From e1c7871de80029b81824df4d59edc6de5293835f Mon Sep 17 00:00:00 2001 From: Todd Short Date: Mon, 21 Dec 2015 15:19:29 -0500 Subject: Use ChaCha only if prioritized by clnt IFF the client has ChaCha first, and server cipher priority is used, and the new SSL_OP_PRIORITIZE_CHACHA_FOR_MOBILE option is used, then reprioritize ChaCha above everything else. This way, A matching ChaCha cipher will be selected if there is a match. If no ChaCha ciphers match, then the other ciphers are used. Reviewed-by: Paul Dale Reviewed-by: Tim Hudson Reviewed-by: Andy Polyakov (Merged from https://github.com/openssl/openssl/pull/4436) --- ssl/s3_lib.c | 52 +++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 51 insertions(+), 1 deletion(-) (limited to 'ssl/s3_lib.c') diff --git a/ssl/s3_lib.c b/ssl/s3_lib.c index f4423b2855..c063fff87a 100644 --- a/ssl/s3_lib.c +++ b/ssl/s3_lib.c @@ -4120,6 +4120,9 @@ const SSL_CIPHER *ssl3_choose_cipher(SSL *s, STACK_OF(SSL_CIPHER) *clnt, STACK_OF(SSL_CIPHER) *prio, *allow; int i, ii, ok; unsigned long alg_k = 0, alg_a = 0, mask_k = 0, mask_a = 0; +#ifndef OPENSSL_NO_CHACHA + STACK_OF(SSL_CIPHER) *prio_chacha = NULL; +#endif /* Let's see which ciphers we can support */ @@ -4145,9 +4148,53 @@ const SSL_CIPHER *ssl3_choose_cipher(SSL *s, STACK_OF(SSL_CIPHER) *clnt, } #endif - if (s->options & SSL_OP_CIPHER_SERVER_PREFERENCE || tls1_suiteb(s)) { + /* SUITE-B takes precedence over server preference and ChaCha priortiy */ + if (tls1_suiteb(s)) { + prio = srvr; + allow = clnt; + } else if (s->options & SSL_OP_CIPHER_SERVER_PREFERENCE) { prio = srvr; allow = clnt; +#ifndef OPENSSL_NO_CHACHA + /* If ChaCha20 is at the top of the client preference list, + and there are ChaCha20 ciphers in the server list, then + temporarily prioritize all ChaCha20 ciphers in the servers list. */ + if (s->options & SSL_OP_PRIORITIZE_CHACHA && sk_SSL_CIPHER_num(clnt) > 0) { + c = sk_SSL_CIPHER_value(clnt, 0); + if (c->algorithm_enc == SSL_CHACHA20POLY1305) { + /* ChaCha20 is client preferred, check server... */ + int num = sk_SSL_CIPHER_num(srvr); + int found = 0; + for (i = 0; i < num; i++) { + c = sk_SSL_CIPHER_value(srvr, i); + if (c->algorithm_enc == SSL_CHACHA20POLY1305) { + found = 1; + break; + } + } + if (found) { + prio_chacha = sk_SSL_CIPHER_new_null(); + /* if reserve fails, then there's likely a memory issue */ + if (prio_chacha != NULL) { + /* Put all ChaCha20 at the top, starting with the one we just found */ + sk_SSL_CIPHER_push(prio_chacha, c); + for (i++; i < num; i++) { + c = sk_SSL_CIPHER_value(srvr, i); + if (c->algorithm_enc == SSL_CHACHA20POLY1305) + sk_SSL_CIPHER_push(prio_chacha, c); + } + /* Pull in the rest */ + for (i = 0; i < num; i++) { + c = sk_SSL_CIPHER_value(srvr, i); + if (c->algorithm_enc != SSL_CHACHA20POLY1305) + sk_SSL_CIPHER_push(prio_chacha, c); + } + prio = prio_chacha; + } + } + } + } +# endif } else { prio = clnt; allow = srvr; @@ -4229,6 +4276,9 @@ const SSL_CIPHER *ssl3_choose_cipher(SSL *s, STACK_OF(SSL_CIPHER) *clnt, break; } } +#ifndef OPENSSL_NO_CHACHA + sk_SSL_CIPHER_free(prio_chacha); +#endif return ret; } -- cgit v1.2.3