diff options
| author | David Howells <dhowells@redhat.com> | 2010-04-23 13:18:00 -0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-04-24 11:31:25 -0700 |
| commit | 93b4a44f3ad69520d605aace3f3486b8eb754b96 (patch) | |
| tree | 8eb946db950ccc6aee1d00b226739f44141dd310 /security/keys | |
| parent | ccdb40048b2972f10bdc944913c0e0ee26b5d1f2 (diff) | |
| download | lwn-93b4a44f3ad69520d605aace3f3486b8eb754b96.tar.gz lwn-93b4a44f3ad69520d605aace3f3486b8eb754b96.zip | |
keys: fix an RCU warning
Fix the following RCU warning:
===================================================
[ INFO: suspicious rcu_dereference_check() usage. ]
---------------------------------------------------
security/keys/request_key.c:116 invoked rcu_dereference_check() without protection!
This was caused by doing:
[root@andromeda ~]# keyctl newring fred @s
539196288
[root@andromeda ~]# keyctl request2 user a a 539196288
request_key: Required key not available
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'security/keys')
| -rw-r--r-- | security/keys/request_key.c | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/security/keys/request_key.c b/security/keys/request_key.c index 03fe63ed55bd..ea97c3120d66 100644 --- a/security/keys/request_key.c +++ b/security/keys/request_key.c @@ -68,7 +68,8 @@ static int call_sbin_request_key(struct key_construction *cons, { const struct cred *cred = current_cred(); key_serial_t prkey, sskey; - struct key *key = cons->key, *authkey = cons->authkey, *keyring; + struct key *key = cons->key, *authkey = cons->authkey, *keyring, + *session; char *argv[9], *envp[3], uid_str[12], gid_str[12]; char key_str[12], keyring_str[3][12]; char desc[20]; @@ -112,10 +113,12 @@ static int call_sbin_request_key(struct key_construction *cons, if (cred->tgcred->process_keyring) prkey = cred->tgcred->process_keyring->serial; - if (cred->tgcred->session_keyring) - sskey = rcu_dereference(cred->tgcred->session_keyring)->serial; - else - sskey = cred->user->session_keyring->serial; + rcu_read_lock(); + session = rcu_dereference(cred->tgcred->session_keyring); + if (!session) + session = cred->user->session_keyring; + sskey = session->serial; + rcu_read_unlock(); sprintf(keyring_str[2], "%d", sskey); |