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Diffstat (limited to 'jpake.c')
| -rw-r--r-- | jpake.c | 456 |
1 files changed, 0 insertions, 456 deletions
diff --git a/jpake.c b/jpake.c deleted file mode 100644 index 3dd87916..00000000 --- a/jpake.c +++ /dev/null @@ -1,456 +0,0 @@ -/* $OpenBSD: jpake.c,v 1.8 2013/05/17 00:13:13 djm Exp $ */ -/* - * Copyright (c) 2008 Damien Miller. All rights reserved. - * - * Permission to use, copy, modify, and distribute this software for any - * purpose with or without fee is hereby granted, provided that the above - * copyright notice and this permission notice appear in all copies. - * - * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES - * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF - * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR - * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES - * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN - * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF - * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. - */ - -/* - * Shared components of zero-knowledge password auth using J-PAKE protocol - * as described in: - * - * F. Hao, P. Ryan, "Password Authenticated Key Exchange by Juggling", - * 16th Workshop on Security Protocols, Cambridge, April 2008 - * - * http://grouper.ieee.org/groups/1363/Research/contributions/hao-ryan-2008.pdf - */ - -#include "includes.h" - -#include <sys/types.h> - -#include <stdio.h> -#include <string.h> -#include <stdarg.h> - -#include <openssl/bn.h> -#include <openssl/evp.h> - -#include "xmalloc.h" -#include "ssh2.h" -#include "key.h" -#include "hostfile.h" -#include "auth.h" -#include "buffer.h" -#include "packet.h" -#include "dispatch.h" -#include "log.h" -#include "misc.h" - -#include "jpake.h" -#include "schnorr.h" - -#ifdef JPAKE - -/* RFC3526 group 5, 1536 bits */ -#define JPAKE_GROUP_G "2" -#define JPAKE_GROUP_P \ - "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74" \ - "020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B302B0A6DF25F1437" \ - "4FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED" \ - "EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE45B3DC2007CB8A163BF05" \ - "98DA48361C55D39A69163FA8FD24CF5F83655D23DCA3AD961C62F356208552BB" \ - "9ED529077096966D670C354E4ABC9804F1746C08CA237327FFFFFFFFFFFFFFFF" - -struct modp_group * -jpake_default_group(void) -{ - return modp_group_from_g_and_safe_p(JPAKE_GROUP_G, JPAKE_GROUP_P); -} - -struct jpake_ctx * -jpake_new(void) -{ - struct jpake_ctx *ret; - - ret = xcalloc(1, sizeof(*ret)); - - ret->grp = jpake_default_group(); - - ret->s = ret->k = NULL; - ret->x1 = ret->x2 = ret->x3 = ret->x4 = NULL; - ret->g_x1 = ret->g_x2 = ret->g_x3 = ret->g_x4 = NULL; - ret->a = ret->b = NULL; - - ret->client_id = ret->server_id = NULL; - ret->h_k_cid_sessid = ret->h_k_sid_sessid = NULL; - - debug3("%s: alloc %p", __func__, ret); - - return ret; -} - -void -jpake_free(struct jpake_ctx *pctx) -{ - debug3("%s: free %p", __func__, pctx); - -#define JPAKE_BN_CLEAR_FREE(v) \ - do { \ - if ((v) != NULL) { \ - BN_clear_free(v); \ - (v) = NULL; \ - } \ - } while (0) -#define JPAKE_BUF_CLEAR_FREE(v, l) \ - do { \ - if ((v) != NULL) { \ - bzero((v), (l)); \ - free(v); \ - (v) = NULL; \ - (l) = 0; \ - } \ - } while (0) - - JPAKE_BN_CLEAR_FREE(pctx->s); - JPAKE_BN_CLEAR_FREE(pctx->k); - JPAKE_BN_CLEAR_FREE(pctx->x1); - JPAKE_BN_CLEAR_FREE(pctx->x2); - JPAKE_BN_CLEAR_FREE(pctx->x3); - JPAKE_BN_CLEAR_FREE(pctx->x4); - JPAKE_BN_CLEAR_FREE(pctx->g_x1); - JPAKE_BN_CLEAR_FREE(pctx->g_x2); - JPAKE_BN_CLEAR_FREE(pctx->g_x3); - JPAKE_BN_CLEAR_FREE(pctx->g_x4); - JPAKE_BN_CLEAR_FREE(pctx->a); - JPAKE_BN_CLEAR_FREE(pctx->b); - - JPAKE_BUF_CLEAR_FREE(pctx->client_id, pctx->client_id_len); - JPAKE_BUF_CLEAR_FREE(pctx->server_id, pctx->server_id_len); - JPAKE_BUF_CLEAR_FREE(pctx->h_k_cid_sessid, pctx->h_k_cid_sessid_len); - JPAKE_BUF_CLEAR_FREE(pctx->h_k_sid_sessid, pctx->h_k_sid_sessid_len); - -#undef JPAKE_BN_CLEAR_FREE -#undef JPAKE_BUF_CLEAR_FREE - - bzero(pctx, sizeof(*pctx)); - free(pctx); -} - -/* dump entire jpake_ctx. NB. includes private values! */ -void -jpake_dump(struct jpake_ctx *pctx, const char *fmt, ...) -{ - char *out; - va_list args; - - out = NULL; - va_start(args, fmt); - vasprintf(&out, fmt, args); - va_end(args); - if (out == NULL) - fatal("%s: vasprintf failed", __func__); - - debug3("%s: %s (ctx at %p)", __func__, out, pctx); - if (pctx == NULL) { - free(out); - return; - } - -#define JPAKE_DUMP_BN(a) do { \ - if ((a) != NULL) \ - JPAKE_DEBUG_BN(((a), "%s = ", #a)); \ - } while (0) -#define JPAKE_DUMP_BUF(a, b) do { \ - if ((a) != NULL) \ - JPAKE_DEBUG_BUF((a, b, "%s", #a)); \ - } while (0) - - JPAKE_DUMP_BN(pctx->s); - JPAKE_DUMP_BN(pctx->k); - JPAKE_DUMP_BN(pctx->x1); - JPAKE_DUMP_BN(pctx->x2); - JPAKE_DUMP_BN(pctx->x3); - JPAKE_DUMP_BN(pctx->x4); - JPAKE_DUMP_BN(pctx->g_x1); - JPAKE_DUMP_BN(pctx->g_x2); - JPAKE_DUMP_BN(pctx->g_x3); - JPAKE_DUMP_BN(pctx->g_x4); - JPAKE_DUMP_BN(pctx->a); - JPAKE_DUMP_BN(pctx->b); - - JPAKE_DUMP_BUF(pctx->client_id, pctx->client_id_len); - JPAKE_DUMP_BUF(pctx->server_id, pctx->server_id_len); - JPAKE_DUMP_BUF(pctx->h_k_cid_sessid, pctx->h_k_cid_sessid_len); - JPAKE_DUMP_BUF(pctx->h_k_sid_sessid, pctx->h_k_sid_sessid_len); - - debug3("%s: %s done", __func__, out); - free(out); -} - -/* Shared parts of step 1 exchange calculation */ -void -jpake_step1(struct modp_group *grp, - u_char **id, u_int *id_len, - BIGNUM **priv1, BIGNUM **priv2, BIGNUM **g_priv1, BIGNUM **g_priv2, - u_char **priv1_proof, u_int *priv1_proof_len, - u_char **priv2_proof, u_int *priv2_proof_len) -{ - BN_CTX *bn_ctx; - - if ((bn_ctx = BN_CTX_new()) == NULL) - fatal("%s: BN_CTX_new", __func__); - - /* Random nonce to prevent replay */ - *id = xmalloc(KZP_ID_LEN); - *id_len = KZP_ID_LEN; - arc4random_buf(*id, *id_len); - - /* - * x1/x3 is a random element of Zq - * x2/x4 is a random element of Z*q - * We also exclude [1] from x1/x3 candidates and [0, 1] from - * x2/x4 candiates to avoid possible degeneracy (i.e. g^0, g^1). - */ - if ((*priv1 = bn_rand_range_gt_one(grp->q)) == NULL || - (*priv2 = bn_rand_range_gt_one(grp->q)) == NULL) - fatal("%s: bn_rand_range_gt_one", __func__); - - /* - * client: g_x1 = g^x1 mod p / server: g_x3 = g^x3 mod p - * client: g_x2 = g^x2 mod p / server: g_x4 = g^x4 mod p - */ - if ((*g_priv1 = BN_new()) == NULL || - (*g_priv2 = BN_new()) == NULL) - fatal("%s: BN_new", __func__); - if (BN_mod_exp(*g_priv1, grp->g, *priv1, grp->p, bn_ctx) == -1) - fatal("%s: BN_mod_exp", __func__); - if (BN_mod_exp(*g_priv2, grp->g, *priv2, grp->p, bn_ctx) == -1) - fatal("%s: BN_mod_exp", __func__); - - /* Generate proofs for holding x1/x3 and x2/x4 */ - if (schnorr_sign_buf(grp->p, grp->q, grp->g, - *priv1, *g_priv1, *id, *id_len, - priv1_proof, priv1_proof_len) != 0) - fatal("%s: schnorr_sign", __func__); - if (schnorr_sign_buf(grp->p, grp->q, grp->g, - *priv2, *g_priv2, *id, *id_len, - priv2_proof, priv2_proof_len) != 0) - fatal("%s: schnorr_sign", __func__); - - BN_CTX_free(bn_ctx); -} - -/* Shared parts of step 2 exchange calculation */ -void -jpake_step2(struct modp_group *grp, BIGNUM *s, - BIGNUM *mypub1, BIGNUM *theirpub1, BIGNUM *theirpub2, BIGNUM *mypriv2, - const u_char *theirid, u_int theirid_len, - const u_char *myid, u_int myid_len, - const u_char *theirpub1_proof, u_int theirpub1_proof_len, - const u_char *theirpub2_proof, u_int theirpub2_proof_len, - BIGNUM **newpub, - u_char **newpub_exponent_proof, u_int *newpub_exponent_proof_len) -{ - BN_CTX *bn_ctx; - BIGNUM *tmp, *exponent; - - /* Validate peer's step 1 values */ - if (BN_cmp(theirpub1, BN_value_one()) <= 0) - fatal("%s: theirpub1 <= 1", __func__); - if (BN_cmp(theirpub1, grp->p) >= 0) - fatal("%s: theirpub1 >= p", __func__); - if (BN_cmp(theirpub2, BN_value_one()) <= 0) - fatal("%s: theirpub2 <= 1", __func__); - if (BN_cmp(theirpub2, grp->p) >= 0) - fatal("%s: theirpub2 >= p", __func__); - - if (schnorr_verify_buf(grp->p, grp->q, grp->g, theirpub1, - theirid, theirid_len, theirpub1_proof, theirpub1_proof_len) != 1) - fatal("%s: schnorr_verify theirpub1 failed", __func__); - if (schnorr_verify_buf(grp->p, grp->q, grp->g, theirpub2, - theirid, theirid_len, theirpub2_proof, theirpub2_proof_len) != 1) - fatal("%s: schnorr_verify theirpub2 failed", __func__); - - if ((bn_ctx = BN_CTX_new()) == NULL) - fatal("%s: BN_CTX_new", __func__); - - if ((*newpub = BN_new()) == NULL || - (tmp = BN_new()) == NULL || - (exponent = BN_new()) == NULL) - fatal("%s: BN_new", __func__); - - /* - * client: exponent = x2 * s mod p - * server: exponent = x4 * s mod p - */ - if (BN_mod_mul(exponent, mypriv2, s, grp->q, bn_ctx) != 1) - fatal("%s: BN_mod_mul (exponent = mypriv2 * s mod p)", - __func__); - - /* - * client: tmp = g^(x1 + x3 + x4) mod p - * server: tmp = g^(x1 + x2 + x3) mod p - */ - if (BN_mod_mul(tmp, mypub1, theirpub1, grp->p, bn_ctx) != 1) - fatal("%s: BN_mod_mul (tmp = mypub1 * theirpub1 mod p)", - __func__); - if (BN_mod_mul(tmp, tmp, theirpub2, grp->p, bn_ctx) != 1) - fatal("%s: BN_mod_mul (tmp = tmp * theirpub2 mod p)", __func__); - - /* - * client: a = tmp^exponent = g^((x1+x3+x4) * x2 * s) mod p - * server: b = tmp^exponent = g^((x1+x2+x3) * x4 * s) mod p - */ - if (BN_mod_exp(*newpub, tmp, exponent, grp->p, bn_ctx) != 1) - fatal("%s: BN_mod_mul (newpub = tmp^exponent mod p)", __func__); - - JPAKE_DEBUG_BN((tmp, "%s: tmp = ", __func__)); - JPAKE_DEBUG_BN((exponent, "%s: exponent = ", __func__)); - - /* Note the generator here is 'tmp', not g */ - if (schnorr_sign_buf(grp->p, grp->q, tmp, exponent, *newpub, - myid, myid_len, - newpub_exponent_proof, newpub_exponent_proof_len) != 0) - fatal("%s: schnorr_sign newpub", __func__); - - BN_clear_free(tmp); /* XXX stash for later use? */ - BN_clear_free(exponent); /* XXX stash for later use? (yes, in conf) */ - - BN_CTX_free(bn_ctx); -} - -/* Confirmation hash calculation */ -void -jpake_confirm_hash(const BIGNUM *k, - const u_char *endpoint_id, u_int endpoint_id_len, - const u_char *sess_id, u_int sess_id_len, - u_char **confirm_hash, u_int *confirm_hash_len) -{ - Buffer b; - - /* - * Calculate confirmation proof: - * client: H(k || client_id || session_id) - * server: H(k || server_id || session_id) - */ - buffer_init(&b); - buffer_put_bignum2(&b, k); - buffer_put_string(&b, endpoint_id, endpoint_id_len); - buffer_put_string(&b, sess_id, sess_id_len); - if (hash_buffer(buffer_ptr(&b), buffer_len(&b), EVP_sha256(), - confirm_hash, confirm_hash_len) != 0) - fatal("%s: hash_buffer", __func__); - buffer_free(&b); -} - -/* Shared parts of key derivation and confirmation calculation */ -void -jpake_key_confirm(struct modp_group *grp, BIGNUM *s, BIGNUM *step2_val, - BIGNUM *mypriv2, BIGNUM *mypub1, BIGNUM *mypub2, - BIGNUM *theirpub1, BIGNUM *theirpub2, - const u_char *my_id, u_int my_id_len, - const u_char *their_id, u_int their_id_len, - const u_char *sess_id, u_int sess_id_len, - const u_char *theirpriv2_s_proof, u_int theirpriv2_s_proof_len, - BIGNUM **k, - u_char **confirm_hash, u_int *confirm_hash_len) -{ - BN_CTX *bn_ctx; - BIGNUM *tmp; - - if ((bn_ctx = BN_CTX_new()) == NULL) - fatal("%s: BN_CTX_new", __func__); - if ((tmp = BN_new()) == NULL || - (*k = BN_new()) == NULL) - fatal("%s: BN_new", __func__); - - /* Validate step 2 values */ - if (BN_cmp(step2_val, BN_value_one()) <= 0) - fatal("%s: step2_val <= 1", __func__); - if (BN_cmp(step2_val, grp->p) >= 0) - fatal("%s: step2_val >= p", __func__); - - /* - * theirpriv2_s_proof is calculated with a different generator: - * tmp = g^(mypriv1+mypriv2+theirpub1) = g^mypub1*g^mypub2*g^theirpub1 - * Calculate it here so we can check the signature. - */ - if (BN_mod_mul(tmp, mypub1, mypub2, grp->p, bn_ctx) != 1) - fatal("%s: BN_mod_mul (tmp = mypub1 * mypub2 mod p)", __func__); - if (BN_mod_mul(tmp, tmp, theirpub1, grp->p, bn_ctx) != 1) - fatal("%s: BN_mod_mul (tmp = tmp * theirpub1 mod p)", __func__); - - JPAKE_DEBUG_BN((tmp, "%s: tmp = ", __func__)); - - if (schnorr_verify_buf(grp->p, grp->q, tmp, step2_val, - their_id, their_id_len, - theirpriv2_s_proof, theirpriv2_s_proof_len) != 1) - fatal("%s: schnorr_verify theirpriv2_s_proof failed", __func__); - - /* - * Derive shared key: - * client: k = (b / g^(x2*x4*s))^x2 = g^((x1+x3)*x2*x4*s) - * server: k = (a / g^(x2*x4*s))^x4 = g^((x1+x3)*x2*x4*s) - * - * Computed as: - * client: k = (g_x4^(q - (x2 * s)) * b)^x2 mod p - * server: k = (g_x2^(q - (x4 * s)) * b)^x4 mod p - */ - if (BN_mul(tmp, mypriv2, s, bn_ctx) != 1) - fatal("%s: BN_mul (tmp = mypriv2 * s)", __func__); - if (BN_mod_sub(tmp, grp->q, tmp, grp->q, bn_ctx) != 1) - fatal("%s: BN_mod_sub (tmp = q - tmp mod q)", __func__); - if (BN_mod_exp(tmp, theirpub2, tmp, grp->p, bn_ctx) != 1) - fatal("%s: BN_mod_exp (tmp = theirpub2^tmp) mod p", __func__); - if (BN_mod_mul(tmp, tmp, step2_val, grp->p, bn_ctx) != 1) - fatal("%s: BN_mod_mul (tmp = tmp * step2_val) mod p", __func__); - if (BN_mod_exp(*k, tmp, mypriv2, grp->p, bn_ctx) != 1) - fatal("%s: BN_mod_exp (k = tmp^mypriv2) mod p", __func__); - - BN_CTX_free(bn_ctx); - BN_clear_free(tmp); - - jpake_confirm_hash(*k, my_id, my_id_len, sess_id, sess_id_len, - confirm_hash, confirm_hash_len); -} - -/* - * Calculate and check confirmation hash from peer. Returns 1 on success - * 0 on failure/mismatch. - */ -int -jpake_check_confirm(const BIGNUM *k, - const u_char *peer_id, u_int peer_id_len, - const u_char *sess_id, u_int sess_id_len, - const u_char *peer_confirm_hash, u_int peer_confirm_hash_len) -{ - u_char *expected_confirm_hash; - u_int expected_confirm_hash_len; - int success = 0; - - /* Calculate and verify expected confirmation hash */ - jpake_confirm_hash(k, peer_id, peer_id_len, sess_id, sess_id_len, - &expected_confirm_hash, &expected_confirm_hash_len); - - JPAKE_DEBUG_BUF((expected_confirm_hash, expected_confirm_hash_len, - "%s: expected confirm hash", __func__)); - JPAKE_DEBUG_BUF((peer_confirm_hash, peer_confirm_hash_len, - "%s: received confirm hash", __func__)); - - if (peer_confirm_hash_len != expected_confirm_hash_len) - error("%s: confirmation length mismatch (my %u them %u)", - __func__, expected_confirm_hash_len, peer_confirm_hash_len); - else if (timingsafe_bcmp(peer_confirm_hash, expected_confirm_hash, - expected_confirm_hash_len) == 0) - success = 1; - bzero(expected_confirm_hash, expected_confirm_hash_len); - free(expected_confirm_hash); - debug3("%s: success = %d", __func__, success); - return success; -} - -/* XXX main() function with tests */ - -#endif /* JPAKE */ - |