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@

4 files changed, 34 insertions, 24 deletions

diff --git a/src/lib/libtls/tls_client.c b/src/lib/libtls/tls_client.c
index b851a6ecd0..43819cf0b6 100644
--- a/src/lib/libtls/tls_client.c
+++ b/src/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/src/lib/libtls/tls_internal.h b/src/lib/libtls/tls_internal.h
index a23e63f7af..bfd7146d7d 100644
--- a/src/lib/libtls/tls_internal.h
+++ b/src/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/src/lib/libtls/tls_verify.c b/src/lib/libtls/tls_verify.c
index ddc403fb10..697432c429 100644
--- a/src/lib/libtls/tls_verify.c
+++ b/src/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);
 }
diff --git a/src/regress/lib/libtls/verify/verifytest.c b/src/regress/lib/libtls/verify/verifytest.c
index bb8b372014..81dcb90a67 100644
--- a/src/regress/lib/libtls/verify/verifytest.c
+++ b/src/regress/lib/libtls/verify/verifytest.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: verifytest.c,v 1.1 2014/11/01 11:55:27 jsing Exp $    */
+/*      $OpenBSD: verifytest.c,v 1.2 2014/12/07 16:56:17 bcook Exp $    */
 /*
  * Copyright (c) 2014 Joel Sing <jsing@openbsd.org>
  *
@@ -20,8 +20,9 @@
 #include <stdlib.h>
 
 #include <openssl/x509v3.h>
+#include <tls.h>
 
-extern int tls_check_hostname(X509 *cert, const char *host);
+extern int tls_check_hostname(struct tls *ctx, X509 *cert, const char *host);
 
 struct verify_test {
         const char common_name[128];
@@ -162,6 +163,7 @@ do_verify_test(int test_no, struct verify_test *vt)
         GENERAL_NAME *alt_name;
         X509_NAME *name;
         X509 *cert;
+        struct tls *tls;
 
         /* Build certificate structure. */
         if ((cert = X509_new()) == NULL)
@@ -174,6 +176,8 @@ do_verify_test(int test_no, struct verify_test *vt)
         if (X509_set_subject_name(cert, name) == 0)
                 errx(1, "failed to set subject name");
         X509_NAME_free(name);
+        if ((tls = tls_client()) == NULL)
+                errx(1, "failed to malloc tls_client");
 
         if (vt->alt_name_type != 0) {
                 if ((alt_name_stack = sk_GENERAL_NAME_new_null()) == NULL)
@@ -209,7 +213,7 @@ do_verify_test(int test_no, struct verify_test *vt)
                 sk_GENERAL_NAME_pop_free(alt_name_stack, GENERAL_NAME_free);
         }
 
-        if (tls_check_hostname(cert, vt->hostname) != vt->want) {
+        if (tls_check_hostname(tls, cert, vt->hostname) != vt->want) {
                 fprintf(stderr, "FAIL: test %i failed with common name "
                     "'%s', alt name '%s' and hostname '%s'\n", test_no,
                     vt->common_name, vt->alt_name, vt->hostname);