2 * Copyright 2004-2023 The OpenSSL Project Authors. All Rights Reserved.
3 * Copyright (c) 2004, EdelKey Project. All Rights Reserved.
5 * Licensed under the Apache License 2.0 (the "License"). You may not use
6 * this file except in compliance with the License. You can obtain a copy
7 * in the file LICENSE in the source distribution or at
8 * https://www.openssl.org/source/license.html
10 * Originally written by Christophe Renou and Peter Sylvester,
11 * for the EdelKey project.
14 /* All the SRP APIs in this file are deprecated */
15 #define OPENSSL_SUPPRESS_DEPRECATED
17 #ifndef OPENSSL_NO_SRP
18 # include "internal/cryptlib.h"
19 # include "crypto/evp.h"
20 # include <openssl/sha.h>
21 # include <openssl/srp.h>
22 # include <openssl/evp.h>
23 # include <openssl/buffer.h>
24 # include <openssl/rand.h>
25 # include <openssl/txt_db.h>
26 # include <openssl/err.h>
28 # define SRP_RANDOM_SALT_LEN 20
32 * Note that SRP uses its own variant of base 64 encoding. A different base64
33 * alphabet is used and no padding '=' characters are added. Instead we pad to
34 * the front with 0 bytes and subsequently strip off leading encoded padding.
35 * This variant is used for compatibility with other SRP implementations -
36 * notably libsrp, but also others. It is also required for backwards
37 * compatibility in order to load verifier files from other OpenSSL versions.
41 * Convert a base64 string into raw byte array representation.
42 * Returns the length of the decoded data, or -1 on error.
44 static int t_fromb64(unsigned char *a, size_t alen, const char *src)
47 int outl = 0, outl2 = 0;
49 const unsigned char *pad = (const unsigned char *)"00";
51 while (*src == ' ' || *src == '\t' || *src == '\n')
54 padsize = 4 - (size & 3);
57 /* Four bytes in src become three bytes output. */
58 if (size > INT_MAX || ((size + padsize) / 4) * 3 > alen)
61 ctx = EVP_ENCODE_CTX_new();
66 * This should never occur because 1 byte of data always requires 2 bytes of
68 * 0 bytes unencoded = 0 bytes encoded
69 * 1 byte unencoded = 2 bytes encoded
70 * 2 bytes unencoded = 3 bytes encoded
71 * 3 bytes unencoded = 4 bytes encoded
72 * 4 bytes unencoded = 6 bytes encoded
80 /* Valid padsize values are now 0, 1 or 2 */
83 evp_encode_ctx_set_flags(ctx, EVP_ENCODE_CTX_USE_SRP_ALPHABET);
85 /* Add any encoded padding that is required */
87 && EVP_DecodeUpdate(ctx, a, &outl, pad, padsize) < 0) {
91 if (EVP_DecodeUpdate(ctx, a, &outl2, (const unsigned char *)src, size) < 0) {
96 EVP_DecodeFinal(ctx, a + outl, &outl2);
99 /* Strip off the leading padding */
101 if ((int)padsize >= outl) {
107 * If we added 1 byte of padding prior to encoding then we have 2 bytes
108 * of "real" data which gets spread across 4 encoded bytes like this:
109 * (6 bits pad)(2 bits pad | 4 bits data)(6 bits data)(6 bits data)
110 * So 1 byte of pre-encoding padding results in 1 full byte of encoded
112 * If we added 2 bytes of padding prior to encoding this gets encoded
114 * (6 bits pad)(6 bits pad)(4 bits pad | 2 bits data)(6 bits data)
115 * So 2 bytes of pre-encoding padding results in 2 full bytes of encoded
116 * padding, i.e. we have to strip the same number of bytes of padding
117 * from the encoded data as we added to the pre-encoded data.
119 memmove(a, a + padsize, outl - padsize);
124 EVP_ENCODE_CTX_free(ctx);
130 * Convert a raw byte string into a null-terminated base64 ASCII string.
131 * Returns 1 on success or 0 on error.
133 static int t_tob64(char *dst, const unsigned char *src, int size)
135 EVP_ENCODE_CTX *ctx = EVP_ENCODE_CTX_new();
136 int outl = 0, outl2 = 0;
137 unsigned char pad[2] = {0, 0};
144 evp_encode_ctx_set_flags(ctx, EVP_ENCODE_CTX_NO_NEWLINES
145 | EVP_ENCODE_CTX_USE_SRP_ALPHABET);
148 * We pad at the front with zero bytes until the length is a multiple of 3
149 * so that EVP_EncodeUpdate/EVP_EncodeFinal does not add any of its own "="
152 leadz = 3 - (size % 3);
154 && !EVP_EncodeUpdate(ctx, (unsigned char *)dst, &outl, pad,
156 EVP_ENCODE_CTX_free(ctx);
160 if (!EVP_EncodeUpdate(ctx, (unsigned char *)dst + outl, &outl2, src,
162 EVP_ENCODE_CTX_free(ctx);
166 EVP_EncodeFinal(ctx, (unsigned char *)dst + outl, &outl2);
169 /* Strip the encoded padding at the front */
171 memmove(dst, dst + leadz, outl - leadz);
172 dst[outl - leadz] = '\0';
175 EVP_ENCODE_CTX_free(ctx);
179 void SRP_user_pwd_free(SRP_user_pwd *user_pwd)
181 if (user_pwd == NULL)
183 BN_free(user_pwd->s);
184 BN_clear_free(user_pwd->v);
185 OPENSSL_free(user_pwd->id);
186 OPENSSL_free(user_pwd->info);
187 OPENSSL_free(user_pwd);
190 SRP_user_pwd *SRP_user_pwd_new(void)
194 if ((ret = OPENSSL_malloc(sizeof(*ret))) == NULL)
205 void SRP_user_pwd_set_gN(SRP_user_pwd *vinfo, const BIGNUM *g,
212 int SRP_user_pwd_set1_ids(SRP_user_pwd *vinfo, const char *id,
215 OPENSSL_free(vinfo->id);
216 OPENSSL_free(vinfo->info);
217 if (id != NULL && NULL == (vinfo->id = OPENSSL_strdup(id)))
219 return (info == NULL || NULL != (vinfo->info = OPENSSL_strdup(info)));
222 static int SRP_user_pwd_set_sv(SRP_user_pwd *vinfo, const char *s,
225 unsigned char tmp[MAX_LEN];
231 len = t_fromb64(tmp, sizeof(tmp), v);
234 if (NULL == (vinfo->v = BN_bin2bn(tmp, len, NULL)))
236 len = t_fromb64(tmp, sizeof(tmp), s);
239 vinfo->s = BN_bin2bn(tmp, len, NULL);
240 if (vinfo->s == NULL)
249 int SRP_user_pwd_set0_sv(SRP_user_pwd *vinfo, BIGNUM *s, BIGNUM *v)
252 BN_clear_free(vinfo->v);
255 return (vinfo->s != NULL && vinfo->v != NULL);
258 static SRP_user_pwd *srp_user_pwd_dup(SRP_user_pwd *src)
264 if ((ret = SRP_user_pwd_new()) == NULL)
267 SRP_user_pwd_set_gN(ret, src->g, src->N);
268 if (!SRP_user_pwd_set1_ids(ret, src->id, src->info)
269 || !SRP_user_pwd_set0_sv(ret, BN_dup(src->s), BN_dup(src->v))) {
270 SRP_user_pwd_free(ret);
276 SRP_VBASE *SRP_VBASE_new(char *seed_key)
278 SRP_VBASE *vb = OPENSSL_malloc(sizeof(*vb));
282 if ((vb->users_pwd = sk_SRP_user_pwd_new_null()) == NULL
283 || (vb->gN_cache = sk_SRP_gN_cache_new_null()) == NULL) {
284 sk_SRP_user_pwd_free(vb->users_pwd);
288 vb->default_g = NULL;
289 vb->default_N = NULL;
291 if ((seed_key != NULL) && (vb->seed_key = OPENSSL_strdup(seed_key)) == NULL) {
292 sk_SRP_user_pwd_free(vb->users_pwd);
293 sk_SRP_gN_cache_free(vb->gN_cache);
300 void SRP_VBASE_free(SRP_VBASE *vb)
304 sk_SRP_user_pwd_pop_free(vb->users_pwd, SRP_user_pwd_free);
305 sk_SRP_gN_cache_free(vb->gN_cache);
306 OPENSSL_free(vb->seed_key);
310 static SRP_gN_cache *SRP_gN_new_init(const char *ch)
312 unsigned char tmp[MAX_LEN];
314 SRP_gN_cache *newgN = OPENSSL_malloc(sizeof(*newgN));
319 len = t_fromb64(tmp, sizeof(tmp), ch);
323 if ((newgN->b64_bn = OPENSSL_strdup(ch)) == NULL)
326 if ((newgN->bn = BN_bin2bn(tmp, len, NULL)))
329 OPENSSL_free(newgN->b64_bn);
335 static void SRP_gN_free(SRP_gN_cache *gN_cache)
337 if (gN_cache == NULL)
339 OPENSSL_free(gN_cache->b64_bn);
340 BN_free(gN_cache->bn);
341 OPENSSL_free(gN_cache);
344 static SRP_gN *SRP_get_gN_by_id(const char *id, STACK_OF(SRP_gN) *gN_tab)
349 if (gN_tab != NULL) {
350 for (i = 0; i < sk_SRP_gN_num(gN_tab); i++) {
351 gN = sk_SRP_gN_value(gN_tab, i);
352 if (gN && (id == NULL || strcmp(gN->id, id) == 0))
357 return SRP_get_default_gN(id);
360 static BIGNUM *SRP_gN_place_bn(STACK_OF(SRP_gN_cache) *gN_cache, char *ch)
363 if (gN_cache == NULL)
366 /* search if we have already one... */
367 for (i = 0; i < sk_SRP_gN_cache_num(gN_cache); i++) {
368 SRP_gN_cache *cache = sk_SRP_gN_cache_value(gN_cache, i);
369 if (strcmp(cache->b64_bn, ch) == 0)
372 { /* it is the first time that we find it */
373 SRP_gN_cache *newgN = SRP_gN_new_init(ch);
375 if (sk_SRP_gN_cache_insert(gN_cache, newgN, 0) > 0)
384 * This function parses the verifier file generated by the srp app.
385 * The format for each entry is:
386 * V base64(verifier) base64(salt) username gNid userinfo(optional)
388 * I base64(N) base64(g)
389 * Note that base64 is the SRP variant of base64 encoding described
393 int SRP_VBASE_init(SRP_VBASE *vb, char *verifier_file)
395 int error_code = SRP_ERR_MEMORY;
396 STACK_OF(SRP_gN) *SRP_gN_tab = sk_SRP_gN_new_null();
397 char *last_index = NULL;
402 SRP_user_pwd *user_pwd = NULL;
404 TXT_DB *tmpdb = NULL;
405 BIO *in = BIO_new(BIO_s_file());
407 if (SRP_gN_tab == NULL)
410 error_code = SRP_ERR_OPEN_FILE;
412 if (in == NULL || BIO_read_filename(in, verifier_file) <= 0)
415 error_code = SRP_ERR_VBASE_INCOMPLETE_FILE;
417 if ((tmpdb = TXT_DB_read(in, DB_NUMBER)) == NULL)
420 error_code = SRP_ERR_MEMORY;
423 last_index = SRP_get_default_gN(NULL)->id;
425 for (i = 0; i < sk_OPENSSL_PSTRING_num(tmpdb->data); i++) {
426 pp = sk_OPENSSL_PSTRING_value(tmpdb->data, i);
427 if (pp[DB_srptype][0] == DB_SRP_INDEX) {
429 * we add this couple in the internal Stack
432 if ((gN = OPENSSL_malloc(sizeof(*gN))) == NULL)
435 if ((gN->id = OPENSSL_strdup(pp[DB_srpid])) == NULL
436 || (gN->N = SRP_gN_place_bn(vb->gN_cache, pp[DB_srpverifier]))
438 || (gN->g = SRP_gN_place_bn(vb->gN_cache, pp[DB_srpsalt]))
440 || sk_SRP_gN_insert(SRP_gN_tab, gN, 0) == 0)
445 if (vb->seed_key != NULL) {
446 last_index = pp[DB_srpid];
448 } else if (pp[DB_srptype][0] == DB_SRP_VALID) {
449 /* it is a user .... */
452 if ((lgN = SRP_get_gN_by_id(pp[DB_srpgN], SRP_gN_tab)) != NULL) {
453 error_code = SRP_ERR_MEMORY;
454 if ((user_pwd = SRP_user_pwd_new()) == NULL)
457 SRP_user_pwd_set_gN(user_pwd, lgN->g, lgN->N);
458 if (!SRP_user_pwd_set1_ids
459 (user_pwd, pp[DB_srpid], pp[DB_srpinfo]))
462 error_code = SRP_ERR_VBASE_BN_LIB;
463 if (!SRP_user_pwd_set_sv
464 (user_pwd, pp[DB_srpsalt], pp[DB_srpverifier]))
467 if (sk_SRP_user_pwd_insert(vb->users_pwd, user_pwd, 0) == 0)
469 user_pwd = NULL; /* abandon responsibility */
474 if (last_index != NULL) {
475 /* this means that we want to simulate a default user */
477 if (((gN = SRP_get_gN_by_id(last_index, SRP_gN_tab)) == NULL)) {
478 error_code = SRP_ERR_VBASE_BN_LIB;
481 vb->default_g = gN->g;
482 vb->default_N = gN->N;
485 error_code = SRP_NO_ERROR;
489 * there may be still some leaks to fix, if this fails, the application
490 * terminates most likely
494 OPENSSL_free(gN->id);
498 SRP_user_pwd_free(user_pwd);
503 sk_SRP_gN_free(SRP_gN_tab);
509 static SRP_user_pwd *find_user(SRP_VBASE *vb, char *username)
517 for (i = 0; i < sk_SRP_user_pwd_num(vb->users_pwd); i++) {
518 user = sk_SRP_user_pwd_value(vb->users_pwd, i);
519 if (strcmp(user->id, username) == 0)
526 int SRP_VBASE_add0_user(SRP_VBASE *vb, SRP_user_pwd *user_pwd)
528 if (sk_SRP_user_pwd_push(vb->users_pwd, user_pwd) <= 0)
533 # ifndef OPENSSL_NO_DEPRECATED_1_1_0
535 * DEPRECATED: use SRP_VBASE_get1_by_user instead.
536 * This method ignores the configured seed and fails for an unknown user.
537 * Ownership of the returned pointer is not released to the caller.
538 * In other words, caller must not free the result.
540 SRP_user_pwd *SRP_VBASE_get_by_user(SRP_VBASE *vb, char *username)
542 return find_user(vb, username);
547 * Ownership of the returned pointer is released to the caller.
548 * In other words, caller must free the result once done.
550 SRP_user_pwd *SRP_VBASE_get1_by_user(SRP_VBASE *vb, char *username)
553 unsigned char digv[SHA_DIGEST_LENGTH];
554 unsigned char digs[SHA_DIGEST_LENGTH];
555 EVP_MD_CTX *ctxt = NULL;
561 if ((user = find_user(vb, username)) != NULL)
562 return srp_user_pwd_dup(user);
564 if ((vb->seed_key == NULL) ||
565 (vb->default_g == NULL) || (vb->default_N == NULL))
568 /* if the user is unknown we set parameters as well if we have a seed_key */
570 if ((user = SRP_user_pwd_new()) == NULL)
573 SRP_user_pwd_set_gN(user, vb->default_g, vb->default_N);
575 if (!SRP_user_pwd_set1_ids(user, username, NULL))
578 if (RAND_priv_bytes(digv, SHA_DIGEST_LENGTH) <= 0)
580 md = EVP_MD_fetch(NULL, SN_sha1, NULL);
583 ctxt = EVP_MD_CTX_new();
585 || !EVP_DigestInit_ex(ctxt, md, NULL)
586 || !EVP_DigestUpdate(ctxt, vb->seed_key, strlen(vb->seed_key))
587 || !EVP_DigestUpdate(ctxt, username, strlen(username))
588 || !EVP_DigestFinal_ex(ctxt, digs, NULL))
590 EVP_MD_CTX_free(ctxt);
594 if (SRP_user_pwd_set0_sv(user,
595 BN_bin2bn(digs, SHA_DIGEST_LENGTH, NULL),
596 BN_bin2bn(digv, SHA_DIGEST_LENGTH, NULL)))
601 EVP_MD_CTX_free(ctxt);
602 SRP_user_pwd_free(user);
607 * create a verifier (*salt,*verifier,g and N are in base64)
609 char *SRP_create_verifier_ex(const char *user, const char *pass, char **salt,
610 char **verifier, const char *N, const char *g,
611 OSSL_LIB_CTX *libctx, const char *propq)
614 char *result = NULL, *vf = NULL;
615 const BIGNUM *N_bn = NULL, *g_bn = NULL;
616 BIGNUM *N_bn_alloc = NULL, *g_bn_alloc = NULL, *s = NULL, *v = NULL;
617 unsigned char tmp[MAX_LEN];
618 unsigned char tmp2[MAX_LEN];
619 char *defgNid = NULL;
622 if ((user == NULL) ||
623 (pass == NULL) || (salt == NULL) || (verifier == NULL))
627 if ((len = t_fromb64(tmp, sizeof(tmp), N)) <= 0)
629 N_bn_alloc = BN_bin2bn(tmp, len, NULL);
630 if (N_bn_alloc == NULL)
633 if ((len = t_fromb64(tmp, sizeof(tmp), g)) <= 0)
635 g_bn_alloc = BN_bin2bn(tmp, len, NULL);
636 if (g_bn_alloc == NULL)
641 SRP_gN *gN = SRP_get_default_gN(g);
650 if (RAND_bytes_ex(libctx, tmp2, SRP_RANDOM_SALT_LEN, 0) <= 0)
653 s = BN_bin2bn(tmp2, SRP_RANDOM_SALT_LEN, NULL);
655 if ((len = t_fromb64(tmp2, sizeof(tmp2), *salt)) <= 0)
657 s = BN_bin2bn(tmp2, len, NULL);
662 if (!SRP_create_verifier_BN_ex(user, pass, &s, &v, N_bn, g_bn, libctx,
666 if (BN_bn2bin(v, tmp) < 0)
668 vfsize = BN_num_bytes(v) * 2;
669 if (((vf = OPENSSL_malloc(vfsize)) == NULL))
671 if (!t_tob64(vf, tmp, BN_num_bytes(v)))
677 if ((tmp_salt = OPENSSL_malloc(SRP_RANDOM_SALT_LEN * 2)) == NULL) {
680 if (!t_tob64(tmp_salt, tmp2, SRP_RANDOM_SALT_LEN)) {
681 OPENSSL_free(tmp_salt);
694 OPENSSL_clear_free(vf, vfsize);
700 char *SRP_create_verifier(const char *user, const char *pass, char **salt,
701 char **verifier, const char *N, const char *g)
703 return SRP_create_verifier_ex(user, pass, salt, verifier, N, g, NULL, NULL);
707 * create a verifier (*salt,*verifier,g and N are BIGNUMs). If *salt != NULL
708 * then the provided salt will be used. On successful exit *verifier will point
709 * to a newly allocated BIGNUM containing the verifier and (if a salt was not
710 * provided) *salt will be populated with a newly allocated BIGNUM containing a
712 * The caller is responsible for freeing the allocated *salt and *verifier
715 int SRP_create_verifier_BN_ex(const char *user, const char *pass, BIGNUM **salt,
716 BIGNUM **verifier, const BIGNUM *N,
717 const BIGNUM *g, OSSL_LIB_CTX *libctx,
722 BN_CTX *bn_ctx = BN_CTX_new_ex(libctx);
723 unsigned char tmp2[MAX_LEN];
724 BIGNUM *salttmp = NULL, *verif;
726 if ((user == NULL) ||
729 (verifier == NULL) || (N == NULL) || (g == NULL) || (bn_ctx == NULL))
733 if (RAND_bytes_ex(libctx, tmp2, SRP_RANDOM_SALT_LEN, 0) <= 0)
736 salttmp = BN_bin2bn(tmp2, SRP_RANDOM_SALT_LEN, NULL);
743 x = SRP_Calc_x_ex(salttmp, user, pass, libctx, propq);
751 if (!BN_mod_exp(verif, g, x, N, bn_ctx)) {
752 BN_clear_free(verif);
761 if (salt != NULL && *salt != salttmp)
762 BN_clear_free(salttmp);
768 int SRP_create_verifier_BN(const char *user, const char *pass, BIGNUM **salt,
769 BIGNUM **verifier, const BIGNUM *N,
772 return SRP_create_verifier_BN_ex(user, pass, salt, verifier, N, g, NULL,