ssl/d1_srtp.c

   1 /*
   2  * Copyright 2011-2016 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the OpenSSL license (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 /*
  11  * DTLS code by Eric Rescorla <ekr@rtfm.com>
  12  *
  13  * Copyright (C) 2006, Network Resonance, Inc. Copyright (C) 2011, RTFM, Inc.
  14  */
  15
  16 #include <stdio.h>
  17 #include <openssl/objects.h>
  18 #include "ssl_locl.h"
  19
  20 #ifndef OPENSSL_NO_SRTP
  21
  22 static SRTP_PROTECTION_PROFILE srtp_known_profiles[] = {
  23     {
  24      "SRTP_AES128_CM_SHA1_80",
  25      SRTP_AES128_CM_SHA1_80,
  26      },
  27     {
  28      "SRTP_AES128_CM_SHA1_32",
  29      SRTP_AES128_CM_SHA1_32,
  30      },
  31     {
  32      "SRTP_AEAD_AES_128_GCM",
  33      SRTP_AEAD_AES_128_GCM,
  34      },
  35     {
  36      "SRTP_AEAD_AES_256_GCM",
  37      SRTP_AEAD_AES_256_GCM,
  38      },
  39     {0}
  40 };
  41
  42 static int find_profile_by_name(char *profile_name,
  43                                 SRTP_PROTECTION_PROFILE **pptr, unsigned len)
  44 {
  45     SRTP_PROTECTION_PROFILE *p;
  46
  47     p = srtp_known_profiles;
  48     while (p->name) {
  49         if ((len == strlen(p->name))
  50             && strncmp(p->name, profile_name, len) == 0) {
  51             *pptr = p;
  52             return 0;
  53         }
  54
  55         p++;
  56     }
  57
  58     return 1;
  59 }
  60
  61 static int ssl_ctx_make_profiles(const char *profiles_string,
  62                                  STACK_OF(SRTP_PROTECTION_PROFILE) **out)
  63 {
  64     STACK_OF(SRTP_PROTECTION_PROFILE) *profiles;
  65
  66     char *col;
  67     char *ptr = (char *)profiles_string;
  68     SRTP_PROTECTION_PROFILE *p;
  69
  70     if ((profiles = sk_SRTP_PROTECTION_PROFILE_new_null()) == NULL) {
  71         SSLerr(SSL_F_SSL_CTX_MAKE_PROFILES,
  72                SSL_R_SRTP_COULD_NOT_ALLOCATE_PROFILES);
  73         return 1;
  74     }
  75
  76     do {
  77         col = strchr(ptr, ':');
  78
  79         if (!find_profile_by_name(ptr, &p, col ? col - ptr : (int)strlen(ptr))) {
  80             if (sk_SRTP_PROTECTION_PROFILE_find(profiles, p) >= 0) {
  81                 SSLerr(SSL_F_SSL_CTX_MAKE_PROFILES,
  82                        SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
  83                 goto err;
  84             }
  85
  86             if (!sk_SRTP_PROTECTION_PROFILE_push(profiles, p)) {
  87                 SSLerr(SSL_F_SSL_CTX_MAKE_PROFILES,
  88                        SSL_R_SRTP_COULD_NOT_ALLOCATE_PROFILES);
  89                 goto err;
  90             }
  91         } else {
  92             SSLerr(SSL_F_SSL_CTX_MAKE_PROFILES,
  93                    SSL_R_SRTP_UNKNOWN_PROTECTION_PROFILE);
  94             goto err;
  95         }
  96
  97         if (col)
  98             ptr = col + 1;
  99     } while (col);
 100
 101     sk_SRTP_PROTECTION_PROFILE_free(*out);
 102
 103     *out = profiles;
 104
 105     return 0;
 106  err:
 107     sk_SRTP_PROTECTION_PROFILE_free(profiles);
 108     return 1;
 109 }
 110
 111 int SSL_CTX_set_tlsext_use_srtp(SSL_CTX *ctx, const char *profiles)
 112 {
 113     return ssl_ctx_make_profiles(profiles, &ctx->srtp_profiles);
 114 }
 115
 116 int SSL_set_tlsext_use_srtp(SSL *s, const char *profiles)
 117 {
 118     return ssl_ctx_make_profiles(profiles, &s->srtp_profiles);
 119 }
 120
 121 STACK_OF(SRTP_PROTECTION_PROFILE) *SSL_get_srtp_profiles(SSL *s)
 122 {
 123     if (s != NULL) {
 124         if (s->srtp_profiles != NULL) {
 125             return s->srtp_profiles;
 126         } else if ((s->ctx != NULL) && (s->ctx->srtp_profiles != NULL)) {
 127             return s->ctx->srtp_profiles;
 128         }
 129     }
 130
 131     return NULL;
 132 }
 133
 134 SRTP_PROTECTION_PROFILE *SSL_get_selected_srtp_profile(SSL *s)
 135 {
 136     return s->srtp_profile;
 137 }
 138
 139 int ssl_parse_clienthello_use_srtp_ext(SSL *s, PACKET *pkt, int *al)
 140 {
 141     SRTP_PROTECTION_PROFILE *sprof;
 142     STACK_OF(SRTP_PROTECTION_PROFILE) *srvr;
 143     unsigned int ct, mki_len, id;
 144     int i, srtp_pref;
 145     PACKET subpkt;
 146
 147     /* Pull off the length of the cipher suite list  and check it is even */
 148     if (!PACKET_get_net_2(pkt, &ct)
 149         || (ct & 1) != 0 || !PACKET_get_sub_packet(pkt, &subpkt, ct)) {
 150         SSLerr(SSL_F_SSL_PARSE_CLIENTHELLO_USE_SRTP_EXT,
 151                SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
 152         *al = SSL_AD_DECODE_ERROR;
 153         return 1;
 154     }
 155
 156     srvr = SSL_get_srtp_profiles(s);
 157     s->srtp_profile = NULL;
 158     /* Search all profiles for a match initially */
 159     srtp_pref = sk_SRTP_PROTECTION_PROFILE_num(srvr);
 160
 161     while (PACKET_remaining(&subpkt)) {
 162         if (!PACKET_get_net_2(&subpkt, &id)) {
 163             SSLerr(SSL_F_SSL_PARSE_CLIENTHELLO_USE_SRTP_EXT,
 164                    SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
 165             *al = SSL_AD_DECODE_ERROR;
 166             return 1;
 167         }
 168
 169         /*
 170          * Only look for match in profiles of higher preference than
 171          * current match.
 172          * If no profiles have been have been configured then this
 173          * does nothing.
 174          */
 175         for (i = 0; i < srtp_pref; i++) {
 176             sprof = sk_SRTP_PROTECTION_PROFILE_value(srvr, i);
 177             if (sprof->id == id) {
 178                 s->srtp_profile = sprof;
 179                 srtp_pref = i;
 180                 break;
 181             }
 182         }
 183     }
 184
 185     /*
 186      * Now extract the MKI value as a sanity check, but discard it for now
 187      */
 188     if (!PACKET_get_1(pkt, &mki_len)) {
 189         SSLerr(SSL_F_SSL_PARSE_CLIENTHELLO_USE_SRTP_EXT,
 190                SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
 191         *al = SSL_AD_DECODE_ERROR;
 192         return 1;
 193     }
 194
 195     if (!PACKET_forward(pkt, mki_len)
 196         || PACKET_remaining(pkt)) {
 197         SSLerr(SSL_F_SSL_PARSE_CLIENTHELLO_USE_SRTP_EXT,
 198                SSL_R_BAD_SRTP_MKI_VALUE);
 199         *al = SSL_AD_DECODE_ERROR;
 200         return 1;
 201     }
 202
 203     return 0;
 204 }
 205
 206 int ssl_parse_serverhello_use_srtp_ext(SSL *s, PACKET *pkt, int *al)
 207 {
 208     unsigned int id, ct, mki;
 209     int i;
 210
 211     STACK_OF(SRTP_PROTECTION_PROFILE) *clnt;
 212     SRTP_PROTECTION_PROFILE *prof;
 213
 214     if (!PACKET_get_net_2(pkt, &ct)
 215         || ct != 2 || !PACKET_get_net_2(pkt, &id)
 216         || !PACKET_get_1(pkt, &mki)
 217         || PACKET_remaining(pkt) != 0) {
 218         SSLerr(SSL_F_SSL_PARSE_SERVERHELLO_USE_SRTP_EXT,
 219                SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
 220         *al = SSL_AD_DECODE_ERROR;
 221         return 1;
 222     }
 223
 224     if (mki != 0) {
 225         /* Must be no MKI, since we never offer one */
 226         SSLerr(SSL_F_SSL_PARSE_SERVERHELLO_USE_SRTP_EXT,
 227                SSL_R_BAD_SRTP_MKI_VALUE);
 228         *al = SSL_AD_ILLEGAL_PARAMETER;
 229         return 1;
 230     }
 231
 232     clnt = SSL_get_srtp_profiles(s);
 233
 234     /* Throw an error if the server gave us an unsolicited extension */
 235     if (clnt == NULL) {
 236         SSLerr(SSL_F_SSL_PARSE_SERVERHELLO_USE_SRTP_EXT,
 237                SSL_R_NO_SRTP_PROFILES);
 238         *al = SSL_AD_DECODE_ERROR;
 239         return 1;
 240     }
 241
 242     /*
 243      * Check to see if the server gave us something we support (and
 244      * presumably offered)
 245      */
 246     for (i = 0; i < sk_SRTP_PROTECTION_PROFILE_num(clnt); i++) {
 247         prof = sk_SRTP_PROTECTION_PROFILE_value(clnt, i);
 248
 249         if (prof->id == id) {
 250             s->srtp_profile = prof;
 251             *al = 0;
 252             return 0;
 253         }
 254     }
 255
 256     SSLerr(SSL_F_SSL_PARSE_SERVERHELLO_USE_SRTP_EXT,
 257            SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
 258     *al = SSL_AD_DECODE_ERROR;
 259     return 1;
 260 }
 261
 262 #endif