KEYS: Add a key type op to permit the key description to be vetted

Add a key type operation to permit the key type to vet the description of a new
key that key_alloc() is about to allocate.  The operation may reject the
description if it wishes with an error of its choosing.  If it does this, the
key will not be allocated.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/security/keys/key.c b/security/keys/key.c
index 1c2d43dc5107..8e315ef2e88e 100644
--- a/security/keys/key.c
+++ b/security/keys/key.c
@@ -249,6 +249,14 @@ struct key *key_alloc(struct key_type *type, const char *desc,
         if (!desc || !*desc)
                 goto error;
 
+        if (type->vet_description) {
+                ret = type->vet_description(desc);
+                if (ret < 0) {
+                        key = ERR_PTR(ret);
+                        goto error;
+                }
+        }
+
         desclen = strlen(desc) + 1;
         quotalen = desclen + type->def_datalen;