diff mbox series

[1/6] keys: Fix request_key() lack of Link perm check on found key

Message ID 155856517025.11737.11943384989202404333.stgit@warthog.procyon.org.uk (mailing list archive)
State New, archived
Headers show
Series keys: request_key() improvements(vspace)s | expand

Commit Message

David Howells May 22, 2019, 10:46 p.m. UTC
The request_key() syscall allows a process to gain access to the 'possessor'
permits of any key that grants it Search permission by virtue of request_key()
not checking whether a key it finds grants Link permission to the caller.

Signed-off-by: David Howells <dhowells@redhat.com>
---

 security/keys/request_key.c |   10 ++++++++++
 1 file changed, 10 insertions(+)
diff mbox series

Patch

diff --git a/security/keys/request_key.c b/security/keys/request_key.c
index e3653c6f85c6..d204d7c0152e 100644
--- a/security/keys/request_key.c
+++ b/security/keys/request_key.c
@@ -559,6 +559,16 @@  struct key *request_key_and_link(struct key_type *type,
 	key_ref = search_process_keyrings(&ctx);
 
 	if (!IS_ERR(key_ref)) {
+		if (dest_keyring) {
+			ret = key_task_permission(key_ref, current_cred(),
+						  KEY_NEED_LINK);
+			if (ret < 0) {
+				key_ref_put(key_ref);
+				key = ERR_PTR(ret);
+				goto error_free;
+			}
+		}
+
 		key = key_ref_to_ptr(key_ref);
 		if (dest_keyring) {
 			ret = key_link(dest_keyring, key);