Allow specific libtls hostname validation errors to propagate.

Remove direct calls to printf from the tls_check_hostname() path. This allows
NUL byte error messages to bubble up to the caller, to be logged in a
program-appropriate way. It also removes non-portable calls to getprogname().

ok jsing@

3 files changed, 27 insertions, 21 deletions

diff --git a/lib/libtls/tls_client.c b/lib/libtls/tls_client.c
index b851a6ecd0e..43819cf0b6f 100644
--- a/lib/libtls/tls_client.c
+++ b/lib/libtls/tls_client.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls_client.c,v 1.4 2014/12/07 15:48:02 bcook Exp $ */
+/* $OpenBSD: tls_client.c,v 1.5 2014/12/07 16:56:17 bcook Exp $ */
 /*
  * Copyright (c) 2014 Joel Sing <jsing@openbsd.org>
  *
@@ -209,9 +209,10 @@ tls_connect_fds(struct tls *ctx, int fd_read, int fd_write,
 			tls_set_error(ctx, "no server certificate");
 			goto err;
 		}
-		if (tls_check_hostname(cert, hostname) != 0) {
-			tls_set_error(ctx, "host `%s' not present in"
-			    " server certificate", hostname);
+		if ((ret = tls_check_hostname(ctx, cert, hostname)) != 0) {
+			if (ret != -2)
+				tls_set_error(ctx, "host `%s' not present in"
+				    " server certificate", hostname);
 			goto err;
 		}
 	}
diff --git a/lib/libtls/tls_internal.h b/lib/libtls/tls_internal.h
index a23e63f7af4..bfd7146d7d0 100644
--- a/lib/libtls/tls_internal.h
+++ b/lib/libtls/tls_internal.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls_internal.h,v 1.3 2014/12/07 15:48:02 bcook Exp $ */
+/* $OpenBSD: tls_internal.h,v 1.4 2014/12/07 16:56:17 bcook Exp $ */
 /*
  * Copyright (c) 2014 Jeremie Courreges-Anglas <jca@openbsd.org>
  * Copyright (c) 2014 Joel Sing <jsing@openbsd.org>
@@ -62,7 +62,7 @@ struct tls {
 struct tls *tls_new(void);
 struct tls *tls_server_conn(struct tls *ctx);
 
-int tls_check_hostname(X509 *cert, const char *host);
+int tls_check_hostname(struct tls *ctx, X509 *cert, const char *host);
 int tls_configure_keypair(struct tls *ctx);
 int tls_configure_server(struct tls *ctx);
 int tls_configure_ssl(struct tls *ctx);
diff --git a/lib/libtls/tls_verify.c b/lib/libtls/tls_verify.c
index ddc403fb10d..697432c429b 100644
--- a/lib/libtls/tls_verify.c
+++ b/lib/libtls/tls_verify.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls_verify.c,v 1.4 2014/12/07 16:01:03 jsing Exp $ */
+/* $OpenBSD: tls_verify.c,v 1.5 2014/12/07 16:56:17 bcook Exp $ */
 /*
  * Copyright (c) 2014 Jeremie Courreges-Anglas <jca@openbsd.org>
  *
@@ -27,8 +27,8 @@
 #include "tls_internal.h"
 
 int tls_match_hostname(const char *cert_hostname, const char *hostname);
-int tls_check_subject_altname(X509 *cert, const char *host);
-int tls_check_common_name(X509 *cert, const char *host);
+int tls_check_subject_altname(struct tls *ctx, X509 *cert, const char *host);
+int tls_check_common_name(struct tls *ctx, X509 *cert, const char *host);
 
 int
 tls_match_hostname(const char *cert_hostname, const char *hostname)
@@ -80,7 +80,7 @@ tls_match_hostname(const char *cert_hostname, const char *hostname)
 }
 
 int
-tls_check_subject_altname(X509 *cert, const char *host)
+tls_check_subject_altname(struct tls *ctx, X509 *cert, const char *host)
 {
 	STACK_OF(GENERAL_NAME) *altname_stack = NULL;
 	union { struct in_addr ip4; struct in6_addr ip6; } addrbuf;
@@ -123,10 +123,11 @@ tls_check_subject_altname(X509 *cert, const char *host)
 
 				if (ASN1_STRING_length(altname->d.dNSName) !=
 				    (int)strlen(data)) {
-					fprintf(stdout, "%s: NUL byte in "
-					    "subjectAltName, probably a "
-					    "malicious certificate.\n",
-					    getprogname());
+					tls_set_error(ctx,
+					    "error verifying host '%s': "
+					    "NUL byte in subjectAltName, "
+					    "probably a malicious certificate",
+					    host);
 					rv = -2;
 					break;
 				}
@@ -135,10 +136,13 @@ tls_check_subject_altname(X509 *cert, const char *host)
 					rv = 0;
 					break;
 				}
-			} else
+			} else {
+#ifdef DEBUG
 				fprintf(stdout, "%s: unhandled subjectAltName "
 				    "dNSName encoding (%d)\n", getprogname(),
 				    format);
+#endif
+			}
 
 		} else if (type == GEN_IPADD) {
 			unsigned char	*data;
@@ -160,7 +164,7 @@ tls_check_subject_altname(X509 *cert, const char *host)
 }
 
 int
-tls_check_common_name(X509 *cert, const char *host)
+tls_check_common_name(struct tls *ctx, X509 *cert, const char *host)
 {
 	X509_NAME *name;
 	char *common_name = NULL;
@@ -186,8 +190,9 @@ tls_check_common_name(X509 *cert, const char *host)
 
 	/* NUL bytes in CN? */
 	if (common_name_len != (int)strlen(common_name)) {
-		fprintf(stdout, "%s: NUL byte in Common Name field, "
-		    "probably a malicious certificate.\n", getprogname());
+		tls_set_error(ctx, "error verifying host '%s': "
+		    "NUL byte in Common Name field, "
+		    "probably a malicious certificate.", host);
 		rv = -2;
 		goto out;
 	}
@@ -213,13 +218,13 @@ out:
 }
 
 int
-tls_check_hostname(X509 *cert, const char *host)
+tls_check_hostname(struct tls *ctx, X509 *cert, const char *host)
 {
 	int	rv;
 
-	rv = tls_check_subject_altname(cert, host);
+	rv = tls_check_subject_altname(ctx, cert, host);
 	if (rv == 0 || rv == -2)
 		return rv;
 
-	return tls_check_common_name(cert, host);
+	return tls_check_common_name(ctx, cert, host);
 }