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openssl/crypto/srp/srp_vfy.c
Matt Caswell bf95cde287 Fix SRP memory leaks 
There were some memory leaks in the creation of an SRP verifier (both on
successful completion and also on some error paths).

Reviewed-by: Emilia Käsper <emilia@openssl.org>
2015-09-21 10:17:58 +01:00

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/* crypto/srp/srp_vfy.c */
/*
* Written by Christophe Renou (christophe.renou@edelweb.fr) with the
* precious help of Peter Sylvester (peter.sylvester@edelweb.fr) for the
* EdelKey project and contributed to the OpenSSL project 2004.
*/
/* ====================================================================
* Copyright (c) 2004 The OpenSSL Project. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. All advertising materials mentioning features or use of this
* software must display the following acknowledgment:
* "This product includes software developed by the OpenSSL Project
* for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
*
* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
* endorse or promote products derived from this software without
* prior written permission. For written permission, please contact
* licensing@OpenSSL.org.
*
* 5. Products derived from this software may not be called "OpenSSL"
* nor may "OpenSSL" appear in their names without prior written
* permission of the OpenSSL Project.
*
* 6. Redistributions of any form whatsoever must retain the following
* acknowledgment:
* "This product includes software developed by the OpenSSL Project
* for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
*
* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
* ====================================================================
*
* This product includes cryptographic software written by Eric Young
* (eay@cryptsoft.com). This product includes software written by Tim
* Hudson (tjh@cryptsoft.com).
*
*/
#ifndef OPENSSL_NO_SRP
# include "internal/cryptlib.h"
# include <openssl/sha.h>
# include <openssl/srp.h>
# include <openssl/evp.h>
# include <openssl/buffer.h>
# include <openssl/rand.h>
# include <openssl/txt_db.h>
# define SRP_RANDOM_SALT_LEN 20
# define MAX_LEN 2500
static char b64table[] =
"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz./";
/*
* the following two conversion routines have been inspired by code from
* Stanford
*/
/*
* Convert a base64 string into raw byte array representation.
*/
static int t_fromb64(unsigned char *a, const char *src)
{
char *loc;
int i, j;
int size;
while (*src && (*src == ' ' || *src == '\t' || *src == '\n'))
++src;
size = strlen(src);
i = 0;
while (i < size) {
loc = strchr(b64table, src[i]);
if (loc == (char *)0)
break;
else
a[i] = loc - b64table;
++i;
}
/* if nothing valid to process we have a zero length response */
if (i == 0)
return 0;
size = i;
i = size - 1;
j = size;
while (1) {
a[j] = a[i];
if (--i < 0)
break;
a[j] |= (a[i] & 3) << 6;
--j;
a[j] = (unsigned char)((a[i] & 0x3c) >> 2);
if (--i < 0)
break;
a[j] |= (a[i] & 0xf) << 4;
--j;
a[j] = (unsigned char)((a[i] & 0x30) >> 4);
if (--i < 0)
break;
a[j] |= (a[i] << 2);
a[--j] = 0;
if (--i < 0)
break;
}
while (a[j] == 0 && j <= size)
++j;
i = 0;
while (j <= size)
a[i++] = a[j++];
return i;
}
/*
* Convert a raw byte string into a null-terminated base64 ASCII string.
*/
static char *t_tob64(char *dst, const unsigned char *src, int size)
{
int c, pos = size % 3;
unsigned char b0 = 0, b1 = 0, b2 = 0, notleading = 0;
char *olddst = dst;
switch (pos) {
case 1:
b2 = src[0];
break;
case 2:
b1 = src[0];
b2 = src[1];
break;
}
while (1) {
c = (b0 & 0xfc) >> 2;
if (notleading || c != 0) {
*dst++ = b64table[c];
notleading = 1;
}
c = ((b0 & 3) << 4) | ((b1 & 0xf0) >> 4);
if (notleading || c != 0) {
*dst++ = b64table[c];
notleading = 1;
}
c = ((b1 & 0xf) << 2) | ((b2 & 0xc0) >> 6);
if (notleading || c != 0) {
*dst++ = b64table[c];
notleading = 1;
}
c = b2 & 0x3f;
if (notleading || c != 0) {
*dst++ = b64table[c];
notleading = 1;
}
if (pos >= size)
break;
else {
b0 = src[pos++];
b1 = src[pos++];
b2 = src[pos++];
}
}
*dst++ = '\0';
return olddst;
}
static void SRP_user_pwd_free(SRP_user_pwd *user_pwd)
{
if (user_pwd == NULL)
return;
BN_free(user_pwd->s);
BN_clear_free(user_pwd->v);
OPENSSL_free(user_pwd->id);
OPENSSL_free(user_pwd->info);
OPENSSL_free(user_pwd);
}
static SRP_user_pwd *SRP_user_pwd_new(void)
{
SRP_user_pwd *ret = OPENSSL_malloc(sizeof(*ret));
if (ret == NULL)
return NULL;
ret->N = NULL;
ret->g = NULL;
ret->s = NULL;
ret->v = NULL;
ret->id = NULL;
ret->info = NULL;
return ret;
}
static void SRP_user_pwd_set_gN(SRP_user_pwd *vinfo, const BIGNUM *g,
const BIGNUM *N)
{
vinfo->N = N;
vinfo->g = g;
}
static int SRP_user_pwd_set_ids(SRP_user_pwd *vinfo, const char *id,
const char *info)
{
if (id != NULL && NULL == (vinfo->id = BUF_strdup(id)))
return 0;
return (info == NULL || NULL != (vinfo->info = BUF_strdup(info)));
}
static int SRP_user_pwd_set_sv(SRP_user_pwd *vinfo, const char *s,
const char *v)
{
unsigned char tmp[MAX_LEN];
int len;
if (strlen(s) > MAX_LEN || strlen(v) > MAX_LEN)
return 0;
len = t_fromb64(tmp, v);
if (NULL == (vinfo->v = BN_bin2bn(tmp, len, NULL)))
return 0;
len = t_fromb64(tmp, s);
return ((vinfo->s = BN_bin2bn(tmp, len, NULL)) != NULL);
}
static int SRP_user_pwd_set_sv_BN(SRP_user_pwd *vinfo, BIGNUM *s, BIGNUM *v)
{
vinfo->v = v;
vinfo->s = s;
return (vinfo->s != NULL && vinfo->v != NULL);
}
SRP_VBASE *SRP_VBASE_new(char *seed_key)
{
SRP_VBASE *vb = OPENSSL_malloc(sizeof(*vb));
if (vb == NULL)
return NULL;
if ((vb->users_pwd = sk_SRP_user_pwd_new_null()) == NULL
|| (vb->gN_cache = sk_SRP_gN_cache_new_null()) == NULL) {
OPENSSL_free(vb);
return NULL;
}
vb->default_g = NULL;
vb->default_N = NULL;
vb->seed_key = NULL;
if ((seed_key != NULL) && (vb->seed_key = BUF_strdup(seed_key)) == NULL) {
sk_SRP_user_pwd_free(vb->users_pwd);
sk_SRP_gN_cache_free(vb->gN_cache);
OPENSSL_free(vb);
return NULL;
}
return vb;
}
void SRP_VBASE_free(SRP_VBASE *vb)
{
if (!vb)
return;
sk_SRP_user_pwd_pop_free(vb->users_pwd, SRP_user_pwd_free);
sk_SRP_gN_cache_free(vb->gN_cache);
OPENSSL_free(vb->seed_key);
OPENSSL_free(vb);
}
static SRP_gN_cache *SRP_gN_new_init(const char *ch)
{
unsigned char tmp[MAX_LEN];
int len;
SRP_gN_cache *newgN = OPENSSL_malloc(sizeof(*newgN));
if (newgN == NULL)
return NULL;
if ((newgN->b64_bn = BUF_strdup(ch)) == NULL)
goto err;
len = t_fromb64(tmp, ch);
if ((newgN->bn = BN_bin2bn(tmp, len, NULL)))
return newgN;
OPENSSL_free(newgN->b64_bn);
err:
OPENSSL_free(newgN);
return NULL;
}
static void SRP_gN_free(SRP_gN_cache *gN_cache)
{
if (gN_cache == NULL)
return;
OPENSSL_free(gN_cache->b64_bn);
BN_free(gN_cache->bn);
OPENSSL_free(gN_cache);
}
static SRP_gN *SRP_get_gN_by_id(const char *id, STACK_OF(SRP_gN) *gN_tab)
{
int i;
SRP_gN *gN;
if (gN_tab != NULL)
for (i = 0; i < sk_SRP_gN_num(gN_tab); i++) {
gN = sk_SRP_gN_value(gN_tab, i);
if (gN && (id == NULL || strcmp(gN->id, id) == 0))
return gN;
}
return SRP_get_default_gN(id);
}
static BIGNUM *SRP_gN_place_bn(STACK_OF(SRP_gN_cache) *gN_cache, char *ch)
{
int i;
if (gN_cache == NULL)
return NULL;
/* search if we have already one... */
for (i = 0; i < sk_SRP_gN_cache_num(gN_cache); i++) {
SRP_gN_cache *cache = sk_SRP_gN_cache_value(gN_cache, i);
if (strcmp(cache->b64_bn, ch) == 0)
return cache->bn;
}
{ /* it is the first time that we find it */
SRP_gN_cache *newgN = SRP_gN_new_init(ch);
if (newgN) {
if (sk_SRP_gN_cache_insert(gN_cache, newgN, 0) > 0)
return newgN->bn;
SRP_gN_free(newgN);
}
}
return NULL;
}
/*
* this function parses verifier file. Format is:
* string(index):base64(N):base64(g):0
* string(username):base64(v):base64(salt):int(index)
*/
int SRP_VBASE_init(SRP_VBASE *vb, char *verifier_file)
{
int error_code;
STACK_OF(SRP_gN) *SRP_gN_tab = sk_SRP_gN_new_null();
char *last_index = NULL;
int i;
char **pp;
SRP_gN *gN = NULL;
SRP_user_pwd *user_pwd = NULL;
TXT_DB *tmpdb = NULL;
BIO *in = BIO_new(BIO_s_file());
error_code = SRP_ERR_OPEN_FILE;
if (in == NULL || BIO_read_filename(in, verifier_file) <= 0)
goto err;
error_code = SRP_ERR_VBASE_INCOMPLETE_FILE;
if ((tmpdb = TXT_DB_read(in, DB_NUMBER)) == NULL)
goto err;
error_code = SRP_ERR_MEMORY;
if (vb->seed_key) {
last_index = SRP_get_default_gN(NULL)->id;
}
for (i = 0; i < sk_OPENSSL_PSTRING_num(tmpdb->data); i++) {
pp = sk_OPENSSL_PSTRING_value(tmpdb->data, i);
if (pp[DB_srptype][0] == DB_SRP_INDEX) {
/*
* we add this couple in the internal Stack
*/
if ((gN = OPENSSL_malloc(sizeof(*gN))) == NULL)
goto err;
if ((gN->id = BUF_strdup(pp[DB_srpid])) == NULL
|| (gN->N = SRP_gN_place_bn(vb->gN_cache, pp[DB_srpverifier]))
== NULL
|| (gN->g = SRP_gN_place_bn(vb->gN_cache, pp[DB_srpsalt]))
== NULL
|| sk_SRP_gN_insert(SRP_gN_tab, gN, 0) == 0)
goto err;
gN = NULL;
if (vb->seed_key != NULL) {
last_index = pp[DB_srpid];
}
} else if (pp[DB_srptype][0] == DB_SRP_VALID) {
/* it is a user .... */
const SRP_gN *lgN;
if ((lgN = SRP_get_gN_by_id(pp[DB_srpgN], SRP_gN_tab)) != NULL) {
error_code = SRP_ERR_MEMORY;
if ((user_pwd = SRP_user_pwd_new()) == NULL)
goto err;
SRP_user_pwd_set_gN(user_pwd, lgN->g, lgN->N);
if (!SRP_user_pwd_set_ids
(user_pwd, pp[DB_srpid], pp[DB_srpinfo]))
goto err;
error_code = SRP_ERR_VBASE_BN_LIB;
if (!SRP_user_pwd_set_sv
(user_pwd, pp[DB_srpsalt], pp[DB_srpverifier]))
goto err;
if (sk_SRP_user_pwd_insert(vb->users_pwd, user_pwd, 0) == 0)
goto err;
user_pwd = NULL; /* abandon responsability */
}
}
}
if (last_index != NULL) {
/* this means that we want to simulate a default user */
if (((gN = SRP_get_gN_by_id(last_index, SRP_gN_tab)) == NULL)) {
error_code = SRP_ERR_VBASE_BN_LIB;
goto err;
}
vb->default_g = gN->g;
vb->default_N = gN->N;
gN = NULL;
}
error_code = SRP_NO_ERROR;
err:
/*
* there may be still some leaks to fix, if this fails, the application
* terminates most likely
*/
if (gN != NULL) {
OPENSSL_free(gN->id);
OPENSSL_free(gN);
}
SRP_user_pwd_free(user_pwd);
TXT_DB_free(tmpdb);
BIO_free_all(in);
sk_SRP_gN_free(SRP_gN_tab);
return error_code;
}
SRP_user_pwd *SRP_VBASE_get_by_user(SRP_VBASE *vb, char *username)
{
int i;
SRP_user_pwd *user;
unsigned char digv[SHA_DIGEST_LENGTH];
unsigned char digs[SHA_DIGEST_LENGTH];
EVP_MD_CTX ctxt;
if (vb == NULL)
return NULL;
for (i = 0; i < sk_SRP_user_pwd_num(vb->users_pwd); i++) {
user = sk_SRP_user_pwd_value(vb->users_pwd, i);
if (strcmp(user->id, username) == 0)
return user;
}
if ((vb->seed_key == NULL) ||
(vb->default_g == NULL) || (vb->default_N == NULL))
return NULL;
/* if the user is unknown we set parameters as well if we have a seed_key */
if ((user = SRP_user_pwd_new()) == NULL)
return NULL;
SRP_user_pwd_set_gN(user, vb->default_g, vb->default_N);
if (!SRP_user_pwd_set_ids(user, username, NULL))
goto err;
if (RAND_bytes(digv, SHA_DIGEST_LENGTH) <= 0)
goto err;
EVP_MD_CTX_init(&ctxt);
EVP_DigestInit_ex(&ctxt, EVP_sha1(), NULL);
EVP_DigestUpdate(&ctxt, vb->seed_key, strlen(vb->seed_key));
EVP_DigestUpdate(&ctxt, username, strlen(username));
EVP_DigestFinal_ex(&ctxt, digs, NULL);
EVP_MD_CTX_cleanup(&ctxt);
if (SRP_user_pwd_set_sv_BN
(user, BN_bin2bn(digs, SHA_DIGEST_LENGTH, NULL),
BN_bin2bn(digv, SHA_DIGEST_LENGTH, NULL)))
return user;
err:
SRP_user_pwd_free(user);
return NULL;
}
/*
* create a verifier (*salt,*verifier,g and N are in base64)
*/
char *SRP_create_verifier(const char *user, const char *pass, char **salt,
char **verifier, const char *N, const char *g)
{
int len;
char *result = NULL, *vf = NULL;
BIGNUM *N_bn = NULL, *g_bn = NULL, *s = NULL, *v = NULL;
unsigned char tmp[MAX_LEN];
unsigned char tmp2[MAX_LEN];
char *defgNid = NULL;
int vfsize = 0;
if ((user == NULL) ||
(pass == NULL) || (salt == NULL) || (verifier == NULL))
goto err;
if (N) {
if ((len = t_fromb64(tmp, N)) == 0)
goto err;
N_bn = BN_bin2bn(tmp, len, NULL);
if ((len = t_fromb64(tmp, g)) == 0)
goto err;
g_bn = BN_bin2bn(tmp, len, NULL);
defgNid = "*";
} else {
SRP_gN *gN = SRP_get_gN_by_id(g, NULL);
if (gN == NULL)
goto err;
N_bn = gN->N;
g_bn = gN->g;
defgNid = gN->id;
}
if (*salt == NULL) {
if (RAND_bytes(tmp2, SRP_RANDOM_SALT_LEN) <= 0)
goto err;
s = BN_bin2bn(tmp2, SRP_RANDOM_SALT_LEN, NULL);
} else {
if ((len = t_fromb64(tmp2, *salt)) == 0)
goto err;
s = BN_bin2bn(tmp2, len, NULL);
}
if (!SRP_create_verifier_BN(user, pass, &s, &v, N_bn, g_bn))
goto err;
BN_bn2bin(v, tmp);
vfsize = BN_num_bytes(v) * 2;
if (((vf = OPENSSL_malloc(vfsize)) == NULL))
goto err;
t_tob64(vf, tmp, BN_num_bytes(v));
if (*salt == NULL) {
char *tmp_salt;
if ((tmp_salt = OPENSSL_malloc(SRP_RANDOM_SALT_LEN * 2)) == NULL) {
goto err;
}
t_tob64(tmp_salt, tmp2, SRP_RANDOM_SALT_LEN);
*salt = tmp_salt;
}
*verifier = vf;
vf = NULL;
result = defgNid;
err:
if (N) {
BN_free(N_bn);
BN_free(g_bn);
}
OPENSSL_clear_free(vf, vfsize);
BN_clear_free(s);
BN_clear_free(v);
return result;
}
/*
* create a verifier (*salt,*verifier,g and N are BIGNUMs). If *salt != NULL
* then the provided salt will be used. On successful exit *verifier will point
* to a newly allocated BIGNUM containing the verifier and (if a salt was not
* provided) *salt will be populated with a newly allocated BIGNUM containing a
* random salt.
* The caller is responsible for freeing the allocated *salt and *verifier
* BIGNUMS.
*/
int SRP_create_verifier_BN(const char *user, const char *pass, BIGNUM **salt,
BIGNUM **verifier, const BIGNUM *N,
const BIGNUM *g)
{
int result = 0;
BIGNUM *x = NULL;
BN_CTX *bn_ctx = BN_CTX_new();
unsigned char tmp2[MAX_LEN];
BIGNUM *salttmp = NULL;
if ((user == NULL) ||
(pass == NULL) ||
(salt == NULL) ||
(verifier == NULL) || (N == NULL) || (g == NULL) || (bn_ctx == NULL))
goto err;
if (*salt == NULL) {
if (RAND_bytes(tmp2, SRP_RANDOM_SALT_LEN) <= 0)
goto err;
salttmp = BN_bin2bn(tmp2, SRP_RANDOM_SALT_LEN, NULL);
} else {
salttmp = *salt;
}
x = SRP_Calc_x(salttmp, user, pass);
*verifier = BN_new();
if (*verifier == NULL)
goto err;
if (!BN_mod_exp(*verifier, g, x, N, bn_ctx)) {
BN_clear_free(*verifier);
goto err;
}
result = 1;
*salt = salttmp;
err:
if (*salt != salttmp)
BN_clear_free(salttmp);
BN_clear_free(x);
BN_CTX_free(bn_ctx);
return result;
}
#endif
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