boringssl/ssl/ssl_ciph.c
Adam Langley a307dfd29f Add (void) to some macros to satisfy compiler.
More modern versions of GCC (at least with aarch64) are warning about an
unused value in these locations. It's incorrect, but I guess that the
macro is confusing it.

Using a (void) tag is a little ugly but solves the problem.

Change-Id: If6ba5083ab6e501c81e7743ae1ed99a89565e57c
Reviewed-on: https://boringssl-review.googlesource.com/2810
Reviewed-by: Adam Langley <agl@google.com>
2015-01-12 23:46:03 +00:00

1446 lines
42 KiB
C

/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
* All rights reserved.
*
* This package is an SSL implementation written
* by Eric Young (eay@cryptsoft.com).
* The implementation was written so as to conform with Netscapes SSL.
*
* This library is free for commercial and non-commercial use as long as
* the following conditions are aheared to. The following conditions
* apply to all code found in this distribution, be it the RC4, RSA,
* lhash, DES, etc., code; not just the SSL code. The SSL documentation
* included with this distribution is covered by the same copyright terms
* except that the holder is Tim Hudson (tjh@cryptsoft.com).
*
* Copyright remains Eric Young's, and as such any Copyright notices in
* the code are not to be removed.
* If this package is used in a product, Eric Young should be given attribution
* as the author of the parts of the library used.
* This can be in the form of a textual message at program startup or
* in documentation (online or textual) provided with the package.
*
* 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 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 acknowledgement:
* "This product includes cryptographic software written by
* Eric Young (eay@cryptsoft.com)"
* The word 'cryptographic' can be left out if the rouines from the library
* being used are not cryptographic related :-).
* 4. If you include any Windows specific code (or a derivative thereof) from
* the apps directory (application code) you must include an acknowledgement:
* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
*
* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
* ANY EXPRESS 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 AUTHOR OR 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.
*
* The licence and distribution terms for any publically available version or
* derivative of this code cannot be changed. i.e. this code cannot simply be
* copied and put under another distribution licence
* [including the GNU Public Licence.]
*/
/* ====================================================================
* Copyright (c) 1998-2007 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
* openssl-core@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).
*
*/
/* ====================================================================
* Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
* ECC cipher suite support in OpenSSL originally developed by
* SUN MICROSYSTEMS, INC., and contributed to the OpenSSL project.
*/
/* ====================================================================
* Copyright 2005 Nokia. All rights reserved.
*
* The portions of the attached software ("Contribution") is developed by
* Nokia Corporation and is licensed pursuant to the OpenSSL open source
* license.
*
* The Contribution, originally written by Mika Kousa and Pasi Eronen of
* Nokia Corporation, consists of the "PSK" (Pre-Shared Key) ciphersuites
* support (see RFC 4279) to OpenSSL.
*
* No patent licenses or other rights except those expressly stated in
* the OpenSSL open source license shall be deemed granted or received
* expressly, by implication, estoppel, or otherwise.
*
* No assurances are provided by Nokia that the Contribution does not
* infringe the patent or other intellectual property rights of any third
* party or that the license provides you with all the necessary rights
* to make use of the Contribution.
*
* THE SOFTWARE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. IN
* ADDITION TO THE DISCLAIMERS INCLUDED IN THE LICENSE, NOKIA
* SPECIFICALLY DISCLAIMS ANY LIABILITY FOR CLAIMS BROUGHT BY YOU OR ANY
* OTHER ENTITY BASED ON INFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS OR
* OTHERWISE. */
#include <stdio.h>
#include <assert.h>
#include <openssl/engine.h>
#include <openssl/mem.h>
#include <openssl/obj.h>
#include "ssl_locl.h"
struct handshake_digest {
long mask;
const EVP_MD *(*md_func)(void);
};
static const struct handshake_digest ssl_handshake_digests[SSL_MAX_DIGEST] = {
{SSL_HANDSHAKE_MAC_MD5, EVP_md5},
{SSL_HANDSHAKE_MAC_SHA, EVP_sha1},
{SSL_HANDSHAKE_MAC_SHA256, EVP_sha256},
{SSL_HANDSHAKE_MAC_SHA384, EVP_sha384},
};
#define CIPHER_ADD 1
#define CIPHER_KILL 2
#define CIPHER_DEL 3
#define CIPHER_ORD 4
#define CIPHER_SPECIAL 5
typedef struct cipher_order_st {
const SSL_CIPHER *cipher;
int active;
int dead;
int in_group;
struct cipher_order_st *next, *prev;
} CIPHER_ORDER;
static const SSL_CIPHER cipher_aliases[] =
{
{0, SSL_TXT_ALL, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
/* "COMPLEMENTOFDEFAULT" (does *not* include ciphersuites not found in
ALL!) */
{0, SSL_TXT_CMPDEF, 0, SSL_kEDH | SSL_kEECDH, SSL_aNULL, 0, 0, 0, 0, 0, 0,
0},
/* key exchange aliases
* (some of those using only a single bit here combine
* multiple key exchange algs according to the RFCs,
* e.g. kEDH combines DHE_DSS and DHE_RSA) */
{0, SSL_TXT_kRSA, 0, SSL_kRSA, 0, 0, 0, 0, 0, 0, 0, 0},
{0, SSL_TXT_kEDH, 0, SSL_kEDH, 0, 0, 0, 0, 0, 0, 0, 0},
{0, SSL_TXT_DH, 0, SSL_kEDH, 0, 0, 0, 0, 0, 0, 0, 0},
{0, SSL_TXT_kEECDH, 0, SSL_kEECDH, 0, 0, 0, 0, 0, 0, 0, 0},
{0, SSL_TXT_ECDH, 0, SSL_kEECDH, 0, 0, 0, 0, 0, 0, 0, 0},
{0, SSL_TXT_kPSK, 0, SSL_kPSK, 0, 0, 0, 0, 0, 0, 0, 0},
/* server authentication aliases */
{0, SSL_TXT_aRSA, 0, 0, SSL_aRSA, 0, 0, 0, 0, 0, 0, 0},
{0, SSL_TXT_aNULL, 0, 0, SSL_aNULL, 0, 0, 0, 0, 0, 0, 0},
{0, SSL_TXT_aECDSA, 0, 0, SSL_aECDSA, 0, 0, 0, 0, 0, 0, 0},
{0, SSL_TXT_ECDSA, 0, 0, SSL_aECDSA, 0, 0, 0, 0, 0, 0, 0},
{0, SSL_TXT_aPSK, 0, 0, SSL_aPSK, 0, 0, 0, 0, 0, 0, 0},
/* aliases combining key exchange and server authentication */
{0, SSL_TXT_EDH, 0, SSL_kEDH, ~SSL_aNULL, 0, 0, 0, 0, 0, 0, 0},
{0, SSL_TXT_EECDH, 0, SSL_kEECDH, ~SSL_aNULL, 0, 0, 0, 0, 0, 0, 0},
{0, SSL_TXT_RSA, 0, SSL_kRSA, SSL_aRSA, 0, 0, 0, 0, 0, 0, 0},
{0, SSL_TXT_ADH, 0, SSL_kEDH, SSL_aNULL, 0, 0, 0, 0, 0, 0, 0},
{0, SSL_TXT_AECDH, 0, SSL_kEECDH, SSL_aNULL, 0, 0, 0, 0, 0, 0, 0},
{0, SSL_TXT_PSK, 0, SSL_kPSK, SSL_aPSK, 0, 0, 0, 0, 0, 0, 0},
/* symmetric encryption aliases */
{0, SSL_TXT_3DES, 0, 0, 0, SSL_3DES, 0, 0, 0, 0, 0, 0},
{0, SSL_TXT_RC4, 0, 0, 0, SSL_RC4, 0, 0, 0, 0, 0, 0},
{0, SSL_TXT_AES128, 0, 0, 0, SSL_AES128 | SSL_AES128GCM, 0, 0, 0, 0, 0, 0},
{0, SSL_TXT_AES256, 0, 0, 0, SSL_AES256 | SSL_AES256GCM, 0, 0, 0, 0, 0, 0},
{0, SSL_TXT_AES, 0, 0, 0, SSL_AES, 0, 0, 0, 0, 0, 0},
{0, SSL_TXT_AES_GCM, 0, 0, 0, SSL_AES128GCM | SSL_AES256GCM, 0, 0, 0, 0, 0,
0},
{0, SSL_TXT_CHACHA20, 0, 0, 0, SSL_CHACHA20POLY1305, 0, 0, 0, 0, 0, 0},
/* MAC aliases */
{0, SSL_TXT_MD5, 0, 0, 0, 0, SSL_MD5, 0, 0, 0, 0, 0},
{0, SSL_TXT_SHA1, 0, 0, 0, 0, SSL_SHA1, 0, 0, 0, 0, 0},
{0, SSL_TXT_SHA, 0, 0, 0, 0, SSL_SHA1, 0, 0, 0, 0, 0},
{0, SSL_TXT_SHA256, 0, 0, 0, 0, SSL_SHA256, 0, 0, 0, 0, 0},
{0, SSL_TXT_SHA384, 0, 0, 0, 0, SSL_SHA384, 0, 0, 0, 0, 0},
/* protocol version aliases */
{0, SSL_TXT_SSLV3, 0, 0, 0, 0, 0, SSL_SSLV3, 0, 0, 0, 0},
{0, SSL_TXT_TLSV1, 0, 0, 0, 0, 0, SSL_TLSV1, 0, 0, 0, 0},
{0, SSL_TXT_TLSV1_2, 0, 0, 0, 0, 0, SSL_TLSV1_2, 0, 0, 0, 0},
/* strength classes */
{0, SSL_TXT_MEDIUM, 0, 0, 0, 0, 0, 0, SSL_MEDIUM, 0, 0, 0},
{0, SSL_TXT_HIGH, 0, 0, 0, 0, 0, 0, SSL_HIGH, 0, 0, 0},
/* FIPS 140-2 approved ciphersuite */
{0, SSL_TXT_FIPS, 0, 0, 0, 0, 0, 0, SSL_FIPS, 0, 0, 0},
};
/* ssl_cipher_get_evp_aead sets |*aead| to point to the correct EVP_AEAD object
* for |s->cipher|. It returns 1 on success and 0 on error. */
int ssl_cipher_get_evp_aead(const SSL_SESSION *s, const EVP_AEAD **aead) {
const SSL_CIPHER *c = s->cipher;
*aead = NULL;
if (c == NULL) {
return 0;
}
if ((c->algorithm2 & SSL_CIPHER_ALGORITHM2_AEAD) == 0 &&
(c->algorithm2 & SSL_CIPHER_ALGORITHM2_STATEFUL_AEAD) == 0) {
return 0;
}
switch (c->algorithm_enc) {
case SSL_AES128GCM:
*aead = EVP_aead_aes_128_gcm();
return 1;
case SSL_AES256GCM:
*aead = EVP_aead_aes_256_gcm();
return 1;
case SSL_CHACHA20POLY1305:
*aead = EVP_aead_chacha20_poly1305();
return 1;
case SSL_RC4:
if (c->algorithm_mac != SSL_MD5) {
return 0;
}
*aead = EVP_aead_rc4_md5_tls();
return 1;
}
return 0;
}
int ssl_cipher_get_evp(const SSL_SESSION *s, const EVP_CIPHER **enc,
const EVP_MD **md, int *mac_pkey_type,
int *mac_secret_size) {
const SSL_CIPHER *c;
c = s->cipher;
if (c == NULL ||
/* This function doesn't deal with EVP_AEAD. See
* |ssl_cipher_get_aead_evp|. */
(c->algorithm2 & SSL_CIPHER_ALGORITHM2_AEAD) ||
enc == NULL ||
md == NULL) {
return 0;
}
switch (c->algorithm_enc) {
case SSL_3DES:
*enc = EVP_des_ede3_cbc();
break;
case SSL_RC4:
*enc = EVP_rc4();
break;
case SSL_AES128:
*enc = EVP_aes_128_cbc();
break;
case SSL_AES256:
*enc = EVP_aes_256_cbc();
break;
default:
return 0;
}
if (!ssl_cipher_get_mac(s, md, mac_pkey_type, mac_secret_size)) {
return 0;
}
assert(*enc != NULL && *md != NULL);
/* TODO(fork): enable the stitched cipher modes. */
#if 0
if (s->ssl_version>>8 != TLS1_VERSION_MAJOR ||
s->ssl_version < TLS1_VERSION)
return 1;
if (c->algorithm_enc == SSL_RC4 &&
c->algorithm_mac == SSL_MD5 &&
(evp=EVP_get_cipherbyname("RC4-HMAC-MD5")))
*enc = evp, *md = NULL;
else if (c->algorithm_enc == SSL_AES128 &&
c->algorithm_mac == SSL_SHA1 &&
(evp=EVP_get_cipherbyname("AES-128-CBC-HMAC-SHA1")))
*enc = evp, *md = NULL;
else if (c->algorithm_enc == SSL_AES256 &&
c->algorithm_mac == SSL_SHA1 &&
(evp=EVP_get_cipherbyname("AES-256-CBC-HMAC-SHA1")))
*enc = evp, *md = NULL;
#endif
return 1;
}
int ssl_cipher_get_mac(const SSL_SESSION *s, const EVP_MD **md,
int *mac_pkey_type, int *mac_secret_size) {
const SSL_CIPHER *c;
c = s->cipher;
if (c == NULL) {
return 0;
}
switch (c->algorithm_mac) {
case SSL_MD5:
*md = EVP_md5();
break;
case SSL_SHA1:
*md = EVP_sha1();
break;
case SSL_SHA256:
*md = EVP_sha256();
break;
case SSL_SHA384:
*md = EVP_sha384();
break;
default:
return 0;
}
if (mac_pkey_type != NULL) {
*mac_pkey_type = EVP_PKEY_HMAC;
}
if (mac_secret_size != NULL) {
*mac_secret_size = EVP_MD_size(*md);
}
return 1;
}
int ssl_get_handshake_digest(int idx, long *mask, const EVP_MD **md) {
if (idx < 0 || idx >= SSL_MAX_DIGEST) {
return 0;
}
*mask = ssl_handshake_digests[idx].mask;
*md = ssl_handshake_digests[idx].md_func();
return 1;
}
#define ITEM_SEP(a) \
(((a) == ':') || ((a) == ' ') || ((a) == ';') || ((a) == ','))
static void ll_append_tail(CIPHER_ORDER **head, CIPHER_ORDER *curr,
CIPHER_ORDER **tail) {
if (curr == *tail) {
return;
}
if (curr == *head) {
*head = curr->next;
}
if (curr->prev != NULL) {
curr->prev->next = curr->next;
}
if (curr->next != NULL) {
curr->next->prev = curr->prev;
}
(*tail)->next = curr;
curr->prev = *tail;
curr->next = NULL;
*tail = curr;
}
static void ll_append_head(CIPHER_ORDER **head, CIPHER_ORDER *curr,
CIPHER_ORDER **tail) {
if (curr == *head) {
return;
}
if (curr == *tail) {
*tail = curr->prev;
}
if (curr->next != NULL) {
curr->next->prev = curr->prev;
}
if (curr->prev != NULL) {
curr->prev->next = curr->next;
}
(*head)->prev = curr;
curr->next = *head;
curr->prev = NULL;
*head = curr;
}
static void ssl_cipher_collect_ciphers(const SSL_PROTOCOL_METHOD *ssl_method,
int num_of_ciphers,
CIPHER_ORDER *co_list,
CIPHER_ORDER **head_p,
CIPHER_ORDER **tail_p) {
int i, co_list_num;
const SSL_CIPHER *c;
/* We have num_of_ciphers descriptions compiled in, depending on the method
* selected (SSLv2 and/or SSLv3, TLSv1 etc). These will later be sorted in a
* linked list with at most num entries. */
/* Get the initial list of ciphers */
co_list_num = 0; /* actual count of ciphers */
for (i = 0; i < num_of_ciphers; i++) {
c = ssl_method->get_cipher(i);
/* drop those that use any of that is not available */
if (c != NULL && c->valid) {
co_list[co_list_num].cipher = c;
co_list[co_list_num].next = NULL;
co_list[co_list_num].prev = NULL;
co_list[co_list_num].active = 0;
co_list[co_list_num].in_group = 0;
co_list_num++;
}
}
/* Prepare linked list from list entries. */
if (co_list_num > 0) {
co_list[0].prev = NULL;
if (co_list_num > 1) {
co_list[0].next = &co_list[1];
for (i = 1; i < co_list_num - 1; i++) {
co_list[i].prev = &co_list[i - 1];
co_list[i].next = &co_list[i + 1];
}
co_list[co_list_num - 1].prev = &co_list[co_list_num - 2];
}
co_list[co_list_num - 1].next = NULL;
*head_p = &co_list[0];
*tail_p = &co_list[co_list_num - 1];
}
}
static void ssl_cipher_collect_aliases(const SSL_CIPHER **ca_list,
int num_of_group_aliases,
CIPHER_ORDER *head) {
CIPHER_ORDER *ciph_curr;
const SSL_CIPHER **ca_curr;
int i;
/* First, add the real ciphers as already collected. */
ciph_curr = head;
ca_curr = ca_list;
while (ciph_curr != NULL) {
*ca_curr = ciph_curr->cipher;
ca_curr++;
ciph_curr = ciph_curr->next;
}
/* Now we add the available ones from the cipher_aliases[] table. They
* represent either one or more algorithms, some of which in any affected
* category must be supported (set in enabled_mask), or represent a cipher
* strength value (will be added in any case because algorithms=0). */
for (i = 0; i < num_of_group_aliases; i++) {
*ca_curr = cipher_aliases + i;
ca_curr++;
}
*ca_curr = NULL; /* end of list */
}
static void ssl_cipher_apply_rule(
unsigned long cipher_id, unsigned long alg_mkey, unsigned long alg_auth,
unsigned long alg_enc, unsigned long alg_mac, unsigned long alg_ssl,
unsigned long algo_strength, int rule, int strength_bits, int in_group,
CIPHER_ORDER **head_p, CIPHER_ORDER **tail_p) {
CIPHER_ORDER *head, *tail, *curr, *next, *last;
const SSL_CIPHER *cp;
int reverse = 0;
if (rule == CIPHER_DEL) {
/* needed to maintain sorting between currently deleted ciphers */
reverse = 1;
}
head = *head_p;
tail = *tail_p;
if (reverse) {
next = tail;
last = head;
} else {
next = head;
last = tail;
}
curr = NULL;
for (;;) {
if (curr == last) {
break;
}
curr = next;
if (curr == NULL) {
break;
}
next = reverse ? curr->prev : curr->next;
cp = curr->cipher;
/* Selection criteria is either the value of strength_bits
* or the algorithms used. */
if (strength_bits >= 0) {
if (strength_bits != cp->strength_bits) {
continue;
}
} else {
if ((alg_mkey && !(alg_mkey & cp->algorithm_mkey)) ||
(alg_auth && !(alg_auth & cp->algorithm_auth)) ||
(alg_enc && !(alg_enc & cp->algorithm_enc)) ||
(alg_mac && !(alg_mac & cp->algorithm_mac)) ||
(alg_ssl && !(alg_ssl & cp->algorithm_ssl)) ||
(algo_strength && !(algo_strength & cp->algo_strength))) {
continue;
}
}
/* add the cipher if it has not been added yet. */
if (rule == CIPHER_ADD) {
/* reverse == 0 */
if (!curr->active) {
ll_append_tail(&head, curr, &tail);
curr->active = 1;
curr->in_group = in_group;
}
}
/* Move the added cipher to this location */
else if (rule == CIPHER_ORD) {
/* reverse == 0 */
if (curr->active) {
ll_append_tail(&head, curr, &tail);
curr->in_group = 0;
}
} else if (rule == CIPHER_DEL) {
/* reverse == 1 */
if (curr->active) {
/* most recently deleted ciphersuites get best positions
* for any future CIPHER_ADD (note that the CIPHER_DEL loop
* works in reverse to maintain the order) */
ll_append_head(&head, curr, &tail);
curr->active = 0;
curr->in_group = 0;
}
} else if (rule == CIPHER_KILL) {
/* reverse == 0 */
if (head == curr) {
head = curr->next;
} else {
curr->prev->next = curr->next;
}
if (tail == curr) {
tail = curr->prev;
}
curr->active = 0;
if (curr->next != NULL) {
curr->next->prev = curr->prev;
}
if (curr->prev != NULL) {
curr->prev->next = curr->next;
}
curr->next = NULL;
curr->prev = NULL;
}
}
*head_p = head;
*tail_p = tail;
}
static int ssl_cipher_strength_sort(CIPHER_ORDER **head_p,
CIPHER_ORDER **tail_p) {
int max_strength_bits, i, *number_uses;
CIPHER_ORDER *curr;
/* This routine sorts the ciphers with descending strength. The sorting must
* keep the pre-sorted sequence, so we apply the normal sorting routine as
* '+' movement to the end of the list. */
max_strength_bits = 0;
curr = *head_p;
while (curr != NULL) {
if (curr->active && curr->cipher->strength_bits > max_strength_bits) {
max_strength_bits = curr->cipher->strength_bits;
}
curr = curr->next;
}
number_uses = OPENSSL_malloc((max_strength_bits + 1) * sizeof(int));
if (!number_uses) {
OPENSSL_PUT_ERROR(SSL, ssl_cipher_strength_sort, ERR_R_MALLOC_FAILURE);
return 0;
}
memset(number_uses, 0, (max_strength_bits + 1) * sizeof(int));
/* Now find the strength_bits values actually used. */
curr = *head_p;
while (curr != NULL) {
if (curr->active) {
number_uses[curr->cipher->strength_bits]++;
}
curr = curr->next;
}
/* Go through the list of used strength_bits values in descending order. */
for (i = max_strength_bits; i >= 0; i--) {
if (number_uses[i] > 0) {
ssl_cipher_apply_rule(0, 0, 0, 0, 0, 0, 0, CIPHER_ORD, i, 0, head_p,
tail_p);
}
}
OPENSSL_free(number_uses);
return 1;
}
static int ssl_cipher_process_rulestr(const char *rule_str,
CIPHER_ORDER **head_p,
CIPHER_ORDER **tail_p,
const SSL_CIPHER **ca_list) {
unsigned long alg_mkey, alg_auth, alg_enc, alg_mac, alg_ssl, algo_strength;
const char *l, *buf;
int j, multi, found, rule, retval, ok, buflen, in_group = 0, has_group = 0;
unsigned long cipher_id = 0;
char ch;
retval = 1;
l = rule_str;
for (;;) {
ch = *l;
if (ch == '\0') {
break; /* done */
}
if (in_group) {
if (ch == ']') {
if (!in_group) {
OPENSSL_PUT_ERROR(SSL, ssl_cipher_process_rulestr,
SSL_R_UNEXPECTED_GROUP_CLOSE);
retval = found = in_group = 0;
break;
}
if (*tail_p) {
(*tail_p)->in_group = 0;
}
in_group = 0;
l++;
continue;
}
if (ch == '|') {
rule = CIPHER_ADD;
l++;
continue;
} else if (!(ch >= 'a' && ch <= 'z') && !(ch >= 'A' && ch <= 'Z') &&
!(ch >= '0' && ch <= '9')) {
OPENSSL_PUT_ERROR(SSL, ssl_cipher_process_rulestr,
SSL_R_UNEXPECTED_OPERATOR_IN_GROUP);
retval = found = in_group = 0;
break;
} else {
rule = CIPHER_ADD;
}
} else if (ch == '-') {
rule = CIPHER_DEL;
l++;
} else if (ch == '+') {
rule = CIPHER_ORD;
l++;
} else if (ch == '!') {
rule = CIPHER_KILL;
l++;
} else if (ch == '@') {
rule = CIPHER_SPECIAL;
l++;
} else if (ch == '[') {
if (in_group) {
OPENSSL_PUT_ERROR(SSL, ssl_cipher_process_rulestr, SSL_R_NESTED_GROUP);
retval = found = in_group = 0;
break;
}
in_group = 1;
has_group = 1;
l++;
continue;
} else {
rule = CIPHER_ADD;
}
/* If preference groups are enabled, the only legal operator is +.
* Otherwise the in_group bits will get mixed up. */
if (has_group && rule != CIPHER_ADD) {
OPENSSL_PUT_ERROR(SSL, ssl_cipher_process_rulestr,
SSL_R_MIXED_SPECIAL_OPERATOR_WITH_GROUPS);
retval = found = in_group = 0;
break;
}
if (ITEM_SEP(ch)) {
l++;
continue;
}
alg_mkey = 0;
alg_auth = 0;
alg_enc = 0;
alg_mac = 0;
alg_ssl = 0;
algo_strength = 0;
for (;;) {
ch = *l;
buf = l;
buflen = 0;
while (((ch >= 'A') && (ch <= 'Z')) || ((ch >= '0') && (ch <= '9')) ||
((ch >= 'a') && (ch <= 'z')) || (ch == '-') || (ch == '.')) {
ch = *(++l);
buflen++;
}
if (buflen == 0) {
/* We hit something we cannot deal with, it is no command or separator
* nor alphanumeric, so we call this an error. */
OPENSSL_PUT_ERROR(SSL, ssl_cipher_process_rulestr,
SSL_R_INVALID_COMMAND);
retval = found = in_group = 0;
l++;
break;
}
if (rule == CIPHER_SPECIAL) {
found = 0; /* unused -- avoid compiler warning */
break; /* special treatment */
}
/* check for multi-part specification */
if (ch == '+') {
multi = 1;
l++;
} else {
multi = 0;
}
/* Now search for the cipher alias in the ca_list. Be careful with the
* strncmp, because the "buflen" limitation will make the rule "ADH:SOME"
* and the cipher "ADH-MY-CIPHER" look like a match for buflen=3. So
* additionally check whether the cipher name found has the correct
* length. We can save a strlen() call: just checking for the '\0' at the
* right place is sufficient, we have to strncmp() anyway. (We cannot use
* strcmp(), because buf is not '\0' terminated.) */
j = found = 0;
cipher_id = 0;
while (ca_list[j]) {
if (!strncmp(buf, ca_list[j]->name, buflen) &&
(ca_list[j]->name[buflen] == '\0')) {
found = 1;
break;
} else {
j++;
}
}
if (!found) {
break; /* ignore this entry */
}
if (ca_list[j]->algorithm_mkey) {
if (alg_mkey) {
alg_mkey &= ca_list[j]->algorithm_mkey;
if (!alg_mkey) {
found = 0;
break;
}
} else {
alg_mkey = ca_list[j]->algorithm_mkey;
}
}
if (ca_list[j]->algorithm_auth) {
if (alg_auth) {
alg_auth &= ca_list[j]->algorithm_auth;
if (!alg_auth) {
found = 0;
break;
}
} else {
alg_auth = ca_list[j]->algorithm_auth;
}
}
if (ca_list[j]->algorithm_enc) {
if (alg_enc) {
alg_enc &= ca_list[j]->algorithm_enc;
if (!alg_enc) {
found = 0;
break;
}
} else {
alg_enc = ca_list[j]->algorithm_enc;
}
}
if (ca_list[j]->algorithm_mac) {
if (alg_mac) {
alg_mac &= ca_list[j]->algorithm_mac;
if (!alg_mac) {
found = 0;
break;
}
} else {
alg_mac = ca_list[j]->algorithm_mac;
}
}
if (ca_list[j]->algo_strength) {
if (algo_strength) {
algo_strength &= ca_list[j]->algo_strength;
if (!algo_strength) {
found = 0;
break;
}
} else {
algo_strength |= ca_list[j]->algo_strength;
}
}
if (ca_list[j]->valid) {
/* explicit ciphersuite found; its protocol version does not become
* part of the search pattern! */
cipher_id = ca_list[j]->id;
} else {
/* not an explicit ciphersuite; only in this case, the protocol version
* is considered part of the search pattern. */
if (ca_list[j]->algorithm_ssl) {
if (alg_ssl) {
alg_ssl &= ca_list[j]->algorithm_ssl;
if (!alg_ssl) {
found = 0;
break;
}
} else {
alg_ssl = ca_list[j]->algorithm_ssl;
}
}
}
if (!multi) {
break;
}
}
/* Ok, we have the rule, now apply it. */
if (rule == CIPHER_SPECIAL) {
/* special command */
ok = 0;
if (buflen == 8 && !strncmp(buf, "STRENGTH", 8)) {
ok = ssl_cipher_strength_sort(head_p, tail_p);
} else {
OPENSSL_PUT_ERROR(SSL, ssl_cipher_process_rulestr,
SSL_R_INVALID_COMMAND);
}
if (ok == 0) {
retval = 0;
}
/* We do not support any "multi" options together with "@", so throw away
* the rest of the command, if any left, until end or ':' is found. */
while (*l != '\0' && !ITEM_SEP(*l)) {
l++;
}
} else if (found) {
ssl_cipher_apply_rule(cipher_id, alg_mkey, alg_auth, alg_enc, alg_mac,
alg_ssl, algo_strength, rule, -1, in_group, head_p,
tail_p);
} else {
while (*l != '\0' && !ITEM_SEP(*l)) {
l++;
}
}
}
if (in_group) {
OPENSSL_PUT_ERROR(SSL, ssl_cipher_process_rulestr, SSL_R_INVALID_COMMAND);
retval = 0;
}
return retval;
}
STACK_OF(SSL_CIPHER) *
ssl_create_cipher_list(const SSL_PROTOCOL_METHOD *ssl_method,
struct ssl_cipher_preference_list_st **cipher_list,
STACK_OF(SSL_CIPHER) * *cipher_list_by_id,
const char *rule_str, CERT *c) {
int ok, num_of_ciphers, num_of_alias_max, num_of_group_aliases;
STACK_OF(SSL_CIPHER) *cipherstack = NULL, *tmp_cipher_list = NULL;
const char *rule_p;
CIPHER_ORDER *co_list = NULL, *head = NULL, *tail = NULL, *curr;
const SSL_CIPHER **ca_list = NULL;
uint8_t *in_group_flags = NULL;
unsigned int num_in_group_flags = 0;
struct ssl_cipher_preference_list_st *pref_list = NULL;
/* Return with error if nothing to do. */
if (rule_str == NULL || cipher_list == NULL) {
return NULL;
}
/* Now we have to collect the available ciphers from the compiled in ciphers.
* We cannot get more than the number compiled in, so it is used for
* allocation. */
num_of_ciphers = ssl_method->num_ciphers();
co_list =
(CIPHER_ORDER *)OPENSSL_malloc(sizeof(CIPHER_ORDER) * num_of_ciphers);
if (co_list == NULL) {
OPENSSL_PUT_ERROR(SSL, ssl_create_cipher_list, ERR_R_MALLOC_FAILURE);
return NULL;
}
ssl_cipher_collect_ciphers(ssl_method, num_of_ciphers, co_list, &head, &tail);
/* Now arrange all ciphers by preference:
* TODO(davidben): Compute this order once and copy it. */
/* Everything else being equal, prefer ECDHE_ECDSA then ECDHE_RSA over other
* key exchange mechanisms */
ssl_cipher_apply_rule(0, SSL_kEECDH, SSL_aECDSA, 0, 0, 0, 0, CIPHER_ADD, -1,
0, &head, &tail);
ssl_cipher_apply_rule(0, SSL_kEECDH, 0, 0, 0, 0, 0, CIPHER_ADD, -1, 0, &head,
&tail);
ssl_cipher_apply_rule(0, SSL_kEECDH, 0, 0, 0, 0, 0, CIPHER_DEL, -1, 0, &head,
&tail);
/* Order the bulk ciphers. First the preferred AEAD ciphers. We prefer
* CHACHA20 unless there is hardware support for fast and constant-time
* AES_GCM. */
if (EVP_has_aes_hardware()) {
ssl_cipher_apply_rule(0, 0, 0, SSL_AES256GCM, 0, 0, 0, CIPHER_ADD, -1, 0,
&head, &tail);
ssl_cipher_apply_rule(0, 0, 0, SSL_AES128GCM, 0, 0, 0, CIPHER_ADD, -1, 0,
&head, &tail);
ssl_cipher_apply_rule(0, 0, 0, SSL_CHACHA20POLY1305, 0, 0, 0, CIPHER_ADD,
-1, 0, &head, &tail);
} else {
ssl_cipher_apply_rule(0, 0, 0, SSL_CHACHA20POLY1305, 0, 0, 0, CIPHER_ADD,
-1, 0, &head, &tail);
ssl_cipher_apply_rule(0, 0, 0, SSL_AES256GCM, 0, 0, 0, CIPHER_ADD, -1, 0,
&head, &tail);
ssl_cipher_apply_rule(0, 0, 0, SSL_AES128GCM, 0, 0, 0, CIPHER_ADD, -1, 0,
&head, &tail);
}
/* Then the legacy non-AEAD ciphers: AES_256_CBC, AES-128_CBC, RC4_128_SHA,
* RC4_128_MD5, 3DES_EDE_CBC_SHA. */
ssl_cipher_apply_rule(0, 0, 0, SSL_AES256, 0, 0, 0, CIPHER_ADD, -1, 0, &head,
&tail);
ssl_cipher_apply_rule(0, 0, 0, SSL_AES128, 0, 0, 0, CIPHER_ADD, -1, 0, &head,
&tail);
ssl_cipher_apply_rule(0, 0, 0, SSL_RC4, ~SSL_MD5, 0, 0, CIPHER_ADD, -1, 0,
&head, &tail);
ssl_cipher_apply_rule(0, 0, 0, SSL_RC4, SSL_MD5, 0, 0, CIPHER_ADD, -1, 0,
&head, &tail);
ssl_cipher_apply_rule(0, 0, 0, SSL_3DES, 0, 0, 0, CIPHER_ADD, -1, 0, &head,
&tail);
/* Temporarily enable everything else for sorting */
ssl_cipher_apply_rule(0, 0, 0, 0, 0, 0, 0, CIPHER_ADD, -1, 0, &head, &tail);
/* Move ciphers without forward secrecy to the end. */
ssl_cipher_apply_rule(0, ~(SSL_kEDH | SSL_kEECDH), 0, 0, 0, 0, 0, CIPHER_ORD,
-1, 0, &head, &tail);
/* Move anonymous ciphers to the end. Usually, these will remain disabled.
* (For applications that allow them, they aren't too bad, but we prefer
* authenticated ciphers.)
* TODO(davidben): Remove them altogether? */
ssl_cipher_apply_rule(0, 0, SSL_aNULL, 0, 0, 0, 0, CIPHER_ORD, -1, 0, &head,
&tail);
/* Now disable everything (maintaining the ordering!) */
ssl_cipher_apply_rule(0, 0, 0, 0, 0, 0, 0, CIPHER_DEL, -1, 0, &head, &tail);
/* We also need cipher aliases for selecting based on the rule_str. There
* might be two types of entries in the rule_str: 1) names of ciphers
* themselves 2) aliases for groups of ciphers. For 1) we need the available
* ciphers and for 2) the cipher groups of cipher_aliases added together in
* one list (otherwise we would be happy with just the cipher_aliases
* table). */
num_of_group_aliases = sizeof(cipher_aliases) / sizeof(SSL_CIPHER);
num_of_alias_max = num_of_ciphers + num_of_group_aliases + 1;
ca_list = OPENSSL_malloc(sizeof(SSL_CIPHER *) * num_of_alias_max);
if (ca_list == NULL) {
OPENSSL_PUT_ERROR(SSL, ssl_create_cipher_list, ERR_R_MALLOC_FAILURE);
goto err;
}
ssl_cipher_collect_aliases(ca_list, num_of_group_aliases, head);
/* If the rule_string begins with DEFAULT, apply the default rule before
* using the (possibly available) additional rules. */
ok = 1;
rule_p = rule_str;
if (strncmp(rule_str, "DEFAULT", 7) == 0) {
ok = ssl_cipher_process_rulestr(SSL_DEFAULT_CIPHER_LIST, &head, &tail,
ca_list);
rule_p += 7;
if (*rule_p == ':') {
rule_p++;
}
}
if (ok && strlen(rule_p) > 0) {
ok = ssl_cipher_process_rulestr(rule_p, &head, &tail, ca_list);
}
OPENSSL_free((void *)ca_list); /* Not needed anymore */
if (!ok) {
goto err;
}
/* Allocate new "cipherstack" for the result, return with error
* if we cannot get one. */
cipherstack = sk_SSL_CIPHER_new_null();
if (cipherstack == NULL) {
goto err;
}
in_group_flags = OPENSSL_malloc(num_of_ciphers);
if (!in_group_flags) {
goto err;
}
/* The cipher selection for the list is done. The ciphers are added
* to the resulting precedence to the STACK_OF(SSL_CIPHER). */
for (curr = head; curr != NULL; curr = curr->next) {
if (curr->active) {
sk_SSL_CIPHER_push(cipherstack, curr->cipher);
in_group_flags[num_in_group_flags++] = curr->in_group;
}
}
OPENSSL_free(co_list); /* Not needed any longer */
co_list = NULL;
tmp_cipher_list = sk_SSL_CIPHER_dup(cipherstack);
if (tmp_cipher_list == NULL) {
goto err;
}
pref_list = OPENSSL_malloc(sizeof(struct ssl_cipher_preference_list_st));
if (!pref_list) {
goto err;
}
pref_list->ciphers = cipherstack;
pref_list->in_group_flags = OPENSSL_malloc(num_in_group_flags);
if (!pref_list->in_group_flags) {
goto err;
}
memcpy(pref_list->in_group_flags, in_group_flags, num_in_group_flags);
OPENSSL_free(in_group_flags);
in_group_flags = NULL;
if (*cipher_list != NULL) {
ssl_cipher_preference_list_free(*cipher_list);
}
*cipher_list = pref_list;
pref_list = NULL;
if (cipher_list_by_id != NULL) {
if (*cipher_list_by_id != NULL) {
sk_SSL_CIPHER_free(*cipher_list_by_id);
}
*cipher_list_by_id = tmp_cipher_list;
tmp_cipher_list = NULL;
(void) sk_SSL_CIPHER_set_cmp_func(*cipher_list_by_id, ssl_cipher_ptr_id_cmp);
sk_SSL_CIPHER_sort(*cipher_list_by_id);
} else {
sk_SSL_CIPHER_free(tmp_cipher_list);
tmp_cipher_list = NULL;
}
return cipherstack;
err:
if (co_list) {
OPENSSL_free(co_list);
}
if (in_group_flags) {
OPENSSL_free(in_group_flags);
}
if (cipherstack) {
sk_SSL_CIPHER_free(cipherstack);
}
if (tmp_cipher_list) {
sk_SSL_CIPHER_free(tmp_cipher_list);
}
if (pref_list && pref_list->in_group_flags) {
OPENSSL_free(pref_list->in_group_flags);
}
if (pref_list) {
OPENSSL_free(pref_list);
}
return NULL;
}
const char *SSL_CIPHER_description(const SSL_CIPHER *cipher, char *buf,
int len) {
const char *ver;
const char *kx, *au, *enc, *mac;
unsigned long alg_mkey, alg_auth, alg_enc, alg_mac, alg_ssl;
static const char *format = "%-23s %s Kx=%-8s Au=%-4s Enc=%-9s Mac=%-4s\n";
alg_mkey = cipher->algorithm_mkey;
alg_auth = cipher->algorithm_auth;
alg_enc = cipher->algorithm_enc;
alg_mac = cipher->algorithm_mac;
alg_ssl = cipher->algorithm_ssl;
if (alg_ssl & SSL_SSLV3) {
ver = "SSLv3";
} else if (alg_ssl & SSL_TLSV1_2) {
ver = "TLSv1.2";
} else {
ver = "unknown";
}
switch (alg_mkey) {
case SSL_kRSA:
kx = "RSA";
break;
case SSL_kEDH:
kx = "DH";
break;
case SSL_kEECDH:
kx = "ECDH";
break;
case SSL_kPSK:
kx = "PSK";
break;
default:
kx = "unknown";
}
switch (alg_auth) {
case SSL_aRSA:
au = "RSA";
break;
case SSL_aNULL:
au = "None";
break;
case SSL_aECDSA:
au = "ECDSA";
break;
case SSL_aPSK:
au = "PSK";
break;
default:
au = "unknown";
break;
}
switch (alg_enc) {
case SSL_3DES:
enc = "3DES(168)";
break;
case SSL_RC4:
enc = "RC4(128)";
break;
case SSL_AES128:
enc = "AES(128)";
break;
case SSL_AES256:
enc = "AES(256)";
break;
case SSL_AES128GCM:
enc = "AESGCM(128)";
break;
case SSL_AES256GCM:
enc = "AESGCM(256)";
break;
case SSL_CHACHA20POLY1305:
enc = "ChaCha20-Poly1305";
break;
default:
enc = "unknown";
break;
}
switch (alg_mac) {
case SSL_MD5:
mac = "MD5";
break;
case SSL_SHA1:
mac = "SHA1";
break;
case SSL_SHA256:
mac = "SHA256";
break;
case SSL_SHA384:
mac = "SHA384";
break;
case SSL_AEAD:
mac = "AEAD";
break;
default:
mac = "unknown";
break;
}
if (buf == NULL) {
len = 128;
buf = OPENSSL_malloc(len);
if (buf == NULL)
return "OPENSSL_malloc Error";
} else if (len < 128) {
return "Buffer too small";
}
BIO_snprintf(buf, len, format, cipher->name, ver, kx, au, enc, mac);
return buf;
}
int SSL_CIPHER_is_AES(const SSL_CIPHER *c) {
return (c->algorithm_enc & SSL_AES) != 0;
}
int SSL_CIPHER_has_MD5_HMAC(const SSL_CIPHER *c) {
return (c->algorithm_mac & SSL_MD5) != 0;
}
int SSL_CIPHER_is_AESGCM(const SSL_CIPHER *c) {
return (c->algorithm_mac & (SSL_AES128GCM | SSL_AES256GCM)) != 0;
}
int SSL_CIPHER_is_CHACHA20POLY1305(const SSL_CIPHER *c) {
return (c->algorithm_enc & SSL_CHACHA20POLY1305) != 0;
}
const char *SSL_CIPHER_get_version(const SSL_CIPHER *c) {
int i;
if (c == NULL) {
return "(NONE)";
}
i = (int)(c->id >> 24L);
if (i == 3) {
return "TLSv1/SSLv3";
} else if (i == 2) {
return "SSLv2";
} else {
return "unknown";
}
}
/* return the actual cipher being used */
const char *SSL_CIPHER_get_name(const SSL_CIPHER *c) {
if (c != NULL) {
return c->name;
}
return "(NONE)";
}
const char *SSL_CIPHER_get_kx_name(const SSL_CIPHER *cipher) {
if (cipher == NULL) {
return "";
}
switch (cipher->algorithm_mkey) {
case SSL_kRSA:
return SSL_TXT_RSA;
case SSL_kEDH:
switch (cipher->algorithm_auth) {
case SSL_aRSA:
return "DHE_" SSL_TXT_RSA;
case SSL_aNULL:
return SSL_TXT_DH "_anon";
default:
return "UNKNOWN";
}
case SSL_kEECDH:
switch (cipher->algorithm_auth) {
case SSL_aECDSA:
return "ECDHE_" SSL_TXT_ECDSA;
case SSL_aRSA:
return "ECDHE_" SSL_TXT_RSA;
case SSL_aNULL:
return SSL_TXT_ECDH "_anon";
default:
return "UNKNOWN";
}
default:
return "UNKNOWN";
}
}
/* number of bits for symmetric cipher */
int SSL_CIPHER_get_bits(const SSL_CIPHER *c, int *alg_bits) {
int ret = 0;
if (c != NULL) {
if (alg_bits != NULL) {
*alg_bits = c->alg_bits;
}
ret = c->strength_bits;
}
return ret;
}
unsigned long SSL_CIPHER_get_id(const SSL_CIPHER *c) { return c->id; }
void *SSL_COMP_get_compression_methods(void) { return NULL; }
int SSL_COMP_add_compression_method(int id, void *cm) { return 1; }
const char *SSL_COMP_get_name(const void *comp) { return NULL; }
/* For a cipher return the index corresponding to the certificate type */
int ssl_cipher_get_cert_index(const SSL_CIPHER *c) {
unsigned long alg_a = c->algorithm_auth;
if (alg_a & SSL_aECDSA) {
return SSL_PKEY_ECC;
} else if (alg_a & SSL_aRSA) {
return SSL_PKEY_RSA_ENC;
}
return -1;
}
/* ssl_cipher_has_server_public_key returns 1 if |cipher| involves a server
* public key in the key exchange, sent in a server Certificate message.
* Otherwise it returns 0. */
int ssl_cipher_has_server_public_key(const SSL_CIPHER *cipher) {
/* Anonymous ciphers do not include a server certificate. */
if (cipher->algorithm_auth & SSL_aNULL) {
return 0;
}
/* Neither do PSK ciphers, except for RSA_PSK. */
if ((cipher->algorithm_auth & SSL_aPSK) &&
!(cipher->algorithm_mkey & SSL_kRSA)) {
return 0;
}
/* All other ciphers include it. */
return 1;
}
/* ssl_cipher_requires_server_key_exchange returns 1 if |cipher| requires a
* ServerKeyExchange message. Otherwise it returns 0.
*
* Unlike ssl_cipher_has_server_public_key, some ciphers take optional
* ServerKeyExchanges. PSK and RSA_PSK only use the ServerKeyExchange to
* communicate a psk_identity_hint, so it is optional. */
int ssl_cipher_requires_server_key_exchange(const SSL_CIPHER *cipher) {
/* Ephemeral Diffie-Hellman key exchanges require a ServerKeyExchange. */
if (cipher->algorithm_mkey & SSL_kEDH || cipher->algorithm_mkey & SSL_kEECDH) {
return 1;
}
/* It is optional in all others. */
return 0;
}