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, 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 <lnet/nidstr.h>
45 #include "write_bytes.h"
47 #define SK_PBKDF2_ITERATIONS 10000
49 static struct sk_crypt_type sk_crypt_types[] = {
50 [SK_CRYPT_AES256_CTR] = {
51 .cht_name = "ctr(aes)",
57 static struct sk_hmac_type sk_hmac_types[] = {
69 # include "lgss_utils.h"
71 # include "gss_util.h"
72 # include "gss_oids.h"
73 # include "err_util.h"
79 * \param[in] program Program name to output
80 * \param[in] verbose Verbose flag
81 * \param[in] fg Whether or not to run in foreground
84 void sk_init_logging(char *program, int verbose, int fg)
86 initerr(program, verbose, fg);
91 * Loads the key from \a filename and returns the struct sk_keyfile_config.
92 * It should be freed by the caller.
94 * \param[in] filename Disk or key payload data
96 * \return sk_keyfile_config sucess
97 * \return NULL failure
99 struct sk_keyfile_config *sk_read_file(char *filename)
101 struct sk_keyfile_config *config;
107 config = malloc(sizeof(*config));
109 printerr(0, "Failed to allocate memory for config\n");
113 /* allow standard input override */
114 if (strcmp(filename, "-") == 0)
117 fd = open(filename, O_RDONLY);
120 printerr(0, "Error opening key file '%s': %s\n", filename,
123 } else if (fd != STDIN_FILENO) {
127 if (rc == 0 && (st.st_mode & ~(S_IFREG | 0600)))
128 fprintf(stderr, "warning: "
129 "secret key '%s' has insecure file mode %#o\n",
130 filename, st.st_mode);
133 ptr = (char *)config;
134 remain = sizeof(*config);
136 rc = read(fd, ptr, remain);
140 printerr(0, "read() failed on %s: %s\n", filename,
143 } else if (rc == 0) {
144 printerr(0, "File %s does not have a complete key\n",
152 if (fd != STDIN_FILENO)
154 sk_config_disk_to_cpu(config);
165 * Checks if a key matching \a description is found in the keyring for
166 * logging purposes and then attempts to load \a payload of \a psize into a key
167 * with \a description.
169 * \param[in] payload Key payload
170 * \param[in] psize Payload size
171 * \param[in] description Description used for key in keyring
176 static key_serial_t sk_load_key(const struct sk_keyfile_config *skc,
177 const char *description)
179 struct sk_keyfile_config payload;
182 memcpy(&payload, skc, sizeof(*skc));
184 /* In the keyring use the disk layout so keyctl pipe can be used */
185 sk_config_cpu_to_disk(&payload);
187 /* Check to see if a key is already loaded matching description */
188 key = keyctl_search(KEY_SPEC_USER_KEYRING, "user", description, 0);
190 printerr(2, "Key %d found in session keyring, replacing\n",
193 key = add_key("user", description, &payload, sizeof(payload),
194 KEY_SPEC_USER_KEYRING);
196 printerr(2, "Added key %d with description %s\n", key,
199 printerr(0, "Failed to add key with %s\n", description);
205 * Reads the key from \a path, verifies it and loads into the session keyring
206 * using a description determined by the the \a type. Existing keys with the
207 * same description are replaced.
209 * \param[in] path Path to key file
210 * \param[in] type Type of key to load which determines the description
215 int sk_load_keyfile(char *path)
217 struct sk_keyfile_config *config;
218 char description[SK_DESCRIPTION_SIZE + 1];
224 rc = stat(path, &buf);
226 printerr(0, "stat() failed for file %s: %s\n", path,
231 config = sk_read_file(path);
235 /* Similar to ssh, require adequate care of key files */
236 if (buf.st_mode & (S_IRGRP | S_IWGRP | S_IWOTH | S_IXOTH)) {
237 printerr(0, "Shared key files must be read/writeable only by "
242 if (sk_validate_config(config))
245 /* The server side can have multiple key files per file system so
246 * the nodemap name is appended to the key description to uniquely
248 if (config->skc_type & SK_TYPE_MGS) {
249 /* Any key can be an MGS key as long as we are told to use it */
250 rc = snprintf(description, SK_DESCRIPTION_SIZE, "lustre:MGS:%s",
251 config->skc_nodemap);
252 if (rc >= SK_DESCRIPTION_SIZE)
254 if (sk_load_key(config, description) == -1)
257 if (config->skc_type & SK_TYPE_SERVER) {
258 /* Server keys need to have the file system name in the key */
259 if (!config->skc_fsname) {
260 printerr(0, "Key configuration has no file system "
261 "attribute. Can't load as server type\n");
264 rc = snprintf(description, SK_DESCRIPTION_SIZE, "lustre:%s:%s",
265 config->skc_fsname, config->skc_nodemap);
266 if (rc >= SK_DESCRIPTION_SIZE)
268 if (sk_load_key(config, description) == -1)
271 if (config->skc_type & SK_TYPE_CLIENT) {
272 /* Load client file system key */
273 if (config->skc_fsname) {
274 rc = snprintf(description, SK_DESCRIPTION_SIZE,
275 "lustre:%s", config->skc_fsname);
276 if (rc >= SK_DESCRIPTION_SIZE)
278 if (sk_load_key(config, description) == -1)
282 /* Load client MGC keys */
283 for (i = 0; i < MAX_MGSNIDS; i++) {
284 if (config->skc_mgsnids[i] == LNET_NID_ANY)
286 rc = snprintf(description, SK_DESCRIPTION_SIZE,
288 libcfs_nid2str(config->skc_mgsnids[i]));
289 if (rc >= SK_DESCRIPTION_SIZE)
291 if (sk_load_key(config, description) == -1)
304 * Byte swaps config from cpu format to disk
306 * \param[in,out] config sk_keyfile_config to swap
308 void sk_config_cpu_to_disk(struct sk_keyfile_config *config)
315 config->skc_version = htobe32(config->skc_version);
316 config->skc_hmac_alg = htobe16(config->skc_hmac_alg);
317 config->skc_crypt_alg = htobe16(config->skc_crypt_alg);
318 config->skc_expire = htobe32(config->skc_expire);
319 config->skc_shared_keylen = htobe32(config->skc_shared_keylen);
320 config->skc_prime_bits = htobe32(config->skc_prime_bits);
322 for (i = 0; i < MAX_MGSNIDS; i++)
323 config->skc_mgsnids[i] = htobe64(config->skc_mgsnids[i]);
329 * Byte swaps config from disk format to cpu
331 * \param[in,out] config sk_keyfile_config to swap
333 void sk_config_disk_to_cpu(struct sk_keyfile_config *config)
340 config->skc_version = be32toh(config->skc_version);
341 config->skc_hmac_alg = be16toh(config->skc_hmac_alg);
342 config->skc_crypt_alg = be16toh(config->skc_crypt_alg);
343 config->skc_expire = be32toh(config->skc_expire);
344 config->skc_shared_keylen = be32toh(config->skc_shared_keylen);
345 config->skc_prime_bits = be32toh(config->skc_prime_bits);
347 for (i = 0; i < MAX_MGSNIDS; i++)
348 config->skc_mgsnids[i] = be64toh(config->skc_mgsnids[i]);
354 * Verifies the on key payload format is valid
356 * \param[in] config sk_keyfile_config
361 int sk_validate_config(const struct sk_keyfile_config *config)
366 printerr(0, "Null configuration passed\n");
369 if (config->skc_version != SK_CONF_VERSION) {
370 printerr(0, "Invalid version\n");
373 if ((config->skc_hmac_alg != CFS_HASH_ALG_SHA256) &&
374 (config->skc_hmac_alg != CFS_HASH_ALG_SHA512)) {
375 printerr(0, "Invalid HMAC algorithm\n");
378 if (config->skc_crypt_alg >= SK_CRYPT_MAX) {
379 printerr(0, "Invalid crypt algorithm\n");
382 if (config->skc_expire < 60 || config->skc_expire > INT_MAX) {
383 /* Try to limit key expiration to some reasonable minimum and
384 * also prevent values over INT_MAX because there appears
385 * to be a type conversion issue */
386 printerr(0, "Invalid expiration time should be between %d "
387 "and %d\n", 60, INT_MAX);
390 if (config->skc_prime_bits % 8 != 0 ||
391 config->skc_prime_bits > SK_MAX_P_BYTES * 8) {
392 printerr(0, "Invalid session key length must be a multiple of 8"
393 " and less then %d bits\n",
397 if (config->skc_shared_keylen % 8 != 0 ||
398 config->skc_shared_keylen > SK_MAX_KEYLEN_BYTES * 8){
399 printerr(0, "Invalid shared key max length must be a multiple "
400 "of 8 and less then %d bits\n",
401 SK_MAX_KEYLEN_BYTES * 8);
405 /* Check for terminating nulls on strings */
406 for (i = 0; i < sizeof(config->skc_fsname) &&
407 config->skc_fsname[i] != '\0'; i++)
409 if (i == sizeof(config->skc_fsname)) {
410 printerr(0, "File system name not null terminated\n");
414 for (i = 0; i < sizeof(config->skc_nodemap) &&
415 config->skc_nodemap[i] != '\0'; i++)
417 if (i == sizeof(config->skc_nodemap)) {
418 printerr(0, "Nodemap name not null terminated\n");
422 if (config->skc_type == SK_TYPE_INVALID) {
423 printerr(0, "Invalid key type\n");
431 * Hashes \a string and places the hash in \a hash
434 * \param[in] string Null terminated string to hash
435 * \param[in] hash_alg OpenSSL EVP_MD to use for hash
436 * \param[in,out] hash gss_buffer_desc to hold the result
441 static int sk_hash_string(const char *string, const EVP_MD *hash_alg,
442 gss_buffer_desc *hash)
444 EVP_MD_CTX *ctx = EVP_MD_CTX_create();
445 size_t len = strlen(string);
446 unsigned int hashlen;
448 if (!hash->value || hash->length < EVP_MD_size(hash_alg))
450 if (!EVP_DigestInit_ex(ctx, hash_alg, NULL))
452 if (!EVP_DigestUpdate(ctx, string, len))
454 if (!EVP_DigestFinal_ex(ctx, hash->value, &hashlen))
457 EVP_MD_CTX_destroy(ctx);
458 hash->length = hashlen;
462 EVP_MD_CTX_destroy(ctx);
467 * Hashes \a string and verifies the resulting hash matches the value
470 * \param[in] string Null terminated string to hash
471 * \param[in] hash_alg OpenSSL EVP_MD to use for hash
472 * \param[in,out] current_hash gss_buffer_desc to compare to
474 * \return gss error failure
475 * \return GSS_S_COMPLETE success
477 uint32_t sk_verify_hash(const char *string, const EVP_MD *hash_alg,
478 const gss_buffer_desc *current_hash)
480 gss_buffer_desc hash;
481 unsigned char hashbuf[EVP_MAX_MD_SIZE];
483 hash.value = hashbuf;
484 hash.length = sizeof(hashbuf);
486 if (sk_hash_string(string, hash_alg, &hash))
487 return GSS_S_FAILURE;
488 if (current_hash->length != hash.length)
489 return GSS_S_DEFECTIVE_TOKEN;
490 if (memcmp(current_hash->value, hash.value, hash.length))
491 return GSS_S_BAD_SIG;
493 return GSS_S_COMPLETE;
496 static inline int sk_config_has_mgsnid(struct sk_keyfile_config *config,
502 nid = libcfs_str2nid(mgsnid);
503 if (nid == LNET_NID_ANY)
506 for (i = 0; i < MAX_MGSNIDS; i++)
507 if (config->skc_mgsnids[i] == nid)
513 * Create an sk_cred structure populated with initial configuration info and the
514 * key. \a tgt and \a nodemap are used in determining the expected key
515 * description so the key can be found by searching the keyring.
516 * This is done because there is no easy way to pass keys from the mount command
517 * all the way to the request_key call. In addition any keys can be dynamically
518 * added to the keyrings and still found. The keyring that needs to be used
519 * must be the session keyring.
521 * \param[in] tgt Target file system
522 * \param[in] nodemap Cluster name for the key. This correlates to
523 * the nodemap name and is used by the server side.
524 * For the client this will be NULL.
525 * \param[in] flags Flags for the credentials
527 * \return sk_cred Allocated struct sk_cred on success
528 * \return NULL failure
530 struct sk_cred *sk_create_cred(const char *tgt, const char *nodemap,
531 const uint32_t flags)
533 struct sk_keyfile_config *config;
534 struct sk_kernel_ctx *kctx;
535 struct sk_cred *skc = NULL;
536 char description[SK_DESCRIPTION_SIZE + 1];
537 char fsname[MTI_NAME_MAXLEN + 1];
538 const char *mgsnid = NULL;
545 printerr(2, "Creating credentials for target: %s with nodemap: %s\n",
548 memset(description, 0, sizeof(description));
549 memset(fsname, 0, sizeof(fsname));
551 /* extract the file system name from target */
552 ptr = index(tgt, '-');
556 /* This must be an MGC target */
557 if (strncmp(tgt, "MGC", 3) || len <= 3) {
558 printerr(0, "Invalid target name\n");
566 if (len > MTI_NAME_MAXLEN) {
567 printerr(0, "Invalid target name\n");
570 memcpy(fsname, tgt, len);
574 rc = snprintf(description, SK_DESCRIPTION_SIZE,
575 "lustre:MGS:%s", nodemap);
577 rc = snprintf(description, SK_DESCRIPTION_SIZE,
578 "lustre:%s:%s", fsname, nodemap);
580 rc = snprintf(description, SK_DESCRIPTION_SIZE, "lustre:%s",
584 if (rc >= SK_DESCRIPTION_SIZE) {
585 printerr(0, "Invalid key description\n");
589 /* It may be a good idea to move Lustre keys to the gss_keyring
590 * (lgssc) type so that they expire when Lustre modules are removed.
591 * Unfortunately it can't be done at mount time because the mount
592 * syscall could trigger the Lustre modules to load and until that
593 * point we don't have a lgssc key type.
595 * TODO: Query the community for a consensus here */
596 printerr(2, "Searching for key with description: %s\n", description);
597 sk_key = keyctl_search(KEY_SPEC_USER_KEYRING, "user",
600 printerr(1, "No key found for %s\n", description);
604 keylen = keyctl_read_alloc(sk_key, (void **)&config);
606 printerr(0, "keyctl_read() failed for key %ld: %s\n", sk_key,
609 } else if (keylen != sizeof(*config)) {
610 printerr(0, "Unexpected key size: %d returned for key %ld, "
611 "expected %zu bytes\n",
612 keylen, sk_key, sizeof(*config));
616 sk_config_disk_to_cpu(config);
618 if (sk_validate_config(config)) {
619 printerr(0, "Invalid key configuration for key: %ld\n", sk_key);
623 if (mgsnid && !sk_config_has_mgsnid(config, mgsnid)) {
624 printerr(0, "Target name does not match key's MGS NIDs\n");
628 if (!mgsnid && strcmp(fsname, config->skc_fsname)) {
629 printerr(0, "Target name does not match key's file system\n");
633 skc = malloc(sizeof(*skc));
635 printerr(0, "Failed to allocate memory for sk_cred\n");
639 /* this initializes all gss_buffer_desc to empty as well */
640 memset(skc, 0, sizeof(*skc));
642 skc->sc_flags = flags;
643 skc->sc_tgt.length = strlen(tgt) + 1;
644 skc->sc_tgt.value = malloc(skc->sc_tgt.length);
645 if (!skc->sc_tgt.value) {
646 printerr(0, "Failed to allocate memory for target\n");
649 memcpy(skc->sc_tgt.value, tgt, skc->sc_tgt.length);
651 skc->sc_nodemap_hash.length = EVP_MD_size(EVP_sha256());
652 skc->sc_nodemap_hash.value = malloc(skc->sc_nodemap_hash.length);
653 if (!skc->sc_nodemap_hash.value) {
654 printerr(0, "Failed to allocate memory for nodemap hash\n");
658 if (sk_hash_string(config->skc_nodemap, EVP_sha256(),
659 &skc->sc_nodemap_hash)) {
660 printerr(0, "Failed to generate hash for nodemap name\n");
664 kctx = &skc->sc_kctx;
665 kctx->skc_version = config->skc_version;
666 kctx->skc_hmac_alg = config->skc_hmac_alg;
667 kctx->skc_crypt_alg = config->skc_crypt_alg;
668 kctx->skc_expire = config->skc_expire;
670 /* key payload format is in bits, convert to bytes */
671 kctx->skc_shared_key.length = config->skc_shared_keylen / 8;
672 kctx->skc_shared_key.value = malloc(kctx->skc_shared_key.length);
673 if (!kctx->skc_shared_key.value) {
674 printerr(0, "Failed to allocate memory for shared key\n");
677 memcpy(kctx->skc_shared_key.value, config->skc_shared_key,
678 kctx->skc_shared_key.length);
680 skc->sc_p.length = config->skc_prime_bits / 8;
681 skc->sc_p.value = malloc(skc->sc_p.length);
682 if (!skc->sc_p.value) {
683 printerr(0, "Failed to allocate p\n");
686 memcpy(skc->sc_p.value, config->skc_p, skc->sc_p.length);
700 * Populates the DH parameters for the DHKE
702 * \param[in,out] skc Shared key credentials structure to
703 * populate with DH parameters
705 * \retval GSS_S_COMPLETE success
706 * \retval GSS_S_FAILURE failure
708 uint32_t sk_gen_params(struct sk_cred *skc)
713 /* Random value used by both the request and response as part of the
714 * key binding material. This also should ensure we have unqiue
715 * tokens that are sent to the remote server which is important because
716 * the token is hashed for the sunrpc cache lookups and a failure there
717 * would cause connection attempts to fail indefinitely due to the large
718 * timeout value on the server side */
719 if (RAND_bytes((unsigned char *)&random, sizeof(random)) != 1) {
720 printerr(0, "Failed to get data for random parameter: %s\n",
721 ERR_error_string(ERR_get_error(), NULL));
722 return GSS_S_FAILURE;
725 /* The random value will always be used in byte range operations
726 * so we keep it as big endian from this point on */
727 skc->sc_kctx.skc_host_random = random;
729 /* Populate DH parameters */
730 skc->sc_params = DH_new();
731 if (!skc->sc_params) {
732 printerr(0, "Failed to allocate DH\n");
733 return GSS_S_FAILURE;
736 skc->sc_params->p = BN_bin2bn(skc->sc_p.value, skc->sc_p.length, NULL);
737 if (!skc->sc_params->p) {
738 printerr(0, "Failed to convert binary to BIGNUM\n");
739 return GSS_S_FAILURE;
742 /* We use a static generator for shared key */
743 skc->sc_params->g = BN_new();
744 if (!skc->sc_params->g) {
745 printerr(0, "Failed to allocate new BIGNUM\n");
746 return GSS_S_FAILURE;
748 if (BN_set_word(skc->sc_params->g, SK_GENERATOR) != 1) {
749 printerr(0, "Failed to set g value for DH params\n");
750 return GSS_S_FAILURE;
753 /* Verify that we have a safe prime and valid generator */
754 if (DH_check(skc->sc_params, &rc) != 1) {
755 printerr(0, "DH_check() failed: %d\n", rc);
756 return GSS_S_FAILURE;
758 printerr(0, "DH_check() returned error codes: 0x%x\n", rc);
759 return GSS_S_FAILURE;
762 if (DH_generate_key(skc->sc_params) != 1) {
763 printerr(0, "Failed to generate public DH key: %s\n",
764 ERR_error_string(ERR_get_error(), NULL));
765 return GSS_S_FAILURE;
768 skc->sc_pub_key.length = BN_num_bytes(skc->sc_params->pub_key);
769 skc->sc_pub_key.value = malloc(skc->sc_pub_key.length);
770 if (!skc->sc_pub_key.value) {
771 printerr(0, "Failed to allocate memory for public key\n");
772 return GSS_S_FAILURE;
775 BN_bn2bin(skc->sc_params->pub_key, skc->sc_pub_key.value);
777 return GSS_S_COMPLETE;
781 * Convert SK hash algorithm into openssl message digest
783 * \param[in,out] alg SK hash algorithm
787 static inline const EVP_MD *sk_hash_to_evp_md(enum cfs_crypto_hash_alg alg)
790 case CFS_HASH_ALG_SHA256:
792 case CFS_HASH_ALG_SHA512:
795 return EVP_md_null();
800 * Signs (via HMAC) the parameters used only in the key initialization protocol.
802 * \param[in] key Key to use for HMAC
803 * \param[in] bufs Array of gss_buffer_desc to generate
805 * \param[in] numbufs Number of buffers in array
806 * \param[in] hash_alg OpenSSL EVP_MD to use for hash
807 * \param[in,out] hmac HMAC of buffers is allocated and placed
808 * in this gss_buffer_desc. Caller must
814 int sk_sign_bufs(gss_buffer_desc *key, gss_buffer_desc *bufs, const int numbufs,
815 const EVP_MD *hash_alg, gss_buffer_desc *hmac)
818 unsigned int hashlen = EVP_MD_size(hash_alg);
822 if (hash_alg == EVP_md_null()) {
823 printerr(0, "Invalid hash algorithm\n");
827 HMAC_CTX_init(&hctx);
829 hmac->length = hashlen;
830 hmac->value = malloc(hashlen);
832 printerr(0, "Failed to allocate memory for HMAC\n");
836 if (HMAC_Init_ex(&hctx, key->value, key->length, hash_alg, NULL) != 1) {
837 printerr(0, "Failed to init HMAC\n");
841 for (i = 0; i < numbufs; i++) {
842 if (HMAC_Update(&hctx, bufs[i].value, bufs[i].length) != 1) {
843 printerr(0, "Failed to update HMAC\n");
848 /* The result gets populated in hmac */
849 if (HMAC_Final(&hctx, hmac->value, &hashlen) != 1) {
850 printerr(0, "Failed to finalize HMAC\n");
854 if (hmac->length != hashlen) {
855 printerr(0, "HMAC size does not match expected\n");
861 HMAC_CTX_cleanup(&hctx);
866 * Generates an HMAC for gss_buffer_desc array in \a bufs of \a numbufs
867 * and verifies against \a hmac.
869 * \param[in] skc Shared key credentials
870 * \param[in] bufs Array of gss_buffer_desc to generate HMAC for
871 * \param[in] numbufs Number of buffers in array
872 * \param[in] hash_alg OpenSSL EVP_MD to use for hash
873 * \param[in] hmac HMAC to verify against
875 * \retval GSS_S_COMPLETE success (match)
876 * \retval gss error failure
878 uint32_t sk_verify_hmac(struct sk_cred *skc, gss_buffer_desc *bufs,
879 const int numbufs, const EVP_MD *hash_alg,
880 gss_buffer_desc *hmac)
882 gss_buffer_desc bufs_hmac;
885 if (sk_sign_bufs(&skc->sc_kctx.skc_shared_key, bufs, numbufs, hash_alg,
887 printerr(0, "Failed to sign buffers to verify HMAC\n");
889 free(bufs_hmac.value);
890 return GSS_S_FAILURE;
893 if (hmac->length != bufs_hmac.length) {
894 printerr(0, "Invalid HMAC size\n");
895 free(bufs_hmac.value);
896 return GSS_S_BAD_SIG;
899 rc = memcmp(hmac->value, bufs_hmac.value, bufs_hmac.length);
900 free(bufs_hmac.value);
903 return GSS_S_BAD_SIG;
905 return GSS_S_COMPLETE;
909 * Cleanup an sk_cred freeing any resources
911 * \param[in,out] skc Shared key credentials to free
913 void sk_free_cred(struct sk_cred *skc)
919 free(skc->sc_p.value);
920 if (skc->sc_pub_key.value)
921 free(skc->sc_pub_key.value);
922 if (skc->sc_tgt.value)
923 free(skc->sc_tgt.value);
924 if (skc->sc_nodemap_hash.value)
925 free(skc->sc_nodemap_hash.value);
926 if (skc->sc_hmac.value)
927 free(skc->sc_hmac.value);
929 /* Overwrite keys and IV before freeing */
930 if (skc->sc_dh_shared_key.value) {
931 memset(skc->sc_dh_shared_key.value, 0,
932 skc->sc_dh_shared_key.length);
933 free(skc->sc_dh_shared_key.value);
935 if (skc->sc_kctx.skc_hmac_key.value) {
936 memset(skc->sc_kctx.skc_hmac_key.value, 0,
937 skc->sc_kctx.skc_hmac_key.length);
938 free(skc->sc_kctx.skc_hmac_key.value);
940 if (skc->sc_kctx.skc_encrypt_key.value) {
941 memset(skc->sc_kctx.skc_encrypt_key.value, 0,
942 skc->sc_kctx.skc_encrypt_key.length);
943 free(skc->sc_kctx.skc_encrypt_key.value);
945 if (skc->sc_kctx.skc_shared_key.value) {
946 memset(skc->sc_kctx.skc_shared_key.value, 0,
947 skc->sc_kctx.skc_shared_key.length);
948 free(skc->sc_kctx.skc_shared_key.value);
950 if (skc->sc_kctx.skc_session_key.value) {
951 memset(skc->sc_kctx.skc_session_key.value, 0,
952 skc->sc_kctx.skc_session_key.length);
953 free(skc->sc_kctx.skc_session_key.value);
957 DH_free(skc->sc_params);
963 /* This function handles key derivation using the hash algorithm specified in
964 * \a hash_alg, buffers in \a key_binding_bufs, and original key in
965 * \a origin_key to produce a \a derived_key. The first element of the
966 * key_binding_bufs array is reserved for the counter used in the KDF. The
967 * derived key in \a derived_key could differ in size from \a origin_key and
968 * must be populated with the expected size and a valid buffer to hold the
971 * If the derived key size is greater than the HMAC algorithm size it will be
972 * a done using several iterations of a counter and the key binding bufs.
974 * If the size is smaller it will take copy the first N bytes necessary to
975 * fill the derived key. */
976 int sk_kdf(gss_buffer_desc *derived_key , gss_buffer_desc *origin_key,
977 gss_buffer_desc *key_binding_bufs, int numbufs,
978 enum cfs_crypto_hash_alg hmac_alg)
984 gss_buffer_desc tmp_hash;
991 /* Use a counter as the first buffer followed by the key binding
992 * buffers in the event we need more than one a single cycle to
993 * produced a symmetric key large enough in size */
994 key_binding_bufs[0].value = &counter;
995 key_binding_bufs[0].length = sizeof(counter);
997 remain = derived_key->length;
998 keydata = derived_key->value;
1000 while (remain > 0) {
1001 counter = htobe32(i++);
1002 rc = sk_sign_bufs(origin_key, key_binding_bufs, numbufs,
1003 sk_hash_to_evp_md(hmac_alg), &tmp_hash);
1006 free(tmp_hash.value);
1010 if (cfs_crypto_hash_digestsize(hmac_alg) != tmp_hash.length) {
1011 free(tmp_hash.value);
1015 bytes = (remain < tmp_hash.length) ? remain : tmp_hash.length;
1016 memcpy(keydata, tmp_hash.value, bytes);
1017 free(tmp_hash.value);
1025 /* Populates the sk_cred's session_key using the a Key Derviation Function (KDF)
1026 * based on the recommendations in NIST Special Publication SP 800-56B Rev 1
1027 * (Sep 2014) Section 5.5.1
1029 * \param[in,out] skc Shared key credentials structure with
1031 * \return -1 failure
1034 int sk_session_kdf(struct sk_cred *skc, lnet_nid_t client_nid,
1035 gss_buffer_desc *client_token, gss_buffer_desc *server_token)
1037 struct sk_kernel_ctx *kctx = &skc->sc_kctx;
1038 gss_buffer_desc *session_key = &kctx->skc_session_key;
1039 gss_buffer_desc bufs[5];
1042 session_key->length = sk_crypt_types[kctx->skc_crypt_alg].cht_bytes;
1043 session_key->value = malloc(session_key->length);
1044 if (!session_key->value) {
1045 printerr(0, "Failed to allocate memory for session key\n");
1049 /* Key binding info ordering
1050 * 1. Reserved for counter
1054 * 4. Server's token */
1055 bufs[0].value = NULL;
1057 bufs[1] = skc->sc_dh_shared_key;
1058 bufs[2].value = &client_nid;
1059 bufs[2].length = sizeof(client_nid);
1060 bufs[3] = *client_token;
1061 bufs[4] = *server_token;
1063 return sk_kdf(&kctx->skc_session_key, &kctx->skc_shared_key, bufs,
1064 5, kctx->skc_hmac_alg);
1067 /* Uses the session key to create an HMAC key and encryption key. In
1068 * integrity mode the session key used to generate the HMAC key uses
1069 * session information which is available on the wire but by creating
1070 * a session based HMAC key we can prevent potential replay as both the
1071 * client and server have random numbers used as part of the key creation.
1073 * The keys used for integrity and privacy are formulated as below using
1074 * the session key that is the output of the key derivation function. The
1075 * HMAC algorithm is determined by the shared key algorithm selected in the
1079 * Session HMAC Key = PBKDF2("Integrity", KDF derived Session Key)
1082 * Session HMAC Key = PBKDF2("Integrity", KDF derived Session Key)
1083 * Session Encryption Key = PBKDF2("Encrypt", KDF derived Session Key)
1085 * \param[in,out] skc Shared key credentials structure with
1087 * \return -1 failure
1090 int sk_compute_keys(struct sk_cred *skc)
1092 struct sk_kernel_ctx *kctx = &skc->sc_kctx;
1093 gss_buffer_desc *session_key = &kctx->skc_session_key;
1094 gss_buffer_desc *hmac_key = &kctx->skc_hmac_key;
1095 gss_buffer_desc *encrypt_key = &kctx->skc_encrypt_key;
1096 char *encrypt = "Encrypt";
1097 char *integrity = "Integrity";
1100 hmac_key->length = cfs_crypto_hash_digestsize(kctx->skc_hmac_alg);
1101 hmac_key->value = malloc(hmac_key->length);
1102 if (!hmac_key->value)
1105 rc = PKCS5_PBKDF2_HMAC(integrity, -1, session_key->value,
1106 session_key->length, SK_PBKDF2_ITERATIONS,
1107 sk_hash_to_evp_md(kctx->skc_hmac_alg),
1108 hmac_key->length, hmac_key->value);
1112 /* Encryption key is only populated in privacy mode */
1113 if ((skc->sc_flags & LGSS_SVC_PRIV) == 0)
1116 encrypt_key->length = cfs_crypto_hash_digestsize(kctx->skc_hmac_alg);
1117 encrypt_key->value = malloc(encrypt_key->length);
1118 if (!encrypt_key->value)
1121 rc = PKCS5_PBKDF2_HMAC(encrypt, -1, session_key->value,
1122 session_key->length, SK_PBKDF2_ITERATIONS,
1123 sk_hash_to_evp_md(kctx->skc_hmac_alg),
1124 encrypt_key->length, encrypt_key->value);
1132 * Computes a session key based on the DH parameters from the host and its peer
1134 * \param[in,out] skc Shared key credentials structure with
1135 * the session key populated with the
1137 * \param[in] pub_key Public key returned from peer in
1139 * \return gss error failure
1140 * \return GSS_S_COMPLETE success
1142 uint32_t sk_compute_dh_key(struct sk_cred *skc, const gss_buffer_desc *pub_key)
1144 gss_buffer_desc *dh_shared = &skc->sc_dh_shared_key;
1145 BIGNUM *remote_pub_key;
1147 uint32_t rc = GSS_S_FAILURE;
1149 remote_pub_key = BN_bin2bn(pub_key->value, pub_key->length, NULL);
1150 if (!remote_pub_key) {
1151 printerr(0, "Failed to convert binary to BIGNUM\n");
1155 dh_shared->length = DH_size(skc->sc_params);
1156 dh_shared->value = malloc(dh_shared->length);
1157 if (!dh_shared->value) {
1158 printerr(0, "Failed to allocate memory for computed shared "
1163 /* This compute the shared key from the DHKE */
1164 status = DH_compute_key(dh_shared->value, remote_pub_key,
1167 printerr(0, "DH_compute_key() failed: %s\n",
1168 ERR_error_string(ERR_get_error(), NULL));
1170 } else if (status < dh_shared->length) {
1171 printerr(0, "DH_compute_key() returned a short key of %d "
1172 "bytes, expected: %zu\n", status, dh_shared->length);
1173 rc = GSS_S_DEFECTIVE_TOKEN;
1177 rc = GSS_S_COMPLETE;
1180 BN_free(remote_pub_key);
1185 * Creates a serialized buffer for the kernel in the order of struct
1188 * \param[in,out] skc Shared key credentials structure
1189 * \param[in,out] ctx_token Serialized buffer for kernel.
1190 * Caller must free this buffer.
1193 * \return -1 failure
1195 int sk_serialize_kctx(struct sk_cred *skc, gss_buffer_desc *ctx_token)
1197 struct sk_kernel_ctx *kctx = &skc->sc_kctx;
1201 bufsize = sizeof(*kctx) + kctx->skc_hmac_key.length +
1202 kctx->skc_encrypt_key.length;
1204 ctx_token->value = malloc(bufsize);
1205 if (!ctx_token->value)
1207 ctx_token->length = bufsize;
1209 p = ctx_token->value;
1210 end = p + ctx_token->length;
1212 if (WRITE_BYTES(&p, end, kctx->skc_version))
1214 if (WRITE_BYTES(&p, end, kctx->skc_hmac_alg))
1216 if (WRITE_BYTES(&p, end, kctx->skc_crypt_alg))
1218 if (WRITE_BYTES(&p, end, kctx->skc_expire))
1220 if (WRITE_BYTES(&p, end, kctx->skc_host_random))
1222 if (WRITE_BYTES(&p, end, kctx->skc_peer_random))
1224 if (write_buffer(&p, end, &kctx->skc_hmac_key))
1226 if (write_buffer(&p, end, &kctx->skc_encrypt_key))
1229 printerr(2, "Serialized buffer of %zu bytes for kernel\n", bufsize);
1235 * Decodes a netstring \a ns into array of gss_buffer_descs at \a bufs
1236 * up to \a numbufs. Memory is allocated for each value and length
1237 * will be populated with the length
1239 * \param[in,out] bufs Array of gss_buffer_descs
1240 * \param[in,out] numbufs number of gss_buffer_desc in array
1241 * \param[in] ns netstring to decode
1243 * \return buffers populated success
1244 * \return -1 failure
1246 int sk_decode_netstring(gss_buffer_desc *bufs, int numbufs, gss_buffer_desc *ns)
1248 char *ptr = ns->value;
1249 size_t remain = ns->length;
1256 for (i = 0; i < numbufs; i++) {
1257 /* read the size of first buffer */
1258 rc = sscanf(ptr, "%9u", &size);
1261 digits = (size) ? ceil(log10(size + 1)) : 1;
1263 /* sep of current string */
1264 sep = size + digits + 2;
1266 /* check to make sure it's valid */
1267 if (remain < sep || ptr[digits] != ':' ||
1268 ptr[sep - 1] != ',')
1271 bufs[i].length = size;
1273 bufs[i].value = NULL;
1275 bufs[i].value = malloc(size);
1278 memcpy(bufs[i].value, &ptr[digits + 1], size);
1285 printerr(2, "Decoded netstring of %zu bytes\n", ns->length);
1291 free(bufs[i].value);
1298 * Creates a netstring in a gss_buffer_desc that consists of all
1299 * the gss_buffer_desc found in \a bufs. The netstring should be treated
1300 * as binary as it can contain null characters.
1302 * \param[in] bufs Array of gss_buffer_desc to use as input
1303 * \param[in] numbufs Number of buffers in array
1304 * \param[in,out] ns Destination gss_buffer_desc to hold
1307 * \return -1 failure
1310 int sk_encode_netstring(gss_buffer_desc *bufs, int numbufs,
1311 gss_buffer_desc *ns)
1318 /* size of string in decimal, string size, colon, and comma */
1319 for (i = 0; i < numbufs; i++) {
1321 if (bufs[i].length == 0)
1324 size += ceil(log10(bufs[i].length + 1)) +
1329 ns->value = malloc(ns->length);
1336 for (i = 0; i < numbufs; i++) {
1338 rc = snprintf((char *) ptr, size, "%zu:", bufs[i].length);
1342 memcpy(ptr, bufs[i].value, bufs[i].length);
1343 ptr += bufs[i].length;
1348 size -= bufs[i].length + rc + 1;
1350 /* should not happen */
1355 printerr(2, "Encoded netstring of %zu bytes\n", ns->length);