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Code Issues Releases Wiki Activity

SSL: Several SSL-backend related fixes

Browse Source 
axTLS:

This will make the axTLS backend perform the RFC2818 checks, honoring
the VERIFYHOST setting similar to the OpenSSL backend.

Generic for OpenSSL and axTLS:

Move the hostcheck and cert_hostcheck functions from the lib/ssluse.c
files to make them genericly available for both the OpenSSL, axTLS and
other SSL backends. They are now in the new lib/hostcheck.c file.

CyaSSL:

CyaSSL now also has the RFC2818 checks enabled by default. There is a
limitation that the verifyhost can not be enabled exclusively on the
Subject CN field comparison. This SSL backend will thus behave like the
NSS and the GnuTLS (meaning: RFC2818 ok, or bust). In other words:
setting verifyhost to 0 or 1 will disable the Subject Alt Names checks
too.

Schannel:

Updated the schannel information messages: Split the IP address usage
message from the verifyhost setting and changed the message about
disabling SNI (Server Name Indication, used in HTTP virtual hosting)
into a message stating that the Subject Alternative Names checks are
being disabled when verifyhost is set to 0 or 1. As a side effect of
switching off the RFC2818 related servername checks with
SCH_CRED_NO_SERVERNAME_CHECK
(http://msdn.microsoft.com/en-us/library/aa923430.aspx) the SNI feature
is being disabled. This effect is not documented in MSDN, but Wireshark
output clearly shows the effect (details on the libcurl maillist).

PolarSSL:

Fix the prototype change in PolarSSL of ssl_set_session() and the move
of the peer_cert from the ssl_context to the ssl_session. Found this
change in the PolarSSL SVN between r1316 and r1317 where the
POLARSSL_VERSION_NUMBER was at 0x01010100. But to accommodate the Ubuntu
PolarSSL version 1.1.4 the check is to discriminate between lower then
PolarSSL version 1.2.0 and 1.2.0 and higher. Note: The PolarSSL SVN
trunk jumped from version 1.1.1 to 1.2.0.

Generic:

All the SSL backends are fixed and checked to work with the
ssl.verifyhost as a boolean, which is an internal API change.
This commit is contained in:
Oscar Koeroo 2012-11-03 02:06:51 +01:00 committed by Daniel Stenberg
parent 18c0e9bd71
commit 1394cad30f
9 changed files with 270 additions and 89 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
lib/Makefile.inc
View File

@ -24,7 +24,7 @@ CSOURCES = file.c timeval.c base64.c hostip.c progress.c formdata.c \
idn_win32.c http_negotiate_sspi.c cyassl.c http_proxy.c non-ascii.c \
asyn-ares.c asyn-thread.c curl_gssapi.c curl_ntlm.c curl_ntlm_wb.c \
curl_ntlm_core.c curl_ntlm_msgs.c curl_sasl.c curl_schannel.c \
curl_multibyte.c curl_darwinssl.c
curl_multibyte.c curl_darwinssl.c hostcheck.c
HHEADERS = arpa_telnet.h netrc.h file.h timeval.h qssl.h hostip.h \
progress.h formdata.h cookie.h http.h sendf.h ftp.h url.h dict.h \
@ -41,4 +41,5 @@ HHEADERS = arpa_telnet.h netrc.h file.h timeval.h qssl.h hostip.h \
warnless.h curl_hmac.h polarssl.h curl_rtmp.h curl_gethostname.h \
gopher.h axtls.h cyassl.h http_proxy.h non-ascii.h asyn.h curl_ntlm.h \
curl_gssapi.h curl_ntlm_wb.h curl_ntlm_core.h curl_ntlm_msgs.h \
curl_sasl.h curl_schannel.h curl_multibyte.h curl_darwinssl.h
curl_sasl.h curl_schannel.h curl_multibyte.h curl_darwinssl.h \
hostcheck.h

66
lib/axtls.c
View File

@ -47,6 +47,8 @@
#include "curl_memory.h"
/* The last #include file should be: */
#include "memdebug.h"
#include "hostcheck.h"
/* SSL_read is opied from axTLS compat layer */
static int SSL_read(SSL *ssl, void *buf, int num)
@ -150,7 +152,11 @@ Curl_axtls_connect(struct connectdata *conn,
int i, ssl_fcn_return;
const uint8_t *ssl_sessionid;
size_t ssl_idsize;
const char *x509;
const char *peer_CN;
uint32_t dns_altname_index;
const char *dns_altname;
int8_t found_subject_alt_names = 0;
int8_t found_subject_alt_name_matching_conn = 0;
/* Assuming users will not compile in custom key/cert to axTLS */
uint32_t client_option = SSL_NO_DEFAULT_KEY|SSL_SERVER_VERIFY_LATER;
@ -296,19 +302,65 @@ Curl_axtls_connect(struct connectdata *conn,
/* Here, gtls.c does issuer verification. axTLS has no straightforward
* equivalent, so omitting for now.*/
/* See if common name was set in server certificate */
x509 = ssl_get_cert_dn(ssl, SSL_X509_CERT_COMMON_NAME);
if(x509 == NULL)
infof(data, "error fetching CN from cert\n");
/* Here, gtls.c does the following
* 1) x509 hostname checking per RFC2818. axTLS doesn't support this, but
* it seems useful. Omitting for now.
* it seems useful. This is now implemented, by Oscar Koeroo
* 2) checks cert validity based on time. axTLS does this in ssl_verify_cert
* 3) displays a bunch of cert information. axTLS doesn't support most of
* this, but a couple fields are available.
*/
/* There is no (DNS) Altnames count in the version 1.4.8 API. There is a
risk of an inifite loop */
for(dns_altname_index = 0; ; dns_altname_index++) {
dns_altname = ssl_get_cert_subject_alt_dnsname(ssl, dns_altname_index);
if(dns_altname == NULL) {
break;
}
found_subject_alt_names = 1;
infof(data, "\tComparing subject alt name DNS with hostname: %s <-> %s\n",
dns_altname, conn->host.name);
if(Curl_cert_hostcheck(dns_altname, conn->host.name)) {
found_subject_alt_name_matching_conn = 1;
break;
}
}
/* RFC2818 checks */
if(found_subject_alt_names && !found_subject_alt_name_matching_conn) {
/* Break connection ! */
Curl_axtls_close(conn, sockindex);
failf(data, "\tsubjectAltName(s) do not match %s\n", conn->host.dispname);
return CURLE_PEER_FAILED_VERIFICATION;
}
else if(found_subject_alt_names == 0) {
/* Per RFC2818, when no Subject Alt Names were available, examine the peer
CN as a legacy fallback */
peer_CN = ssl_get_cert_dn(ssl, SSL_X509_CERT_COMMON_NAME);
if(peer_CN == NULL) {
/* Similar behaviour to the OpenSSL interface */
Curl_axtls_close(conn, sockindex);
failf(data, "unable to obtain common name from peer certificate");
return CURLE_PEER_FAILED_VERIFICATION;
}
else {
if(!Curl_cert_hostcheck((const char *)peer_CN, conn->host.name)) {
if(data->set.ssl.verifyhost) {
/* Break connection ! */
Curl_axtls_close(conn, sockindex);
failf(data, "\tcommon name \"%s\" does not match \"%s\"\n",
peer_CN, conn->host.dispname);
return CURLE_PEER_FAILED_VERIFICATION;
}
else
infof(data, "\tcommon name \"%s\" does not match \"%s\"\n",
peer_CN, conn->host.dispname);
}
}
}
/* General housekeeping */
conn->ssl[sockindex].state = ssl_connection_complete;
conn->ssl[sockindex].ssl = ssl;

10
lib/curl_darwinssl.c
View File

@ -803,6 +803,8 @@ static CURLcode darwinssl_connect_step1(struct connectdata *conn,
}
#endif /* defined(__MAC_10_6) || defined(__IPHONE_5_0) */
/* If this is a domain name and not an IP address, then configure SNI.
* Also: the verifyhost setting influences SNI usage */
/* If this is a domain name and not an IP address, then configure SNI: */
if((0 == Curl_inet_pton(AF_INET, conn->host.name, &addr)) &&
#ifdef ENABLE_IPV6
@ -862,7 +864,6 @@ darwinssl_connect_step2(struct connectdata *conn, int sockindex)
connssl->connecting_state = connssl->ssl_direction ?
ssl_connect_2_writing : ssl_connect_2_reading;
return CURLE_OK;
break;
case errSSLServerAuthCompleted:
/* the documentation says we need to call SSLHandshake() again */
@ -874,13 +875,16 @@ darwinssl_connect_step2(struct connectdata *conn, int sockindex)
case errSSLCertExpired:
failf(data, "SSL certificate problem: OSStatus %d", err);
return CURLE_SSL_CACERT;
break;
case errSSLHostNameMismatch:
failf(data, "SSL certificate peer verification failed, the "
"certificate did not match \"%s\"\n", conn->host.dispname);
return CURLE_PEER_FAILED_VERIFICATION;
default:
failf(data, "Unknown SSL protocol error in connection to %s:%d",
conn->host.name, err);
return CURLE_SSL_CONNECT_ERROR;
break;
}
}
else {

18
lib/curl_schannel.c
View File

@ -156,14 +156,22 @@ schannel_connect_step1(struct connectdata *conn, int sockindex)
infof(data, "schannel: disable server certificate revocation checks\n");
}
if(Curl_inet_pton(AF_INET, conn->host.name, &addr) ||
if(Curl_inet_pton(AF_INET, conn->host.name, &addr)
#ifdef ENABLE_IPV6
Curl_inet_pton(AF_INET6, conn->host.name, &addr6) ||
|| Curl_inet_pton(AF_INET6, conn->host.name, &addr6)
#endif
!data->set.ssl.verifyhost) {
) {
schannel_cred.dwFlags |= SCH_CRED_NO_SERVERNAME_CHECK;
infof(data, "schannel: using IP address, disable SNI servername "
"check\n");
infof(data, "schannel: using IP address, SNI is being disabled by "
"disabling the servername check against the "
"subject names in server certificates.\n");
}
if(!data->set.ssl.verifyhost) {
schannel_cred.dwFlags |= SCH_CRED_NO_SERVERNAME_CHECK;
infof(data, "schannel: verifyhost setting prevents Schannel from "
"comparing the supplied target name with the subject "
"names in server certificates. Also disables SNI.\n");
}
switch(data->set.ssl.version) {

43
lib/cyassl.c
View File

@ -53,6 +53,8 @@
#include "curl_memory.h"
/* The last #include file should be: */
#include "memdebug.h"
#include <cyassl/ssl.h>
#include <cyassl/error.h>
static Curl_recv cyassl_recv;
@ -237,6 +239,13 @@ cyassl_connect_step2(struct connectdata *conn,
conn->recv[sockindex] = cyassl_recv;
conn->send[sockindex] = cyassl_send;
/* Enable RFC2818 checks */
if(data->set.ssl.verifyhost) {
ret = CyaSSL_check_domain_name(conssl->handle, conn->host.name);
if(ret == SSL_FAILURE)
return CURLE_OUT_OF_MEMORY;
}
ret = SSL_connect(conssl->handle);
if(ret != 1) {
char error_buffer[80];
@ -246,16 +255,44 @@ cyassl_connect_step2(struct connectdata *conn,
conssl->connecting_state = ssl_connect_2_reading;
return CURLE_OK;
}
if(SSL_ERROR_WANT_WRITE == detail) {
else if(SSL_ERROR_WANT_WRITE == detail) {
conssl->connecting_state = ssl_connect_2_writing;
return CURLE_OK;
}
/* There is no easy way to override only the CN matching.
* This will enable the override of both mismatching SubjectAltNames
* as also mismatching CN fields */
else if(DOMAIN_NAME_MISMATCH == detail) {
#if 1
failf(data, "\tsubject alt name(s) or common name do not match \"%s\"\n",
conn->host.dispname);
return CURLE_PEER_FAILED_VERIFICATION;
#else
/* When the CyaSSL_check_domain_name() is used and you desire to continue
* on a DOMAIN_NAME_MISMATCH, i.e. 'data->set.ssl.verifyhost == 0',
* CyaSSL version 2.4.0 will fail with an INCOMPLETE_DATA error. The only
* way to do this is currently to switch the CyaSSL_check_domain_name()
* in and out based on the 'data->set.ssl.verifyhost' value. */
if(data->set.ssl.verifyhost) {
failf(data,
"\tsubject alt name(s) or common name do not match \"%s\"\n",
conn->host.dispname);
return CURLE_PEER_FAILED_VERIFICATION;
}
else {
infof(data,
"\tsubject alt name(s) and/or common name do not match \"%s\"\n",
conn->host.dispname);
return CURLE_OK;
}
#endif
}
else {
failf(data, "SSL_connect failed with error %d: %s", detail,
ERR_error_string(detail, error_buffer));
return CURLE_SSL_CONNECT_ERROR;
}
}
conssl->connecting_state = ssl_connect_3;
infof(data, "SSL connected\n");

91
lib/hostcheck.c Normal file
View File

@ -0,0 +1,91 @@
/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2012, Daniel Stenberg, <daniel@haxx.se>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at http://curl.haxx.se/docs/copyright.html.
*
* You may opt to use, copy, modify, merge, publish, distribute and/or sell
* copies of the Software, and permit persons to whom the Software is
* furnished to do so, under the terms of the COPYING file.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
***************************************************************************/
#include "setup.h"
#include "hostcheck.h"
#include "rawstr.h"
/*
* Match a hostname against a wildcard pattern.
* E.g.
* "foo.host.com" matches "*.host.com".
*
* We use the matching rule described in RFC6125, section 6.4.3.
* http://tools.ietf.org/html/rfc6125#section-6.4.3
*/
int Curl_hostmatch(const char *hostname, const char *pattern)
{
const char *pattern_label_end, *pattern_wildcard, *hostname_label_end;
int wildcard_enabled;
size_t prefixlen, suffixlen;
pattern_wildcard = strchr(pattern, '*');
if(pattern_wildcard == NULL)
return Curl_raw_equal(pattern, hostname) ?
CURL_HOST_MATCH : CURL_HOST_NOMATCH;
/* We require at least 2 dots in pattern to avoid too wide wildcard
match. */
wildcard_enabled = 1;
pattern_label_end = strchr(pattern, '.');
if(pattern_label_end == NULL || strchr(pattern_label_end+1, '.') == NULL ||
pattern_wildcard > pattern_label_end ||
Curl_raw_nequal(pattern, "xn--", 4)) {
wildcard_enabled = 0;
}
if(!wildcard_enabled)
return Curl_raw_equal(pattern, hostname) ?
CURL_HOST_MATCH : CURL_HOST_NOMATCH;
hostname_label_end = strchr(hostname, '.');
if(hostname_label_end == NULL ||
!Curl_raw_equal(pattern_label_end, hostname_label_end))
return CURL_HOST_NOMATCH;
/* The wildcard must match at least one character, so the left-most
label of the hostname is at least as large as the left-most label
of the pattern. */
if(hostname_label_end - hostname < pattern_label_end - pattern)
return CURL_HOST_NOMATCH;
prefixlen = pattern_wildcard - pattern;
suffixlen = pattern_label_end - (pattern_wildcard+1);
return Curl_raw_nequal(pattern, hostname, prefixlen) &&
Curl_raw_nequal(pattern_wildcard+1, hostname_label_end - suffixlen,
suffixlen) ?
CURL_HOST_MATCH : CURL_HOST_NOMATCH;
}
int Curl_cert_hostcheck(const char *match_pattern, const char *hostname)
{
if(!match_pattern || !*match_pattern ||
!hostname || !*hostname) /* sanity check */
return 0;
if(Curl_raw_equal(hostname, match_pattern)) /* trivial case */
return 1;
if(Curl_hostmatch(hostname,match_pattern) == CURL_HOST_MATCH)
return 1;
return 0;
}

32
lib/hostcheck.h Normal file
View File

@ -0,0 +1,32 @@
#ifndef __HOSTCHECK_H
#define __HOSTCHECK_H
/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2012, Daniel Stenberg, <daniel@haxx.se>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at http://curl.haxx.se/docs/copyright.html.
*
* You may opt to use, copy, modify, merge, publish, distribute and/or sell
* copies of the Software, and permit persons to whom the Software is
* furnished to do so, under the terms of the COPYING file.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
***************************************************************************/
#include <curl/curl.h>
#define CURL_HOST_NOMATCH 0
#define CURL_HOST_MATCH 1
int Curl_hostmatch(const char *hostname, const char *pattern);
int Curl_cert_hostcheck(const char *match_pattern, const char *hostname);
#endif

20
lib/polarssl.c
View File

@ -212,8 +212,15 @@ polarssl_connect_step1(struct connectdata *conn,
infof(data, "PolarSSL re-using session\n");
}
/* PolarSSL SVN revision r1316 to r1317, matching <1.2.0 is to cover Ubuntu's
1.1.4 version and the like */
#if POLARSSL_VERSION_NUMBER<0x01020000
ssl_set_session(&connssl->ssl, 1, 600,
&connssl->ssn);
#else
ssl_set_session(&connssl->ssl,
&connssl->ssn);
#endif
ssl_set_ca_chain(&connssl->ssl,
&connssl->cacert,
@ -306,12 +313,25 @@ polarssl_connect_step2(struct connectdata *conn,
return CURLE_PEER_FAILED_VERIFICATION;
}
/* PolarSSL SVN revision r1316 to r1317, matching <1.2.0 is to cover Ubuntu's
1.1.4 version and the like */
#if POLARSSL_VERSION_NUMBER<0x01020000
if(conn->ssl[sockindex].ssl.peer_cert) {
#else
if(ssl_get_peer_cert(&(connssl->ssl))) {
#endif
/* If the session was resumed, there will be no peer certs */
memset(buffer, 0, sizeof(buffer));
/* PolarSSL SVN revision r1316 to r1317, matching <1.2.0 is to cover Ubuntu's
1.1.4 version and the like */
#if POLARSSL_VERSION_NUMBER<0x01020000
if(x509parse_cert_info(buffer, sizeof(buffer), (char *)"* ",
conn->ssl[sockindex].ssl.peer_cert) != -1)
#else
if(x509parse_cert_info(buffer, sizeof(buffer), (char *)"* ",
ssl_get_peer_cert(&(connssl->ssl))) != -1)
#endif
infof(data, "Dumping cert info:\n%s\n", buffer);
}

70
lib/ssluse.c
View File

@ -50,6 +50,7 @@
#include "select.h"
#include "sslgen.h"
#include "rawstr.h"
#include "hostcheck.h"
#define _MPRINTF_REPLACE /* use the internal *printf() functions */
#include <curl/mprintf.h>
@ -1039,71 +1040,6 @@ static int asn1_output(const ASN1_UTCTIME *tm,
/* ====================================================== */
/*
* Match a hostname against a wildcard pattern.
* E.g.
* "foo.host.com" matches "*.host.com".
*
* We use the matching rule described in RFC6125, section 6.4.3.
* http://tools.ietf.org/html/rfc6125#section-6.4.3
*/
#define HOST_NOMATCH 0
#define HOST_MATCH 1
static int hostmatch(const char *hostname, const char *pattern)
{
const char *pattern_label_end, *pattern_wildcard, *hostname_label_end;
int wildcard_enabled;
size_t prefixlen, suffixlen;
pattern_wildcard = strchr(pattern, '*');
if(pattern_wildcard == NULL) {
return Curl_raw_equal(pattern, hostname) ? HOST_MATCH : HOST_NOMATCH;
}
/* We require at least 2 dots in pattern to avoid too wide wildcard
match. */
wildcard_enabled = 1;
pattern_label_end = strchr(pattern, '.');
if(pattern_label_end == NULL || strchr(pattern_label_end+1, '.') == NULL ||
pattern_wildcard > pattern_label_end ||
Curl_raw_nequal(pattern, "xn--", 4)) {
wildcard_enabled = 0;
}
if(!wildcard_enabled) {
return Curl_raw_equal(pattern, hostname) ? HOST_MATCH : HOST_NOMATCH;
}
hostname_label_end = strchr(hostname, '.');
if(hostname_label_end == NULL ||
!Curl_raw_equal(pattern_label_end, hostname_label_end)) {
return HOST_NOMATCH;
}
/* The wildcard must match at least one character, so the left-most
label of the hostname is at least as large as the left-most label
of the pattern. */
if(hostname_label_end - hostname < pattern_label_end - pattern) {
return HOST_NOMATCH;
}
prefixlen = pattern_wildcard - pattern;
suffixlen = pattern_label_end - (pattern_wildcard+1);
return Curl_raw_nequal(pattern, hostname, prefixlen) &&
Curl_raw_nequal(pattern_wildcard+1, hostname_label_end - suffixlen,
suffixlen) ?
HOST_MATCH : HOST_NOMATCH;
}
static int
cert_hostcheck(const char *match_pattern, const char *hostname)
{
if(!match_pattern || !*match_pattern ||
!hostname || !*hostname) /* sanity check */
return 0;
if(Curl_raw_equal(hostname, match_pattern)) /* trivial case */
return 1;
if(hostmatch(hostname,match_pattern) == HOST_MATCH)
return 1;
return 0;
}
/* Quote from RFC2818 section 3.1 "Server Identity"
@ -1192,7 +1128,7 @@ static CURLcode verifyhost(struct connectdata *conn,
if((altlen == strlen(altptr)) &&
/* if this isn't true, there was an embedded zero in the name
string and we cannot match it. */
cert_hostcheck(altptr, conn->host.name))
Curl_cert_hostcheck(altptr, conn->host.name))
matched = 1;
else
matched = 0;
@ -1291,7 +1227,7 @@ static CURLcode verifyhost(struct connectdata *conn,
"SSL: unable to obtain common name from peer certificate");
res = CURLE_PEER_FAILED_VERIFICATION;
}
else if(!cert_hostcheck((const char *)peer_CN, conn->host.name)) {
else if(!Curl_cert_hostcheck((const char *)peer_CN, conn->host.name)) {
failf(data, "SSL: certificate subject name '%s' does not match "
"target host name '%s'", peer_CN, conn->host.dispname);
res = CURLE_PEER_FAILED_VERIFICATION;