diff options
| author | Cyrill Gorcunov <gorcunov@gmail.com> | 2014-08-08 00:26:15 +0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-09-08 15:55:25 -0700 |
| commit | b216df53848129c969a465bb9237fbc9b8fafaad (patch) | |
| tree | 58db0c4a3a54dfa04f136fc2b80999a0a069b1aa /drivers/tty/tty_io.c | |
| parent | 8b374399468da1c25db5b5d436b167aafc10fbdc (diff) | |
tty: Fix potential use after free in release_one_tty
In case if we're releasing the last tty reference the following
call sequence is possible
tty_driver_kref_put
destruct_tty_driver
kfree(driver);
where @driver is used in next module_put call, which leads to
| [ 285.964007] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
| [ 285.964007] Workqueue: events release_one_tty
| [ 285.964007] task: ffff8800cc7ea5f0 ti: ffff8800cb800000 task.ti: ffff8800cb800000
| [ 285.964007] RIP: 0010:[<ffffffff810aeaf5>] [<ffffffff810aeaf5>] module_put+0x24/0xf4
| [ 285.964007] RSP: 0018:ffff8800cb801d48 EFLAGS: 00010213
| [ 285.964007] RAX: ffff8800cb801fd8 RBX: ffff8800ca3429d0 RCX: ffff8800cb1db400
| [ 285.964007] RDX: 0000000000000000 RSI: ffffffff817349c1 RDI: 0000000000000001
| [ 285.964007] RBP: ffff8800cb801d60 R08: ffff8800cd632b40 R09: 0000000000000000
| [ 285.964007] R10: 00000000ffffffff R11: ffff88011f40a000 R12: 6b6b6b6b6b6b6b6b
| [ 285.964007] R13: ffff8800ca342520 R14: 0000000000000000 R15: ffff88011f5d8200
| [ 285.964007] FS: 0000000000000000(0000) GS:ffff88011f400000(0000) knlGS:0000000000000000
| [ 285.964007] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
| [ 285.964007] CR2: 00007faf5229d090 CR3: 0000000001c0b000 CR4: 00000000000006f0
| [ 285.964007] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
| [ 285.964007] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
| [ 285.964007] Stack:
| [ 285.964007] ffff8800ca3429d0 ffff8800ca342a30 ffff8800ca342520 ffff8800cb801d88
| [ 285.964007] ffffffff8146554a ffff8800cc77cc78 ffff8800ca3429d0 ffff88011f5d3800
| [ 285.964007] ffff8800cb801e08 ffffffff810683c1 ffffffff810682ff 0000000000000046
| [ 285.964007] Call Trace:
| [ 285.964007] [<ffffffff8146554a>] release_one_tty+0x54/0xa3
| [ 285.964007] [<ffffffff810683c1>] process_one_work+0x223/0x404
| [ 285.964007] [<ffffffff810682ff>] ? process_one_work+0x161/0x404
| [ 285.964007] [<ffffffff81068971>] worker_thread+0x136/0x205
| [ 285.964007] [<ffffffff8106883b>] ? rescuer_thread+0x26a/0x26a
| [ 285.964007] [<ffffffff8106e5bf>] kthread+0xa2/0xaa
| [ 285.964007] [<ffffffff810a4586>] ? trace_hardirqs_on_caller+0x16/0x1eb
| [ 285.964007] [<ffffffff8106e51d>] ? __kthread_parkme+0x65/0x65
| [ 285.964007] [<ffffffff8173f59c>] ret_from_fork+0x7c/0xb0
| [ 285.964007] [<ffffffff8106e51d>] ? __kthread_parkme+0x65/0x65
| [ 285.964007] Code: 09 00 5b 41 5c 5d c3 0f 1f 44 00 00 55 48 85 ff 48 89 e5 41 55 41 54 49 89 fc 53 0f 84 d3 00
| 00 00 bf 01 00 00 00 e8 d0 a1 fc ff <49> 8b 84 24 50 02 00 00 65 48 ff 40 08 4c 8b 6d 08 0f 1f 44 00
so simply keep a local reference to the module owner and
use it later.
CC: Pavel Emelyanov <xemul@parallels.com>
CC: Jiri Slaby <jslaby@suse.cz>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/tty_io.c')
| -rw-r--r-- | drivers/tty/tty_io.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 8fbad3410c75..d4eb2a8b7047 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -1544,13 +1544,14 @@ static void release_one_tty(struct work_struct *work) struct tty_struct *tty = container_of(work, struct tty_struct, hangup_work); struct tty_driver *driver = tty->driver; + struct module *owner = driver->owner; if (tty->ops->cleanup) tty->ops->cleanup(tty); tty->magic = 0; tty_driver_kref_put(driver); - module_put(driver->owner); + module_put(owner); spin_lock(&tty_files_lock); list_del_init(&tty->tty_files); |