Disable EXPORT and LOW SSLv3+ ciphers by default

Reviewed-by: Emilia Käsper <emilia@openssl.org>

CHANGES

@@ -4,6 +4,11 @@
 
  Changes between 1.0.1r and 1.0.1s [xx XXX xxxx]
 
+  * Disable weak ciphers in SSLv3 and up in default builds of OpenSSL.
+    Builds that are not configured with "enable-weak-ssl-ciphers" will not
+    provide any "EXPORT" or "LOW" strength ciphers.
+    [Viktor Dukhovni]
+
   * Disable SSLv2 default build, default negotiation and weak ciphers.  SSLv2
     is by default disabled at build-time.  Builds that are not configured with
     "enable-ssl2" will not support SSLv2.  Even if "enable-ssl2" is used,

Configure

@@ -58,6 +58,10 @@ my $usage="Usage: Configure [no-<cipher> ...] [enable-<cipher> ...] [experimenta
 #		library and will be loaded in run-time by the OpenSSL library.
 # sctp          include SCTP support
 # 386           generate 80386 code
+# enable-weak-ssl-ciphers
+#		Enable EXPORT and LOW SSLv3 ciphers that are disabled by
+#		default.  Note, weak SSLv2 ciphers are unconditionally
+#		disabled.
 # no-sse2	disables IA-32 SSE2 code, above option implies no-sse2
 # no-<cipher>   build without specified algorithm (rsa, idea, rc5, ...)
 # -<xxx> +<xxx> compiler options are passed through 
@@ -729,6 +733,7 @@ my %disabled = ( # "what"         => "comment" [or special keyword "experimental
 		 "ssl2"           => "default",
 		 "store"	  => "experimental",
 		 "unit-test"	  => "default",
+		 "weak-ssl-ciphers" => "default",
 		 "zlib"           => "default",
 		 "zlib-dynamic"   => "default"
 	       );

NEWS

@@ -7,6 +7,7 @@
 
   Major changes between OpenSSL 1.0.1r and OpenSSL 1.0.1s [under development]
 
+      o Disable weak ciphers in SSLv3 and up in default builds of OpenSSL.
       o Disable SSLv2 default build, default negotiation and weak ciphers.
 
   Major changes between OpenSSL 1.0.1q and OpenSSL 1.0.1r [28 Jan 2016]

doc/apps/ciphers.pod

@@ -136,34 +136,46 @@ than 128 bits, and some cipher suites with 128-bit keys.
 
 =item B<LOW>
 
-"low" encryption cipher suites, currently those using 64 or 56 bit encryption algorithms
+Low strength encryption cipher suites, currently those using 64 or 56 bit
-but excluding export cipher suites.
+encryption algorithms but excluding export cipher suites.
+As of OpenSSL 1.0.1s, these are disabled in default builds.
 
 =item B<EXP>, B<EXPORT>
 
-export encryption algorithms. Including 40 and 56 bits algorithms.
+Export strength encryption algorithms. Including 40 and 56 bits algorithms.
+As of OpenSSL 1.0.1s, these are disabled in default builds.
 
 =item B<EXPORT40>
 
-40 bit export encryption algorithms
+40-bit export encryption algorithms
+As of OpenSSL 1.0.1s, these are disabled in default builds.
 
 =item B<EXPORT56>
 
-56 bit export encryption algorithms. In OpenSSL 0.9.8c and later the set of
+56-bit export encryption algorithms. In OpenSSL 0.9.8c and later the set of
 56 bit export ciphers is empty unless OpenSSL has been explicitly configured
 with support for experimental ciphers.
+As of OpenSSL 1.0.1s, these are disabled in default builds.
 
 =item B<eNULL>, B<NULL>
 
-the "NULL" ciphers that is those offering no encryption. Because these offer no
+The "NULL" ciphers that is those offering no encryption. Because these offer no
-encryption at all and are a security risk they are disabled unless explicitly
+encryption at all and are a security risk they are not enabled via either the
-included.
+B<DEFAULT> or B<ALL> cipher strings.
+Be careful when building cipherlists out of lower-level primitives such as
+B<kRSA> or B<aECDSA> as these do overlap with the B<eNULL> ciphers.
+When in doubt, include B<!eNULL> in your cipherlist.
 
 =item B<aNULL>
 
-the cipher suites offering no authentication. This is currently the anonymous
+The cipher suites offering no authentication. This is currently the anonymous
 DH algorithms and anonymous ECDH algorithms. These cipher suites are vulnerable
 to a "man in the middle" attack and so their use is normally discouraged.
+These are excluded from the B<DEFAULT> ciphers, but included in the B<ALL>
+ciphers.
+Be careful when building cipherlists out of lower-level primitives such as
+B<kDHE> or B<AES> as these do overlap with the B<aNULL> ciphers.
+When in doubt, include B<!aNULL> in your cipherlist.
 
 =item B<kRSA>, B<RSA>
 

ssl/s3_lib.c

@@ -203,6 +203,7 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      },
 
 /* Cipher 03 */
+#ifndef OPENSSL_NO_WEAK_SSL_CIPHERS
     {
      1,
      SSL3_TXT_RSA_RC4_40_MD5,
@@ -217,6 +218,7 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      40,
      128,
      },
+#endif
 
 /* Cipher 04 */
     {
@@ -251,6 +253,7 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      },
 
 /* Cipher 06 */
+#ifndef OPENSSL_NO_WEAK_SSL_CIPHERS
     {
      1,
      SSL3_TXT_RSA_RC2_40_MD5,
@@ -265,6 +268,7 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      40,
      128,
      },
+#endif
 
 /* Cipher 07 */
 #ifndef OPENSSL_NO_IDEA
@@ -285,6 +289,7 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
 #endif
 
 /* Cipher 08 */
+#ifndef OPENSSL_NO_WEAK_SSL_CIPHERS
     {
      1,
      SSL3_TXT_RSA_DES_40_CBC_SHA,
@@ -299,8 +304,10 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      40,
      56,
      },
+#endif
 
 /* Cipher 09 */
+#ifndef OPENSSL_NO_WEAK_SSL_CIPHERS
     {
      1,
      SSL3_TXT_RSA_DES_64_CBC_SHA,
@@ -315,6 +322,7 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      56,
      56,
      },
+#endif
 
 /* Cipher 0A */
     {
@@ -334,6 +342,7 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
 
 /* The DH ciphers */
 /* Cipher 0B */
+#ifndef OPENSSL_NO_WEAK_SSL_CIPHERS
     {
      0,
      SSL3_TXT_DH_DSS_DES_40_CBC_SHA,
@@ -348,8 +357,10 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      40,
      56,
      },
+#endif
 
 /* Cipher 0C */
+#ifndef OPENSSL_NO_WEAK_SSL_CIPHERS
     {
      0,                         /* not implemented (non-ephemeral DH) */
      SSL3_TXT_DH_DSS_DES_64_CBC_SHA,
@@ -364,6 +375,7 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      56,
      56,
      },
+#endif
 
 /* Cipher 0D */
     {
@@ -382,6 +394,7 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      },
 
 /* Cipher 0E */
+#ifndef OPENSSL_NO_WEAK_SSL_CIPHERS
     {
      0,                         /* not implemented (non-ephemeral DH) */
      SSL3_TXT_DH_RSA_DES_40_CBC_SHA,
@@ -396,8 +409,10 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      40,
      56,
      },
+#endif
 
 /* Cipher 0F */
+#ifndef OPENSSL_NO_WEAK_SSL_CIPHERS
     {
      0,                         /* not implemented (non-ephemeral DH) */
      SSL3_TXT_DH_RSA_DES_64_CBC_SHA,
@@ -412,6 +427,7 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      56,
      56,
      },
+#endif
 
 /* Cipher 10 */
     {
@@ -431,6 +447,7 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
 
 /* The Ephemeral DH ciphers */
 /* Cipher 11 */
+#ifndef OPENSSL_NO_WEAK_SSL_CIPHERS
     {
      1,
      SSL3_TXT_EDH_DSS_DES_40_CBC_SHA,
@@ -445,8 +462,10 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      40,
      56,
      },
+#endif
 
 /* Cipher 12 */
+#ifndef OPENSSL_NO_WEAK_SSL_CIPHERS
     {
      1,
      SSL3_TXT_EDH_DSS_DES_64_CBC_SHA,
@@ -461,6 +480,7 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      56,
      56,
      },
+#endif
 
 /* Cipher 13 */
     {
@@ -479,6 +499,7 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      },
 
 /* Cipher 14 */
+#ifndef OPENSSL_NO_WEAK_SSL_CIPHERS
     {
      1,
      SSL3_TXT_EDH_RSA_DES_40_CBC_SHA,
@@ -493,8 +514,10 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      40,
      56,
      },
+#endif
 
 /* Cipher 15 */
+#ifndef OPENSSL_NO_WEAK_SSL_CIPHERS
     {
      1,
      SSL3_TXT_EDH_RSA_DES_64_CBC_SHA,
@@ -509,6 +532,7 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      56,
      56,
      },
+#endif
 
 /* Cipher 16 */
     {
@@ -527,6 +551,7 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      },
 
 /* Cipher 17 */
+#ifndef OPENSSL_NO_WEAK_SSL_CIPHERS
     {
      1,
      SSL3_TXT_ADH_RC4_40_MD5,
@@ -541,6 +566,7 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      40,
      128,
      },
+#endif
 
 /* Cipher 18 */
     {
@@ -559,6 +585,7 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      },
 
 /* Cipher 19 */
+#ifndef OPENSSL_NO_WEAK_SSL_CIPHERS
     {
      1,
      SSL3_TXT_ADH_DES_40_CBC_SHA,
@@ -573,8 +600,10 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      40,
      128,
      },
+#endif
 
 /* Cipher 1A */
+#ifndef OPENSSL_NO_WEAK_SSL_CIPHERS
     {
      1,
      SSL3_TXT_ADH_DES_64_CBC_SHA,
@@ -589,6 +618,7 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      56,
      56,
      },
+#endif
 
 /* Cipher 1B */
     {
@@ -660,6 +690,7 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
 #ifndef OPENSSL_NO_KRB5
 /* The Kerberos ciphers*/
 /* Cipher 1E */
+# ifndef OPENSSL_NO_WEAK_SSL_CIPHERS
     {
      1,
      SSL3_TXT_KRB5_DES_64_CBC_SHA,
@@ -674,6 +705,7 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      56,
      56,
      },
+# endif
 
 /* Cipher 1F */
     {
@@ -724,6 +756,7 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      },
 
 /* Cipher 22 */
+# ifndef OPENSSL_NO_WEAK_SSL_CIPHERS
     {
      1,
      SSL3_TXT_KRB5_DES_64_CBC_MD5,
@@ -738,6 +771,7 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      56,
      56,
      },
+# endif
 
 /* Cipher 23 */
     {
@@ -788,6 +822,7 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      },
 
 /* Cipher 26 */
+# ifndef OPENSSL_NO_WEAK_SSL_CIPHERS
     {
      1,
      SSL3_TXT_KRB5_DES_40_CBC_SHA,
@@ -802,8 +837,10 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      40,
      56,
      },
+# endif
 
 /* Cipher 27 */
+# ifndef OPENSSL_NO_WEAK_SSL_CIPHERS
     {
      1,
      SSL3_TXT_KRB5_RC2_40_CBC_SHA,
@@ -818,8 +855,10 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      40,
      128,
      },
+# endif
 
 /* Cipher 28 */
+# ifndef OPENSSL_NO_WEAK_SSL_CIPHERS
     {
      1,
      SSL3_TXT_KRB5_RC4_40_SHA,
@@ -834,8 +873,10 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      40,
      128,
      },
+# endif
 
 /* Cipher 29 */
+# ifndef OPENSSL_NO_WEAK_SSL_CIPHERS
     {
      1,
      SSL3_TXT_KRB5_DES_40_CBC_MD5,
@@ -850,8 +891,10 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      40,
      56,
      },
+# endif
 
 /* Cipher 2A */
+# ifndef OPENSSL_NO_WEAK_SSL_CIPHERS
     {
      1,
      SSL3_TXT_KRB5_RC2_40_CBC_MD5,
@@ -866,8 +909,10 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      40,
      128,
      },
+# endif
 
 /* Cipher 2B */
+# ifndef OPENSSL_NO_WEAK_SSL_CIPHERS
     {
      1,
      SSL3_TXT_KRB5_RC4_40_MD5,
@@ -882,6 +927,7 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      40,
      128,
      },
+# endif
 #endif                          /* OPENSSL_NO_KRB5 */
 
 /* New AES ciphersuites */
@@ -1305,6 +1351,7 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
 # endif
 
     /* Cipher 62 */
+# ifndef OPENSSL_NO_WEAK_SSL_CIPHERS
     {
      1,
      TLS1_TXT_RSA_EXPORT1024_WITH_DES_CBC_SHA,
@@ -1319,8 +1366,10 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      56,
      56,
      },
+# endif
 
     /* Cipher 63 */
+# ifndef OPENSSL_NO_WEAK_SSL_CIPHERS
     {
      1,
      TLS1_TXT_DHE_DSS_EXPORT1024_WITH_DES_CBC_SHA,
@@ -1335,8 +1384,10 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      56,
      56,
      },
+# endif
 
     /* Cipher 64 */
+# ifndef OPENSSL_NO_WEAK_SSL_CIPHERS
     {
      1,
      TLS1_TXT_RSA_EXPORT1024_WITH_RC4_56_SHA,
@@ -1351,8 +1402,10 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      56,
      128,
      },
+# endif
 
     /* Cipher 65 */
+# ifndef OPENSSL_NO_WEAK_SSL_CIPHERS
     {
      1,
      TLS1_TXT_DHE_DSS_EXPORT1024_WITH_RC4_56_SHA,
@@ -1367,6 +1420,7 @@ OPENSSL_GLOBAL SSL_CIPHER ssl3_ciphers[] = {
      56,
      128,
      },
+# endif
 
     /* Cipher 66 */
     {