Rework tls_check_subject_altname() error handling

Default to having rv = -1 and explicitly goto done to set rv = 0.
This matches other code better.

ok jsing

1 files changed, 13 insertions, 12 deletions

diff --git a/src/lib/libtls/tls_verify.c b/src/lib/libtls/tls_verify.c
index c3127fa4fe..c588f027c5 100644
--- a/src/lib/libtls/tls_verify.c
+++ b/src/lib/libtls/tls_verify.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls_verify.c,v 1.27 2023/06/01 07:29:15 tb Exp $ */
+/* $OpenBSD: tls_verify.c,v 1.28 2023/06/01 07:32:25 tb Exp $ */
 /*
  * Copyright (c) 2014 Jeremie Courreges-Anglas <jca@openbsd.org>
  *
@@ -93,7 +93,7 @@ tls_check_subject_altname(struct tls *ctx, X509 *cert, const char *name,
         int addrlen, type;
         int count, i;
         int critical = 0;
-        int rv = 0;
+        int rv = -1;
 
         *alt_match = 0;
         *alt_exists = 0;
@@ -103,9 +103,9 @@ tls_check_subject_altname(struct tls *ctx, X509 *cert, const char *name,
         if (altname_stack == NULL) {
                 if (critical != -1) {
                         tls_set_errorx(ctx, "error decoding subjectAltName");
-                        return -1;
+                        goto err;
                 }
-                return 0;
+                goto done;
         }
 
         if (inet_pton(AF_INET, name, &addrbuf) == 1) {
@@ -146,8 +146,7 @@ tls_check_subject_altname(struct tls *ctx, X509 *cert, const char *name,
                                             "NUL byte in subjectAltName, "
                                             "probably a malicious certificate",
                                             name);
-                                        rv = -1;
-                                        break;
+                                        goto err;
                                 }
 
                                 /*
@@ -160,13 +159,12 @@ tls_check_subject_altname(struct tls *ctx, X509 *cert, const char *name,
                                             "error verifying name '%s': "
                                             "a dNSName of \" \" must not be "
                                             "used", name);
-                                        rv = -1;
-                                        break;
+                                        goto err;
                                 }
 
                                 if (tls_match_name(data, name) == 0) {
                                         *alt_match = 1;
-                                        break;
+                                        goto done;
                                 }
                         } else {
 #ifdef DEBUG
@@ -187,8 +185,7 @@ tls_check_subject_altname(struct tls *ctx, X509 *cert, const char *name,
                                 tls_set_errorx(ctx,
                                     "Unexpected negative length for an "
                                     "IP address: %d", datalen);
-                                rv = -1;
-                                break;
+                                goto err;
                         }
 
                         /*
@@ -198,11 +195,15 @@ tls_check_subject_altname(struct tls *ctx, X509 *cert, const char *name,
                         if (datalen == addrlen &&
                             memcmp(data, &addrbuf, addrlen) == 0) {
                                 *alt_match = 1;
-                                break;
+                                goto done;
                         }
                 }
         }
 
+ done:
+        rv = 0;
+
+ err:
         sk_GENERAL_NAME_pop_free(altname_stack, GENERAL_NAME_free);
         return rv;
 }