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>
44 #include "write_bytes.h"
46 #define SK_PBKDF2_ITERATIONS 10000
49 # include "lgss_utils.h"
51 # include "gss_util.h"
52 # include "gss_oids.h"
53 # include "err_util.h"
59 * \param[in] program Program name to output
60 * \param[in] verbose Verbose flag
61 * \param[in] fg Whether or not to run in foreground
64 void sk_init_logging(char *program, int verbose, int fg)
66 initerr(program, verbose, fg);
71 * Loads the key from \a filename and returns the struct sk_keyfile_config.
72 * It should be freed by the caller.
74 * \param[in] filename Disk or key payload data
76 * \return sk_keyfile_config sucess
77 * \return NULL failure
79 struct sk_keyfile_config *sk_read_file(char *filename)
81 struct sk_keyfile_config *config;
87 config = malloc(sizeof(*config));
89 printerr(0, "Failed to allocate memory for config\n");
93 /* allow standard input override */
94 if (strcmp(filename, "-") == 0)
97 fd = open(filename, O_RDONLY);
100 printerr(0, "Error opening key file '%s': %s\n", filename,
103 } else if (fd != STDIN_FILENO) {
107 if (rc == 0 && (st.st_mode & ~(S_IFREG | 0600)))
108 fprintf(stderr, "warning: "
109 "secret key '%s' has insecure file mode %#o\n",
110 filename, st.st_mode);
113 ptr = (char *)config;
114 remain = sizeof(*config);
116 rc = read(fd, ptr, remain);
120 printerr(0, "read() failed on %s: %s\n", filename,
123 } else if (rc == 0) {
124 printerr(0, "File %s does not have a complete key\n",
132 if (fd != STDIN_FILENO)
134 sk_config_disk_to_cpu(config);
145 * Checks if a key matching \a description is found in the keyring for
146 * logging purposes and then attempts to load \a payload of \a psize into a key
147 * with \a description.
149 * \param[in] payload Key payload
150 * \param[in] psize Payload size
151 * \param[in] description Description used for key in keyring
156 static key_serial_t sk_load_key(const struct sk_keyfile_config *skc,
157 const char *description)
159 struct sk_keyfile_config payload;
162 memcpy(&payload, skc, sizeof(*skc));
164 /* In the keyring use the disk layout so keyctl pipe can be used */
165 sk_config_cpu_to_disk(&payload);
167 /* Check to see if a key is already loaded matching description */
168 key = keyctl_search(KEY_SPEC_USER_KEYRING, "user", description, 0);
170 printerr(2, "Key %d found in session keyring, replacing\n",
173 key = add_key("user", description, &payload, sizeof(payload),
174 KEY_SPEC_USER_KEYRING);
176 printerr(2, "Added key %d with description %s\n", key,
179 printerr(0, "Failed to add key with %s\n", description);
185 * Reads the key from \a path, verifies it and loads into the session keyring
186 * using a description determined by the the \a type. Existing keys with the
187 * same description are replaced.
189 * \param[in] path Path to key file
190 * \param[in] type Type of key to load which determines the description
195 int sk_load_keyfile(char *path)
197 struct sk_keyfile_config *config;
198 char description[SK_DESCRIPTION_SIZE + 1];
204 rc = stat(path, &buf);
206 printerr(0, "stat() failed for file %s: %s\n", path,
211 config = sk_read_file(path);
215 /* Similar to ssh, require adequate care of key files */
216 if (buf.st_mode & (S_IRGRP | S_IWGRP | S_IWOTH | S_IXOTH)) {
217 printerr(0, "Shared key files must be read/writeable only by "
222 if (sk_validate_config(config))
225 /* The server side can have multiple key files per file system so
226 * the nodemap name is appended to the key description to uniquely
228 if (config->skc_type & SK_TYPE_MGS) {
229 /* Any key can be an MGS key as long as we are told to use it */
230 rc = snprintf(description, SK_DESCRIPTION_SIZE, "lustre:MGS:%s",
231 config->skc_nodemap);
232 if (rc >= SK_DESCRIPTION_SIZE)
234 if (sk_load_key(config, description) == -1)
237 if (config->skc_type & SK_TYPE_SERVER) {
238 /* Server keys need to have the file system name in the key */
239 if (!config->skc_fsname) {
240 printerr(0, "Key configuration has no file system "
241 "attribute. Can't load as server type\n");
244 rc = snprintf(description, SK_DESCRIPTION_SIZE, "lustre:%s:%s",
245 config->skc_fsname, config->skc_nodemap);
246 if (rc >= SK_DESCRIPTION_SIZE)
248 if (sk_load_key(config, description) == -1)
251 if (config->skc_type & SK_TYPE_CLIENT) {
252 /* Load client file system key */
253 if (config->skc_fsname) {
254 rc = snprintf(description, SK_DESCRIPTION_SIZE,
255 "lustre:%s", config->skc_fsname);
256 if (rc >= SK_DESCRIPTION_SIZE)
258 if (sk_load_key(config, description) == -1)
262 /* Load client MGC keys */
263 for (i = 0; i < MAX_MGSNIDS; i++) {
264 if (config->skc_mgsnids[i] == LNET_NID_ANY)
266 rc = snprintf(description, SK_DESCRIPTION_SIZE,
268 libcfs_nid2str(config->skc_mgsnids[i]));
269 if (rc >= SK_DESCRIPTION_SIZE)
271 if (sk_load_key(config, description) == -1)
284 * Byte swaps config from cpu format to disk
286 * \param[in,out] config sk_keyfile_config to swap
288 void sk_config_cpu_to_disk(struct sk_keyfile_config *config)
295 config->skc_version = htobe32(config->skc_version);
296 config->skc_hmac_alg = htobe16(config->skc_hmac_alg);
297 config->skc_crypt_alg = htobe16(config->skc_crypt_alg);
298 config->skc_expire = htobe32(config->skc_expire);
299 config->skc_shared_keylen = htobe32(config->skc_shared_keylen);
300 config->skc_prime_bits = htobe32(config->skc_prime_bits);
302 for (i = 0; i < MAX_MGSNIDS; i++)
303 config->skc_mgsnids[i] = htobe64(config->skc_mgsnids[i]);
307 * Byte swaps config from disk format to cpu
309 * \param[in,out] config sk_keyfile_config to swap
311 void sk_config_disk_to_cpu(struct sk_keyfile_config *config)
318 config->skc_version = be32toh(config->skc_version);
319 config->skc_hmac_alg = be16toh(config->skc_hmac_alg);
320 config->skc_crypt_alg = be16toh(config->skc_crypt_alg);
321 config->skc_expire = be32toh(config->skc_expire);
322 config->skc_shared_keylen = be32toh(config->skc_shared_keylen);
323 config->skc_prime_bits = be32toh(config->skc_prime_bits);
325 for (i = 0; i < MAX_MGSNIDS; i++)
326 config->skc_mgsnids[i] = be64toh(config->skc_mgsnids[i]);
330 * Verifies the on key payload format is valid
332 * \param[in] config sk_keyfile_config
337 int sk_validate_config(const struct sk_keyfile_config *config)
342 printerr(0, "Null configuration passed\n");
346 if (config->skc_version != SK_CONF_VERSION) {
347 printerr(0, "Invalid version\n");
351 if (config->skc_hmac_alg == SK_HMAC_INVALID) {
352 printerr(0, "Invalid HMAC algorithm\n");
356 if (config->skc_crypt_alg == SK_CRYPT_INVALID) {
357 printerr(0, "Invalid crypt algorithm\n");
361 if (config->skc_expire < 60 || config->skc_expire > INT_MAX) {
362 /* Try to limit key expiration to some reasonable minimum and
363 * also prevent values over INT_MAX because there appears
364 * to be a type conversion issue */
365 printerr(0, "Invalid expiration time should be between %d "
366 "and %d\n", 60, INT_MAX);
369 if (config->skc_prime_bits % 8 != 0 ||
370 config->skc_prime_bits > SK_MAX_P_BYTES * 8) {
371 printerr(0, "Invalid session key length must be a multiple of 8"
372 " and less then %d bits\n",
376 if (config->skc_shared_keylen % 8 != 0 ||
377 config->skc_shared_keylen > SK_MAX_KEYLEN_BYTES * 8){
378 printerr(0, "Invalid shared key max length must be a multiple "
379 "of 8 and less then %d bits\n",
380 SK_MAX_KEYLEN_BYTES * 8);
384 /* Check for terminating nulls on strings */
385 for (i = 0; i < sizeof(config->skc_fsname) &&
386 config->skc_fsname[i] != '\0'; i++)
388 if (i == sizeof(config->skc_fsname)) {
389 printerr(0, "File system name not null terminated\n");
393 for (i = 0; i < sizeof(config->skc_nodemap) &&
394 config->skc_nodemap[i] != '\0'; i++)
396 if (i == sizeof(config->skc_nodemap)) {
397 printerr(0, "Nodemap name not null terminated\n");
401 if (config->skc_type == SK_TYPE_INVALID) {
402 printerr(0, "Invalid key type\n");
410 * Hashes \a string and places the hash in \a hash
413 * \param[in] string Null terminated string to hash
414 * \param[in] hash_alg OpenSSL EVP_MD to use for hash
415 * \param[in,out] hash gss_buffer_desc to hold the result
420 static int sk_hash_string(const char *string, const EVP_MD *hash_alg,
421 gss_buffer_desc *hash)
423 EVP_MD_CTX *ctx = EVP_MD_CTX_create();
424 size_t len = strlen(string);
425 unsigned int hashlen;
427 if (!hash->value || hash->length < EVP_MD_size(hash_alg))
429 if (!EVP_DigestInit_ex(ctx, hash_alg, NULL))
431 if (!EVP_DigestUpdate(ctx, string, len))
433 if (!EVP_DigestFinal_ex(ctx, hash->value, &hashlen))
436 EVP_MD_CTX_destroy(ctx);
437 hash->length = hashlen;
441 EVP_MD_CTX_destroy(ctx);
446 * Hashes \a string and verifies the resulting hash matches the value
449 * \param[in] string Null terminated string to hash
450 * \param[in] hash_alg OpenSSL EVP_MD to use for hash
451 * \param[in,out] current_hash gss_buffer_desc to compare to
453 * \return gss error failure
454 * \return GSS_S_COMPLETE success
456 uint32_t sk_verify_hash(const char *string, const EVP_MD *hash_alg,
457 const gss_buffer_desc *current_hash)
459 gss_buffer_desc hash;
460 unsigned char hashbuf[EVP_MAX_MD_SIZE];
462 hash.value = hashbuf;
463 hash.length = sizeof(hashbuf);
465 if (sk_hash_string(string, hash_alg, &hash))
466 return GSS_S_FAILURE;
467 if (current_hash->length != hash.length)
468 return GSS_S_DEFECTIVE_TOKEN;
469 if (memcmp(current_hash->value, hash.value, hash.length))
470 return GSS_S_BAD_SIG;
472 return GSS_S_COMPLETE;
475 static inline int sk_config_has_mgsnid(struct sk_keyfile_config *config,
481 nid = libcfs_str2nid(mgsnid);
482 if (nid == LNET_NID_ANY)
485 for (i = 0; i < MAX_MGSNIDS; i++)
486 if (config->skc_mgsnids[i] == nid)
492 * Create an sk_cred structure populated with initial configuration info and the
493 * key. \a tgt and \a nodemap are used in determining the expected key
494 * description so the key can be found by searching the keyring.
495 * This is done because there is no easy way to pass keys from the mount command
496 * all the way to the request_key call. In addition any keys can be dynamically
497 * added to the keyrings and still found. The keyring that needs to be used
498 * must be the session keyring.
500 * \param[in] tgt Target file system
501 * \param[in] nodemap Cluster name for the key. This correlates to
502 * the nodemap name and is used by the server side.
503 * For the client this will be NULL.
504 * \param[in] flags Flags for the credentials
506 * \return sk_cred Allocated struct sk_cred on success
507 * \return NULL failure
509 struct sk_cred *sk_create_cred(const char *tgt, const char *nodemap,
510 const uint32_t flags)
512 struct sk_keyfile_config *config;
513 struct sk_kernel_ctx *kctx;
514 struct sk_cred *skc = NULL;
515 char description[SK_DESCRIPTION_SIZE + 1];
516 char fsname[MTI_NAME_MAXLEN + 1];
517 const char *mgsnid = NULL;
524 printerr(2, "Creating credentials for target: %s with nodemap: %s\n",
527 memset(description, 0, sizeof(description));
528 memset(fsname, 0, sizeof(fsname));
530 /* extract the file system name from target */
531 ptr = index(tgt, '-');
535 /* This must be an MGC target */
536 if (strncmp(tgt, "MGC", 3) || len <= 3) {
537 printerr(0, "Invalid target name\n");
545 if (len > MTI_NAME_MAXLEN) {
546 printerr(0, "Invalid target name\n");
549 memcpy(fsname, tgt, len);
553 rc = snprintf(description, SK_DESCRIPTION_SIZE,
554 "lustre:MGS:%s", nodemap);
556 rc = snprintf(description, SK_DESCRIPTION_SIZE,
557 "lustre:%s:%s", fsname, nodemap);
559 rc = snprintf(description, SK_DESCRIPTION_SIZE, "lustre:%s",
563 if (rc >= SK_DESCRIPTION_SIZE) {
564 printerr(0, "Invalid key description\n");
568 /* It may be a good idea to move Lustre keys to the gss_keyring
569 * (lgssc) type so that they expire when Lustre modules are removed.
570 * Unfortunately it can't be done at mount time because the mount
571 * syscall could trigger the Lustre modules to load and until that
572 * point we don't have a lgssc key type.
574 * TODO: Query the community for a consensus here */
575 printerr(2, "Searching for key with description: %s\n", description);
576 sk_key = keyctl_search(KEY_SPEC_USER_KEYRING, "user",
579 printerr(1, "No key found for %s\n", description);
583 keylen = keyctl_read_alloc(sk_key, (void **)&config);
585 printerr(0, "keyctl_read() failed for key %ld: %s\n", sk_key,
588 } else if (keylen != sizeof(*config)) {
589 printerr(0, "Unexpected key size: %d returned for key %ld, "
590 "expected %zu bytes\n",
591 keylen, sk_key, sizeof(*config));
595 sk_config_disk_to_cpu(config);
597 if (sk_validate_config(config)) {
598 printerr(0, "Invalid key configuration for key: %ld\n", sk_key);
602 if (mgsnid && !sk_config_has_mgsnid(config, mgsnid)) {
603 printerr(0, "Target name does not match key's MGS NIDs\n");
607 if (!mgsnid && strcmp(fsname, config->skc_fsname)) {
608 printerr(0, "Target name does not match key's file system\n");
612 skc = malloc(sizeof(*skc));
614 printerr(0, "Failed to allocate memory for sk_cred\n");
618 /* this initializes all gss_buffer_desc to empty as well */
619 memset(skc, 0, sizeof(*skc));
621 skc->sc_flags = flags;
622 skc->sc_tgt.length = strlen(tgt) + 1;
623 skc->sc_tgt.value = malloc(skc->sc_tgt.length);
624 if (!skc->sc_tgt.value) {
625 printerr(0, "Failed to allocate memory for target\n");
628 memcpy(skc->sc_tgt.value, tgt, skc->sc_tgt.length);
630 skc->sc_nodemap_hash.length = EVP_MD_size(EVP_sha256());
631 skc->sc_nodemap_hash.value = malloc(skc->sc_nodemap_hash.length);
632 if (!skc->sc_nodemap_hash.value) {
633 printerr(0, "Failed to allocate memory for nodemap hash\n");
637 if (sk_hash_string(config->skc_nodemap, EVP_sha256(),
638 &skc->sc_nodemap_hash)) {
639 printerr(0, "Failed to generate hash for nodemap name\n");
643 kctx = &skc->sc_kctx;
644 kctx->skc_version = config->skc_version;
645 strcpy(kctx->skc_hmac_alg, sk_hmac2name(config->skc_hmac_alg));
646 strcpy(kctx->skc_crypt_alg, sk_crypt2name(config->skc_crypt_alg));
647 kctx->skc_expire = config->skc_expire;
649 /* key payload format is in bits, convert to bytes */
650 kctx->skc_shared_key.length = config->skc_shared_keylen / 8;
651 kctx->skc_shared_key.value = malloc(kctx->skc_shared_key.length);
652 if (!kctx->skc_shared_key.value) {
653 printerr(0, "Failed to allocate memory for shared key\n");
656 memcpy(kctx->skc_shared_key.value, config->skc_shared_key,
657 kctx->skc_shared_key.length);
659 skc->sc_p.length = config->skc_prime_bits / 8;
660 skc->sc_p.value = malloc(skc->sc_p.length);
661 if (!skc->sc_p.value) {
662 printerr(0, "Failed to allocate p\n");
665 memcpy(skc->sc_p.value, config->skc_p, skc->sc_p.length);
679 * Populates the DH parameters for the DHKE
681 * \param[in,out] skc Shared key credentials structure to
682 * populate with DH parameters
684 * \retval GSS_S_COMPLETE success
685 * \retval GSS_S_FAILURE failure
687 uint32_t sk_gen_params(struct sk_cred *skc)
691 const BIGNUM *pub_key;
694 /* Random value used by both the request and response as part of the
695 * key binding material. This also should ensure we have unqiue
696 * tokens that are sent to the remote server which is important because
697 * the token is hashed for the sunrpc cache lookups and a failure there
698 * would cause connection attempts to fail indefinitely due to the large
699 * timeout value on the server side */
700 if (RAND_bytes((unsigned char *)&random, sizeof(random)) != 1) {
701 printerr(0, "Failed to get data for random parameter: %s\n",
702 ERR_error_string(ERR_get_error(), NULL));
703 return GSS_S_FAILURE;
706 /* The random value will always be used in byte range operations
707 * so we keep it as big endian from this point on */
708 skc->sc_kctx.skc_host_random = random;
710 /* Populate DH parameters */
711 skc->sc_params = DH_new();
712 if (!skc->sc_params) {
713 printerr(0, "Failed to allocate DH\n");
714 return GSS_S_FAILURE;
717 p = BN_bin2bn(skc->sc_p.value, skc->sc_p.length, NULL);
719 printerr(0, "Failed to convert binary to BIGNUM\n");
720 return GSS_S_FAILURE;
723 /* We use a static generator for shared key */
726 printerr(0, "Failed to allocate new BIGNUM\n");
727 return GSS_S_FAILURE;
729 if (BN_set_word(g, SK_GENERATOR) != 1) {
730 printerr(0, "Failed to set g value for DH params\n");
731 return GSS_S_FAILURE;
734 if (!DH_set0_pqg(skc->sc_params, p, NULL, g)) {
735 printerr(0, "Failed to set pqg\n");
736 return GSS_S_FAILURE;
739 /* Verify that we have a safe prime and valid generator */
740 if (DH_check(skc->sc_params, &rc) != 1) {
741 printerr(0, "DH_check() failed: %d\n", rc);
742 return GSS_S_FAILURE;
744 printerr(0, "DH_check() returned error codes: 0x%x\n", rc);
745 return GSS_S_FAILURE;
748 if (DH_generate_key(skc->sc_params) != 1) {
749 printerr(0, "Failed to generate public DH key: %s\n",
750 ERR_error_string(ERR_get_error(), NULL));
751 return GSS_S_FAILURE;
754 DH_get0_key(skc->sc_params, &pub_key, NULL);
755 skc->sc_pub_key.length = BN_num_bytes(pub_key);
756 skc->sc_pub_key.value = malloc(skc->sc_pub_key.length);
757 if (!skc->sc_pub_key.value) {
758 printerr(0, "Failed to allocate memory for public key\n");
759 return GSS_S_FAILURE;
762 BN_bn2bin(pub_key, skc->sc_pub_key.value);
764 return GSS_S_COMPLETE;
768 * Convert SK hash algorithm into openssl message digest
770 * \param[in,out] alg SK hash algorithm
774 static inline const EVP_MD *sk_hash_to_evp_md(enum cfs_crypto_hash_alg alg)
777 case CFS_HASH_ALG_SHA256:
779 case CFS_HASH_ALG_SHA512:
782 return EVP_md_null();
787 * Signs (via HMAC) the parameters used only in the key initialization protocol.
789 * \param[in] key Key to use for HMAC
790 * \param[in] bufs Array of gss_buffer_desc to generate
792 * \param[in] numbufs Number of buffers in array
793 * \param[in] hash_alg OpenSSL EVP_MD to use for hash
794 * \param[in,out] hmac HMAC of buffers is allocated and placed
795 * in this gss_buffer_desc. Caller must
801 int sk_sign_bufs(gss_buffer_desc *key, gss_buffer_desc *bufs, const int numbufs,
802 const EVP_MD *hash_alg, gss_buffer_desc *hmac)
805 unsigned int hashlen = EVP_MD_size(hash_alg);
809 if (hash_alg == EVP_md_null()) {
810 printerr(0, "Invalid hash algorithm\n");
814 hctx = HMAC_CTX_new();
816 hmac->length = hashlen;
817 hmac->value = malloc(hashlen);
819 printerr(0, "Failed to allocate memory for HMAC\n");
823 if (HMAC_Init_ex(hctx, key->value, key->length, hash_alg, NULL) != 1) {
824 printerr(0, "Failed to init HMAC\n");
828 for (i = 0; i < numbufs; i++) {
829 if (HMAC_Update(hctx, bufs[i].value, bufs[i].length) != 1) {
830 printerr(0, "Failed to update HMAC\n");
835 /* The result gets populated in hmac */
836 if (HMAC_Final(hctx, hmac->value, &hashlen) != 1) {
837 printerr(0, "Failed to finalize HMAC\n");
841 if (hmac->length != hashlen) {
842 printerr(0, "HMAC size does not match expected\n");
853 * Generates an HMAC for gss_buffer_desc array in \a bufs of \a numbufs
854 * and verifies against \a hmac.
856 * \param[in] skc Shared key credentials
857 * \param[in] bufs Array of gss_buffer_desc to generate HMAC for
858 * \param[in] numbufs Number of buffers in array
859 * \param[in] hash_alg OpenSSL EVP_MD to use for hash
860 * \param[in] hmac HMAC to verify against
862 * \retval GSS_S_COMPLETE success (match)
863 * \retval gss error failure
865 uint32_t sk_verify_hmac(struct sk_cred *skc, gss_buffer_desc *bufs,
866 const int numbufs, const EVP_MD *hash_alg,
867 gss_buffer_desc *hmac)
869 gss_buffer_desc bufs_hmac;
872 if (sk_sign_bufs(&skc->sc_kctx.skc_shared_key, bufs, numbufs, hash_alg,
874 printerr(0, "Failed to sign buffers to verify HMAC\n");
876 free(bufs_hmac.value);
877 return GSS_S_FAILURE;
880 if (hmac->length != bufs_hmac.length) {
881 printerr(0, "Invalid HMAC size\n");
882 free(bufs_hmac.value);
883 return GSS_S_BAD_SIG;
886 rc = memcmp(hmac->value, bufs_hmac.value, bufs_hmac.length);
887 free(bufs_hmac.value);
890 return GSS_S_BAD_SIG;
892 return GSS_S_COMPLETE;
896 * Cleanup an sk_cred freeing any resources
898 * \param[in,out] skc Shared key credentials to free
900 void sk_free_cred(struct sk_cred *skc)
906 free(skc->sc_p.value);
907 if (skc->sc_pub_key.value)
908 free(skc->sc_pub_key.value);
909 if (skc->sc_tgt.value)
910 free(skc->sc_tgt.value);
911 if (skc->sc_nodemap_hash.value)
912 free(skc->sc_nodemap_hash.value);
913 if (skc->sc_hmac.value)
914 free(skc->sc_hmac.value);
916 /* Overwrite keys and IV before freeing */
917 if (skc->sc_dh_shared_key.value) {
918 memset(skc->sc_dh_shared_key.value, 0,
919 skc->sc_dh_shared_key.length);
920 free(skc->sc_dh_shared_key.value);
922 if (skc->sc_kctx.skc_hmac_key.value) {
923 memset(skc->sc_kctx.skc_hmac_key.value, 0,
924 skc->sc_kctx.skc_hmac_key.length);
925 free(skc->sc_kctx.skc_hmac_key.value);
927 if (skc->sc_kctx.skc_encrypt_key.value) {
928 memset(skc->sc_kctx.skc_encrypt_key.value, 0,
929 skc->sc_kctx.skc_encrypt_key.length);
930 free(skc->sc_kctx.skc_encrypt_key.value);
932 if (skc->sc_kctx.skc_shared_key.value) {
933 memset(skc->sc_kctx.skc_shared_key.value, 0,
934 skc->sc_kctx.skc_shared_key.length);
935 free(skc->sc_kctx.skc_shared_key.value);
937 if (skc->sc_kctx.skc_session_key.value) {
938 memset(skc->sc_kctx.skc_session_key.value, 0,
939 skc->sc_kctx.skc_session_key.length);
940 free(skc->sc_kctx.skc_session_key.value);
944 DH_free(skc->sc_params);
950 /* This function handles key derivation using the hash algorithm specified in
951 * \a hash_alg, buffers in \a key_binding_bufs, and original key in
952 * \a origin_key to produce a \a derived_key. The first element of the
953 * key_binding_bufs array is reserved for the counter used in the KDF. The
954 * derived key in \a derived_key could differ in size from \a origin_key and
955 * must be populated with the expected size and a valid buffer to hold the
958 * If the derived key size is greater than the HMAC algorithm size it will be
959 * a done using several iterations of a counter and the key binding bufs.
961 * If the size is smaller it will take copy the first N bytes necessary to
962 * fill the derived key. */
963 int sk_kdf(gss_buffer_desc *derived_key , gss_buffer_desc *origin_key,
964 gss_buffer_desc *key_binding_bufs, int numbufs,
965 enum cfs_crypto_hash_alg hmac_alg)
971 gss_buffer_desc tmp_hash;
978 /* Use a counter as the first buffer followed by the key binding
979 * buffers in the event we need more than one a single cycle to
980 * produced a symmetric key large enough in size */
981 key_binding_bufs[0].value = &counter;
982 key_binding_bufs[0].length = sizeof(counter);
984 remain = derived_key->length;
985 keydata = derived_key->value;
988 counter = htobe32(i++);
989 rc = sk_sign_bufs(origin_key, key_binding_bufs, numbufs,
990 sk_hash_to_evp_md(hmac_alg), &tmp_hash);
993 free(tmp_hash.value);
997 if (cfs_crypto_hash_digestsize(hmac_alg) != tmp_hash.length) {
998 free(tmp_hash.value);
1002 bytes = (remain < tmp_hash.length) ? remain : tmp_hash.length;
1003 memcpy(keydata, tmp_hash.value, bytes);
1004 free(tmp_hash.value);
1012 /* Populates the sk_cred's session_key using the a Key Derviation Function (KDF)
1013 * based on the recommendations in NIST Special Publication SP 800-56B Rev 1
1014 * (Sep 2014) Section 5.5.1
1016 * \param[in,out] skc Shared key credentials structure with
1018 * \return -1 failure
1021 int sk_session_kdf(struct sk_cred *skc, lnet_nid_t client_nid,
1022 gss_buffer_desc *client_token, gss_buffer_desc *server_token)
1024 struct sk_kernel_ctx *kctx = &skc->sc_kctx;
1025 gss_buffer_desc *session_key = &kctx->skc_session_key;
1026 gss_buffer_desc bufs[5];
1027 enum cfs_crypto_crypt_alg crypt_alg;
1030 crypt_alg = cfs_crypto_crypt_alg(kctx->skc_crypt_alg);
1031 session_key->length = cfs_crypto_crypt_keysize(crypt_alg);
1032 session_key->value = malloc(session_key->length);
1033 if (!session_key->value) {
1034 printerr(0, "Failed to allocate memory for session key\n");
1038 /* Key binding info ordering
1039 * 1. Reserved for counter
1043 * 4. Server's token */
1044 bufs[0].value = NULL;
1046 bufs[1] = skc->sc_dh_shared_key;
1047 bufs[2].value = &client_nid;
1048 bufs[2].length = sizeof(client_nid);
1049 bufs[3] = *client_token;
1050 bufs[4] = *server_token;
1052 return sk_kdf(&kctx->skc_session_key, &kctx->skc_shared_key, bufs,
1053 5, cfs_crypto_hash_alg(kctx->skc_hmac_alg));
1056 /* Uses the session key to create an HMAC key and encryption key. In
1057 * integrity mode the session key used to generate the HMAC key uses
1058 * session information which is available on the wire but by creating
1059 * a session based HMAC key we can prevent potential replay as both the
1060 * client and server have random numbers used as part of the key creation.
1062 * The keys used for integrity and privacy are formulated as below using
1063 * the session key that is the output of the key derivation function. The
1064 * HMAC algorithm is determined by the shared key algorithm selected in the
1068 * Session HMAC Key = PBKDF2("Integrity", KDF derived Session Key)
1071 * Session HMAC Key = PBKDF2("Integrity", KDF derived Session Key)
1072 * Session Encryption Key = PBKDF2("Encrypt", KDF derived Session Key)
1074 * \param[in,out] skc Shared key credentials structure with
1076 * \return -1 failure
1079 int sk_compute_keys(struct sk_cred *skc)
1081 struct sk_kernel_ctx *kctx = &skc->sc_kctx;
1082 gss_buffer_desc *session_key = &kctx->skc_session_key;
1083 gss_buffer_desc *hmac_key = &kctx->skc_hmac_key;
1084 gss_buffer_desc *encrypt_key = &kctx->skc_encrypt_key;
1085 enum cfs_crypto_hash_alg hmac_alg;
1086 enum cfs_crypto_crypt_alg crypt_alg;
1087 char *encrypt = "Encrypt";
1088 char *integrity = "Integrity";
1091 hmac_alg = cfs_crypto_hash_alg(kctx->skc_hmac_alg);
1092 hmac_key->length = cfs_crypto_hash_digestsize(hmac_alg);
1093 hmac_key->value = malloc(hmac_key->length);
1094 if (!hmac_key->value)
1097 rc = PKCS5_PBKDF2_HMAC(integrity, -1, session_key->value,
1098 session_key->length, SK_PBKDF2_ITERATIONS,
1099 sk_hash_to_evp_md(hmac_alg),
1100 hmac_key->length, hmac_key->value);
1104 /* Encryption key is only populated in privacy mode */
1105 if ((skc->sc_flags & LGSS_SVC_PRIV) == 0)
1108 crypt_alg = cfs_crypto_crypt_alg(kctx->skc_crypt_alg);
1109 encrypt_key->length = cfs_crypto_crypt_keysize(crypt_alg);
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(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);