diff options
| author | Trond Myklebust <Trond.Myklebust@netapp.com> | 2013-10-01 14:24:58 -0400 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2014-01-03 04:33:14 +0000 |
| commit | 920362294face70e146b4b2f65dc642c2e9b67f8 (patch) | |
| tree | 7f6a31b550d761a0ab0721c9050caaccbb66d4f8 /fs | |
| parent | b18bcfee90ed988e8e4f2072ce97173bbe05b201 (diff) | |
| download | lwn-920362294face70e146b4b2f65dc642c2e9b67f8.tar.gz lwn-920362294face70e146b4b2f65dc642c2e9b67f8.zip | |
NFSv4: Fix a use-after-free situation in _nfs4_proc_getlk()
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: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/nfs/nfs4proc.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index 5639efd3298e..64fe3db05b9d 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -4052,6 +4052,7 @@ static int _nfs4_proc_getlk(struct nfs4_state *state, int cmd, struct file_lock status = 0; } request->fl_ops->fl_release_private(request); + request->fl_ops = NULL; out: return status; } |