Restore OpenSSL 1.1, and earlier support.

Restores code that c8115514b4830a668ce726b2fcb8ab4a3d438ec9 removed,
but make it conditionally compiled. Have configure.ac autodetect the
openssl version.

Correctly UTF8-ize SSL_set_tlsext_host_name()'s parameter.

3 files changed, 211 insertions, 12 deletions

diff --git a/imap/configure.ac b/imap/configure.ac
index 9bf0201..6ac8577 100644
--- a/imap/configure.ac
+++ b/imap/configure.ac
@@ -4,7 +4,7 @@ dnl
 dnl Copyright 1998 - 2019 Double Precision, Inc.  See COPYING for
 dnl distribution information.
 
-AC_INIT(courier-imap, 5.0.8.20191205, [courier-users@lists.sourceforge.net])
+AC_INIT(courier-imap, 5.0.8.20191210, [courier-users@lists.sourceforge.net])
 
 >confdefs.h  # Kill PACKAGE_ macros
 
diff --git a/tcpd/configure.ac b/tcpd/configure.ac
index 872a0ad..08ba7d0 100644
--- a/tcpd/configure.ac
+++ b/tcpd/configure.ac
@@ -552,7 +552,7 @@ RAND_bytes(dummy, 1);
 ]
 )
 		LIBS="-lssl $LIBS"
-		AC_CHECK_FUNCS(TLSv1_1_method TLSv1_2_method)
+		AC_CHECK_FUNCS(TLSv1_1_method TLSv1_2_method X509_VERIFY_PARAM_set1_host)
 		LIBS="$save_LIBS"
 
 		AC_TRY_COMPILE( [
diff --git a/tcpd/libcouriertls.c b/tcpd/libcouriertls.c
index d4d1643..ac05caf 100644
--- a/tcpd/libcouriertls.c
+++ b/tcpd/libcouriertls.c
@@ -142,6 +142,7 @@ static int ssl_verify_callback(int goodcert, X509_STORE_CTX *x509)
 	return (1);
 }
 
+#if HAVE_X509_VERIFY_PARAM_SET1_HOST
 static int verifypeer(const struct tls_info *info, SSL *ssl)
 {
 	if (!info->peer_verify_domain)
@@ -149,6 +150,199 @@ static int verifypeer(const struct tls_info *info, SSL *ssl)
 
 	return SSL_get_verify_result(ssl) == X509_V_OK;
 }
+#else
+
+static int hostmatch_utf8(const char *a, const char *b)
+{
+	while (*a || *b)
+	{
+		char ca=*a;
+		char cb=*b;
+
+		if (ca >= 'A' && ca <= 'Z')
+			ca += 'a'-'A';
+		if (cb >= 'A' && cb <= 'Z')
+			cb += 'a'-'A';
+		if (ca != cb)
+			return 0;
+
+		++a;
+		++b;
+	}
+	return 1;
+}
+
+static int hostmatch(const struct tls_info *info, const char *domain)
+{
+	const char *p=domain;
+	const char *verify_domain=info->peer_verify_domain;
+	char *idn_domain1;
+	char *idn_domain2;
+	int rc;
+
+	if (*p == '*')
+	{
+		++p;
+
+		if (*p != '.')
+			return 0;
+
+		while (*verify_domain)
+		{
+			if (*verify_domain++ == '.')
+				break;
+		}
+	}
+
+	if (idna_to_unicode_8z8z(info->peer_verify_domain, &idn_domain1, 0)
+	    != IDNA_SUCCESS)
+		idn_domain1=0;
+
+	if (idna_to_unicode_8z8z(p, &idn_domain2, 0)
+	    != IDNA_SUCCESS)
+		idn_domain2=0;
+
+	rc=hostmatch_utf8(idn_domain1 ? idn_domain1:info->peer_verify_domain,
+			  idn_domain2 ? idn_domain2:p);
+
+	if (idn_domain1)
+		free(idn_domain1);
+	if (idn_domain2)
+		free(idn_domain2);
+	return rc;
+}
+
+static int verifypeer1(const struct tls_info *info, X509 *x,
+		       STACK_OF(GENERAL_NAME) *subject_alt_names);
+
+static int verifypeer(const struct tls_info *info, SSL *ssl)
+{
+	X509 *x=NULL;
+	int rc;
+	STACK_OF(GENERAL_NAME) *subject_alt_names;
+
+	if (!info->peer_verify_domain)
+		return (1);
+
+	if (SSL_get_verify_result(ssl) != X509_V_OK)
+		return (1);
+
+	x=SSL_get_peer_certificate(ssl);
+
+	if (!x)
+		return (0);
+
+	subject_alt_names=
+		X509_get_ext_d2i(x, NID_subject_alt_name, NULL, NULL);
+
+	rc=verifypeer1(info, x, subject_alt_names);
+
+	if (subject_alt_names)
+		GENERAL_NAMES_free(subject_alt_names);
+
+	X509_free(x);
+
+	return rc;
+}
+
+static int verifypeer1(const struct tls_info *info, X509 *x,
+		       STACK_OF(GENERAL_NAME) *subject_alt_names)
+{
+	X509_NAME *subj=NULL;
+	int nentries, j;
+	char domain[256];
+	char errmsg[1000];
+
+	if(subject_alt_names)
+	{
+		int n=sk_GENERAL_NAME_num(subject_alt_names);
+		int i;
+
+		for (i=0; i<n; i++)
+		{
+			const GENERAL_NAME *gn=
+				sk_GENERAL_NAME_value(subject_alt_names, i);
+			const char *str;
+			int l;
+
+			if (gn->type != GEN_DNS)
+				continue;
+
+#ifdef HAVE_OPENSSL110
+			str = (const char *)ASN1_STRING_get0_data(gn->d.ia5);
+#else
+			str = (const char *)ASN1_STRING_data(gn->d.ia5);
+#endif
+			l=ASN1_STRING_length(gn->d.ia5);
+
+			if (l >= sizeof(domain)-1)
+				l=sizeof(domain)-1;
+
+			memcpy(domain, str, l);
+			domain[l]=0;
+
+			if (hostmatch(info, domain))
+				return 1;
+		}
+	}
+
+	subj=X509_get_subject_name(x);
+
+	nentries=0;
+	if (subj)
+		nentries=X509_NAME_entry_count(subj);
+
+	domain[0]=0;
+	for (j=0; j<nentries; j++)
+	{
+		const char *obj_name;
+		X509_NAME_ENTRY *e;
+		ASN1_OBJECT *o;
+		ASN1_STRING *d;
+
+		int dlen;
+		const unsigned char *ddata;
+
+		e=X509_NAME_get_entry(subj, j);
+		if (!e)
+			continue;
+
+		o=X509_NAME_ENTRY_get_object(e);
+		d=X509_NAME_ENTRY_get_data(e);
+
+		if (!o || !d)
+			continue;
+
+		obj_name=OBJ_nid2sn(OBJ_obj2nid(o));
+
+		dlen=ASN1_STRING_length(d);
+#ifdef HAVE_OPENSSL110
+		ddata=ASN1_STRING_get0_data(d);
+#else
+		ddata=ASN1_STRING_data(d);
+#endif
+		if (strcasecmp(obj_name, "CN") == 0)
+		{
+			if (dlen >= sizeof(domain)-1)
+				dlen=sizeof(domain)-1;
+
+			memcpy(domain, ddata, dlen);
+			domain[dlen]=0;
+		}
+	}
+
+	if (domain[0] && hostmatch(info, domain))
+		return 1;
+
+	strcpy(errmsg, "couriertls: Mismatched SSL certificate: CN=");
+	strcat(errmsg, domain);
+	strcat(errmsg, " (expected ");
+	strncat(errmsg, info->peer_verify_domain, 256);
+	strcat(errmsg, ")");
+	(*info->tls_err_msg)(errmsg, info->app_data);
+	return (0);
+}
+#endif
 
 static void nonsslerror(const struct tls_info *info, const char *pfix)
 {
@@ -1083,32 +1277,37 @@ SSL *tls_connect(SSL_CTX *ctx, int fd)
 	}
 	else
 	{
+		char *idn_domain1;
+
+		if (idna_to_unicode_8z8z(info->peer_verify_domain,
+					 &idn_domain1, 0)
+		    != IDNA_SUCCESS)
+			idn_domain1=0;
+
 		SSL_set_connect_state(ssl);
 
 #ifdef HAVE_OPENSSL_SNI
 		if (info->peer_verify_domain)
 		{
-			SSL_set_tlsext_host_name(ssl, info->peer_verify_domain);
+			SSL_set_tlsext_host_name(ssl,
+						 idn_domain1 ? idn_domain1
+						 : (char *)
+						 info->peer_verify_domain);
 		}
 #endif
+#if HAVE_X509_VERIFY_PARAM_SET1_HOST
 		if (info->peer_verify_domain)
 		{
-			char *idn_domain1;
-
-			if (idna_to_unicode_8z8z(info->peer_verify_domain,
-						 &idn_domain1, 0)
-			    != IDNA_SUCCESS)
-				idn_domain1=0;
-
 			X509_VERIFY_PARAM *param = SSL_get0_param(ssl);
 			X509_VERIFY_PARAM_set1_host(param,
 						    idn_domain1 ?
 						    idn_domain1 :
 						    info->peer_verify_domain,
 						    0);
-			if (idn_domain1)
-				free(idn_domain1);
 		}
+#endif
+		if (idn_domain1)
+			free(idn_domain1);
 
 		if ((rc=SSL_connect(ssl)) > 0)
 		{