Avoid potential NULL dereference in ssl_set_pkey()

Switch from X509_get_pubkey() to X509_get0_pubkey() to avoid an unnecessary
EVP_PKEY_free(). Check the return values of X509_get0_pubkey() and
EVP_PKEY_copy_parameters(). If the former returns NULL, the latter will
dereference NULL.

CID 25020

ok jsing

1 files changed, 9 insertions, 5 deletions

diff --git a/src/lib/libssl/ssl_rsa.c b/src/lib/libssl/ssl_rsa.c
index 192dc4291e..98c1e1b7b3 100644
--- a/src/lib/libssl/ssl_rsa.c
+++ b/src/lib/libssl/ssl_rsa.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssl_rsa.c,v 1.45 2022/06/30 09:08:35 tb Exp $ */
+/* $OpenBSD: ssl_rsa.c,v 1.46 2022/08/31 06:51:36 tb Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -184,9 +184,13 @@ ssl_set_pkey(SSL_CTX *ctx, SSL *ssl, EVP_PKEY *pkey)
 
         if (c->pkeys[i].x509 != NULL) {
                 EVP_PKEY *pktmp;
-                pktmp = X509_get_pubkey(c->pkeys[i].x509);
-                EVP_PKEY_copy_parameters(pktmp, pkey);
-                EVP_PKEY_free(pktmp);
+
+                if ((pktmp = X509_get0_pubkey(c->pkeys[i].x509)) == NULL)
+                        return 0;
+
+                if (!EVP_PKEY_copy_parameters(pktmp, pkey))
+                        return 0;
+
                 ERR_clear_error();
 
                 /*
@@ -209,7 +213,7 @@ ssl_set_pkey(SSL_CTX *ctx, SSL *ssl, EVP_PKEY *pkey)
         c->key = &(c->pkeys[i]);
 
         c->valid = 0;
-        return (1);
+        return 1;
 }
 
 int