diff options
| author |   Jann Horn <jannh@google.com> | 2019-03-27 16:55:08 +0100 |
|---|---|---|
| committer |   James Morris <james.morris@microsoft.com> | 2019-04-10 10:29:50 -0700 |
| commit | 0b9dc6c9f01c4a726558b82a3b6082a89d264eb5 (patch) | |
| tree | 1acfa81de568fa53ee14fac6219a140cd6560778 /security/keys/request_key.c | |
| parent | security: don't use RCU accessors for cred->session_keyring (diff) | |
| download | wireguard-linux-0b9dc6c9f01c4a726558b82a3b6082a89d264eb5.tar.xz wireguard-linux-0b9dc6c9f01c4a726558b82a3b6082a89d264eb5.zip | |
keys: safe concurrent user->{session,uid}_keyring access
The current code can perform concurrent updates and reads on
user->session_keyring and user->uid_keyring. Add a comment to
struct user_struct to document the nontrivial locking semantics, and use
READ_ONCE() for unlocked readers and smp_store_release() for writers to
prevent memory ordering issues.
Fixes: 69664cf16af4 ("keys: don't generate user and user session keyrings unless they're accessed")
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: James Morris <james.morris@microsoft.com>
Diffstat (limited to 'security/keys/request_key.c')
| -rw-r--r-- | security/keys/request_key.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/security/keys/request_key.c b/security/keys/request_key.c index db72dc4d7639..75d87f9e0f49 100644 --- a/security/keys/request_key.c +++ b/security/keys/request_key.c @@ -293,11 +293,12 @@ static int construct_get_dest_keyring(struct key **_dest_keyring) /* fall through */ case KEY_REQKEY_DEFL_USER_SESSION_KEYRING: dest_keyring = - key_get(cred->user->session_keyring); + key_get(READ_ONCE(cred->user->session_keyring)); break; case KEY_REQKEY_DEFL_USER_KEYRING: - dest_keyring = key_get(cred->user->uid_keyring); + dest_keyring = + key_get(READ_ONCE(cred->user->uid_keyring)); break; case KEY_REQKEY_DEFL_GROUP_KEYRING: |