diff options
| -rw-r--r-- | CHANGES | 8 | ||||
| -rw-r--r-- | doc/ssl/SSL_CTX_set_options.pod | 10 | ||||
| -rw-r--r-- | doc/ssl/SSL_CTX_set_tmp_rsa_callback.pod | 23 | ||||
| -rw-r--r-- | ssl/d1_srvr.c | 21 | ||||
| -rw-r--r-- | ssl/s3_clnt.c | 7 | ||||
| -rw-r--r-- | ssl/s3_srvr.c | 21 | ||||
| -rw-r--r-- | ssl/ssl.h | 5 |
7 files changed, 38 insertions, 57 deletions
@@ -666,6 +666,14 @@ (CVE-2014-3572) [Steve Henson] + *) Remove non-export ephemeral RSA code on client and server. This code + violated the TLS standard by allowing the use of temporary RSA keys in + non-export ciphersuites and could be used by a server to effectively + downgrade the RSA key length used to a value smaller than the server + certificate. Thanks for Karthikeyan Bhargavan for reporting this issue. + (CVE-2015-0204) + [Steve Henson] + *) Ensure that the session ID context of an SSL is updated when its SSL_CTX is updated via SSL_set_SSL_CTX. diff --git a/doc/ssl/SSL_CTX_set_options.pod b/doc/ssl/SSL_CTX_set_options.pod index 1594fb6eec..593435c493 100644 --- a/doc/ssl/SSL_CTX_set_options.pod +++ b/doc/ssl/SSL_CTX_set_options.pod @@ -151,15 +151,7 @@ temporary/ephemeral DH parameters are used. =item SSL_OP_EPHEMERAL_RSA -Always use ephemeral (temporary) RSA key when doing RSA operations -(see L<SSL_CTX_set_tmp_rsa_callback(3)|SSL_CTX_set_tmp_rsa_callback(3)>). -According to the specifications this is only done, when a RSA key -can only be used for signature operations (namely under export ciphers -with restricted RSA keylength). By setting this option, ephemeral -RSA keys are always used. This option breaks compatibility with the -SSL/TLS specifications and may lead to interoperability problems with -clients and should therefore never be used. Ciphers with DHE (ephemeral -Diffie-Hellman) key exchange should be used instead. +This option is no longer implemented and is treated as no op. =item SSL_OP_CIPHER_SERVER_PREFERENCE diff --git a/doc/ssl/SSL_CTX_set_tmp_rsa_callback.pod b/doc/ssl/SSL_CTX_set_tmp_rsa_callback.pod index b23e43a963..94c55b8045 100644 --- a/doc/ssl/SSL_CTX_set_tmp_rsa_callback.pod +++ b/doc/ssl/SSL_CTX_set_tmp_rsa_callback.pod @@ -74,21 +74,14 @@ exchange and use DHE (Ephemeral Diffie-Hellman) key exchange instead in order to achieve forward secrecy (see L<SSL_CTX_set_tmp_dh_callback(3)|SSL_CTX_set_tmp_dh_callback(3)>). -On OpenSSL servers ephemeral RSA key exchange is therefore disabled by default -and must be explicitly enabled using the SSL_OP_EPHEMERAL_RSA option of -L<SSL_CTX_set_options(3)|SSL_CTX_set_options(3)>, violating the TLS/SSL -standard. When ephemeral RSA key exchange is required for export ciphers, -it will automatically be used without this option! - -An application may either directly specify the key or can supply the key via -a callback function. The callback approach has the advantage, that the -callback may generate the key only in case it is actually needed. As the -generation of a RSA key is however costly, it will lead to a significant -delay in the handshake procedure. Another advantage of the callback function -is that it can supply keys of different size (e.g. for SSL_OP_EPHEMERAL_RSA -usage) while the explicit setting of the key is only useful for key size of -512 bits to satisfy the export restricted ciphers and does give away key length -if a longer key would be allowed. +An application may either directly specify the key or can supply the key via a +callback function. The callback approach has the advantage, that the callback +may generate the key only in case it is actually needed. As the generation of a +RSA key is however costly, it will lead to a significant delay in the handshake +procedure. Another advantage of the callback function is that it can supply +keys of different size while the explicit setting of the key is only useful for +key size of 512 bits to satisfy the export restricted ciphers and does give +away key length if a longer key would be allowed. The B<tmp_rsa_callback> is called with the B<keylength> needed and the B<is_export> information. The B<is_export> flag is set, when the diff --git a/ssl/d1_srvr.c b/ssl/d1_srvr.c index bcadd310fd..8a5c5a1cd2 100644 --- a/ssl/d1_srvr.c +++ b/ssl/d1_srvr.c @@ -472,24 +472,15 @@ int dtls1_accept(SSL *s) case SSL3_ST_SW_KEY_EXCH_B: alg_k = s->s3->tmp.new_cipher->algorithm_mkey; - /* clear this, it may get reset by - * send_server_key_exchange */ - if ((s->options & SSL_OP_EPHEMERAL_RSA) -#ifndef OPENSSL_NO_KRB5 - && !(alg_k & SSL_kKRB5) -#endif /* OPENSSL_NO_KRB5 */ - ) - /* option SSL_OP_EPHEMERAL_RSA sends temporary RSA key - * even when forbidden by protocol specs - * (handshake may fail as clients are not required to - * be able to handle this) */ - s->s3->tmp.use_rsa_tmp=1; - else - s->s3->tmp.use_rsa_tmp=0; + /* + * clear this, it may get reset by + * send_server_key_exchange + */ + s->s3->tmp.use_rsa_tmp=0; /* only send if a DH key exchange or * RSA but we have a sign only certificate */ - if (s->s3->tmp.use_rsa_tmp + if ( /* PSK: send ServerKeyExchange if PSK identity * hint if provided */ #ifndef OPENSSL_NO_PSK diff --git a/ssl/s3_clnt.c b/ssl/s3_clnt.c index 2313fbc1e7..aa9dcbb5b3 100644 --- a/ssl/s3_clnt.c +++ b/ssl/s3_clnt.c @@ -1636,6 +1636,13 @@ int ssl3_get_key_exchange(SSL *s) #ifndef OPENSSL_NO_RSA if (alg_k & SSL_kRSA) { + /* Temporary RSA keys only allowed in export ciphersuites */ + if (!SSL_C_IS_EXPORT(s->s3->tmp.new_cipher)) + { + al=SSL_AD_UNEXPECTED_MESSAGE; + SSLerr(SSL_F_SSL3_GET_SERVER_CERTIFICATE,SSL_R_UNEXPECTED_MESSAGE); + goto f_err; + } if ((rsa=RSA_new()) == NULL) { SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE,ERR_R_MALLOC_FAILURE); diff --git a/ssl/s3_srvr.c b/ssl/s3_srvr.c index 6c0bdcf437..e5a32ee90f 100644 --- a/ssl/s3_srvr.c +++ b/ssl/s3_srvr.c @@ -453,20 +453,11 @@ int ssl3_accept(SSL *s) case SSL3_ST_SW_KEY_EXCH_B: alg_k = s->s3->tmp.new_cipher->algorithm_mkey; - /* clear this, it may get reset by - * send_server_key_exchange */ - if ((s->options & SSL_OP_EPHEMERAL_RSA) -#ifndef OPENSSL_NO_KRB5 - && !(alg_k & SSL_kKRB5) -#endif /* OPENSSL_NO_KRB5 */ - ) - /* option SSL_OP_EPHEMERAL_RSA sends temporary RSA key - * even when forbidden by protocol specs - * (handshake may fail as clients are not required to - * be able to handle this) */ - s->s3->tmp.use_rsa_tmp=1; - else - s->s3->tmp.use_rsa_tmp=0; + /* + * clear this, it may get reset by + * send_server_key_exchange + */ + s->s3->tmp.use_rsa_tmp=0; /* only send if a DH key exchange, fortezza or @@ -480,7 +471,7 @@ int ssl3_accept(SSL *s) * server certificate contains the server's * public key for key exchange. */ - if (s->s3->tmp.use_rsa_tmp + if ( /* PSK: send ServerKeyExchange if PSK identity * hint if provided */ #ifndef OPENSSL_NO_PSK @@ -606,9 +606,8 @@ struct ssl_session_st #define SSL_OP_SINGLE_ECDH_USE 0x00080000L /* If set, always create a new key when using tmp_dh parameters */ #define SSL_OP_SINGLE_DH_USE 0x00100000L -/* Set to always use the tmp_rsa key when doing RSA operations, - * even when this violates protocol specs */ -#define SSL_OP_EPHEMERAL_RSA 0x00200000L +/* Does nothing: retained for compatibiity */ +#define SSL_OP_EPHEMERAL_RSA 0x0 /* Set on servers to choose the cipher according to the server's * preferences */ #define SSL_OP_CIPHER_SERVER_PREFERENCE 0x00400000L |