1 files changed, 42 insertions, 34 deletions

diff --git a/src/lib/libcrypto/pkcs7/pk7_doit.c b/src/lib/libcrypto/pkcs7/pk7_doit.c
index 3a2076a25f..e39d960780 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 1.60 2025/05/10 05:54:38 tb Exp $ */
+/* $OpenBSD: pk7_doit.c,v 1.61 2025/07/27 07:06:41 tb Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -1208,43 +1208,51 @@ PKCS7_set_attributes(PKCS7_SIGNER_INFO *p7si, STACK_OF(X509_ATTRIBUTE) *sk)
 LCRYPTO_ALIAS(PKCS7_set_attributes);
 
 static int
-add_attribute(STACK_OF(X509_ATTRIBUTE) **sk, int nid, int atrtype, void *value)
+add_attribute(STACK_OF(X509_ATTRIBUTE) **in_sk, int nid, int atrtype, void *value)
 {
-        X509_ATTRIBUTE *attr = NULL;
+        STACK_OF(X509_ATTRIBUTE) *sk;
+        X509_ATTRIBUTE *old_attr = NULL, *new_attr = NULL;
+        int need_pop = 0;
+        int i;
 
-        if (*sk == NULL) {
-                *sk = sk_X509_ATTRIBUTE_new_null();
-                if (*sk == NULL)
-                        return 0;
-new_attrib:
-                if (!(attr = X509_ATTRIBUTE_create(nid, atrtype, value)))
-                        return 0;
-                if (!sk_X509_ATTRIBUTE_push(*sk, attr)) {
-                        X509_ATTRIBUTE_free(attr);
-                        return 0;
-                }
-        } else {
-                int i;
-
-                for (i = 0; i < sk_X509_ATTRIBUTE_num(*sk); i++) {
-                        attr = sk_X509_ATTRIBUTE_value(*sk, i);
-                        if (OBJ_obj2nid(attr->object) == nid) {
-                                X509_ATTRIBUTE_free(attr);
-                                attr = X509_ATTRIBUTE_create(nid, atrtype,
-                                    value);
-                                if (attr == NULL)
-                                        return 0;
-                                if (!sk_X509_ATTRIBUTE_set(*sk, i, attr)) {
-                                        X509_ATTRIBUTE_free(attr);
-                                        return 0;
-                                }
-                                goto end;
-                        }
-                }
-                goto new_attrib;
+        if ((sk = *in_sk) == NULL)
+                sk = sk_X509_ATTRIBUTE_new_null();
+        if (sk == NULL)
+                goto err;
+
+        /* Replace an already existing attribute with the given nid. */
+        for (i = 0; i < sk_X509_ATTRIBUTE_num(sk); i++) {
+                old_attr = sk_X509_ATTRIBUTE_value(sk, i);
+                if(OBJ_obj2nid(old_attr->object) == nid)
+                        break;
+        }
+
+        /* If there is none, make room for the new one, so _set() succeeds. */
+        if (i == sk_X509_ATTRIBUTE_num(sk)) {
+                old_attr = NULL;
+                if (sk_X509_ATTRIBUTE_push(sk, NULL) <= 0)
+                        goto err;
+                need_pop = 1;
         }
-end:
+
+        /* On success, new_attr owns value. */
+        if ((new_attr = X509_ATTRIBUTE_create(nid, atrtype, value)) == NULL)
+                goto err;
+
+        X509_ATTRIBUTE_free(old_attr);
+        (void)sk_X509_ATTRIBUTE_set(sk, i, new_attr);
+
+        *in_sk = sk;
+
         return 1;
+
+ err:
+        if (need_pop)
+                (void)sk_X509_ATTRIBUTE_pop(sk);
+        if (*in_sk != sk)
+                sk_X509_ATTRIBUTE_pop_free(sk, X509_ATTRIBUTE_free);
+
+        return 0;
 }
 
 int