Merge "KEYS: add missing permission check for request_key() destination" into staging/n/fp2
diff --git a/security/keys/request_key.c b/security/keys/request_key.c
index cc37903..02cb0b4 100644
--- a/security/keys/request_key.c
+++ b/security/keys/request_key.c
@@ -267,11 +267,12 @@
* The keyring selected is returned with an extra reference upon it which the
* caller must release.
*/
-static void construct_get_dest_keyring(struct key **_dest_keyring)
+static int construct_get_dest_keyring(struct key **_dest_keyring)
{
struct request_key_auth *rka;
const struct cred *cred = current_cred();
struct key *dest_keyring = *_dest_keyring, *authkey;
+ int ret;
kenter("%p", dest_keyring);
@@ -280,6 +281,8 @@
/* the caller supplied one */
key_get(dest_keyring);
} else {
+ bool do_perm_check = true;
+
/* use a default keyring; falling through the cases until we
* find one that we actually have */
switch (cred->jit_keyring) {
@@ -294,8 +297,10 @@
dest_keyring =
key_get(rka->dest_keyring);
up_read(&authkey->sem);
- if (dest_keyring)
+ if (dest_keyring) {
+ do_perm_check = false;
break;
+ }
}
case KEY_REQKEY_DEFL_THREAD_KEYRING:
@@ -330,11 +335,29 @@
default:
BUG();
}
+
+ /*
+ * Require Write permission on the keyring. This is essential
+ * because the default keyring may be the session keyring, and
+ * joining a keyring only requires Search permission.
+ *
+ * However, this check is skipped for the "requestor keyring" so
+ * that /sbin/request-key can itself use request_key() to add
+ * keys to the original requestor's destination keyring.
+ */
+ if (dest_keyring && do_perm_check) {
+ ret = key_permission(make_key_ref(dest_keyring, 1),
+ KEY_WRITE);
+ if (ret) {
+ key_put(dest_keyring);
+ return ret;
+ }
+ }
}
*_dest_keyring = dest_keyring;
kleave(" [dk %d]", key_serial(dest_keyring));
- return;
+ return 0;
}
/*
@@ -449,11 +472,16 @@
kenter("");
- user = key_user_lookup(current_fsuid(), current_user_ns());
- if (!user)
- return ERR_PTR(-ENOMEM);
+ ret = construct_get_dest_keyring(&dest_keyring);
+ if (ret)
+ goto error;
- construct_get_dest_keyring(&dest_keyring);
+ user = key_user_lookup(current_fsuid(), current_user_ns());
+ if (!user) {
+ ret = -ENOMEM;
+ goto error_put_dest_keyring;
+ }
+
ret = construct_alloc_key(type, description, dest_keyring, flags, user,
&key);
@@ -469,7 +497,7 @@
} else if (ret == -EINPROGRESS) {
ret = 0;
} else {
- goto couldnt_alloc_key;
+ goto error_put_dest_keyring;
}
key_put(dest_keyring);
@@ -479,8 +507,9 @@
construction_failed:
key_negate_and_link(key, key_negative_timeout, NULL, NULL);
key_put(key);
-couldnt_alloc_key:
+error_put_dest_keyring:
key_put(dest_keyring);
+error:
kleave(" = %d", ret);
return ERR_PTR(ret);
}