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Fix two bugs in clienthello processing

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- Always process ALPN (previously there was an early return in the
  certificate status handling)
- Don't send a duplicate alert. Previously, both
  ssl_check_clienthello_tlsext_late and its caller would send an
  alert. Consolidate alert sending code in the caller.

Reviewed-by: Rich Salz <rsalz@openssl.org>
This commit is contained in:
Emilia Kasper 2016-07-04 20:32:28 +02:00
parent ce2cdac278
commit 70c22888c1
3 changed files with 37 additions and 54 deletions
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2
ssl/ssl_locl.h
View file

@ -2004,7 +2004,7 @@ __owur unsigned char *ssl_add_serverhello_tlsext(SSL *s, unsigned char *buf,
__owur int ssl_parse_clienthello_tlsext(SSL *s, PACKET *pkt);
void ssl_set_default_md(SSL *s);
__owur int tls1_set_server_sigalgs(SSL *s);
__owur int ssl_check_clienthello_tlsext_late(SSL *s);
__owur int ssl_check_clienthello_tlsext_late(SSL *s, int *al);
__owur int ssl_parse_serverhello_tlsext(SSL *s, PACKET *pkt);
__owur int ssl_prepare_clienthello_tlsext(SSL *s);
__owur int ssl_prepare_serverhello_tlsext(SSL *s);

2
ssl/statem/statem_srvr.c
View file

@ -1454,7 +1454,7 @@ WORK_STATE tls_post_process_client_hello(SSL *s, WORK_STATE wst)
/* Handles TLS extensions that we couldn't check earlier */
if (s->version >= SSL3_VERSION) {
if (ssl_check_clienthello_tlsext_late(s) <= 0) {
if (!ssl_check_clienthello_tlsext_late(s, &al)) {
SSLerr(SSL_F_TLS_POST_PROCESS_CLIENT_HELLO,
SSL_R_CLIENTHELLO_TLSEXT);
goto f_err;

87
ssl/t1_lib.c
View file

@ -1678,11 +1678,10 @@ static int tls1_alpn_handle_client_hello(SSL *s, PACKET *pkt, int *al)
/*
* Process the ALPN extension in a ClientHello.
* ret: a pointer to the TLSEXT return value: SSL_TLSEXT_ERR_*
* al: a pointer to the alert value to send in the event of a failure.
* returns 1 on success, 0
* returns 1 on success, 0 on error.
*/
static int tls1_alpn_handle_client_hello_late(SSL *s, int *ret, int *al)
static int tls1_alpn_handle_client_hello_late(SSL *s, int *al)
{
const unsigned char *selected = NULL;
unsigned char selected_len = 0;
@ -1698,7 +1697,6 @@ static int tls1_alpn_handle_client_hello_late(SSL *s, int *ret, int *al)
s->s3->alpn_selected = OPENSSL_memdup(selected, selected_len);
if (s->s3->alpn_selected == NULL) {
*al = SSL_AD_INTERNAL_ERROR;
*ret = SSL_TLSEXT_ERR_ALERT_FATAL;
return 0;
}
s->s3->alpn_selected_len = selected_len;
@ -1708,7 +1706,6 @@ static int tls1_alpn_handle_client_hello_late(SSL *s, int *ret, int *al)
#endif
} else {
*al = SSL_AD_NO_APPLICATION_PROTOCOL;
*ret = SSL_TLSEXT_ERR_ALERT_FATAL;
return 0;
}
}
@ -2661,10 +2658,13 @@ int tls1_set_server_sigalgs(SSL *s)
return 0;
}
int ssl_check_clienthello_tlsext_late(SSL *s)
/*
* Upon success, returns 1.
* Upon failure, returns 0 and sets |al| to the appropriate fatal alert.
*/
int ssl_check_clienthello_tlsext_late(SSL *s, int *al)
{
int ret = SSL_TLSEXT_ERR_OK;
int al = SSL_AD_INTERNAL_ERROR;
s->tlsext_status_expected = 0;
/*
* If status request then ask callback what to do. Note: this must be
@ -2673,58 +2673,41 @@ int ssl_check_clienthello_tlsext_late(SSL *s)
* influence which certificate is sent
*/
if ((s->tlsext_status_type != -1) && s->ctx && s->ctx->tlsext_status_cb) {
int r;
int ret;
CERT_PKEY *certpkey;
certpkey = ssl_get_server_send_pkey(s);
/* If no certificate can't return certificate status */
if (certpkey == NULL) {
s->tlsext_status_expected = 0;
return 1;
}
/*
* Set current certificate to one we will use so SSL_get_certificate
* et al can pick it up.
*/
s->cert->key = certpkey;
r = s->ctx->tlsext_status_cb(s, s->ctx->tlsext_status_arg);
switch (r) {
/* We don't want to send a status request response */
case SSL_TLSEXT_ERR_NOACK:
s->tlsext_status_expected = 0;
break;
/* status request response should be sent */
case SSL_TLSEXT_ERR_OK:
if (s->tlsext_ocsp_resp)
s->tlsext_status_expected = 1;
else
if (certpkey != NULL) {
/*
* Set current certificate to one we will use so SSL_get_certificate
* et al can pick it up.
*/
s->cert->key = certpkey;
ret = s->ctx->tlsext_status_cb(s, s->ctx->tlsext_status_arg);
switch (ret) {
/* We don't want to send a status request response */
case SSL_TLSEXT_ERR_NOACK:
s->tlsext_status_expected = 0;
break;
/* something bad happened */
case SSL_TLSEXT_ERR_ALERT_FATAL:
ret = SSL_TLSEXT_ERR_ALERT_FATAL;
al = SSL_AD_INTERNAL_ERROR;
goto err;
break;
/* status request response should be sent */
case SSL_TLSEXT_ERR_OK:
if (s->tlsext_ocsp_resp)
s->tlsext_status_expected = 1;
break;
/* something bad happened */
case SSL_TLSEXT_ERR_ALERT_FATAL:
default:
*al = SSL_AD_INTERNAL_ERROR;
return 0;
}
}
} else
s->tlsext_status_expected = 0;
if (!tls1_alpn_handle_client_hello_late(s, &ret, &al)) {
goto err;
}
err:
switch (ret) {
case SSL_TLSEXT_ERR_ALERT_FATAL:
ssl3_send_alert(s, SSL3_AL_FATAL, al);
return -1;
case SSL_TLSEXT_ERR_ALERT_WARNING:
ssl3_send_alert(s, SSL3_AL_WARNING, al);
return 1;
default:
return 1;
if (!tls1_alpn_handle_client_hello_late(s, al)) {
return 0;
}
return 1;
}
int ssl_check_serverhello_tlsext(SSL *s)