[PATCH 0/9] keys: Namespacing [ver #4]

From: David Howells
Date: Wed Jun 19 2019 - 12:51:52 EST

Here are some patches to make keys and keyrings more namespace aware.

Firstly some miscellaneous patches to make the process easier:

(1) Simplify key index_key handling so that the word-sized chunks
assoc_array requires don't have to be shifted about, making it easier
to add more bits into the key.

(2) Cache the hash value in the key so that we don't have to calculate on
every key we examine during a search (it involves a bunch of

(3) Allow keying_search() to search non-recursively.

Then the main patches:

(4) Make it so that keyring names are per-user_namespace from the point of
view of KEYCTL_JOIN_SESSION_KEYRING so that they're not accessible

keyctl_capabilities() shows KEYCTL_CAPS1_NS_KEYRING_NAME for this.

(5) Move the user and user-session keyrings to the user_namespace rather
than the user_struct. This prevents them propagating directly across
user_namespaces boundaries (ie. the KEY_SPEC_* flags will only pick
from the current user_namespace).

(6) Make it possible to include the target namespace in which the key shall
operate in the index_key. This will allow the possibility of multiple
keys with the same description, but different target domains to be held
in the same keyring.

keyctl_capabilities() shows KEYCTL_CAPS1_NS_KEY_TAG for this.

(7) Make it so that keys are implicitly invalidated by removal of a domain
tag, causing them to be garbage collected.

(8) Institute a network namespace domain tag that allows keys to be
differentiated by the network namespace in which they operate. New keys
that are of a type marked 'KEY_TYPE_NET_DOMAIN' are assigned the network
domain in force when they are created.

(9) Make it so that the desired network namespace can be handed down into the
request_key() mechanism. This allows AFS, NFS, etc. to request keys
specific to the network namespace of the superblock.

This also means that the keys in the DNS record cache are thenceforth
namespaced, provided network filesystems pass the appropriate network
namespace down into dns_query().

For DNS, AFS and NFS are good; CIFS and Ceph are not. Other cache
keyrings, such as idmapper keyrings, also need to set the domain tag -
for which they need access to the network namespace of the superblock.

The patches can be found on the following branch:


David Howells (9):
keys: Simplify key description management
keys: Cache the hash value to avoid lots of recalculation
keys: Add a 'recurse' flag for keyring searches
keys: Namespace keyring names
keys: Move the user and user-session keyrings to the user_namespace
keys: Include target namespace in match criteria
keys: Garbage collect keys for which the domain has been removed
keys: Network namespace domain tag
keys: Pass the network namespace into request_key mechanism

Documentation/security/keys/core.rst | 38 +++-
Documentation/security/keys/request-key.rst | 29 ++-
certs/blacklist.c | 2
crypto/asymmetric_keys/asymmetric_type.c | 2
fs/afs/addr_list.c | 4
fs/afs/dynroot.c | 8 +
fs/cifs/dns_resolve.c | 3
fs/nfs/dns_resolve.c | 3
fs/nfs/nfs4idmap.c | 2
include/linux/dns_resolver.h | 3
include/linux/key-type.h | 3
include/linux/key.h | 81 ++++++++
include/linux/sched/user.h | 14 -
include/linux/user_namespace.h | 12 +
include/net/net_namespace.h | 3
include/uapi/linux/keyctl.h | 2
kernel/user.c | 8 -
kernel/user_namespace.c | 9 -
lib/digsig.c | 2
net/ceph/messenger.c | 3
net/core/net_namespace.c | 19 ++
net/dns_resolver/dns_key.c | 1
net/dns_resolver/dns_query.c | 7 +
net/rxrpc/key.c | 6 -
net/rxrpc/security.c | 2
security/integrity/digsig_asymmetric.c | 4
security/keys/gc.c | 2
security/keys/internal.h | 10 +
security/keys/key.c | 5 -
security/keys/keyctl.c | 8 +
security/keys/keyring.c | 263 +++++++++++++++------------
security/keys/persistent.c | 10 +
security/keys/proc.c | 3
security/keys/process_keys.c | 262 +++++++++++++++++----------
security/keys/request_key.c | 62 ++++--
security/keys/request_key_auth.c | 3
36 files changed, 588 insertions(+), 310 deletions(-)