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boringssl/ssl/ssl_ciph.c
Adam Langley 0e2a3cf98a Remove KSSL_DEBUG. 
As far as I know, this is scar tissue left over from a Solaris feature:
http://www.c0t0d0s0.org/archives/5575-Less-known-Solaris-Features-kssl.html

Change-Id: I9fdc21de225f15d29bf856174bcd42e2592f8d95
Reviewed-on: https://boringssl-review.googlesource.com/2141
Reviewed-by: David Benjamin <davidben@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>
2014-11-04 19:35:38 +00:00

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/* 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)
*aead = EVP_aead_rc4_md5_tls();
else
return 0;
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) return(0);
/* This function doesn't deal with EVP_AEAD. See
* |ssl_cipher_get_aead_evp|. */
if (c->algorithm2 & SSL_CIPHER_ALGORITHM2_AEAD)
return(0);
if ((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_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;
#ifdef CIPHER_DEBUG
printf("Applying rule %d with %08lx/%08lx/%08lx/%08lx/%08lx %08lx (%d) in_group:%d\n",
rule, alg_mkey, alg_auth, alg_enc, alg_mac, alg_ssl, algo_strength, strength_bits, in_group);
#endif
if (rule == CIPHER_DEL)
reverse = 1; /* needed to maintain sorting between currently deleted ciphers */
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
{
#ifdef CIPHER_DEBUG
printf("\nName: %s:\nAlgo = %08lx/%08lx/%08lx/%08lx/%08lx Algo_strength = %08lx\n", cp->name, cp->algorithm_mkey, cp->algorithm_auth, cp->algorithm_enc, cp->algorithm_mac, cp->algorithm_ssl, cp->algo_strength);
#endif
if (alg_mkey && !(alg_mkey & cp->algorithm_mkey))
continue;
if (alg_auth && !(alg_auth & cp->algorithm_auth))
continue;
if (alg_enc && !(alg_enc & cp->algorithm_enc))
continue;
if (alg_mac && !(alg_mac & cp->algorithm_mac))
continue;
if (alg_ssl && !(alg_ssl & cp->algorithm_ssl))
continue;
if (algo_strength && !(algo_strength & cp->algo_strength))
continue;
}
#ifdef CIPHER_DEBUG
printf("Action = %d\n", rule);
#endif
/* 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_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;
unsigned char *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); /* Failure */
}
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 ephemeral ECDH over other key exchange mechanisms */
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.
*/
if ((cipherstack = sk_SSL_CIPHER_new_null()) == 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;
#ifdef CIPHER_DEBUG
printf("<%s>\n",curr->cipher->name);
#endif
}
}
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);
}
/* Next three functions require non-null cipher */
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.
*
* Also, as implemented, the RSA key exchange takes an optional
* ServerKeyExchange containing a signed ephemeral RSA encryption key.
*
* TODO(davidben): Can we remove the RSA one? This is a remnant of
* RSA_EXPORT ciphers which required this (it was used to generate an
* ephemeral 512-bit RSA encryption key), but it's allowed for all RSA
* ciphers. */
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;
}
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