File 85bbc05b21678e80423815d2ef1dfe26208491ab.patch of Package irssi
From 85bbc05b21678e80423815d2ef1dfe26208491ab Mon Sep 17 00:00:00 2001
From: coekie <coekie@dbcabf3a-b0e7-0310-adc4-f8d773084564>
Date: Mon, 28 Dec 2009 12:15:18 +0000
Subject: [PATCH] Check if an SSL certificate matches the hostname of the server we are connecting to
git-svn-id: http://svn.irssi.org/repos/irssi/trunk@5104 dbcabf3a-b0e7-0310-adc4-f8d773084564
---
src/core/network-openssl.c | 157 ++++++++++++++++++++++++++++++++++++++++++--
src/core/network.h | 2 +-
src/core/servers.c | 2 +-
3 files changed, 154 insertions(+), 7 deletions(-)
diff --git a/src/core/network-openssl.c b/src/core/network-openssl.c
index 92832ba..5a9c9bc 100644
--- a/src/core/network-openssl.c
+++ b/src/core/network-openssl.c
@@ -26,6 +26,7 @@
#include <openssl/crypto.h>
#include <openssl/x509.h>
+#include <openssl/x509v3.h>
#include <openssl/pem.h>
#include <openssl/ssl.h>
#include <openssl/err.h>
@@ -39,6 +40,7 @@ typedef struct
SSL *ssl;
SSL_CTX *ctx;
unsigned int verify:1;
+ const char *hostname;
} GIOSSLChannel;
static SSL_CTX *ssl_ctx = NULL;
@@ -53,7 +55,149 @@ static void irssi_ssl_free(GIOChannel *handle)
g_free(chan);
}
-static gboolean irssi_ssl_verify(SSL *ssl, SSL_CTX *ctx, X509 *cert)
+/* Checks if the given string has internal NUL characters. */
+static gboolean has_internal_nul(const char* str, int len) {
+ /* Remove trailing nul characters. They would give false alarms */
+ while (len > 0 && str[len-1] == 0)
+ len--;
+ return strlen(str) != len;
+}
+
+/* tls_dns_name - Extract valid DNS name from subjectAltName value */
+static const char *tls_dns_name(const GENERAL_NAME * gn)
+{
+ const char *dnsname;
+
+ /* We expect the OpenSSL library to construct GEN_DNS extension objects as
+ ASN1_IA5STRING values. Check we got the right union member. */
+ if (ASN1_STRING_type(gn->d.ia5) != V_ASN1_IA5STRING) {
+ g_warning("Invalid ASN1 value type in subjectAltName");
+ return NULL;
+ }
+
+ /* Safe to treat as an ASCII string possibly holding a DNS name */
+ dnsname = (char *) ASN1_STRING_data(gn->d.ia5);
+
+ if (has_internal_nul(dnsname, ASN1_STRING_length(gn->d.ia5))) {
+ g_warning("Internal NUL in subjectAltName");
+ return NULL;
+ }
+
+ return dnsname;
+}
+
+/* tls_text_name - extract certificate property value by name */
+static char *tls_text_name(X509_NAME *name, int nid)
+{
+ int pos;
+ X509_NAME_ENTRY *entry;
+ ASN1_STRING *entry_str;
+ int utf8_length;
+ unsigned char *utf8_value;
+ char *result;
+
+ if (name == 0 || (pos = X509_NAME_get_index_by_NID(name, nid, -1)) < 0) {
+ return NULL;
+ }
+
+ entry = X509_NAME_get_entry(name, pos);
+ g_return_val_if_fail(entry != NULL, NULL);
+ entry_str = X509_NAME_ENTRY_get_data(entry);
+ g_return_val_if_fail(entry_str != NULL, NULL);
+
+ /* Convert everything into UTF-8. It's up to OpenSSL to do something
+ reasonable when converting ASCII formats that contain non-ASCII
+ content. */
+ if ((utf8_length = ASN1_STRING_to_UTF8(&utf8_value, entry_str)) < 0) {
+ g_warning("Error decoding ASN.1 type=%d", ASN1_STRING_type(entry_str));
+ return NULL;
+ }
+
+ if (has_internal_nul((char *)utf8_value, utf8_length)) {
+ g_warning("NUL character in hostname in certificate");
+ OPENSSL_free(utf8_value);
+ return NULL;
+ }
+
+ result = g_strdup((char *) utf8_value);
+ OPENSSL_free(utf8_value);
+ return result;
+}
+
+
+/** check if a hostname in the certificate matches the hostname we used for the connection */
+static gboolean match_hostname(const char *cert_hostname, const char *hostname)
+{
+ const char *hostname_left;
+
+ if (!strcasecmp(cert_hostname, hostname)) { /* exact match */
+ return TRUE;
+ } else if (cert_hostname[0] == '*' && cert_hostname[1] == '.' && cert_hostname[2] != 0) { /* wildcard match */
+ /* The initial '*' matches exactly one hostname component */
+ hostname_left = strchr(hostname, '.');
+ if (hostname_left != NULL && ! strcasecmp(hostname_left + 1, cert_hostname + 2)) {
+ return TRUE;
+ }
+ }
+ return FALSE;
+}
+
+/* based on verify_extract_name from tls_client.c in postfix */
+static gboolean irssi_ssl_verify_hostname(X509 *cert, const char *hostname)
+{
+ int gen_index, gen_count;
+ gboolean matched = FALSE, has_dns_name = FALSE;
+ const char *cert_dns_name;
+ char *cert_subject_cn;
+ const GENERAL_NAME *gn;
+ STACK_OF(GENERAL_NAME) * gens;
+
+ /* Verify the dNSName(s) in the peer certificate against the hostname. */
+ gens = X509_get_ext_d2i(cert, NID_subject_alt_name, 0, 0);
+ if (gens) {
+ gen_count = sk_GENERAL_NAME_num(gens);
+ for (gen_index = 0; gen_index < gen_count && !matched; ++gen_index) {
+ gn = sk_GENERAL_NAME_value(gens, gen_index);
+ if (gn->type != GEN_DNS)
+ continue;
+
+ /* Even if we have an invalid DNS name, we still ultimately
+ ignore the CommonName, because subjectAltName:DNS is
+ present (though malformed). */
+ has_dns_name = TRUE;
+ cert_dns_name = tls_dns_name(gn);
+ if (cert_dns_name && *cert_dns_name) {
+ matched = match_hostname(cert_dns_name, hostname);
+ }
+ }
+
+ /* Free stack *and* member GENERAL_NAME objects */
+ sk_GENERAL_NAME_pop_free(gens, GENERAL_NAME_free);
+ }
+
+ if (has_dns_name) {
+ if (! matched) {
+ /* The CommonName in the issuer DN is obsolete when SubjectAltName is available. */
+ g_warning("None of the Subject Alt Names in the certificate match hostname '%s'", hostname);
+ }
+ return matched;
+ } else { /* No subjectAltNames, look at CommonName */
+ cert_subject_cn = tls_text_name(X509_get_subject_name(cert), NID_commonName);
+ if (cert_subject_cn && *cert_subject_cn) {
+ matched = match_hostname(cert_subject_cn, hostname);
+ if (! matched) {
+ g_warning("SSL certificate common name '%s' doesn't match host name '%s'", cert_subject_cn, hostname);
+ }
+ } else {
+ g_warning("No subjectAltNames and no valid common name in certificate");
+ }
+ free(cert_subject_cn);
+ }
+
+ return matched;
+}
+
+static gboolean irssi_ssl_verify(SSL *ssl, SSL_CTX *ctx, const char* hostname, X509 *cert)
{
if (SSL_get_verify_result(ssl) != X509_V_OK) {
unsigned char md[EVP_MAX_MD_SIZE];
@@ -89,6 +233,8 @@ static gboolean irssi_ssl_verify(SSL *ssl, SSL_CTX *ctx, X509 *cert)
}
}
return FALSE;
+ } else if (! irssi_ssl_verify_hostname(cert, hostname)){
+ return FALSE;
}
return TRUE;
}
@@ -241,7 +387,7 @@ static gboolean irssi_ssl_init(void)
}
-static GIOChannel *irssi_ssl_get_iochannel(GIOChannel *handle, const char *mycert, const char *mypkey, const char *cafile, const char *capath, gboolean verify)
+static GIOChannel *irssi_ssl_get_iochannel(GIOChannel *handle, const char *hostname, const char *mycert, const char *mypkey, const char *cafile, const char *capath, gboolean verify)
{
GIOSSLChannel *chan;
GIOChannel *gchan;
@@ -326,6 +472,7 @@ static GIOChannel *irssi_ssl_get_iochannel(GIOChannel *handle, const char *mycer
chan->ssl = ssl;
chan->ctx = ctx;
chan->verify = verify;
+ chan->hostname = hostname;
gchan = (GIOChannel *)chan;
gchan->funcs = &irssi_ssl_channel_funcs;
@@ -336,14 +483,14 @@ static GIOChannel *irssi_ssl_get_iochannel(GIOChannel *handle, const char *mycer
return gchan;
}
-GIOChannel *net_connect_ip_ssl(IPADDR *ip, int port, IPADDR *my_ip, const char *cert, const char *pkey, const char *cafile, const char *capath, gboolean verify)
+GIOChannel *net_connect_ip_ssl(IPADDR *ip, int port, const char* hostname, IPADDR *my_ip, const char *cert, const char *pkey, const char *cafile, const char *capath, gboolean verify)
{
GIOChannel *handle, *ssl_handle;
handle = net_connect_ip(ip, port, my_ip);
if (handle == NULL)
return NULL;
- ssl_handle = irssi_ssl_get_iochannel(handle, cert, pkey, cafile, capath, verify);
+ ssl_handle = irssi_ssl_get_iochannel(handle, hostname, cert, pkey, cafile, capath, verify);
if (ssl_handle == NULL)
g_io_channel_unref(handle);
return ssl_handle;
@@ -385,7 +532,7 @@ int irssi_ssl_handshake(GIOChannel *handle)
g_warning("SSL server supplied no certificate");
return -1;
}
- ret = !chan->verify || irssi_ssl_verify(chan->ssl, chan->ctx, cert);
+ ret = !chan->verify || irssi_ssl_verify(chan->ssl, chan->ctx, chan->hostname, cert);
X509_free(cert);
return ret ? 0 : -1;
}
diff --git a/src/core/network.h b/src/core/network.h
index 65505ea..8583724 100644
--- a/src/core/network.h
+++ b/src/core/network.h
@@ -47,7 +47,7 @@ int net_ip_compare(IPADDR *ip1, IPADDR *ip2);
/* Connect to socket */
GIOChannel *net_connect(const char *addr, int port, IPADDR *my_ip);
/* Connect to socket with ip address and SSL*/
-GIOChannel *net_connect_ip_ssl(IPADDR *ip, int port, IPADDR *my_ip, const char *cert, const char *pkey, const char *cafile, const char *capath, gboolean verify);
+GIOChannel *net_connect_ip_ssl(IPADDR *ip, int port, const char* hostname, IPADDR *my_ip, const char *cert, const char *pkey, const char *cafile, const char *capath, gboolean verify);
int irssi_ssl_handshake(GIOChannel *handle);
/* Connect to socket with ip address */
GIOChannel *net_connect_ip(IPADDR *ip, int port, IPADDR *my_ip);
diff --git a/src/core/servers.c b/src/core/servers.c
index d5844e7..017a203 100644
--- a/src/core/servers.c
+++ b/src/core/servers.c
@@ -224,7 +224,7 @@ static void server_real_connect(SERVER_REC *server, IPADDR *ip,
port = server->connrec->proxy != NULL ?
server->connrec->proxy_port : server->connrec->port;
handle = server->connrec->use_ssl ?
- net_connect_ip_ssl(ip, port, own_ip, server->connrec->ssl_cert, server->connrec->ssl_pkey,
+ net_connect_ip_ssl(ip, port, server->connrec->address, own_ip, server->connrec->ssl_cert, server->connrec->ssl_pkey,
server->connrec->ssl_cafile, server->connrec->ssl_capath, server->connrec->ssl_verify) :
net_connect_ip(ip, port, own_ip);
} else {
--
1.7.0.2
