Simplify X509_ATTRIBUTE ASN.1 encoding.

For some unknown historical reason, X509_ATTRIBUTE allows for a single
ASN.1 value or an ASN.1 SET OF, rather than requiring an ASN.1 SET OF.
Simplify encoding and remove support for single values - this is similar
to OpenSSL e20b57270dec.

This removes the last use of COMBINE in the ASN.1 decoder.

ok tb@

1 files changed, 3 insertions, 7 deletions

diff --git a/src/lib/libcrypto/pkcs7/pk7_doit.c b/src/lib/libcrypto/pkcs7/pk7_doit.c
index c9d64bcf34..b314069610 100644
--- a/src/lib/libcrypto/pkcs7/pk7_doit.c
+++ b/src/lib/libcrypto/pkcs7/pk7_doit.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: pk7_doit.c,v 1.46 2021/12/12 21:30:14 tb Exp $ */
+/* $OpenBSD: pk7_doit.c,v 1.47 2022/05/09 19:19:33 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -1129,12 +1129,8 @@ get_attribute(STACK_OF(X509_ATTRIBUTE) *sk, int nid)
                 return (NULL);
         for (i = 0; i < sk_X509_ATTRIBUTE_num(sk); i++) {
                 xa = sk_X509_ATTRIBUTE_value(sk, i);
-                if (OBJ_cmp(xa->object, o) == 0) {
-                        if (!xa->single && sk_ASN1_TYPE_num(xa->value.set))
-                                return (sk_ASN1_TYPE_value(xa->value.set, 0));
-                        else
-                                return (NULL);
-                }
+                if (OBJ_cmp(xa->object, o) == 0)
+                        return (sk_ASN1_TYPE_value(xa->set, 0));
         }
         return (NULL);
 }