Commit 83764a98 authored by Dr. Stephen Henson's avatar Dr. Stephen Henson Committed by Matt Caswell
Browse files

Fix SRP ciphersuite DoS vulnerability. 



If a client attempted to use an SRP ciphersuite and it had not been
set up correctly it would crash with a null pointer read. A malicious
server could exploit this in a DoS attack.

Thanks to Joonas Kuorilehto and Riku Hietamäki from Codenomicon
for reporting this issue.

CVE-2014-5139
Reviewed-by: default avatarTim Hudson <tjh@openssl.org>
parent 86788e1e

ssl/s3_clnt.c

+9 −0
Original line number Diff line number Diff line
@@ -954,6 +954,15 @@ int ssl3_get_server_hello(SSL *s) 
		SSLerr(SSL_F_SSL3_GET_SERVER_HELLO,SSL_R_WRONG_CIPHER_RETURNED);

		goto f_err;

		}

#ifndef OPENSSL_NO_SRP

	if (((c->algorithm_mkey & SSL_kSRP) || (c->algorithm_auth & SSL_aSRP)) &&

		    !(s->srp_ctx.srp_Mask & SSL_kSRP))

		{

		al=SSL_AD_ILLEGAL_PARAMETER;

		SSLerr(SSL_F_SSL3_GET_SERVER_HELLO,SSL_R_WRONG_CIPHER_RETURNED);

		goto f_err;

		}

#endif /* OPENSSL_NO_SRP */

	p+=ssl_put_cipher_by_char(s,NULL,NULL);



	sk=ssl_get_ciphers_by_id(s);

ssl/ssl_lib.c

+5 −0
Original line number Diff line number Diff line
@@ -1406,6 +1406,11 @@ int ssl_cipher_list_to_bytes(SSL *s,STACK_OF(SSL_CIPHER) *sk,unsigned char *p, 
		    s->psk_client_callback == NULL)

			continue;

#endif /* OPENSSL_NO_PSK */

#ifndef OPENSSL_NO_SRP

		if (((c->algorithm_mkey & SSL_kSRP) || (c->algorithm_auth & SSL_aSRP)) &&

		    !(s->srp_ctx.srp_Mask & SSL_kSRP))

		    continue;

#endif /* OPENSSL_NO_SRP */

		j = put_cb ? put_cb(c,p) : ssl_put_cipher_by_char(s,c,p);

		p+=j;

		}