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Support TLS_FALLBACK_SCSV.

Browse Source 
Reviewed-by: Stephen Henson <steve@openssl.org>
This commit is contained in:
Bodo Moeller 2014-10-15 04:03:28 +02:00
parent ffa08b3242
commit cf6da05304
16 changed files with 154 additions and 30 deletions
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6
CHANGES
View File

@ -305,6 +305,12 @@
Changes between 1.0.1h and 1.0.2 [xx XXX xxxx]
*) Add support for TLS_FALLBACK_SCSV.
Client applications doing fallback retries should call
SSL_set_mode(s, SSL_MODE_SEND_FALLBACK_SCSV).
(CVE-2014-3566)
[Adam Langley, Bodo Moeller]
*) Accelerated NIST P-256 elliptic curve implementation for x86_64
(other platforms pending).
[Shay Gueron (Intel Corp), Andy Polyakov]

10
apps/s_client.c
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@ -341,6 +341,7 @@ static void sc_usage(void)
BIO_printf(bio_err," -tls1_1 - just use TLSv1.1\n");
BIO_printf(bio_err," -tls1 - just use TLSv1\n");
BIO_printf(bio_err," -dtls1 - just use DTLSv1\n");
BIO_printf(bio_err," -fallback_scsv - send TLS_FALLBACK_SCSV\n");
BIO_printf(bio_err," -mtu - set the link layer MTU\n");
BIO_printf(bio_err," -no_tls1_2/-no_tls1_1/-no_tls1/-no_ssl3/-no_ssl2 - turn off that protocol\n");
BIO_printf(bio_err," -bugs - Switch on all SSL implementation bug workarounds\n");
@ -650,6 +651,7 @@ int MAIN(int argc, char **argv)
char *sess_out = NULL;
struct sockaddr peer;
int peerlen = sizeof(peer);
int fallback_scsv = 0;
int enable_timeouts = 0 ;
long socket_mtu = 0;
#ifndef OPENSSL_NO_JPAKE
@ -940,6 +942,10 @@ static char *jpake_secret = NULL;
meth=DTLSv1_2_client_method();
socket_type=SOCK_DGRAM;
}
else if (strcmp(*argv,"-fallback_scsv") == 0)
{
fallback_scsv = 1;
}
else if (strcmp(*argv,"-timeout") == 0)
enable_timeouts=1;
else if (strcmp(*argv,"-mtu") == 0)
@ -1439,6 +1445,10 @@ bad:
SSL_set_session(con, sess);
SSL_SESSION_free(sess);
}
if (fallback_scsv)
SSL_set_mode(con, SSL_MODE_SEND_FALLBACK_SCSV);
#ifndef OPENSSL_NO_TLSEXT
if (servername != NULL)
{

1
crypto/err/openssl.ec
View File

@ -74,6 +74,7 @@ R SSL_R_TLSV1_ALERT_EXPORT_RESTRICTION 1060
R SSL_R_TLSV1_ALERT_PROTOCOL_VERSION 1070
R SSL_R_TLSV1_ALERT_INSUFFICIENT_SECURITY 1071
R SSL_R_TLSV1_ALERT_INTERNAL_ERROR 1080
R SSL_R_SSLV3_ALERT_INAPPROPRIATE_FALLBACK 1086
R SSL_R_TLSV1_ALERT_USER_CANCELLED 1090
R SSL_R_TLSV1_ALERT_NO_RENEGOTIATION 1100
R SSL_R_TLSV1_UNSUPPORTED_EXTENSION 1110

19
ssl/d1_lib.c
View File

@ -294,6 +294,25 @@ long dtls1_ctrl(SSL *s, int cmd, long larg, void *parg)
case DTLS_CTRL_LISTEN:
ret = dtls1_listen(s, parg);
break;
case SSL_CTRL_CHECK_PROTO_VERSION:
/* For library-internal use; checks that the current protocol
* is the highest enabled version (according to s->ctx->method,
* as version negotiation may have changed s->method). */
if (s->version == s->ctx->method->version)
return 1;
/* Apparently we're using a version-flexible SSL_METHOD
* (not at its highest protocol version). */
if (s->ctx->method->version == DTLS_method()->version)
{
#if DTLS_MAX_VERSION != DTLS1_2_VERSION
# error Code needs update for DTLS_method() support beyond DTLS1_2_VERSION.
#endif
if (!(s->options & SSL_OP_NO_DTLSv1_2))
return s->version == DTLS1_2_VERSION;
if (!(s->options & SSL_OP_NO_DTLSv1))
return s->version == DTLS1_VERSION;
}
return 0; /* Unexpected state; fail closed. */
default:
ret = ssl3_ctrl(s, cmd, larg, parg);

6
ssl/dtls1.h
View File

@ -84,8 +84,11 @@ extern "C" {
#endif
#define DTLS1_VERSION 0xFEFF
#define DTLS1_BAD_VER 0x0100
#define DTLS1_2_VERSION 0xFEFD
#define DTLS_MAX_VERSION DTLS1_2_VERSION
#define DTLS1_BAD_VER 0x0100
/* Special value for method supporting multiple versions */
#define DTLS_ANY_VERSION 0x1FFFF
@ -287,4 +290,3 @@ typedef struct dtls1_record_data_st
}
#endif
#endif

3
ssl/s23_clnt.c
View File

@ -752,6 +752,9 @@ static int ssl23_get_server_hello(SSL *s)
goto err;
}
/* ensure that TLS_MAX_VERSION is up-to-date */
OPENSSL_assert(s->version <= TLS_MAX_VERSION);
if (!ssl_security(s, SSL_SECOP_VERSION, 0, s->version, NULL))
{
SSLerr(SSL_F_SSL23_GET_SERVER_HELLO,SSL_R_VERSION_TOO_LOW);

3
ssl/s23_srvr.c
View File

@ -421,6 +421,9 @@ int ssl23_get_client_hello(SSL *s)
}
}
/* ensure that TLS_MAX_VERSION is up-to-date */
OPENSSL_assert(s->version <= TLS_MAX_VERSION);
if (s->version < TLS1_2_VERSION && tls1_suiteb(s))
{
SSLerr(SSL_F_SSL23_GET_CLIENT_HELLO,

4
ssl/s2_lib.c
View File

@ -391,6 +391,8 @@ long ssl2_ctrl(SSL *s, int cmd, long larg, void *parg)
case SSL_CTRL_GET_SESSION_REUSED:
ret=s->hit;
break;
case SSL_CTRL_CHECK_PROTO_VERSION:
return ssl3_ctrl(s, SSL_CTRL_CHECK_PROTO_VERSION, larg, parg);
default:
break;
}
@ -434,7 +436,7 @@ int ssl2_put_cipher_by_char(const SSL_CIPHER *c, unsigned char *p)
if (p != NULL)
{
l=c->id;
if ((l & 0xff000000) != 0x02000000) return(0);
if ((l & 0xff000000) != 0x02000000 && l != SSL3_CK_FALLBACK_SCSV) return(0);
p[0]=((unsigned char)(l>>16L))&0xFF;
p[1]=((unsigned char)(l>> 8L))&0xFF;
p[2]=((unsigned char)(l ))&0xFF;

2
ssl/s3_enc.c
View File

@ -937,7 +937,7 @@ int ssl3_alert_code(int code)
case SSL_AD_BAD_CERTIFICATE_STATUS_RESPONSE: return(SSL3_AD_HANDSHAKE_FAILURE);
case SSL_AD_BAD_CERTIFICATE_HASH_VALUE: return(SSL3_AD_HANDSHAKE_FAILURE);
case SSL_AD_UNKNOWN_PSK_IDENTITY:return(TLS1_AD_UNKNOWN_PSK_IDENTITY);
case SSL_AD_INAPPROPRIATE_FALLBACK:return(TLS1_AD_INAPPROPRIATE_FALLBACK);
default: return(-1);
}
}

28
ssl/s3_lib.c
View File

@ -3924,6 +3924,33 @@ long ssl3_ctrl(SSL *s, int cmd, long larg, void *parg)
return (int)sess->tlsext_ecpointformatlist_length;
}
#endif
case SSL_CTRL_CHECK_PROTO_VERSION:
/* For library-internal use; checks that the current protocol
* is the highest enabled version (according to s->ctx->method,
* as version negotiation may have changed s->method). */
if (s->version == s->ctx->method->version)
return 1;
/* Apparently we're using a version-flexible SSL_METHOD
* (not at its highest protocol version). */
if (s->ctx->method->version == SSLv23_method()->version)
{
#if TLS_MAX_VERSION != TLS1_2_VERSION
# error Code needs update for SSLv23_method() support beyond TLS1_2_VERSION.
#endif
if (!(s->options & SSL_OP_NO_TLSv1_2))
return s->version == TLS1_2_VERSION;
if (!(s->options & SSL_OP_NO_TLSv1_1))
return s->version == TLS1_1_VERSION;
if (!(s->options & SSL_OP_NO_TLSv1))
return s->version == TLS1_VERSION;
if (!(s->options & SSL_OP_NO_SSLv3))
return s->version == SSL3_VERSION;
if (!(s->options & SSL_OP_NO_SSLv2))
return s->version == SSL2_VERSION;
}
return 0; /* Unexpected state; fail closed. */
default:
break;
}
@ -4844,4 +4871,3 @@ long ssl_get_algorithm2(SSL *s)
return SSL_HANDSHAKE_MAC_SHA256 | TLS1_PRF_SHA256;
return alg2;
}

12
ssl/ssl.h
View File

@ -685,6 +685,10 @@ struct ssl_session_st
*/
#define SSL_MODE_SEND_CLIENTHELLO_TIME 0x00000020L
#define SSL_MODE_SEND_SERVERHELLO_TIME 0x00000040L
/* Send TLS_FALLBACK_SCSV in the ClientHello.
* To be set by applications that reconnect with a downgraded protocol
* version; see draft-ietf-tls-downgrade-scsv-00 for details. */
#define SSL_MODE_SEND_FALLBACK_SCSV 0x00000080L
/* Cert related flags */
/* Many implementations ignore some aspects of the TLS standards such as
@ -1693,6 +1697,7 @@ DECLARE_PEM_rw(SSL_SESSION, SSL_SESSION)
#define SSL_AD_BAD_CERTIFICATE_STATUS_RESPONSE TLS1_AD_BAD_CERTIFICATE_STATUS_RESPONSE
#define SSL_AD_BAD_CERTIFICATE_HASH_VALUE TLS1_AD_BAD_CERTIFICATE_HASH_VALUE
#define SSL_AD_UNKNOWN_PSK_IDENTITY TLS1_AD_UNKNOWN_PSK_IDENTITY /* fatal */
#define SSL_AD_INAPPROPRIATE_FALLBACK TLS1_AD_INAPPROPRIATE_FALLBACK /* fatal */
#define SSL_ERROR_NONE 0
#define SSL_ERROR_SSL 1
@ -1832,11 +1837,14 @@ DECLARE_PEM_rw(SSL_SESSION, SSL_SESSION)
#define SSL_CTRL_SELECT_CURRENT_CERT 116
#define SSL_CTRL_SET_CURRENT_CERT 117
#define SSL_CTRL_SET_DH_AUTO 118
#define SSL_CTRL_CHECK_PROTO_VERSION 119
#define SSL_CERT_SET_FIRST 1
#define SSL_CERT_SET_NEXT 2
#define SSL_CERT_SET_SERVER 3
#define SSL_CTRL_SET_DH_AUTO 118
#define DTLSv1_get_timeout(ssl, arg) \
SSL_ctrl(ssl,DTLS_CTRL_GET_TIMEOUT,0, (void *)arg)
@ -2869,6 +2877,7 @@ void ERR_load_SSL_strings(void);
#define SSL_R_HTTP_REQUEST 156
#define SSL_R_ILLEGAL_PADDING 283
#define SSL_R_ILLEGAL_SUITEB_DIGEST 380
#define SSL_R_INAPPROPRIATE_FALLBACK 373
#define SSL_R_INCONSISTENT_COMPRESSION 340
#define SSL_R_INVALID_CHALLENGE_LENGTH 158
#define SSL_R_INVALID_COMMAND 280
@ -3027,6 +3036,7 @@ void ERR_load_SSL_strings(void);
#define SSL_R_TLSV1_ALERT_DECRYPTION_FAILED 1021
#define SSL_R_TLSV1_ALERT_DECRYPT_ERROR 1051
#define SSL_R_TLSV1_ALERT_EXPORT_RESTRICTION 1060
#define SSL_R_TLSV1_ALERT_INAPPROPRIATE_FALLBACK 1086
#define SSL_R_TLSV1_ALERT_INSUFFICIENT_SECURITY 1071
#define SSL_R_TLSV1_ALERT_INTERNAL_ERROR 1080
#define SSL_R_TLSV1_ALERT_NO_RENEGOTIATION 1100

7
ssl/ssl3.h
View File

@ -128,9 +128,14 @@
extern "C" {
#endif
/* Signalling cipher suite value: from draft-ietf-tls-renegotiation-03.txt */
/* Signalling cipher suite value from RFC 5746
* (TLS_EMPTY_RENEGOTIATION_INFO_SCSV) */
#define SSL3_CK_SCSV 0x030000FF
/* Signalling cipher suite value from draft-ietf-tls-downgrade-scsv-00
* (TLS_FALLBACK_SCSV) */
#define SSL3_CK_FALLBACK_SCSV 0x03005600
#define SSL3_CK_RSA_NULL_MD5 0x03000001
#define SSL3_CK_RSA_NULL_SHA 0x03000002
#define SSL3_CK_RSA_RC4_40_MD5 0x03000003

2
ssl/ssl_err.c
View File

@ -404,6 +404,7 @@ static ERR_STRING_DATA SSL_str_reasons[]=
{ERR_REASON(SSL_R_HTTP_REQUEST) ,"http request"},
{ERR_REASON(SSL_R_ILLEGAL_PADDING) ,"illegal padding"},
{ERR_REASON(SSL_R_ILLEGAL_SUITEB_DIGEST) ,"illegal Suite B digest"},
{ERR_REASON(SSL_R_INAPPROPRIATE_FALLBACK),"inappropriate fallback"},
{ERR_REASON(SSL_R_INCONSISTENT_COMPRESSION),"inconsistent compression"},
{ERR_REASON(SSL_R_INVALID_CHALLENGE_LENGTH),"invalid challenge length"},
{ERR_REASON(SSL_R_INVALID_COMMAND) ,"invalid command"},
@ -562,6 +563,7 @@ static ERR_STRING_DATA SSL_str_reasons[]=
{ERR_REASON(SSL_R_TLSV1_ALERT_DECRYPTION_FAILED),"tlsv1 alert decryption failed"},
{ERR_REASON(SSL_R_TLSV1_ALERT_DECRYPT_ERROR),"tlsv1 alert decrypt error"},
{ERR_REASON(SSL_R_TLSV1_ALERT_EXPORT_RESTRICTION),"tlsv1 alert export restriction"},
{ERR_REASON(SSL_R_TLSV1_ALERT_INAPPROPRIATE_FALLBACK),"tlsv1 alert inappropriate fallback"},
{ERR_REASON(SSL_R_TLSV1_ALERT_INSUFFICIENT_SECURITY),"tlsv1 alert insufficient security"},
{ERR_REASON(SSL_R_TLSV1_ALERT_INTERNAL_ERROR),"tlsv1 alert internal error"},
{ERR_REASON(SSL_R_TLSV1_ALERT_NO_RENEGOTIATION),"tlsv1 alert no renegotiation"},

63
ssl/ssl_lib.c
View File

@ -1491,12 +1491,14 @@ int ssl_cipher_list_to_bytes(SSL *s,STACK_OF(SSL_CIPHER) *sk,unsigned char *p,
int i,j=0;
SSL_CIPHER *c;
unsigned char *q;
int no_scsv = s->renegotiate;
int empty_reneg_info_scsv = !s->renegotiate;
/* Set disabled masks for this session */
ssl_set_client_disabled(s);
if (sk == NULL) return(0);
q=p;
if (put_cb == NULL)
put_cb = s->method->put_cipher_by_char;
for (i=0; i<sk_SSL_CIPHER_num(sk); i++)
{
@ -1507,29 +1509,40 @@ int ssl_cipher_list_to_bytes(SSL *s,STACK_OF(SSL_CIPHER) *sk,unsigned char *p,
#ifdef OPENSSL_SSL_DEBUG_BROKEN_PROTOCOL
if (c->id == SSL3_CK_SCSV)
{
if (no_scsv)
if (!empty_reneg_info_scsv)
continue;
else
no_scsv = 1;
empty_reneg_info_scsv = 0;
}
#endif
j = put_cb ? put_cb(c,p) : ssl_put_cipher_by_char(s,c,p);
j = put_cb(c,p);
p+=j;
}
/* If p == q, no ciphers and caller indicates an error. Otherwise
* add SCSV if not renegotiating.
*/
if (p != q && !no_scsv)
/* If p == q, no ciphers; caller indicates an error.
* Otherwise, add applicable SCSVs. */
if (p != q)
{
static SSL_CIPHER scsv =
if (empty_reneg_info_scsv)
{
0, NULL, SSL3_CK_SCSV, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
j = put_cb ? put_cb(&scsv,p) : ssl_put_cipher_by_char(s,&scsv,p);
p+=j;
static SSL_CIPHER scsv =
{
0, NULL, SSL3_CK_SCSV, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
j = put_cb(&scsv,p);
p+=j;
#ifdef OPENSSL_RI_DEBUG
fprintf(stderr, "SCSV sent by client\n");
fprintf(stderr, "TLS_EMPTY_RENEGOTIATION_INFO_SCSV sent by client\n");
#endif
}
if (s->mode & SSL_MODE_SEND_FALLBACK_SCSV)
{
static SSL_CIPHER scsv =
{
0, NULL, SSL3_CK_FALLBACK_SCSV, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
j = put_cb(&scsv,p);
p+=j;
}
}
return(p-q);
@ -1541,11 +1554,12 @@ STACK_OF(SSL_CIPHER) *ssl_bytes_to_cipher_list(SSL *s,unsigned char *p,int num,
const SSL_CIPHER *c;
STACK_OF(SSL_CIPHER) *sk;
int i,n;
if (s->s3)
s->s3->send_connection_binding = 0;
n=ssl_put_cipher_by_char(s,NULL,NULL);
if ((num%n) != 0)
if (n == 0 || (num%n) != 0)
{
SSLerr(SSL_F_SSL_BYTES_TO_CIPHER_LIST,SSL_R_ERROR_IN_RECEIVED_CIPHER_LIST);
return(NULL);
@ -1570,7 +1584,7 @@ STACK_OF(SSL_CIPHER) *ssl_bytes_to_cipher_list(SSL *s,unsigned char *p,int num,
for (i=0; i<num; i+=n)
{
/* Check for SCSV */
/* Check for TLS_EMPTY_RENEGOTIATION_INFO_SCSV */
if (s->s3 && (n != 3 || !p[0]) &&
(p[n-2] == ((SSL3_CK_SCSV >> 8) & 0xff)) &&
(p[n-1] == (SSL3_CK_SCSV & 0xff)))
@ -1590,6 +1604,23 @@ STACK_OF(SSL_CIPHER) *ssl_bytes_to_cipher_list(SSL *s,unsigned char *p,int num,
continue;
}
/* Check for TLS_FALLBACK_SCSV */
if ((n != 3 || !p[0]) &&
(p[n-2] == ((SSL3_CK_FALLBACK_SCSV >> 8) & 0xff)) &&
(p[n-1] == (SSL3_CK_FALLBACK_SCSV & 0xff)))
{
/* The SCSV indicates that the client previously tried a higher version.
* Fail if the current version is an unexpected downgrade. */
if (!SSL_ctrl(s, SSL_CTRL_CHECK_PROTO_VERSION, 0, NULL))
{
SSLerr(SSL_F_SSL_BYTES_TO_CIPHER_LIST,SSL_R_INAPPROPRIATE_FALLBACK);
if (s->s3)
ssl3_send_alert(s,SSL3_AL_FATAL,SSL_AD_INAPPROPRIATE_FALLBACK);
goto err;
}
continue;
}
c=ssl_get_cipher_by_char(s,p);
p+=n;
if (c != NULL)

1
ssl/t1_enc.c
View File

@ -1278,6 +1278,7 @@ int tls1_alert_code(int code)
case SSL_AD_BAD_CERTIFICATE_STATUS_RESPONSE: return(TLS1_AD_BAD_CERTIFICATE_STATUS_RESPONSE);
case SSL_AD_BAD_CERTIFICATE_HASH_VALUE: return(TLS1_AD_BAD_CERTIFICATE_HASH_VALUE);
case SSL_AD_UNKNOWN_PSK_IDENTITY:return(TLS1_AD_UNKNOWN_PSK_IDENTITY);
case SSL_AD_INAPPROPRIATE_FALLBACK:return(TLS1_AD_INAPPROPRIATE_FALLBACK);
#if 0 /* not appropriate for TLS, not used for DTLS */
case DTLS1_AD_MISSING_HANDSHAKE_MESSAGE: return
(DTLS1_AD_MISSING_HANDSHAKE_MESSAGE);

17
ssl/tls1.h
View File

@ -164,17 +164,19 @@ extern "C" {
#define TLS1_ALLOW_EXPERIMENTAL_CIPHERSUITES 0
#define TLS1_2_VERSION 0x0303
#define TLS1_2_VERSION_MAJOR 0x03
#define TLS1_2_VERSION_MINOR 0x03
#define TLS1_VERSION 0x0301
#define TLS1_1_VERSION 0x0302
#define TLS1_2_VERSION 0x0303
#define TLS_MAX_VERSION TLS1_2_VERSION
#define TLS1_VERSION_MAJOR 0x03
#define TLS1_VERSION_MINOR 0x01
#define TLS1_1_VERSION_MAJOR 0x03
#define TLS1_1_VERSION_MINOR 0x02
#define TLS1_VERSION 0x0301
#define TLS1_VERSION_MAJOR 0x03
#define TLS1_VERSION_MINOR 0x01
#define TLS1_2_VERSION_MAJOR 0x03
#define TLS1_2_VERSION_MINOR 0x03
#define TLS1_get_version(s) \
((s->version >> 8) == TLS1_VERSION_MAJOR ? s->version : 0)
@ -192,6 +194,7 @@ extern "C" {
#define TLS1_AD_PROTOCOL_VERSION 70 /* fatal */
#define TLS1_AD_INSUFFICIENT_SECURITY 71 /* fatal */
#define TLS1_AD_INTERNAL_ERROR 80 /* fatal */
#define TLS1_AD_INAPPROPRIATE_FALLBACK 86 /* fatal */
#define TLS1_AD_USER_CANCELLED 90
#define TLS1_AD_NO_RENEGOTIATION 100
/* codes 110-114 are from RFC3546 */