Add ssl_set_arc4_support()
Rationale: if people want to disable RC4 but otherwise keep the default suite
list, it was cumbersome. Also, since it uses a global array,
ssl_list_ciphersuite() is not a convenient place. So the SSL modules look like
the best place, even if it means temporarily adding one SSL setting.
diff --git a/ChangeLog b/ChangeLog
index 255d359..a965f8d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -4,6 +4,10 @@
Changes
* Example programs for SSL client and server now disable SSLv3 by default.
+Features
+ * Add ssl_set_arc4_support() to make it easier to diable RC4 at runtime
+ while using the default ciphersuite list.
+
= PolarSSL 1.3.9 released 2014-10-20
Security
* Lowest common hash was selected from signature_algorithms extension in
diff --git a/include/polarssl/ssl.h b/include/polarssl/ssl.h
index 4cabf7c..7943d14 100644
--- a/include/polarssl/ssl.h
+++ b/include/polarssl/ssl.h
@@ -238,6 +238,9 @@
#define SSL_SESSION_TICKETS_DISABLED 0
#define SSL_SESSION_TICKETS_ENABLED 1
+#define SSL_ARC4_ENABLED 0
+#define SSL_ARC4_DISABLED 1
+
/**
* \name SECTION: Module settings
*
@@ -697,6 +700,8 @@
int min_major_ver; /*!< min. major version used */
int min_minor_ver; /*!< min. minor version used */
+ char arc4_disabled; /*!< flag for disabling RC4 */
+
/*
* Callbacks (RNG, debug, I/O, verification)
*/
@@ -1385,6 +1390,21 @@
*/
void ssl_set_min_version( ssl_context *ssl, int major, int minor );
+/**
+ * \brief Disable or enable support for RC4
+ * (Default: SSL_ARC4_ENABLED)
+ *
+ * \note Though the default is RC4 for compatibility reasons in the
+ * 1.3 branch, the recommended value is SSL_ARC4_DISABLED.
+ *
+ * \note This function will likely be removed in future versions as
+ * RC4 will then be disabled by default at compile time.
+ *
+ * \param ssl SSL context
+ * \param arc4 SSL_ARC4_ENABLED or SSL_ARC4_DISABLED
+ */
+void ssl_set_arc4_support( ssl_context *ssl, char arc4 );
+
#if defined(POLARSSL_SSL_MAX_FRAGMENT_LENGTH)
/**
* \brief Set the maximum fragment length to emit and/or negotiate
diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index 27abb3e..cf46080 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -588,6 +588,10 @@
ciphersuite_info->max_minor_ver < ssl->min_minor_ver )
continue;
+ if( ssl->arc4_disabled == SSL_ARC4_DISABLED &&
+ ciphersuite_info->cipher == POLARSSL_CIPHER_ARC4_128 )
+ continue;
+
SSL_DEBUG_MSG( 3, ( "client hello, add ciphersuite: %2d",
ciphersuites[i] ) );
@@ -879,6 +883,7 @@
unsigned char *buf, *ext;
int renegotiation_info_seen = 0;
int handshake_failure = 0;
+ const ssl_ciphersuite_t *suite_info;
#if defined(POLARSSL_DEBUG_C)
uint32_t t;
#endif
@@ -1059,6 +1064,16 @@
SSL_DEBUG_MSG( 3, ( "server hello, chosen ciphersuite: %d", i ) );
SSL_DEBUG_MSG( 3, ( "server hello, compress alg.: %d", buf[41 + n] ) );
+ suite_info = ssl_ciphersuite_from_id( ssl->session_negotiate->ciphersuite );
+ if( suite_info == NULL ||
+ ( ssl->arc4_disabled &&
+ suite_info->cipher == POLARSSL_CIPHER_ARC4_128 ) )
+ {
+ SSL_DEBUG_MSG( 1, ( "bad server hello message" ) );
+ return( POLARSSL_ERR_SSL_BAD_HS_SERVER_HELLO );
+ }
+
+
i = 0;
while( 1 )
{
diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index 01b0aca..d611920 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -847,6 +847,10 @@
suite_info->max_minor_ver < ssl->minor_ver )
return( 0 );
+ if( ssl->arc4_disabled == SSL_ARC4_DISABLED &&
+ suite_info->cipher == POLARSSL_CIPHER_ARC4_128 )
+ return( 0 );
+
#if defined(POLARSSL_ECDH_C) || defined(POLARSSL_ECDSA_C)
if( ssl_ciphersuite_uses_ec( suite_info ) &&
( ssl->handshake->curves == NULL ||
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 5f080de..a091d8a 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -3977,6 +3977,11 @@
}
}
+void ssl_set_arc4_support( ssl_context *ssl, char arc4 )
+{
+ ssl->arc4_disabled = arc4;
+}
+
#if defined(POLARSSL_SSL_MAX_FRAGMENT_LENGTH)
int ssl_set_max_frag_len( ssl_context *ssl, unsigned char mfl_code )
{
diff --git a/programs/ssl/ssl_client2.c b/programs/ssl/ssl_client2.c
index 505ce10..35771f5 100644
--- a/programs/ssl/ssl_client2.c
+++ b/programs/ssl/ssl_client2.c
@@ -88,6 +88,7 @@
#define DFL_EXCHANGES 1
#define DFL_MIN_VERSION SSL_MINOR_VERSION_1
#define DFL_MAX_VERSION -1
+#define DFL_ARC4 SSL_ARC4_DISABLED
#define DFL_AUTH_MODE SSL_VERIFY_REQUIRED
#define DFL_MFL_CODE SSL_MAX_FRAG_LEN_NONE
#define DFL_TRUNC_HMAC 0
@@ -125,6 +126,7 @@
int exchanges; /* number of data exchanges */
int min_version; /* minimum protocol version accepted */
int max_version; /* maximum protocol version accepted */
+ int arc4; /* flag for arc4 suites support */
int auth_mode; /* verify mode for connection */
unsigned char mfl_code; /* code for maximum fragment length */
int trunc_hmac; /* negotiate truncated hmac or not */
@@ -316,6 +318,7 @@
"\n" \
" min_version=%%s default: \"\" (ssl3)\n" \
" max_version=%%s default: \"\" (tls1_2)\n" \
+ " arc4=%%d default: 0 (disabled)\n" \
" force_version=%%s default: \"\" (none)\n" \
" options: ssl3, tls1, tls1_1, tls1_2\n" \
" auth_mode=%%s default: \"required\"\n" \
@@ -406,6 +409,7 @@
opt.exchanges = DFL_EXCHANGES;
opt.min_version = DFL_MIN_VERSION;
opt.max_version = DFL_MAX_VERSION;
+ opt.arc4 = DFL_ARC4;
opt.auth_mode = DFL_AUTH_MODE;
opt.mfl_code = DFL_MFL_CODE;
opt.trunc_hmac = DFL_TRUNC_HMAC;
@@ -545,6 +549,15 @@
else
goto usage;
}
+ else if( strcmp( p, "arc4" ) == 0 )
+ {
+ switch( atoi( q ) )
+ {
+ case 0: opt.arc4 = SSL_ARC4_DISABLED; break;
+ case 1: opt.arc4 = SSL_ARC4_ENABLED; break;
+ default: goto usage;
+ }
+ }
else if( strcmp( p, "force_version" ) == 0 )
{
if( strcmp( q, "ssl3" ) == 0 )
@@ -907,8 +920,11 @@
}
#endif
+ /* RC4 setting is redundant if we use only one ciphersuite */
if( opt.force_ciphersuite[0] != DFL_FORCE_CIPHER )
ssl_set_ciphersuites( &ssl, opt.force_ciphersuite );
+ else
+ ssl_set_arc4_support( &ssl, opt.arc4 );
ssl_set_renegotiation( &ssl, opt.renegotiation );
ssl_legacy_renegotiation( &ssl, opt.allow_legacy );
diff --git a/programs/ssl/ssl_server2.c b/programs/ssl/ssl_server2.c
index 3fecb47..9310ed5 100644
--- a/programs/ssl/ssl_server2.c
+++ b/programs/ssl/ssl_server2.c
@@ -107,6 +107,7 @@
#define DFL_EXCHANGES 1
#define DFL_MIN_VERSION SSL_MINOR_VERSION_1
#define DFL_MAX_VERSION -1
+#define DFL_ARC4 SSL_ARC4_DISABLED
#define DFL_AUTH_MODE SSL_VERIFY_OPTIONAL
#define DFL_MFL_CODE SSL_MAX_FRAG_LEN_NONE
#define DFL_TICKETS SSL_SESSION_TICKETS_ENABLED
@@ -167,6 +168,7 @@
int exchanges; /* number of data exchanges */
int min_version; /* minimum protocol version accepted */
int max_version; /* maximum protocol version accepted */
+ int arc4; /* flag for arc4 suites support */
int auth_mode; /* verify mode for connection */
unsigned char mfl_code; /* code for maximum fragment length */
int tickets; /* enable / disable session tickets */
@@ -327,6 +329,7 @@
"\n" \
" min_version=%%s default: \"ssl3\"\n" \
" max_version=%%s default: \"tls1_2\"\n" \
+ " arc4=%%d default: 0 (disabled)\n" \
" force_version=%%s default: \"\" (none)\n" \
" options: ssl3, tls1, tls1_1, tls1_2\n" \
"\n" \
@@ -704,6 +707,7 @@
opt.exchanges = DFL_EXCHANGES;
opt.min_version = DFL_MIN_VERSION;
opt.max_version = DFL_MAX_VERSION;
+ opt.arc4 = DFL_ARC4;
opt.auth_mode = DFL_AUTH_MODE;
opt.mfl_code = DFL_MFL_CODE;
opt.tickets = DFL_TICKETS;
@@ -827,6 +831,15 @@
else
goto usage;
}
+ else if( strcmp( p, "arc4" ) == 0 )
+ {
+ switch( atoi( q ) )
+ {
+ case 0: opt.arc4 = SSL_ARC4_DISABLED; break;
+ case 1: opt.arc4 = SSL_ARC4_ENABLED; break;
+ default: goto usage;
+ }
+ }
else if( strcmp( p, "force_version" ) == 0 )
{
if( strcmp( q, "ssl3" ) == 0 )
@@ -1293,6 +1306,8 @@
if( opt.force_ciphersuite[0] != DFL_FORCE_CIPHER )
ssl_set_ciphersuites( &ssl, opt.force_ciphersuite );
+ else
+ ssl_set_arc4_support( &ssl, opt.arc4 );
if( opt.version_suites != NULL )
{
diff --git a/tests/compat.sh b/tests/compat.sh
index 260b26f..b06c232 100755
--- a/tests/compat.sh
+++ b/tests/compat.sh
@@ -667,7 +667,7 @@
exit 1;
esac
- P_SERVER_ARGS="server_port=$PORT server_addr=0.0.0.0 force_version=$MODE"
+ P_SERVER_ARGS="server_port=$PORT server_addr=0.0.0.0 force_version=$MODE arc4=1"
O_SERVER_ARGS="-accept $PORT -www -cipher NULL,ALL -$MODE"
G_SERVER_ARGS="-p $PORT --http"
G_SERVER_PRIO="EXPORT:+NULL:+MD5:+PSK:+DHE-PSK:+ECDHE-PSK:+RSA-PSK:-VERS-TLS-ALL:$G_PRIO_MODE"
diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index 361d393..bb8bd62 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -393,6 +393,26 @@
-S "error" \
-C "error"
+# Tests for rc4 option
+
+run_test "RC4: server disabled, client enabled" \
+ "$P_SRV" \
+ "$P_CLI force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA" \
+ 1 \
+ -s "SSL - The server has no ciphersuites in common"
+
+run_test "RC4: server enabled, client disabled" \
+ "$P_SRV force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA" \
+ "$P_CLI" \
+ 1 \
+ -s "SSL - The server has no ciphersuites in common"
+
+run_test "RC4: both enabled" \
+ "$P_SRV arc4=1" \
+ "$P_CLI force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA" \
+ 0 \
+ -S "SSL - The server has no ciphersuites in common"
+
# Test for SSLv2 ClientHello
requires_openssl_with_sslv2
@@ -1575,8 +1595,8 @@
-c "Ciphersuite is TLS-RSA-WITH-3DES-EDE-CBC-SHA"
run_test "Per-version suites: TLS 1.0" \
- "$P_SRV version_suites=TLS-RSA-WITH-3DES-EDE-CBC-SHA,TLS-RSA-WITH-RC4-128-SHA,TLS-RSA-WITH-AES-128-CBC-SHA,TLS-RSA-WITH-AES-128-GCM-SHA256" \
- "$P_CLI force_version=tls1" \
+ "$P_SRV arc4=1 version_suites=TLS-RSA-WITH-3DES-EDE-CBC-SHA,TLS-RSA-WITH-RC4-128-SHA,TLS-RSA-WITH-AES-128-CBC-SHA,TLS-RSA-WITH-AES-128-GCM-SHA256" \
+ "$P_CLI force_version=tls1 arc4=1" \
0 \
-c "Ciphersuite is TLS-RSA-WITH-RC4-128-SHA"
@@ -1616,7 +1636,7 @@
-s "Read from client: 1 bytes read"
run_test "Small packet SSLv3 StreamCipher" \
- "$P_SRV min_version=ssl3" \
+ "$P_SRV min_version=ssl3 arc4=1" \
"$P_CLI request_size=1 force_version=ssl3 \
force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA" \
0 \
@@ -1638,7 +1658,7 @@
-s "Read from client: 1 bytes read"
run_test "Small packet TLS 1.0 StreamCipher truncated MAC" \
- "$P_SRV" \
+ "$P_SRV arc4=1" \
"$P_CLI request_size=1 force_version=tls1 \
force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA \
trunc_hmac=1" \
@@ -1653,7 +1673,7 @@
-s "Read from client: 1 bytes read"
run_test "Small packet TLS 1.1 StreamCipher" \
- "$P_SRV" \
+ "$P_SRV arc4=1" \
"$P_CLI request_size=1 force_version=tls1_1 \
force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA" \
0 \
@@ -1668,7 +1688,7 @@
-s "Read from client: 1 bytes read"
run_test "Small packet TLS 1.1 StreamCipher truncated MAC" \
- "$P_SRV" \
+ "$P_SRV arc4=1" \
"$P_CLI request_size=1 force_version=tls1_1 \
force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA \
trunc_hmac=1" \
@@ -1697,14 +1717,14 @@
-s "Read from client: 1 bytes read"
run_test "Small packet TLS 1.2 StreamCipher" \
- "$P_SRV" \
+ "$P_SRV arc4=1" \
"$P_CLI request_size=1 force_version=tls1_2 \
force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA" \
0 \
-s "Read from client: 1 bytes read"
run_test "Small packet TLS 1.2 StreamCipher truncated MAC" \
- "$P_SRV" \
+ "$P_SRV arc4=1" \
"$P_CLI request_size=1 force_version=tls1_2 \
force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA \
trunc_hmac=1" \
@@ -1735,7 +1755,7 @@
-s "Read from client: 16384 bytes read"
run_test "Large packet SSLv3 StreamCipher" \
- "$P_SRV min_version=ssl3" \
+ "$P_SRV min_version=ssl3 arc4=1" \
"$P_CLI request_size=16384 force_version=ssl3 \
force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA" \
0 \
@@ -1757,7 +1777,7 @@
-s "Read from client: 16384 bytes read"
run_test "Large packet TLS 1.0 StreamCipher truncated MAC" \
- "$P_SRV" \
+ "$P_SRV arc4=1" \
"$P_CLI request_size=16384 force_version=tls1 \
force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA \
trunc_hmac=1" \
@@ -1772,7 +1792,7 @@
-s "Read from client: 16384 bytes read"
run_test "Large packet TLS 1.1 StreamCipher" \
- "$P_SRV" \
+ "$P_SRV arc4=1" \
"$P_CLI request_size=16384 force_version=tls1_1 \
force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA" \
0 \
@@ -1787,7 +1807,7 @@
-s "Read from client: 16384 bytes read"
run_test "Large packet TLS 1.1 StreamCipher truncated MAC" \
- "$P_SRV" \
+ "$P_SRV arc4=1" \
"$P_CLI request_size=16384 force_version=tls1_1 \
force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA \
trunc_hmac=1" \
@@ -1816,14 +1836,14 @@
-s "Read from client: 16384 bytes read"
run_test "Large packet TLS 1.2 StreamCipher" \
- "$P_SRV" \
+ "$P_SRV arc4=1" \
"$P_CLI request_size=16384 force_version=tls1_2 \
force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA" \
0 \
-s "Read from client: 16384 bytes read"
run_test "Large packet TLS 1.2 StreamCipher truncated MAC" \
- "$P_SRV" \
+ "$P_SRV arc4=1" \
"$P_CLI request_size=16384 force_version=tls1_2 \
force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA \
trunc_hmac=1" \