From b206f281d0ee14969878469816a69db22d5838e8 Mon Sep 17 00:00:00 2001 From: David Howells Date: Wed, 26 Jun 2019 21:02:32 +0100 Subject: keys: Namespace keyring names Keyring names are held in a single global list that any process can pick from by means of keyctl_join_session_keyring (provided the keyring grants Search permission). This isn't very container friendly, however. Make the following changes: (1) Make default session, process and thread keyring names begin with a '.' instead of '_'. (2) Keyrings whose names begin with a '.' aren't added to the list. Such keyrings are system specials. (3) Replace the global list with per-user_namespace lists. A keyring adds its name to the list for the user_namespace that it is currently in. (4) When a user_namespace is deleted, it just removes itself from the keyring name list. The global keyring_name_lock is retained for accessing the name lists. This allows (4) to work. This can be tested by: # keyctl newring foo @s 995906392 # unshare -U $ keyctl show ... 995906392 --alswrv 65534 65534 \_ keyring: foo ... $ keyctl session foo Joined session keyring: 935622349 As can be seen, a new session keyring was created. The capability bit KEYCTL_CAPS1_NS_KEYRING_NAME is set if the kernel is employing this feature. Signed-off-by: David Howells cc: Eric W. Biederman --- include/linux/key.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux/key.h') diff --git a/include/linux/key.h b/include/linux/key.h index ff102731b3db..ae1177302d70 100644 --- a/include/linux/key.h +++ b/include/linux/key.h @@ -361,6 +361,7 @@ extern void key_set_timeout(struct key *, unsigned); extern key_ref_t lookup_user_key(key_serial_t id, unsigned long flags, key_perm_t perm); +extern void key_free_user_ns(struct user_namespace *); /* * The permissions required on a key that we're looking up. @@ -434,6 +435,7 @@ extern void key_init(void); #define key_fsuid_changed(c) do { } while(0) #define key_fsgid_changed(c) do { } while(0) #define key_init() do { } while(0) +#define key_free_user_ns(ns) do { } while(0) #endif /* CONFIG_KEYS */ #endif /* __KERNEL__ */ -- cgit v1.2.3-59-g8ed1b