openssl-CVE-2014-3566.patch

   1 From 6bfe55380abbf7528e04e59f18921bd6c896af1c Mon Sep 17 00:00:00 2001
   2 From: Bodo Moeller <bodo@openssl.org>
   3 Date: Wed, 15 Oct 2014 04:05:42 +0200
   4 Subject: [PATCH] Support TLS_FALLBACK_SCSV.
   5
   6 Reviewed-by: Rich Salz <rsalz@openssl.org>
   7 ---
   8  CHANGES               |    6 +++++
   9  apps/s_client.c       |   10 +++++++++
  10  crypto/err/openssl.ec |    1 +
  11  ssl/d1_lib.c          |   10 +++++++++
  12  ssl/dtls1.h           |    3 ++-
  13  ssl/s23_clnt.c        |    3 +++
  14  ssl/s23_srvr.c        |    3 +++
  15  ssl/s2_lib.c          |    4 +++-
  16  ssl/s3_enc.c          |    2 +-
  17  ssl/s3_lib.c          |   29 +++++++++++++++++++++++-
  18  ssl/ssl.h             |    9 ++++++++
  19  ssl/ssl3.h            |    7 +++++-
  20  ssl/ssl_err.c         |    2 ++
  21  ssl/ssl_lib.c         |   60 +++++++++++++++++++++++++++++++++++++------------
  22  ssl/t1_enc.c          |    1 +
  23  ssl/tls1.h            |   15 ++++++++-----
  24  16 files changed, 140 insertions(+), 25 deletions(-)
  25
  26 ;  *) Add support for TLS_FALLBACK_SCSV.
  27 ;     Client applications doing fallback retries should call
  28 ;     SSL_set_mode(s, SSL_MODE_SEND_FALLBACK_SCSV).
  29 ;     (CVE-2014-3566)
  30 ;     [Adam Langley, Bodo Moeller]
  31 ;
  32 diff --git a/apps/s_client.c b/apps/s_client.c
  33 index 4625467..c2e160c 100644
  34 --- a/apps/s_client.c
  35 +++ b/apps/s_client.c
  36 @@ -337,6 +337,7 @@ static void sc_usage(void)
  37         BIO_printf(bio_err," -tls1_1       - just use TLSv1.1\n");
  38         BIO_printf(bio_err," -tls1         - just use TLSv1\n");
  39         BIO_printf(bio_err," -dtls1        - just use DTLSv1\n");
  40 +       BIO_printf(bio_err," -fallback_scsv - send TLS_FALLBACK_SCSV\n");
  41         BIO_printf(bio_err," -mtu          - set the link layer MTU\n");
  42         BIO_printf(bio_err," -no_tls1_2/-no_tls1_1/-no_tls1/-no_ssl3/-no_ssl2 - turn off that protocol\n");
  43         BIO_printf(bio_err," -bugs         - Switch on all SSL implementation bug workarounds\n");
  44 @@ -617,6 +618,7 @@ int MAIN(int argc, char **argv)
  45         char *sess_out = NULL;
  46         struct sockaddr peer;
  47         int peerlen = sizeof(peer);
  48 +       int fallback_scsv = 0;
  49         int enable_timeouts = 0 ;
  50         long socket_mtu = 0;
  51  #ifndef OPENSSL_NO_JPAKE
  52 @@ -823,6 +825,10 @@ int MAIN(int argc, char **argv)
  53                         meth=DTLSv1_client_method();
  54                         socket_type=SOCK_DGRAM;
  55                         }
  56 +               else if (strcmp(*argv,"-fallback_scsv") == 0)
  57 +                       {
  58 +                       fallback_scsv = 1;
  59 +                       }
  60                 else if (strcmp(*argv,"-timeout") == 0)
  61                         enable_timeouts=1;
  62                 else if (strcmp(*argv,"-mtu") == 0)
  63 @@ -1235,6 +1241,10 @@ bad:
  64                 SSL_set_session(con, sess);
  65                 SSL_SESSION_free(sess);
  66                 }
  67 +
  68 +       if (fallback_scsv)
  69 +               SSL_set_mode(con, SSL_MODE_SEND_FALLBACK_SCSV);
  70 +
  71  #ifndef OPENSSL_NO_TLSEXT
  72         if (servername != NULL)
  73                 {
  74 diff --git a/crypto/err/openssl.ec b/crypto/err/openssl.ec
  75 index e0554b4..34754e5 100644
  76 --- a/crypto/err/openssl.ec
  77 +++ b/crypto/err/openssl.ec
  78 @@ -71,6 +71,7 @@ R SSL_R_TLSV1_ALERT_EXPORT_RESTRICTION                1060
  79  R SSL_R_TLSV1_ALERT_PROTOCOL_VERSION           1070
  80  R SSL_R_TLSV1_ALERT_INSUFFICIENT_SECURITY      1071
  81  R SSL_R_TLSV1_ALERT_INTERNAL_ERROR             1080
  82 +R SSL_R_SSLV3_ALERT_INAPPROPRIATE_FALLBACK     1086
  83  R SSL_R_TLSV1_ALERT_USER_CANCELLED             1090
  84  R SSL_R_TLSV1_ALERT_NO_RENEGOTIATION           1100
  85  R SSL_R_TLSV1_UNSUPPORTED_EXTENSION            1110
  86 diff --git a/ssl/d1_lib.c b/ssl/d1_lib.c
  87 index 6bde16f..82ca653 100644
  88 --- a/ssl/d1_lib.c
  89 +++ b/ssl/d1_lib.c
  90 @@ -266,6 +266,16 @@ long dtls1_ctrl(SSL *s, int cmd, long larg, void *parg)
  91         case DTLS_CTRL_LISTEN:
  92                 ret = dtls1_listen(s, parg);
  93                 break;
  94 +       case SSL_CTRL_CHECK_PROTO_VERSION:
  95 +               /* For library-internal use; checks that the current protocol
  96 +                * is the highest enabled version (according to s->ctx->method,
  97 +                * as version negotiation may have changed s->method). */
  98 +#if DTLS_MAX_VERSION != DTLS1_VERSION
  99 +#  error Code needs update for DTLS_method() support beyond DTLS1_VERSION.
 100 +#endif
 101 +               /* Just one protocol version is supported so far;
 102 +                * fail closed if the version is not as expected. */
 103 +               return s->version == DTLS_MAX_VERSION;
 104
 105         default:
 106                 ret = ssl3_ctrl(s, cmd, larg, parg);
 107 diff --git a/ssl/dtls1.h b/ssl/dtls1.h
 108 index e65d501..192c5de 100644
 109 --- a/ssl/dtls1.h
 110 +++ b/ssl/dtls1.h
 111 @@ -84,6 +84,8 @@ extern "C" {
 112  #endif
 113
 114  #define DTLS1_VERSION                  0xFEFF
 115 +#define DTLS_MAX_VERSION               DTLS1_VERSION
 116 +
 117  #define DTLS1_BAD_VER                  0x0100
 118
 119  #if 0
 120 @@ -284,4 +286,3 @@ typedef struct dtls1_record_data_st
 121  }
 122  #endif
 123  #endif
 124 -
 125 diff --git a/ssl/s23_clnt.c b/ssl/s23_clnt.c
 126 index 2b93c63..d4e43c3 100644
 127 --- a/ssl/s23_clnt.c
 128 +++ b/ssl/s23_clnt.c
 129 @@ -736,6 +736,9 @@ static int ssl23_get_server_hello(SSL *s)
 130                         goto err;
 131                         }
 132
 133 +               /* ensure that TLS_MAX_VERSION is up-to-date */
 134 +               OPENSSL_assert(s->version <= TLS_MAX_VERSION);
 135 +
 136                 if (p[0] == SSL3_RT_ALERT && p[5] != SSL3_AL_WARNING)
 137                         {
 138                         /* fatal alert */
 139 diff --git a/ssl/s23_srvr.c b/ssl/s23_srvr.c
 140 index 2901a6b..567a6b1 100644
 141 --- a/ssl/s23_srvr.c
 142 +++ b/ssl/s23_srvr.c
 143 @@ -421,6 +421,9 @@ int ssl23_get_client_hello(SSL *s)
 144                         }
 145                 }
 146
 147 +       /* ensure that TLS_MAX_VERSION is up-to-date */
 148 +       OPENSSL_assert(s->version <= TLS_MAX_VERSION);
 149 +
 150  #ifdef OPENSSL_FIPS
 151         if (FIPS_mode() && (s->version < TLS1_VERSION))
 152                 {
 153 diff --git a/ssl/s2_lib.c b/ssl/s2_lib.c
 154 index c0bdae5..c63be30 100644
 155 --- a/ssl/s2_lib.c
 156 +++ b/ssl/s2_lib.c
 157 @@ -391,6 +391,8 @@ long ssl2_ctrl(SSL *s, int cmd, long larg, void *parg)
 158         case SSL_CTRL_GET_SESSION_REUSED:
 159                 ret=s->hit;
 160                 break;
 161 +       case SSL_CTRL_CHECK_PROTO_VERSION:
 162 +               return ssl3_ctrl(s, SSL_CTRL_CHECK_PROTO_VERSION, larg, parg);
 163         default:
 164                 break;
 165                 }
 166 @@ -437,7 +439,7 @@ int ssl2_put_cipher_by_char(const SSL_CIPHER *c, unsigned char *p)
 167         if (p != NULL)
 168                 {
 169                 l=c->id;
 170 -               if ((l & 0xff000000) != 0x02000000) return(0);
 171 +               if ((l & 0xff000000) != 0x02000000 && l != SSL3_CK_FALLBACK_SCSV) return(0);
 172                 p[0]=((unsigned char)(l>>16L))&0xFF;
 173                 p[1]=((unsigned char)(l>> 8L))&0xFF;
 174                 p[2]=((unsigned char)(l     ))&0xFF;
 175 diff --git a/ssl/s3_enc.c b/ssl/s3_enc.c
 176 index 9962677..9db45af 100644
 177 --- a/ssl/s3_enc.c
 178 +++ b/ssl/s3_enc.c
 179 @@ -900,7 +900,7 @@ int ssl3_alert_code(int code)
 180         case SSL_AD_BAD_CERTIFICATE_STATUS_RESPONSE: return(SSL3_AD_HANDSHAKE_FAILURE);
 181         case SSL_AD_BAD_CERTIFICATE_HASH_VALUE: return(SSL3_AD_HANDSHAKE_FAILURE);
 182         case SSL_AD_UNKNOWN_PSK_IDENTITY:return(TLS1_AD_UNKNOWN_PSK_IDENTITY);
 183 +       case SSL_AD_INAPPROPRIATE_FALLBACK:return(TLS1_AD_INAPPROPRIATE_FALLBACK);
 184         default:                        return(-1);
 185                 }
 186         }
 187 -
 188 diff --git a/ssl/s3_lib.c b/ssl/s3_lib.c
 189 index e17f126..3f17453 100644
 190 --- a/ssl/s3_lib.c
 191 +++ b/ssl/s3_lib.c
 192 @@ -3355,6 +3355,33 @@ long ssl3_ctrl(SSL *s, int cmd, long larg, void *parg)
 193  #endif
 194
 195  #endif /* !OPENSSL_NO_TLSEXT */
 196 +
 197 +       case SSL_CTRL_CHECK_PROTO_VERSION:
 198 +               /* For library-internal use; checks that the current protocol
 199 +                * is the highest enabled version (according to s->ctx->method,
 200 +                * as version negotiation may have changed s->method). */
 201 +               if (s->version == s->ctx->method->version)
 202 +                       return 1;
 203 +               /* Apparently we're using a version-flexible SSL_METHOD
 204 +                * (not at its highest protocol version). */
 205 +               if (s->ctx->method->version == SSLv23_method()->version)
 206 +                       {
 207 +#if TLS_MAX_VERSION != TLS1_2_VERSION
 208 +#  error Code needs update for SSLv23_method() support beyond TLS1_2_VERSION.
 209 +#endif
 210 +                       if (!(s->options & SSL_OP_NO_TLSv1_2))
 211 +                               return s->version == TLS1_2_VERSION;
 212 +                       if (!(s->options & SSL_OP_NO_TLSv1_1))
 213 +                               return s->version == TLS1_1_VERSION;
 214 +                       if (!(s->options & SSL_OP_NO_TLSv1))
 215 +                               return s->version == TLS1_VERSION;
 216 +                       if (!(s->options & SSL_OP_NO_SSLv3))
 217 +                               return s->version == SSL3_VERSION;
 218 +                       if (!(s->options & SSL_OP_NO_SSLv2))
 219 +                               return s->version == SSL2_VERSION;
 220 +                       }
 221 +               return 0; /* Unexpected state; fail closed. */
 222 +
 223         default:
 224                 break;
 225                 }
 226 @@ -3714,6 +3741,7 @@ long ssl3_ctx_callback_ctrl(SSL_CTX *ctx, int cmd, void (*fp)(void))
 227                 break;
 228  #endif
 229  #endif
 230 +
 231         default:
 232                 return(0);
 233                 }
 234 @@ -4296,4 +4324,3 @@ long ssl_get_algorithm2(SSL *s)
 235                 return SSL_HANDSHAKE_MAC_SHA256 | TLS1_PRF_SHA256;
 236         return alg2;
 237         }
 238 -
 239 diff --git a/ssl/ssl.h b/ssl/ssl.h
 240 index b73da5e..b78a1cc 100644
 241 --- a/ssl/ssl.h
 242 +++ b/ssl/ssl.h
 243 @@ -653,6 +653,10 @@ struct ssl_session_st
 244   */
 245  #define SSL_MODE_SEND_CLIENTHELLO_TIME 0x00000020L
 246  #define SSL_MODE_SEND_SERVERHELLO_TIME 0x00000040L
 247 +/* Send TLS_FALLBACK_SCSV in the ClientHello.
 248 + * To be set by applications that reconnect with a downgraded protocol
 249 + * version; see draft-ietf-tls-downgrade-scsv-00 for details. */
 250 +#define SSL_MODE_SEND_FALLBACK_SCSV 0x00000080L
 251
 252  /* Note: SSL[_CTX]_set_{options,mode} use |= op on the previous value,
 253   * they cannot be used to clear bits. */
 254 @@ -1511,6 +1515,7 @@ DECLARE_PEM_rw(SSL_SESSION, SSL_SESSION)
 255  #define SSL_AD_BAD_CERTIFICATE_STATUS_RESPONSE TLS1_AD_BAD_CERTIFICATE_STATUS_RESPONSE
 256  #define SSL_AD_BAD_CERTIFICATE_HASH_VALUE TLS1_AD_BAD_CERTIFICATE_HASH_VALUE
 257  #define SSL_AD_UNKNOWN_PSK_IDENTITY     TLS1_AD_UNKNOWN_PSK_IDENTITY /* fatal */
 258 +#define SSL_AD_INAPPROPRIATE_FALLBACK  TLS1_AD_INAPPROPRIATE_FALLBACK /* fatal */
 259
 260  #define SSL_ERROR_NONE                 0
 261  #define SSL_ERROR_SSL                  1
 262 @@ -1621,6 +1626,8 @@ DECLARE_PEM_rw(SSL_SESSION, SSL_SESSION)
 263  #define SSL_CTRL_GET_EXTRA_CHAIN_CERTS         82
 264  #define SSL_CTRL_CLEAR_EXTRA_CHAIN_CERTS       83
 265
 266 +#define SSL_CTRL_CHECK_PROTO_VERSION           119
 267 +
 268  #define DTLSv1_get_timeout(ssl, arg) \
 269         SSL_ctrl(ssl,DTLS_CTRL_GET_TIMEOUT,0, (void *)arg)
 270  #define DTLSv1_handle_timeout(ssl) \
 271 @@ -2379,6 +2386,7 @@ void ERR_load_SSL_strings(void);
 272  #define SSL_R_HTTPS_PROXY_REQUEST                       155
 273  #define SSL_R_HTTP_REQUEST                              156
 274  #define SSL_R_ILLEGAL_PADDING                           283
 275 +#define SSL_R_INAPPROPRIATE_FALLBACK                    373
 276  #define SSL_R_INCONSISTENT_COMPRESSION                  340
 277  #define SSL_R_INVALID_CHALLENGE_LENGTH                  158
 278  #define SSL_R_INVALID_COMMAND                           280
 279 @@ -2525,6 +2533,7 @@ void ERR_load_SSL_strings(void);
 280  #define SSL_R_TLSV1_ALERT_DECRYPTION_FAILED             1021
 281  #define SSL_R_TLSV1_ALERT_DECRYPT_ERROR                         1051
 282  #define SSL_R_TLSV1_ALERT_EXPORT_RESTRICTION            1060
 283 +#define SSL_R_TLSV1_ALERT_INAPPROPRIATE_FALLBACK        1086
 284  #define SSL_R_TLSV1_ALERT_INSUFFICIENT_SECURITY                 1071
 285  #define SSL_R_TLSV1_ALERT_INTERNAL_ERROR                1080
 286  #define SSL_R_TLSV1_ALERT_NO_RENEGOTIATION              1100
 287 diff --git a/ssl/ssl3.h b/ssl/ssl3.h
 288 index 37f19e3..85f1504 100644
 289 --- a/ssl/ssl3.h
 290 +++ b/ssl/ssl3.h
 291 @@ -128,9 +128,14 @@
 292  extern "C" {
 293  #endif
 294
 295 -/* Signalling cipher suite value: from draft-ietf-tls-renegotiation-03.txt */
 296 +/* Signalling cipher suite value from RFC 5746
 297 + * (TLS_EMPTY_RENEGOTIATION_INFO_SCSV) */
 298  #define SSL3_CK_SCSV                           0x030000FF
 299
 300 +/* Signalling cipher suite value from draft-ietf-tls-downgrade-scsv-00
 301 + * (TLS_FALLBACK_SCSV) */
 302 +#define SSL3_CK_FALLBACK_SCSV                  0x03005600
 303 +
 304  #define SSL3_CK_RSA_NULL_MD5                   0x03000001
 305  #define SSL3_CK_RSA_NULL_SHA                   0x03000002
 306  #define SSL3_CK_RSA_RC4_40_MD5                         0x03000003
 307 diff --git a/ssl/ssl_err.c b/ssl/ssl_err.c
 308 index d2f0dec..1b7eb47 100644
 309 --- a/ssl/ssl_err.c
 310 +++ b/ssl/ssl_err.c
 311 @@ -383,6 +383,7 @@ static ERR_STRING_DATA SSL_str_reasons[]=
 312  {ERR_REASON(SSL_R_HTTPS_PROXY_REQUEST)   ,"https proxy request"},
 313  {ERR_REASON(SSL_R_HTTP_REQUEST)          ,"http request"},
 314  {ERR_REASON(SSL_R_ILLEGAL_PADDING)       ,"illegal padding"},
 315 +{ERR_REASON(SSL_R_INAPPROPRIATE_FALLBACK),"inappropriate fallback"},
 316  {ERR_REASON(SSL_R_INCONSISTENT_COMPRESSION),"inconsistent compression"},
 317  {ERR_REASON(SSL_R_INVALID_CHALLENGE_LENGTH),"invalid challenge length"},
 318  {ERR_REASON(SSL_R_INVALID_COMMAND)       ,"invalid command"},
 319 @@ -529,6 +530,7 @@ static ERR_STRING_DATA SSL_str_reasons[]=
 320  {ERR_REASON(SSL_R_TLSV1_ALERT_DECRYPTION_FAILED),"tlsv1 alert decryption failed"},
 321  {ERR_REASON(SSL_R_TLSV1_ALERT_DECRYPT_ERROR),"tlsv1 alert decrypt error"},
 322  {ERR_REASON(SSL_R_TLSV1_ALERT_EXPORT_RESTRICTION),"tlsv1 alert export restriction"},
 323 +{ERR_REASON(SSL_R_TLSV1_ALERT_INAPPROPRIATE_FALLBACK),"tlsv1 alert inappropriate fallback"},
 324  {ERR_REASON(SSL_R_TLSV1_ALERT_INSUFFICIENT_SECURITY),"tlsv1 alert insufficient security"},
 325  {ERR_REASON(SSL_R_TLSV1_ALERT_INTERNAL_ERROR),"tlsv1 alert internal error"},
 326  {ERR_REASON(SSL_R_TLSV1_ALERT_NO_RENEGOTIATION),"tlsv1 alert no renegotiation"},
 327 diff --git a/ssl/ssl_lib.c b/ssl/ssl_lib.c
 328 index cc094e4..3f66fc0 100644
 329 --- a/ssl/ssl_lib.c
 330 +++ b/ssl/ssl_lib.c
 331 @@ -1387,6 +1387,8 @@ int ssl_cipher_list_to_bytes(SSL *s,STACK_OF(SSL_CIPHER) *sk,unsigned char *p,
 332
 333         if (sk == NULL) return(0);
 334         q=p;
 335 +       if (put_cb == NULL)
 336 +               put_cb = s->method->put_cipher_by_char;
 337
 338         for (i=0; i<sk_SSL_CIPHER_num(sk); i++)
 339                 {
 340 @@ -1411,24 +1413,36 @@ int ssl_cipher_list_to_bytes(SSL *s,STACK_OF(SSL_CIPHER) *sk,unsigned char *p,
 341                     !(s->srp_ctx.srp_Mask & SSL_kSRP))
 342                     continue;
 343  #endif /* OPENSSL_NO_SRP */
 344 -               j = put_cb ? put_cb(c,p) : ssl_put_cipher_by_char(s,c,p);
 345 +               j = put_cb(c,p);
 346                 p+=j;
 347                 }
 348 -       /* If p == q, no ciphers and caller indicates an error. Otherwise
 349 -        * add SCSV if not renegotiating.
 350 -        */
 351 -       if (p != q && !s->renegotiate)
 352 +       /* If p == q, no ciphers; caller indicates an error.
 353 +        * Otherwise, add applicable SCSVs. */
 354 +       if (p != q)
 355                 {
 356 -               static SSL_CIPHER scsv =
 357 +               if (!s->renegotiate)
 358                         {
 359 -                       0, NULL, SSL3_CK_SCSV, 0, 0, 0, 0, 0, 0, 0, 0, 0
 360 -                       };
 361 -               j = put_cb ? put_cb(&scsv,p) : ssl_put_cipher_by_char(s,&scsv,p);
 362 -               p+=j;
 363 +                       static SSL_CIPHER scsv =
 364 +                               {
 365 +                               0, NULL, SSL3_CK_SCSV, 0, 0, 0, 0, 0, 0, 0, 0, 0
 366 +                               };
 367 +                       j = put_cb(&scsv,p);
 368 +                       p+=j;
 369  #ifdef OPENSSL_RI_DEBUG
 370 -               fprintf(stderr, "SCSV sent by client\n");
 371 +                       fprintf(stderr, "TLS_EMPTY_RENEGOTIATION_INFO_SCSV sent by client\n");
 372  #endif
 373 -               }
 374 +                       }
 375 +
 376 +               if (s->mode & SSL_MODE_SEND_FALLBACK_SCSV)
 377 +                       {
 378 +                       static SSL_CIPHER scsv =
 379 +                               {
 380 +                               0, NULL, SSL3_CK_FALLBACK_SCSV, 0, 0, 0, 0, 0, 0, 0, 0, 0
 381 +                               };
 382 +                       j = put_cb(&scsv,p);
 383 +                       p+=j;
 384 +                       }
 385 +               }
 386
 387         return(p-q);
 388         }
 389 @@ -1439,11 +1453,12 @@ STACK_OF(SSL_CIPHER) *ssl_bytes_to_cipher_list(SSL *s,unsigned char *p,int num,
 390         const SSL_CIPHER *c;
 391         STACK_OF(SSL_CIPHER) *sk;
 392         int i,n;
 393 +
 394         if (s->s3)
 395                 s->s3->send_connection_binding = 0;
 396
 397         n=ssl_put_cipher_by_char(s,NULL,NULL);
 398 -       if ((num%n) != 0)
 399 +       if (n == 0 || (num%n) != 0)
 400                 {
 401                 SSLerr(SSL_F_SSL_BYTES_TO_CIPHER_LIST,SSL_R_ERROR_IN_RECEIVED_CIPHER_LIST);
 402                 return(NULL);
 403 @@ -1458,7 +1473,7 @@ STACK_OF(SSL_CIPHER) *ssl_bytes_to_cipher_list(SSL *s,unsigned char *p,int num,
 404
 405         for (i=0; i<num; i+=n)
 406                 {
 407 -               /* Check for SCSV */
 408 +               /* Check for TLS_EMPTY_RENEGOTIATION_INFO_SCSV */
 409                 if (s->s3 && (n != 3 || !p[0]) &&
 410                         (p[n-2] == ((SSL3_CK_SCSV >> 8) & 0xff)) &&
 411                         (p[n-1] == (SSL3_CK_SCSV & 0xff)))
 412 @@ -1478,6 +1493,23 @@ STACK_OF(SSL_CIPHER) *ssl_bytes_to_cipher_list(SSL *s,unsigned char *p,int num,
 413                         continue;
 414                         }
 415
 416 +               /* Check for TLS_FALLBACK_SCSV */
 417 +               if ((n != 3 || !p[0]) &&
 418 +                       (p[n-2] == ((SSL3_CK_FALLBACK_SCSV >> 8) & 0xff)) &&
 419 +                       (p[n-1] == (SSL3_CK_FALLBACK_SCSV & 0xff)))
 420 +                       {
 421 +                       /* The SCSV indicates that the client previously tried a higher version.
 422 +                        * Fail if the current version is an unexpected downgrade. */
 423 +                       if (!SSL_ctrl(s, SSL_CTRL_CHECK_PROTO_VERSION, 0, NULL))
 424 +                               {
 425 +                               SSLerr(SSL_F_SSL_BYTES_TO_CIPHER_LIST,SSL_R_INAPPROPRIATE_FALLBACK);
 426 +                               if (s->s3)
 427 +                                       ssl3_send_alert(s,SSL3_AL_FATAL,SSL_AD_INAPPROPRIATE_FALLBACK);
 428 +                               goto err;
 429 +                               }
 430 +                       continue;
 431 +                       }
 432 +
 433                 c=ssl_get_cipher_by_char(s,p);
 434                 p+=n;
 435                 if (c != NULL)
 436 diff --git a/ssl/t1_enc.c b/ssl/t1_enc.c
 437 index 1427484..1923cf3 100644
 438 --- a/ssl/t1_enc.c
 439 +++ b/ssl/t1_enc.c
 440 @@ -1241,6 +1241,7 @@ int tls1_alert_code(int code)
 441         case SSL_AD_BAD_CERTIFICATE_STATUS_RESPONSE: return(TLS1_AD_BAD_CERTIFICATE_STATUS_RESPONSE);
 442         case SSL_AD_BAD_CERTIFICATE_HASH_VALUE: return(TLS1_AD_BAD_CERTIFICATE_HASH_VALUE);
 443         case SSL_AD_UNKNOWN_PSK_IDENTITY:return(TLS1_AD_UNKNOWN_PSK_IDENTITY);
 444 +       case SSL_AD_INAPPROPRIATE_FALLBACK:return(TLS1_AD_INAPPROPRIATE_FALLBACK);
 445  #if 0 /* not appropriate for TLS, not used for DTLS */
 446         case DTLS1_AD_MISSING_HANDSHAKE_MESSAGE: return
 447                                           (DTLS1_AD_MISSING_HANDSHAKE_MESSAGE);
 448 diff --git a/ssl/tls1.h b/ssl/tls1.h
 449 index c992091..6ae8876 100644
 450 --- a/ssl/tls1.h
 451 +++ b/ssl/tls1.h
 452 @@ -159,17 +159,19 @@ extern "C" {
 453
 454  #define TLS1_ALLOW_EXPERIMENTAL_CIPHERSUITES   0
 455
 456 +#define TLS1_VERSION                   0x0301
 457 +#define TLS1_1_VERSION                 0x0302
 458  #define TLS1_2_VERSION                 0x0303
 459 -#define TLS1_2_VERSION_MAJOR           0x03
 460 -#define TLS1_2_VERSION_MINOR           0x03
 461 +#define TLS_MAX_VERSION                        TLS1_2_VERSION
 462 +
 463 +#define TLS1_VERSION_MAJOR             0x03
 464 +#define TLS1_VERSION_MINOR             0x01
 465
 466 -#define TLS1_1_VERSION                 0x0302
 467  #define TLS1_1_VERSION_MAJOR           0x03
 468  #define TLS1_1_VERSION_MINOR           0x02
 469
 470 -#define TLS1_VERSION                   0x0301
 471 -#define TLS1_VERSION_MAJOR             0x03
 472 -#define TLS1_VERSION_MINOR             0x01
 473 +#define TLS1_2_VERSION_MAJOR           0x03
 474 +#define TLS1_2_VERSION_MINOR           0x03
 475
 476  #define TLS1_get_version(s) \
 477                 ((s->version >> 8) == TLS1_VERSION_MAJOR ? s->version : 0)
 478 @@ -187,6 +189,7 @@ extern "C" {
 479  #define TLS1_AD_PROTOCOL_VERSION       70      /* fatal */
 480  #define TLS1_AD_INSUFFICIENT_SECURITY  71      /* fatal */
 481  #define TLS1_AD_INTERNAL_ERROR         80      /* fatal */
 482 +#define TLS1_AD_INAPPROPRIATE_FALLBACK 86      /* fatal */
 483  #define TLS1_AD_USER_CANCELLED         90
 484  #define TLS1_AD_NO_RENEGOTIATION       100
 485  /* codes 110-114 are from RFC3546 */
 486 --
 487 1.7.9.5
 488