in] fg Whether or not to run in foreground
65 void sk_init_logging(char *program, int verbose, int fg)
67 initerr(program, verbose, fg);
72 * Loads the key from \a filename and returns the struct sk_keyfile_config.
73 * It should be freed by the caller.
75 * \param[in] filename Disk or key payload data
77 * \return sk_keyfile_config sucess
78 * \return NULL failure
80 struct sk_keyfile_config *sk_read_file(char *filename)
82 struct sk_keyfile_config *config;
88 config = malloc(sizeof(*config));
90 printerr(0, "Failed to allocate memory for config\n");
94 /* allow standard input override */
95 if (strcmp(filename, "-") == 0)
98 fd = open(filename, O_RDONLY);
101 printerr(0, "Error opening key file '%s': %s\n", filename,
104 } else if (fd != STDIN_FILENO) {
108 if (rc == 0 && (st.st_mode & ~(S_IFREG | 0600)))
109 fprintf(stderr, "warning: "
110 "secret key '%s' has insecure file mode %#o\n",
111 filename, st.st_mode);
114 ptr = (char *)config;
115 remain = sizeof(*config);
117 rc = read(fd, ptr, remain);
121 printerr(0, "read() failed on %s: %s\n", filename,
124 } else if (rc == 0) {
125 printerr(0, "File %s does not have a complete key\n",
133 if (fd != STDIN_FILENO)
135 sk_config_disk_to_cpu(config);
146 * Checks if a key matching \a description is found in the keyring for
147 * logging purposes and then attempts to load \a payload of \a psize into a key
148 * with \a description.
150 * \param[in] payload Key payload
151 * \param[in] psize Payload size
152 * \param[in] description Description used for key in keyring
157 static key_serial_t sk_load_key(const struct sk_keyfile_config *skc,
158 const char *description)
160 struct sk_keyfile_config payload;
163 memcpy(&payload, skc, sizeof(*skc));
165 /* In the keyring use the disk layout so keyctl pipe can be used */
166 sk_config_cpu_to_disk(&payload);
168 /* Check to see if a key is already loaded matching description */
169 key = keyctl_search(KEY_SPEC_USER_KEYRING, "user", description, 0);
171 printerr(2, "Key %d found in session keyring, replacing\n",
174 key = add_key("user", description, &payload, sizeof(payload),
175 KEY_SPEC_USER_KEYRING);
177 printerr(2, "Added key %d with description %s\n", key,
180 printerr(0, "Failed to add key with %s\n", description);
186 * Reads the key from \a path, verifies it and loads into the session keyring
187 * using a description determined by the the \a type. Existing keys with the
188 * same description are replaced.
190 * \param[in] path Path to key file
191 * \param[in] type Type of key to load which determines the description
196 int sk_load_keyfile(char *path)
198 struct sk_keyfile_config *config;
199 char description[SK_DESCRIPTION_SIZE + 1];
205 rc = stat(path, &buf);
207 printerr(0, "stat() failed for file %s: %s\n", path,
212 config = sk_read_file(path);
216 /* Similar to ssh, require adequate care of key files */
217 if (buf.st_mode & (S_IRGRP | S_IWGRP | S_IWOTH | S_IXOTH)) {
218 printerr(0, "Shared key files must be read/writeable only by "
223 if (sk_validate_config(config))
226 /* The server side can have multiple key files per file system so
227 * the nodemap name is appended to the key description to uniquely
229 if (config->skc_type & SK_TYPE_MGS) {
230 /* Any key can be an MGS key as long as we are told to use it */
231 rc = snprintf(description, SK_DESCRIPTION_SIZE, "lustre:MGS:%s",
232 config->skc_nodemap);
233 if (rc >= SK_DESCRIPTION_SIZE)
235 if (sk_load_key(config, description) == -1)
238 if (config->skc_type & SK_TYPE_SERVER) {
239 /* Server keys need to have the file system name in the key */
240 if (!config->skc_fsname) {
241 printerr(0, "Key configuration has no file system "
242 "attribute. Can't load as server type\n");
245 rc = snprintf(description, SK_DESCRIPTION_SIZE, "lustre:%s:%s",
246 config->skc_fsname, config->skc_nodemap);
247 if (rc >= SK_DESCRIPTION_SIZE)
249 if (sk_load_key(config, description) == -1)
252 if (config->skc_type & SK_TYPE_CLIENT) {
253 /* Load client file system key */
254 if (config->skc_fsname) {
255 rc = snprintf(description, SK_DESCRIPTION_SIZE,
256 "lustre:%s", config->skc_fsname);
257 if (rc >= SK_DESCRIPTION_SIZE)
259 if (sk_load_key(config, description) == -1)
263 /* Load client MGC keys */
264 for (i = 0; i < MAX_MGSNIDS; i++) {
265 if (config->skc_mgsnids[i] == LNET_NID_ANY)
267 rc = snprintf(description, SK_DESCRIPTION_SIZE,
269 libcfs_nid2str(config->skc_mgsnids[i]));
270 if (rc >= SK_DESCRIPTION_SIZE)
272 if (sk_load_key(config, description) == -1)
285 * Byte swaps config from cpu format to disk
287 * \param[in,out] config sk_keyfile_config to swap
289 void sk_config_cpu_to_disk(struct sk_keyfile_config *config)
296 config->skc_version = htobe32(config->skc_version);
297 config->skc_hmac_alg = htobe16(config->skc_hmac_alg);
298 config->skc_crypt_alg = htobe16(config->skc_crypt_alg);
299 config->skc_expire = htobe32(config->skc_expire);
300 config->skc_shared_keylen = htobe32(config->skc_shared_keylen);
301 config->skc_prime_bits = htobe32(config->skc_prime_bits);
303 for (i = 0; i < MAX_MGSNIDS; i++)
304 config->skc_mgsnids[i] = htobe64(config->skc_mgsnids[i]);
308 * Byte swaps config from disk format to cpu
310 * \param[in,out] config sk_keyfile_config to swap
312 void sk_config_disk_to_cpu(struct sk_keyfile_config *config)
319 config->skc_version = be32toh(config->skc_version);
320 config->skc_hmac_alg = be16toh(config->skc_hmac_alg);
321 config->skc_crypt_alg = be16toh(config->skc_crypt_alg);
322 config->skc_expire = be32toh(config->skc_expire);
323 config->skc_shared_keylen = be32toh(config->skc_shared_keylen);
324 config->skc_prime_bits = be32toh(config->skc_prime_bits);
326 for (i = 0; i < MAX_MGSNIDS; i++)
327 config->skc_mgsnids[i] = be64toh(config->skc_mgsnids[i]);
331 * Verifies the on key payload format is valid
333 * \param[in] config sk_keyfile_config
338 int sk_validate_config(const struct sk_keyfile_config *config)
343 printerr(0, "Null configuration passed\n");
347 if (config->skc_version != SK_CONF_VERSION) {
348 printerr(0, "Invalid version\n");
352 if (config->skc_hmac_alg == SK_HMAC_INVALID) {
353 printerr(0, "Invalid HMAC algorithm\n");
357 if (config->skc_crypt_alg == SK_CRYPT_INVALID) {
358 printerr(0, "Invalid crypt algorithm\n");
362 if (config->skc_expire < 60 || config->skc_expire > INT_MAX) {
363 /* Try to limit key expiration to some reasonable minimum and
364 * also prevent values over INT_MAX because there appears
365 * to be a type conversion issue */
366 printerr(0, "Invalid expiration time should be between %d "
367 "and %d\n", 60, INT_MAX);
370 if (config->skc_prime_bits % 8 != 0 ||
371 config->skc_prime_bits > SK_MAX_P_BYTES * 8) {
372 printerr(0, "Invalid session key length must be a multiple of 8"
373 " and less then %d bits\n",
377 if (config->skc_shared_keylen % 8 != 0 ||
378 config->skc_shared_keylen > SK_MAX_KEYLEN_BYTES * 8){
379 printerr(0, "Invalid shared key max length must be a multiple "
380 "of 8 and less then %d bits\n",
381 SK_MAX_KEYLEN_BYTES * 8);
385 /* Check for terminating nulls on strings */
386 for (i = 0; i < sizeof(config->skc_fsname) &&
387 config->skc_fsname[i] != '\0'; i++)
389 if (i == sizeof(config->skc_fsname)) {
390 printerr(0, "File system name not null terminated\n");
394 for (i = 0; i < sizeof(config->skc_nodemap) &&
395 config->skc_nodemap[i] != '\0'; i++)
397 if (i == sizeof(config->skc_nodemap)) {
398 printerr(0, "Nodemap name not null terminated\n");
402 if (config->skc_type == SK_TYPE_INVALID) {
403 printerr(0, "Invalid key type\n");
411 * Hashes \a string and places the hash in \a hash
414 * \param[in] string Null terminated string to hash
415 * \param[in] hash_alg OpenSSL EVP_MD to use for hash
416 * \param[in,out] hash gss_buffer_desc to hold the result
421 static int sk_hash_string(const char *string, const EVP_MD *hash_alg,
422 gss_buffer_desc *hash)
424 EVP_MD_CTX *ctx = EVP_MD_CTX_create();
425 size_t len = strlen(string);
426 unsigned int hashlen;
428 if (!hash->value || hash->length < EVP_MD_size(hash_alg))
430 if (!EVP_DigestInit_ex(ctx, hash_alg, NULL))
432 if (!EVP_DigestUpdate(ctx, string, len))
434 if (!EVP_DigestFinal_ex(ctx, hash->value, &hashlen))
437 EVP_MD_CTX_destroy(ctx);
438 hash->length = hashlen;
442 EVP_MD_CTX_destroy(ctx);
447 * Hashes \a string and verifies the resulting hash matches the value
450 * \param[in] string Null terminated string to hash
451 * \param[in] hash_alg OpenSSL EVP_MD to use for hash
452 * \param[in,out] current_hash gss_buffer_desc to compare to
454 * \return gss error failure
455 * \return GSS_S_COMPLETE success
457 uint32_t sk_verify_hash(const char *string, const EVP_MD *hash_alg,
458 const gss_buffer_desc *current_hash)
460 gss_buffer_desc hash;
461 unsigned char hashbuf[EVP_MAX_MD_SIZE];
463 hash.value = hashbuf;
464 hash.length = sizeof(hashbuf);
466 if (sk_hash_string(string, hash_alg, &hash))
467 return GSS_S_FAILURE;
468 if (current_hash->length != hash.length)
469 return GSS_S_DEFECTIVE_TOKEN;
470 if (memcmp(current_hash->value, hash.value, hash.length))
471 return GSS_S_BAD_SIG;
473 return GSS_S_COMPLETE;
476 static inline int sk_config_has_mgsnid(struct sk_keyfile_config *config,
482 nid = libcfs_str2nid(mgsnid);
483 if (nid == LNET_NID_ANY)
486 for (i = 0; i < MAX_MGSNIDS; i++)
487 if (config->skc_mgsnids[i] == nid)
493 * Create an sk_cred structure populated with initial configuration info and the
494 * key. \a tgt and \a nodemap are used in determining the expected key
495 * description so the key can be found by searching the keyring.
496 * This is done because there is no easy way to pass keys from the mount command
497 * all the way to the request_key call. In addition any keys can be dynamically
498 * added to the keyrings and still found. The keyring that needs to be used
499 * must be the session keyring.
501 * \param[in] tgt Target file system
502 * \param[in] nodemap Cluster name for the key. This correlates to
503 * the nodemap name and is used by the server side.
504 * For the client this will be NULL.
505 * \param[in] flags Flags for the credentials
507 * \return sk_cred Allocated struct sk_cred on success
508 * \return NULL failure
510 struct sk_cred *sk_create_cred(const char *tgt, const char *nodemap,
511 const uint32_t flags)
513 struct sk_keyfile_config *config;
514 struct sk_kernel_ctx *kctx;
515 struct sk_cred *skc = NULL;
516 char description[SK_DESCRIPTION_SIZE + 1];
517 char fsname[MTI_NAME_MAXLEN + 1];
518 const char *mgsnid = NULL;
525 printerr(2, "Creating credentials for target: %s with nodemap: %s\n",
528 memset(description, 0, sizeof(description));
529 memset(fsname, 0, sizeof(fsname));
531 /* extract the file system name from target */
532 ptr = index(tgt, '-');
536 /* This must be an MGC target */
537 if (strncmp(tgt, "MGC", 3) || len <= 3) {
538 printerr(0, "Invalid target name\n");
546 if (len > MTI_NAME_MAXLEN) {
547 printerr(0, "Invalid target name\n");
550 memcpy(fsname, tgt, len);
554 rc = snprintf(description, SK_DESCRIPTION_SIZE,
555 "lustre:MGS:%s", nodemap);
557 rc = snprintf(description, SK_DESCRIPTION_SIZE,
558 "lustre:%s:%s", fsname, nodemap);
560 rc = snprintf(description, SK_DESCRIPTION_SIZE, "lustre:%s",
564 if (rc >= SK_DESCRIPTION_SIZE) {
565 printerr(0, "Invalid key description\n");
569 /* It may be a good idea to move Lustre keys to the gss_keyring
570 * (lgssc) type so that they expire when Lustre modules are removed.
571 * Unfortunately it can't be done at mount time because the mount
572 * syscall could trigger the Lustre modules to load and until that
573 * point we don't have a lgssc key type.
575 * TODO: Query the community for a consensus here */
576 printerr(2, "Searching for key with description: %s\n", description);
577 sk_key = keyctl_search(KEY_SPEC_USER_KEYRING, "user",
580 printerr(1, "No key found for %s\n", description);
584 keylen = keyctl_read_alloc(sk_key, (void **)&config);
586 printerr(0, "keyctl_read() failed for key %ld: %s\n", sk_key,
589 } else if (keylen != sizeof(*config)) {
590 printerr(0, "Unexpected key size: %d returned for key %ld, "
591 "expected %zu bytes\n",
592 keylen, sk_key, sizeof(*config));
596 sk_config_disk_to_cpu(config);
598 if (sk_validate_config(config)) {
599 printerr(0, "Invalid key configuration for key: %ld\n", sk_key);
603 if (mgsnid && !sk_config_has_mgsnid(config, mgsnid)) {
604 printerr(0, "Target name does not match key's MGS NIDs\n");
608 if (!mgsnid && strcmp(fsname, config->skc_fsname)) {
609 printerr(0, "Target name does not match key's file system\n");
613 skc = malloc(sizeof(*skc));
615 printerr(0, "Failed to allocate memory for sk_cred\n");
619 /* this initializes all gss_buffer_desc to empty as well */
620 memset(skc, 0, sizeof(*skc));
622 skc->sc_flags = flags;
623 skc->sc_tgt.length = strlen(tgt) + 1;
624 skc->sc_tgt.value = malloc(skc->sc_tgt.length);
625 if (!skc->sc_tgt.value) {
626 printerr(0, "Failed to allocate memory for target\n");
629 memcpy(skc->sc_tgt.value, tgt, skc->sc_tgt.length);
631 skc->sc_nodemap_hash.length = EVP_MD_size(EVP_sha256());
632 skc->sc_nodemap_hash.value = malloc(skc->sc_nodemap_hash.length);
633 if (!skc->sc_nodemap_hash.value) {
634 printerr(0, "Failed to allocate memory for nodemap hash\n");
638 if (sk_hash_string(config->skc_nodemap, EVP_sha256(),
639 &skc->sc_nodemap_hash)) {
640 printerr(0, "Failed to generate hash for nodemap name\n");
644 kctx = &skc->sc_kctx;
645 kctx->skc_version = config->skc_version;
646 strcpy(kctx->skc_hmac_alg, sk_hmac2name(config->skc_hmac_alg));
647 strcpy(kctx->skc_crypt_alg, sk_crypt2name(config->skc_crypt_alg));
648 kctx->skc_expire = config->skc_expire;
650 /* key payload format is in bits, convert to bytes */
651 kctx->skc_shared_key.length = config->skc_shared_keylen / 8;
652 kctx->skc_shared_key.value = malloc(kctx->skc_shared_key.length);
653 if (!kctx->skc_shared_key.value) {
654 printerr(0, "Failed to allocate memory for shared key\n");
657 memcpy(kctx->skc_shared_key.value, config->skc_shared_key,
658 kctx->skc_shared_key.length);
660 skc->sc_p.length = config->skc_prime_bits / 8;
661 skc->sc_p.value = malloc(skc->sc_p.length);
662 if (!skc->sc_p.value) {
663 printerr(0, "Failed to allocate p\n");
666 memcpy(skc->sc_p.value, config->skc_p, skc->sc_p.length);
680 * Populates the DH parameters for the DHKE
682 * \param[in,out] skc Shared key credentials structure to
683 * populate with DH parameters
685 * \retval GSS_S_COMPLETE success
686 * \retval GSS_S_FAILURE failure
688 uint32_t sk_gen_params(struct sk_cred *skc)
692 const BIGNUM *pub_key;
695 /* Random value used by both the request and response as part of the
696 * key binding material. This also should ensure we have unqiue
697 * tokens that are sent to the remote server which is important because
698 * the token is hashed for the sunrpc cache lookups and a failure there
699 * would cause connection attempts to fail indefinitely due to the large
700 * timeout value on the server side */
701 if (RAND_bytes((unsigned char *)&random, sizeof(random)) != 1) {
702 printerr(0, "Failed to get data for random parameter: %s\n",
703 ERR_error_string(ERR_get_error(), NULL));
704 return GSS_S_FAILURE;
707 /* The random value will always be used in byte range operations
708 * so we keep it as big endian from this point on */
709 skc->sc_kctx.skc_host_random = random;
711 /* Populate DH parameters */
712 skc->sc_params = DH_new();
713 if (!skc->sc_params) {
714 printerr(0, "Failed to allocate DH\n");
715 return GSS_S_FAILURE;
718 p = BN_bin2bn(skc->sc_p.value, skc->sc_p.length, NULL);
720 printerr(0, "Failed to convert binary to BIGNUM\n");
721 return GSS_S_FAILURE;
724 /* We use a static generator for shared key */
727 printerr(0, "Failed to allocate new BIGNUM\n");
728 return GSS_S_FAILURE;
730 if (BN_set_word(g, SK_GENERATOR) != 1) {
731 printerr(0, "Failed to set g value for DH params\n");
732 return GSS_S_FAILURE;
735 if (!DH_set0_pqg(skc->sc_params, p, NULL, g)) {
736 printerr(0, "Failed to set pqg\n");
737 return GSS_S_FAILURE;
740 /* Verify that we have a safe prime and valid generator */
741 if (DH_check(skc->sc_params, &rc) != 1) {
742 printerr(0, "DH_check() failed: %d\n", rc);
743 return GSS_S_FAILURE;
745 printerr(0, "DH_check() returned error codes: 0x%x\n", rc);
746 return GSS_S_FAILURE;
749 if (DH_generate_key(skc->sc_params) != 1) {
750 printerr(0, "Failed to generate public DH key: %s\n",
751 ERR_error_string(ERR_get_error(), NULL));
752 return GSS_S_FAILURE;
755 DH_get0_key(skc->sc_params, &pub_key, NULL);
756 skc->sc_pub_key.length = BN_num_bytes(pub_key);
757 skc->sc_pub_key.value = malloc(skc->sc_pub_key.length);
758 if (!skc->sc_pub_key.value) {
759 printerr(0, "Failed to allocate memory for public key\n");
760 return GSS_S_FAILURE;
763 BN_bn2bin(pub_key, skc->sc_pub_key.value);
765 return GSS_S_COMPLETE;
769 * Convert SK hash algorithm into openssl message digest
771 * \param[in,out] alg SK hash algorithm
775 static inline const EVP_MD *sk_hash_to_evp_md(enum cfs_crypto_hash_alg alg)
778 case CFS_HASH_ALG_SHA256:
780 case CFS_HASH_ALG_SHA512:
783 return EVP_md_null();
788 * Signs (via HMAC) the parameters used only in the key initialization protocol.
790 * \param[in] key Key to use for HMAC
791 * \param[in] bufs Array of gss_buffer_desc to generate
793 * \param[in] numbufs Number of buffers in array
794 * \param[in] hash_alg OpenSSL EVP_MD to use for hash
795 * \param[in,out] hmac HMAC of buffers is allocated and placed
796 * in this gss_buffer_desc. Caller must
802 int sk_sign_bufs(gss_buffer_desc *key, gss_buffer_desc *bufs, const int numbufs,
803 const EVP_MD *hash_alg, gss_buffer_desc *hmac)
806 unsigned int hashlen = EVP_MD_size(hash_alg);
810 if (hash_alg == EVP_md_null()) {
811 printerr(0, "Invalid hash algorithm\n");
815 hctx = HMAC_CTX_new();
817 hmac->length = hashlen;
818 hmac->value = malloc(hashlen);
820 printerr(0, "Failed to allocate memory for HMAC\n");
824 if (HMAC_Init_ex(hctx, key->value, key->length, hash_alg, NULL) != 1) {
825 printerr(0, "Failed to init HMAC\n");
829 for (i = 0; i < numbufs; i++) {
830 if (HMAC_Update(hctx, bufs[i].value, bufs[i].length) != 1) {
831 printerr(0, "Failed to update HMAC\n");
836 /* The result gets populated in hmac */
837 if (HMAC_Final(hctx, hmac->value, &hashlen) != 1) {
838 printerr(0, "Failed to finalize HMAC\n");
842 if (hmac->length != hashlen) {
843 printerr(0, "HMAC size does not match expected\n");
854 * Generates an HMAC for gss_buffer_desc array in \a bufs of \a numbufs
855 * and verifies against \a hmac.
857 * \param[in] skc Shared key credentials
858 * \param[in] bufs Array of gss_buffer_desc to generate HMAC for
859 * \param[in] numbufs Number of buffers in array
860 * \param[in] hash_alg OpenSSL EVP_MD to use for hash
861 * \param[in] hmac HMAC to verify against
863 * \retval GSS_S_COMPLETE success (match)
864 * \retval gss error failure
866 uint32_t sk_verify_hmac(struct sk_cred *skc, gss_buffer_desc *bufs,
867 const int numbufs, const EVP_MD *hash_alg,
868 gss_buffer_desc *hmac)
870 gss_buffer_desc bufs_hmac;
873 if (sk_sign_bufs(&skc->sc_kctx.skc_shared_key, bufs, numbufs, hash_alg,
875 printerr(0, "Failed to sign buffers to verify HMAC\n");
877 free(bufs_hmac.value);
878 return GSS_S_FAILURE;
881 if (hmac->length != bufs_hmac.length) {
882 printerr(0, "Invalid HMAC size\n");
883 free(bufs_hmac.value);
884 return GSS_S_BAD_SIG;
887 rc = memcmp(hmac->value, bufs_hmac.value, bufs_hmac.length);
888 free(bufs_hmac.value);
891 return GSS_S_BAD_SIG;
893 return GSS_S_COMPLETE;
897 * Cleanup an sk_cred freeing any resources
899 * \param[in,out] skc Shared key credentials to free
901 void sk_free_cred(struct sk_cred *skc)
907 free(skc->sc_p.value);
908 if (skc->sc_pub_key.value)
909 free(skc->sc_pub_key.value);
910 if (skc->sc_tgt.value)
911 free(skc->sc_tgt.value);
912 if (skc->sc_nodemap_hash.value)
913 free(skc->sc_nodemap_hash.value);
914 if (skc->sc_hmac.value)
915 free(skc->sc_hmac.value);
917 /* Overwrite keys and IV before freeing */
918 if (skc->sc_dh_shared_key.value) {
919 memset(skc->sc_dh_shared_key.value, 0,
920 skc->sc_dh_shared_key.length);
921 free(skc->sc_dh_shared_key.value);
923 if (skc->sc_kctx.skc_hmac_key.value) {
924 memset(skc->sc_kctx.skc_hmac_key.value, 0,
925 skc->sc_kctx.skc_hmac_key.length);
926 free(skc->sc_kctx.skc_hmac_key.value);
928 if (skc->sc_kctx.skc_encrypt_key.value) {
929 memset(skc->sc_kctx.skc_encrypt_key.value, 0,
930 skc->sc_kctx.skc_encrypt_key.length);
931 free(skc->sc_kctx.skc_encrypt_key.value);
933 if (skc->sc_kctx.skc_shared_key.value) {
934 memset(skc->sc_kctx.skc_shared_key.value, 0,
935 skc->sc_kctx.skc_shared_key.length);
936 free(skc->sc_kctx.skc_shared_key.value);
938 if (skc->sc_kctx.skc_session_key.value) {
939 memset(skc->sc_kctx.skc_session_key.value, 0,
940 skc->sc_kctx.skc_session_key.length);
941 free(skc->sc_kctx.skc_session_key.value);
945 DH_free(skc->sc_params);
951 /* This function handles key derivation using the hash algorithm specified in
952 * \a hash_alg, buffers in \a key_binding_bufs, and original key in
953 * \a origin_key to produce a \a derived_key. The first element of the
954 * key_binding_bufs array is reserved for the counter used in the KDF. The
955 * derived key in \a derived_key could differ in size from \a origin_key and
956 * must be populated with the expected size and a valid buffer to hold the
959 * If the derived key size is greater than the HMAC algorithm size it will be
960 * a done using several iterations of a counter and the key binding bufs.
962 * If the size is smaller it will take copy the first N bytes necessary to
963 * fill the derived key. */
964 int sk_kdf(gss_buffer_desc *derived_key , gss_buffer_desc *origin_key,
965 gss_buffer_desc *key_binding_bufs, int numbufs,
966 enum cfs_crypto_hash_alg hmac_alg)
972 gss_buffer_desc tmp_hash;
979 /* Use a counter as the first buffer followed by the key binding
980 * buffers in the event we need more than one a single cycle to
981 * produced a symmetric key large enough in size */
982 key_binding_bufs[0].value = &counter;
983 key_binding_bufs[0].length = sizeof(counter);
985 remain = derived_key->length;
986 keydata = derived_key->value;
989 counter = htobe32(i++);
990 rc = sk_sign_bufs(origin_key, key_binding_bufs, numbufs,
991 sk_hash_to_evp_md(hmac_alg), &tmp_hash);
994 free(tmp_hash.value);
998 if (cfs_crypto_hash_digestsize(hmac_alg) != tmp_hash.length) {
999 free(tmp_hash.value);
1003 bytes = (remain < tmp_hash.length) ? remain : tmp_hash.length;
1004 memcpy(keydata, tmp_hash.value, bytes);
1005 free(tmp_hash.value);
1013 /* Populates the sk_cred's session_key using the a Key Derviation Function (KDF)
1014 * based on the recommendations in NIST Special Publication SP 800-56B Rev 1
1015 * (Sep 2014) Section 5.5.1
1017 * \param[in,out] skc Shared key credentials structure with
1019 * \return -1 failure
1022 int sk_session_kdf(struct sk_cred *skc, lnet_nid_t client_nid,
1023 gss_buffer_desc *client_token, gss_buffer_desc *server_token)
1025 struct sk_kernel_ctx *kctx = &skc->sc_kctx;
1026 gss_buffer_desc *session_key = &kctx->skc_session_key;
1027 gss_buffer_desc bufs[5];
1028 enum cfs_crypto_crypt_alg crypt_alg;
1031 crypt_alg = cfs_crypto_crypt_alg(kctx->skc_crypt_alg);
1032 session_key->length = cfs_crypto_crypt_keysize(crypt_alg);
1033 session_key->value = malloc(session_key->length);
1034 if (!session_key->value) {
1035 printerr(0, "Failed to allocate memory for session key\n");
1039 /* Key binding info ordering
1040 * 1. Reserved for counter
1044 * 4. Server's token */
1045 bufs[0].value = NULL;
1047 bufs[1] = skc->sc_dh_shared_key;
1048 bufs[2].value = &client_nid;
1049 bufs[2].length = sizeof(client_nid);
1050 bufs[3] = *client_token;
1051 bufs[4] = *server_token;
1053 return sk_kdf(&kctx->skc_session_key, &kctx->skc_shared_key, bufs,
1054 5, cfs_crypto_hash_alg(kctx->skc_hmac_alg));
1057 /* Uses the session key to create an HMAC key and encryption key. In
1058 * integrity mode the session key used to generate the HMAC key uses
1059 * session information which is available on the wire but by creating
1060 * a session based HMAC key we can prevent potential replay as both the
1061 * client and server have random numbers used as part of the key creation.
1063 * The keys used for integrity and privacy are formulated as below using
1064 * the session key that is the output of the key derivation function. The
1065 * HMAC algorithm is determined by the shared key algorithm selected in the
1069 * Session HMAC Key = PBKDF2("Integrity", KDF derived Session Key)
1072 * Session HMAC Key = PBKDF2("Integrity", KDF derived Session Key)
1073 * Session Encryption Key = PBKDF2("Encrypt", KDF derived Session Key)
1075 * \param[in,out] skc Shared key credentials structure with
1077 * \return -1 failure
1080 int sk_compute_keys(struct sk_cred *skc)
1082 struct sk_kernel_ctx *kctx = &skc->sc_kctx;
1083 gss_buffer_desc *session_key = &kctx->skc_session_key;
1084 gss_buffer_desc *hmac_key = &kctx->skc_hmac_key;
1085 gss_buffer_desc *encrypt_key = &kctx->skc_encrypt_key;
1086 enum cfs_crypto_hash_alg hmac_alg;
1087 enum cfs_crypto_crypt_alg crypt_alg;
1088 char *encrypt = "Encrypt";
1089 char *integrity = "Integrity";
1092 hmac_alg = cfs_crypto_hash_alg(kctx->skc_hmac_alg);
1093 hmac_key->length = cfs_crypto_hash_digestsize(hmac_alg);
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(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 crypt_alg = cfs_crypto_crypt_alg(kctx->skc_crypt_alg);
1110 encrypt_key->length = cfs_crypto_crypt_keysize(crypt_alg);
1111 encrypt_key->value = malloc(encrypt_key->length);
1112 if (!encrypt_key->value)
1115 rc = PKCS5_PBKDF2_HMAC(encrypt, -1, session_key->value,
1116 session_key->length, SK_PBKDF2_ITERATIONS,
1117 sk_hash_to_evp_md(hmac_alg),
1118 encrypt_key->length, encrypt_key->value);
1126 * Computes a session key based on the DH parameters from the host and its peer
1128 * \param[in,out] skc Shared key credentials structure with
1129 * the session key populated with the
1131 * \param[in] pub_key Public key returned from peer in
1133 * \return gss error failure
1134 * \return GSS_S_COMPLETE success
1136 uint32_t sk_compute_dh_key(struct sk_cred *skc, const gss_buffer_desc *pub_key)
1138 gss_buffer_desc *dh_shared = &skc->sc_dh_shared_key;
1139 BIGNUM *remote_pub_key;
1141 uint32_t rc = GSS_S_FAILURE;
1143 remote_pub_key = BN_bin2bn(pub_key->value, pub_key->length, NULL);
1144 if (!remote_pub_key) {
1145 printerr(0, "Failed to convert binary to BIGNUM\n");
1149 dh_shared->length = DH_size(skc->sc_params);
1150 dh_shared->value = malloc(dh_shared->length);
1151 if (!dh_shared->value) {
1152 printerr(0, "Failed to allocate memory for computed shared "
1157 /* This compute the shared key from the DHKE */
1158 status = DH_compute_key(dh_shared->value, remote_pub_key,
1161 printerr(0, "DH_compute_key() failed: %s\n",
1162 ERR_error_string(ERR_get_error(), NULL));
1164 } else if (status < dh_shared->length) {
1165 printerr(0, "DH_compute_key() returned a short key of %d "
1166 "bytes, expected: %zu\n", status, dh_shared->length);
1167 rc = GSS_S_DEFECTIVE_TOKEN;
1171 rc = GSS_S_COMPLETE;
1174 BN_free(remote_pub_key);
1179 * Creates a serialized buffer for the kernel in the order of struct
1182 * \param[in,out] skc Shared key credentials structure
1183 * \param[in,out] ctx_token Serialized buffer for kernel.
1184 * Caller must free this buffer.
1187 * \return -1 failure
1189 int sk_serialize_kctx(struct sk_cred *skc, gss_buffer_desc *ctx_token)
1191 struct sk_kernel_ctx *kctx = &skc->sc_kctx;
1195 bufsize = sizeof(*kctx) + kctx->skc_hmac_key.length +
1196 kctx->skc_encrypt_key.length;
1198 ctx_token->value = malloc(bufsize);
1199 if (!ctx_token->value)
1201 ctx_token->length = bufsize;
1203 p = ctx_token->value;
1204 end = p + ctx_token->length;
1206 if (WRITE_BYTES(&p, end, kctx->skc_version))
1208 if (WRITE_BYTES(&p, end, kctx->skc_hmac_alg))
1210 if (WRITE_BYTES(&p, end, kctx->skc_crypt_alg))
1212 if (WRITE_BYTES(&p, end, kctx->skc_expire))
1214 if (WRITE_BYTES(&p, end, kctx->skc_host_random))
1216 if (WRITE_BYTES(&p, end, kctx->skc_peer_random))
1218 if (write_buffer(&p, end, &kctx->skc_hmac_key))
1220 if (write_buffer(&p, end, &kctx->skc_encrypt_key))
1223 printerr(2, "Serialized buffer of %zu bytes for kernel\n", bufsize);
1229 * Decodes a netstring \a ns into array of gss_buffer_descs at \a bufs
1230 * up to \a numbufs. Memory is allocated for each value and length
1231 * will be populated with the length
1233 * \param[in,out] bufs Array of gss_buffer_descs
1234 * \param[in,out] numbufs number of gss_buffer_desc in array
1235 * \param[in] ns netstring to decode
1237 * \return buffers populated success
1238 * \return -1 failure
1240 int sk_decode_netstring(gss_buffer_desc *bufs, int numbufs, gss_buffer_desc *ns)
1242 char *ptr = ns->value;
1243 size_t remain = ns->length;
1250 for (i = 0; i < numbufs; i++) {
1251 /* read the size of first buffer */
1252 rc = sscanf(ptr, "%9u", &size);
1255 digits = (size) ? ceil(log10(size + 1)) : 1;
1257 /* sep of current string */
1258 sep = size + digits + 2;
1260 /* check to make sure it's valid */
1261 if (remain < sep || ptr[digits] != ':' ||
1262 ptr[sep - 1] != ',')
1265 bufs[i].length = size;
1267 bufs[i].value = NULL;
1269 bufs[i].value = malloc(size);
1272 memcpy(bufs[i].value, &ptr[digits + 1], size);
1279 printerr(2, "Decoded netstring of %zu bytes\n", ns->length);
1285 free(bufs[i].value);
1292 * Creates a netstring in a gss_buffer_desc that consists of all
1293 * the gss_buffer_desc found in \a bufs. The netstring should be treated
1294 * as binary as it can contain null characters.
1296 * \param[in] bufs Array of gss_buffer_desc to use as input
1297 * \param[in] numbufs Number of buffers in array
1298 * \param[in,out] ns Destination gss_buffer_desc to hold
1301 * \return -1 failure
1304 int sk_encode_netstring(gss_buffer_desc *bufs, int numbufs,
1305 gss_buffer_desc *ns)
1312 /* size of string in decimal, string size, colon, and comma */
1313 for (i = 0; i < numbufs; i++) {
1315 if (bufs[i].length == 0)
1318 size += ceil(log10(bufs[i].length + 1)) +
1323 ns->value = malloc(ns->length);
1330 for (i = 0; i < numbufs; i++) {
1332 rc = scnprintf((char *) ptr, size, "%zu:", bufs[i].length);
1336 memcpy(ptr, bufs[i].value, bufs[i].length);
1337 ptr += bufs[i].length;
1342 size -= bufs[i].length + rc + 1;
1344 /* should not happen */
1349 printerr(2, "Encoded netstring of %zu bytes\n", ns->length);