| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.12 060/116] NFSv4: Fix a use-after-free situation in _nfs4_proc_getlk() | Date | Tue, 26 Nov 2013 16:57:13 -0800 |
| |
3.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Trond Myklebust <Trond.Myklebust@netapp.com>
commit a6f951ddbdfb7bd87d31a44f61abe202ed6ce57f upstream.
In nfs4_proc_getlk(), when some error causes a retry of the call to _nfs4_proc_getlk(), we can end up with Oopses of the form
BUG: unable to handle kernel NULL pointer dereference at 0000000000000134 IP: [<ffffffff8165270e>] _raw_spin_lock+0xe/0x30 <snip> Call Trace: [<ffffffff812f287d>] _atomic_dec_and_lock+0x4d/0x70 [<ffffffffa053c4f2>] nfs4_put_lock_state+0x32/0xb0 [nfsv4] [<ffffffffa053c585>] nfs4_fl_release_lock+0x15/0x20 [nfsv4] [<ffffffffa0522c06>] _nfs4_proc_getlk.isra.40+0x146/0x170 [nfsv4] [<ffffffffa052ad99>] nfs4_proc_lock+0x399/0x5a0 [nfsv4]
The problem is that we don't clear the request->fl_ops after the first try and so when we retry, nfs4_set_lock_state() exits early without setting the lock stateid. Regression introduced by commit 70cc6487a4e08b8698c0e2ec935fb48d10490162 (locks: make ->lock release private data before returning in GETLK case)
Reported-by: Weston Andros Adamson <dros@netapp.com> Reported-by: Jorge Mora <mora@netapp.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- fs/nfs/nfs4proc.c | 1 + 1 file changed, 1 insertion(+)
--- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -5106,6 +5106,7 @@ static int _nfs4_proc_getlk(struct nfs4_ status = 0; } request->fl_ops->fl_release_private(request); + request->fl_ops = NULL; out: return status; }
|