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Stop DTLS servers asking for unsafe legacy renegotiation

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If a DTLS client that does not support secure renegotiation connects to an
OpenSSL DTLS server then, by default, renegotiation is disabled. If a
server application attempts to initiate a renegotiation then OpenSSL is
supposed to prevent this. However due to a discrepancy between the TLS and
DTLS code, the server sends a HelloRequest anyway in DTLS.

This is not a security concern because the handshake will still fail later
in the process when the client responds with a ClientHello.

Reviewed-by: Tim Hudson <tjh@openssl.org>
(cherry picked from commit d40ec4ab8e)
This commit is contained in:
Matt Caswell 2015-11-10 15:17:42 +00:00
parent e83009840a
commit 78b9d13474
1 changed files with 13 additions and 0 deletions
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13
ssl/d1_srvr.c
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@ -267,6 +267,19 @@ int dtls1_accept(SSL *s)
ssl3_init_finished_mac(s);
s->state = SSL3_ST_SR_CLNT_HELLO_A;
s->ctx->stats.sess_accept++;
} else if (!s->s3->send_connection_binding &&
!(s->options &
SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION)) {
/*
* Server attempting to renegotiate with client that doesn't
* support secure renegotiation.
*/
SSLerr(SSL_F_DTLS1_ACCEPT,
SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);
ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
ret = -1;
s->state = SSL_ST_ERR;
goto end;
} else {
/*
* s->state == SSL_ST_RENEGOTIATE, we will just send a