New function ssl_set_client_disabled to set masks for any ciphersuites
authorDr. Stephen Henson <steve@openssl.org>
Wed, 18 Jul 2012 14:09:46 +0000 (14:09 +0000)
committerDr. Stephen Henson <steve@openssl.org>
Wed, 18 Jul 2012 14:09:46 +0000 (14:09 +0000)
that are disabled for this session (as opposed to always disabled by
configuration).

CHANGES
ssl/s3_clnt.c
ssl/s3_srvr.c
ssl/ssl_lib.c
ssl/ssl_locl.h
ssl/t1_lib.c

diff --git a/CHANGES b/CHANGES
index 9aaaa06..8759585 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -4,6 +4,11 @@
 
  Changes between 1.0.1 and 1.1.0  [xx XXX xxxx]
 
+  *) New function ssl_set_client_disabled to set a ciphersuite disabled
+     mask based on the current session, check mask when sending client
+     hello and checking the requested ciphersuite.
+     [Steve Henson]
+
   *) New ctrls to retrieve and set certificate types in a certificate
      request message. Print out received values in s_client. If certificate
      types is not set with custom values set sensible values based on
index 812af8c..b6345b5 100644 (file)
@@ -837,6 +837,7 @@ int ssl3_get_server_hello(SSL *s)
        {
        STACK_OF(SSL_CIPHER) *sk;
        const SSL_CIPHER *c;
+       CERT *ct = s->cert;
        unsigned char *p,*d;
        int i,al=SSL_AD_INTERNAL_ERROR,ok;
        unsigned int j;
@@ -959,9 +960,12 @@ int ssl3_get_server_hello(SSL *s)
                SSLerr(SSL_F_SSL3_GET_SERVER_HELLO,SSL_R_UNKNOWN_CIPHER_RETURNED);
                goto f_err;
                }
-       /* TLS v1.2 only ciphersuites require v1.2 or later */
-       if ((c->algorithm_ssl & SSL_TLSV1_2) && 
-               (TLS1_get_version(s) < TLS1_2_VERSION))
+       /* If it is a disabled cipher we didn't send it in client hello,
+        * so return an error.
+        */
+       if (c->algorithm_ssl & ct->mask_ssl ||
+               c->algorithm_mkey & ct->mask_k ||
+               c->algorithm_auth & ct->mask_a)
                {
                al=SSL_AD_ILLEGAL_PARAMETER;
                SSLerr(SSL_F_SSL3_GET_SERVER_HELLO,SSL_R_WRONG_CIPHER_RETURNED);
index 879d074..6cb405d 100644 (file)
@@ -2074,9 +2074,11 @@ int ssl3_send_certificate_request(SSL *s)
 
                if (TLS1_get_version(s) >= TLS1_2_VERSION)
                        {
-                       nl = tls12_get_sig_algs(s, p + 2);
+                       const unsigned char *psigs;
+                       nl = tls12_get_psigalgs(s, &psigs);
                        s2n(nl, p);
-                       p += nl + 2;
+                       memcpy(p, psigs, nl);
+                       p += nl;
                        n += nl + 2;
                        }
 
index 1ba6e2d..a0af428 100644 (file)
@@ -1410,10 +1410,10 @@ int ssl_cipher_list_to_bytes(SSL *s,STACK_OF(SSL_CIPHER) *sk,unsigned char *p,
        {
        int i,j=0;
        SSL_CIPHER *c;
+       CERT *ct = s->cert;
        unsigned char *q;
-#ifndef OPENSSL_NO_KRB5
-       int nokrb5 = !kssl_tgt_is_available(s->kssl_ctx);
-#endif /* OPENSSL_NO_KRB5 */
+       /* Set disabled masks for this session */
+       ssl_set_client_disabled(s);
 
        if (sk == NULL) return(0);
        q=p;
@@ -1421,21 +1421,11 @@ int ssl_cipher_list_to_bytes(SSL *s,STACK_OF(SSL_CIPHER) *sk,unsigned char *p,
        for (i=0; i<sk_SSL_CIPHER_num(sk); i++)
                {
                c=sk_SSL_CIPHER_value(sk,i);
-               /* Skip TLS v1.2 only ciphersuites if lower than v1.2 */
-               if ((c->algorithm_ssl & SSL_TLSV1_2) && 
-                       (TLS1_get_client_version(s) < TLS1_2_VERSION))
-                       continue;
-#ifndef OPENSSL_NO_KRB5
-               if (((c->algorithm_mkey & SSL_kKRB5) || (c->algorithm_auth & SSL_aKRB5)) &&
-                   nokrb5)
-                   continue;
-#endif /* OPENSSL_NO_KRB5 */
-#ifndef OPENSSL_NO_PSK
-               /* with PSK there must be client callback set */
-               if (((c->algorithm_mkey & SSL_kPSK) || (c->algorithm_auth & SSL_aPSK)) &&
-                   s->psk_client_callback == NULL)
+               /* Skip disabled ciphers */
+               if (c->algorithm_ssl & ct->mask_ssl ||
+                       c->algorithm_mkey & ct->mask_k ||
+                       c->algorithm_auth & ct->mask_a)
                        continue;
-#endif /* OPENSSL_NO_PSK */
                j = put_cb ? put_cb(c,p) : ssl_put_cipher_by_char(s,c,p);
                p+=j;
                }
index 7512875..e64228f 100644 (file)
@@ -505,13 +505,18 @@ typedef struct cert_st
                         * Probably it would make more sense to store
                         * an index, not a pointer. */
  
-       /* The following masks are for the key and auth
-        * algorithms that are supported by the certs below */
+       /* For servers the following masks are for the key and auth
+        * algorithms that are supported by the certs below.
+        * For clients they are masks of *disabled* algorithms based
+        * on the current session.
+        */
        int valid;
        unsigned long mask_k;
        unsigned long mask_a;
        unsigned long export_mask_k;
        unsigned long export_mask_a;
+       /* Client only */
+       unsigned long mask_ssl;
 #ifndef OPENSSL_NO_RSA
        RSA *rsa_tmp;
        RSA *(*rsa_tmp_cb)(SSL *ssl,int is_export,int keysize);
@@ -1237,7 +1242,8 @@ int ssl_parse_clienthello_renegotiate_ext(SSL *s, unsigned char *d, int len,
                                          int *al);
 long ssl_get_algorithm2(SSL *s);
 int tls1_process_sigalgs(SSL *s, const unsigned char *data, int dsize);
-size_t tls12_get_sig_algs(SSL *s, unsigned char *p);
+size_t tls12_get_psigalgs(SSL *s, const unsigned char **psigs);
+void ssl_set_client_disabled(SSL *s);
 
 int ssl_add_clienthello_use_srtp_ext(SSL *s, unsigned char *p, int *len, int maxlen);
 int ssl_parse_clienthello_use_srtp_ext(SSL *s, unsigned char *d, int len,int *al);
index eb6aa55..3421e34 100644 (file)
@@ -635,35 +635,110 @@ static unsigned char tls12_sigalgs[] = {
 #endif
 };
 
-size_t tls12_get_sig_algs(SSL *s, unsigned char *p)
+size_t tls12_get_psigalgs(SSL *s, const unsigned char **psigs)
        {
-       const unsigned char *sigs;
-       size_t sigslen;
        /* If server use client authentication sigalgs if not NULL */
        if (s->server && s->cert->client_sigalgs)
                {
-               sigs = s->cert->client_sigalgs;
-               sigslen = s->cert->client_sigalgslen;
+               *psigs = s->cert->client_sigalgs;
+               return s->cert->client_sigalgslen;
                }
        else if (s->cert->conf_sigalgs)
                {
-               sigs = s->cert->conf_sigalgs;
-               sigslen = s->cert->conf_sigalgslen;
+               *psigs = s->cert->conf_sigalgs;
+               return s->cert->conf_sigalgslen;
                }
        else
                {
-               sigs = tls12_sigalgs;
-               sigslen = sizeof(tls12_sigalgs);
+               *psigs = tls12_sigalgs;
 #ifdef OPENSSL_FIPS
                /* If FIPS mode don't include MD5 which is last */
                if (FIPS_mode())
-                       sigslen -= 2;
+                       return sizeof(tls12_sigalgs) - 2;
+               else
 #endif
+                       return sizeof(tls12_sigalgs);
                }
-
-       if (p)
-               memcpy(p, sigs, sigslen);
-       return sigslen;
+       }
+/* Get a mask of disabled algorithms: an algorithm is disabled
+ * if it isn't supported or doesn't appear in supported signature
+ * algorithms. Unlike ssl_cipher_get_disabled this applies to a specific
+ * session and not global settings.
+ * 
+ */
+void ssl_set_client_disabled(SSL *s)
+       {
+       CERT *c = s->cert;
+       const unsigned char *sigalgs;
+       size_t i, sigalgslen;
+       int have_rsa = 0, have_dsa = 0, have_ecdsa = 0;
+       c->mask_a = 0;
+       c->mask_k = 0;
+       /* If less than TLS 1.2 don't allow TLS 1.2 only ciphers */
+       if (TLS1_get_version(s) < TLS1_2_VERSION)
+               c->mask_ssl = SSL_TLSV1_2;
+       else
+               c->mask_ssl = 0;
+       /* Now go through all signature algorithms seeing if we support
+        * any for RSA, DSA, ECDSA. Do this for all versions not just
+        * TLS 1.2.
+        */
+       sigalgslen = tls12_get_psigalgs(s, &sigalgs);
+       for (i = 0; i < sigalgslen; i += 2, sigalgs += 2)
+               {
+               switch(sigalgs[1])
+                       {
+#ifndef OPENSSL_NO_RSA
+               case TLSEXT_signature_rsa:
+                       have_rsa = 1;
+                       break;
+#endif
+#ifndef OPENSSL_NO_DSA
+               case TLSEXT_signature_dsa:
+                       have_dsa = 1;
+                       break;
+#endif
+#ifndef OPENSSL_NO_ECDSA
+               case TLSEXT_signature_ecdsa:
+                       have_ecdsa = 1;
+                       break;
+#endif
+                       }
+               }
+       /* Disable auth and static DH if we don't include any appropriate
+        * signature algorithms.
+        */
+       if (!have_rsa)
+               {
+               c->mask_a |= SSL_aRSA;
+               c->mask_k |= SSL_kDHr|SSL_kECDHr;
+               }
+       if (!have_dsa)
+               {
+               c->mask_a |= SSL_aDSS;
+               c->mask_k |= SSL_kDHd;
+               }
+       if (!have_ecdsa)
+               {
+               c->mask_a |= SSL_aECDSA;
+               c->mask_k |= SSL_kECDHe;
+               }
+#ifndef OPENSSL_NO_KRB5
+       if (!kssl_tgt_is_available(s->kssl_ctx))
+               {
+               c->mask_a |= SSL_aKRB5;
+               c->mask_k |= SSL_kKRB5;
+               }
+#endif
+#ifndef OPENSSL_NO_PSK
+       /* with PSK there must be client callback set */
+       if (!s->psk_client_callback)
+               {
+               c->mask_a |= SSL_aPSK;
+               c->mask_k |= SSL_kPSK;
+               }
+#endif /* OPENSSL_NO_PSK */
+       c->valid = 1;
        }
 
 /* byte_compare is a compare function for qsort(3) that compares bytes. */
@@ -899,13 +974,14 @@ unsigned char *ssl_add_clienthello_tlsext(SSL *s, unsigned char *p, unsigned cha
        if (TLS1_get_client_version(s) >= TLS1_2_VERSION)
                {
                size_t salglen;
-               salglen = tls12_get_sig_algs(s, NULL);
+               const unsigned char *salg;
+               salglen = tls12_get_psigalgs(s, &salg);
                if ((size_t)(limit - ret) < salglen + 6)
                        return NULL; 
                s2n(TLSEXT_TYPE_signature_algorithms,ret);
                s2n(salglen + 2, ret);
                s2n(salglen, ret);
-               tls12_get_sig_algs(s, ret);
+               memcpy(ret, salg, salglen);
                ret += salglen;
                }