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| author |   David Howells <dhowells@redhat.com> | 2010-04-20 11:25:49 +0100 |
|---|---|---|
| committer |   Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2010-05-04 09:24:58 -0700 |
| commit | bfeb0360de7713de8240cafd7ecf6058b6dbea0b (patch) | |
| tree | 65ec28e5c97f78dd70c49ba278bda215ef4da37b /security/keys/request_key.c | |
| parent | rcu: Fix RCU lockdep splat on freezer_fork path (diff) | |
| download | linux-dev-bfeb0360de7713de8240cafd7ecf6058b6dbea0b.tar.xz linux-dev-bfeb0360de7713de8240cafd7ecf6058b6dbea0b.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!
other info that might help us debug this:
rcu_scheduler_active = 1, debug_locks = 0
1 lock held by keyctl/5372:
#0: (key_types_sem){.+.+.+}, at: [<ffffffff811a4e3d>] key_type_lookup+0x1c/0x70
stack backtrace:
Pid: 5372, comm: keyctl Not tainted 2.6.34-rc3-cachefs #150
Call Trace:
[<ffffffff810515f8>] lockdep_rcu_dereference+0xaa/0xb2
[<ffffffff811a9220>] call_sbin_request_key+0x156/0x2b6
[<ffffffff811a4c66>] ? __key_instantiate_and_link+0xb1/0xdc
[<ffffffff811a4cd3>] ? key_instantiate_and_link+0x42/0x5f
[<ffffffff811a96b8>] ? request_key_auth_new+0x17b/0x1f3
[<ffffffff811a8e00>] ? request_key_and_link+0x271/0x400
[<ffffffff810aba6f>] ? kmem_cache_alloc+0xe1/0x118
[<ffffffff811a8f1a>] request_key_and_link+0x38b/0x400
[<ffffffff811a7b72>] sys_request_key+0xf7/0x14a
[<ffffffff81052227>] ? trace_hardirqs_on_caller+0x10c/0x130
[<ffffffff81393f5c>] ? trace_hardirqs_on_thunk+0x3a/0x3f
[<ffffffff81001eeb>] system_call_fastpath+0x16/0x1b
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: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to '')
| -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); |