Correct tls_config_clear_keys() behaviour.

Previously this incorrectly called tls_keypair_clear(), which results in
the private key being cleared, along with the certificate, OCSP staple and
pubkey hash. This breaks OCSP stapling if tls_config_clear_keys() is called
following tls_configure(), as is done by httpd.

Fix this by calling tls_keypair_clear_key() so that only the private key is
cleared, leaving the other public data untouched. While here, remove
tls_keypair_clear() and fold the necessary parts into tls_keypair_free().

ok beck@

3 files changed, 18 insertions, 30 deletions

diff --git a/src/lib/libtls/tls_config.c b/src/lib/libtls/tls_config.c
index d32176fe6e..07019252a7 100644
--- a/src/lib/libtls/tls_config.c
+++ b/src/lib/libtls/tls_config.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls_config.c,v 1.51 2018/03/20 15:40:10 jsing Exp $ */
+/* $OpenBSD: tls_config.c,v 1.52 2018/04/07 16:35:34 jsing Exp $ */
 /*
  * Copyright (c) 2014 Joel Sing <jsing@openbsd.org>
  *
@@ -189,10 +189,7 @@ tls_config_clear_keys(struct tls_config *config)
         struct tls_keypair *kp;
 
         for (kp = config->keypair; kp != NULL; kp = kp->next)
-                tls_keypair_clear(kp);
-
-        tls_config_set_ca_mem(config, NULL, 0);
-        tls_config_set_crl_mem(config, NULL, 0);
+                tls_keypair_clear_key(kp);
 }
 
 int
diff --git a/src/lib/libtls/tls_internal.h b/src/lib/libtls/tls_internal.h
index 0d7e2289d3..b236204e81 100644
--- a/src/lib/libtls/tls_internal.h
+++ b/src/lib/libtls/tls_internal.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls_internal.h,v 1.71 2018/03/19 16:34:47 jsing Exp $ */
+/* $OpenBSD: tls_internal.h,v 1.72 2018/04/07 16:35:34 jsing Exp $ */
 /*
  * Copyright (c) 2014 Jeremie Courreges-Anglas <jca@openbsd.org>
  * Copyright (c) 2014 Joel Sing <jsing@openbsd.org>
@@ -199,7 +199,7 @@ int tls_set_mem(char **_dest, size_t *_destlen, const void *_src,
 int tls_set_string(const char **_dest, const char *_src);
 
 struct tls_keypair *tls_keypair_new(void);
-void tls_keypair_clear(struct tls_keypair *_keypair);
+void tls_keypair_clear_key(struct tls_keypair *_keypair);
 void tls_keypair_free(struct tls_keypair *_keypair);
 int tls_keypair_set_cert_file(struct tls_keypair *_keypair,
     struct tls_error *_error, const char *_cert_file);
diff --git a/src/lib/libtls/tls_keypair.c b/src/lib/libtls/tls_keypair.c
index 03e7f4ad76..a98e5c2e7e 100644
--- a/src/lib/libtls/tls_keypair.c
+++ b/src/lib/libtls/tls_keypair.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls_keypair.c,v 1.5 2018/02/10 04:57:35 jsing Exp $ */
+/* $OpenBSD: tls_keypair.c,v 1.6 2018/04/07 16:35:34 jsing Exp $ */
 /*
  * Copyright (c) 2014 Joel Sing <jsing@openbsd.org>
  *
@@ -29,14 +29,6 @@ tls_keypair_new(void)
         return calloc(1, sizeof(struct tls_keypair));
 }
 
-static void
-tls_keypair_clear_key(struct tls_keypair *keypair)
-{
-        freezero(keypair->key_mem, keypair->key_len);
-        keypair->key_mem = NULL;
-        keypair->key_len = 0;
-}
-
 static int
 tls_keypair_pubkey_hash(struct tls_keypair *keypair, struct tls_error *error)
 {
@@ -64,6 +56,14 @@ tls_keypair_pubkey_hash(struct tls_keypair *keypair, struct tls_error *error)
         return (rv);
 }
 
+void
+tls_keypair_clear_key(struct tls_keypair *keypair)
+{
+        freezero(keypair->key_mem, keypair->key_len);
+        keypair->key_mem = NULL;
+        keypair->key_len = 0;
+}
+
 int
 tls_keypair_set_cert_file(struct tls_keypair *keypair, struct tls_error *error,
     const char *cert_file)
@@ -117,25 +117,16 @@ tls_keypair_set_ocsp_staple_mem(struct tls_keypair *keypair,
 }
 
 void
-tls_keypair_clear(struct tls_keypair *keypair)
-{
-        struct tls_error error;
-
-        tls_keypair_set_cert_mem(keypair, &error, NULL, 0);
-        tls_keypair_set_key_mem(keypair, &error, NULL, 0);
-        tls_keypair_set_ocsp_staple_mem(keypair, &error, NULL, 0);
-
-        free(keypair->pubkey_hash);
-        keypair->pubkey_hash = NULL;
-}
-
-void
 tls_keypair_free(struct tls_keypair *keypair)
 {
         if (keypair == NULL)
                 return;
 
-        tls_keypair_clear(keypair);
+        tls_keypair_clear_key(keypair);
+
+        free(keypair->cert_mem);
+        free(keypair->ocsp_staple);
+        free(keypair->pubkey_hash);
 
         free(keypair);
 }