KEYS: instantiation and atomicity fixes

From: Eric Biggers <[email protected]>

The first two patches in this series fix bugs related to instantiating keys which allowed unprivileged users to cause a kernel oops. Specifically, the first patch removes the ability for add_key() to update an uninstantiated key, as this was heavily broken; and the second patch fixes a race condition related to add_key() updating a negative key into a positive one.

The remaining patches fix some other, more theoretical atomicity issues with accessing key->flags and key->expiry, then eliminate KEY_FLAG_NEGATIVE, which becomes unnecessary after the second patch.

Eric Biggers (7):
KEYS: don't let add_key() update an uninstantiated key
KEYS: fix race between updating and finding negative key
KEYS: load key flags atomically in key_is_instantiated()
KEYS: load key flags and expiry time atomically in key_validate()
KEYS: load key flags and expiry time atomically in
keyring_search_iterator()
KEYS: load key flags and expiry time atomically in proc_keys_show()
KEYS: remove KEY_FLAG_NEGATIVE

 include/linux/key.h                      | 25 +++++++++++++++++++++----
 security/keys/encrypted-keys/encrypted.c |  2 +-
 security/keys/gc.c                       |  4 +---
 security/keys/key.c                      | 24 +++++++++++++++++-------
 security/keys/keyctl.c                   |  5 ++++-
 security/keys/keyring.c                  | 22 +++++++++++++---------
 security/keys/permission.c               |  7 ++++---
 security/keys/proc.c                     | 28 ++++++++++++++++------------
 security/keys/request_key.c              | 11 +++++++----
 security/keys/trusted.c                  |  2 +-
 security/keys/user_defined.c             |  2 +-
 11 files changed, 86 insertions(+), 46 deletions(-)

2.14.2.822.g60be5d43e6-goog