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| author | Duoming Zhou <duoming@zju.edu.cn> | 2022-09-28 16:39:38 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-10-26 14:19:26 +0300 |
| commit | 27f74a47d5b1cf52d48af15993bb1caa31ad8f5b (patch) | |
| tree | e774661fe63aceabe478331facc84e9ffabc95c7 /drivers/isdn | |
| parent | 7aac8c63f604e6a6a46560c0f0188cd0332cf320 (diff) | |
| download | linux-27f74a47d5b1cf52d48af15993bb1caa31ad8f5b.tar.xz | |
mISDN: fix use-after-free bugs in l1oip timer handlers
[ Upstream commit 2568a7e0832ee30b0a351016d03062ab4e0e0a3f ]
The l1oip_cleanup() traverses the l1oip_ilist and calls
release_card() to cleanup module and stack. However,
release_card() calls del_timer() to delete the timers
such as keep_tl and timeout_tl. If the timer handler is
running, the del_timer() will not stop it and result in
UAF bugs. One of the processes is shown below:
(cleanup routine) | (timer handler)
release_card() | l1oip_timeout()
... |
del_timer() | ...
... |
kfree(hc) //FREE |
| hc->timeout_on = 0 //USE
Fix by calling del_timer_sync() in release_card(), which
makes sure the timer handlers have finished before the
resources, such as l1oip and so on, have been deallocated.
What's more, the hc->workq and hc->socket_thread can kick
those timers right back in. We add a bool flag to show
if card is released. Then, check this flag in hc->workq
and hc->socket_thread.
Fixes: 3712b42d4b1b ("Add layer1 over IP support")
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/isdn')
| -rw-r--r-- | drivers/isdn/mISDN/l1oip.h | 1 | ||||
| -rw-r--r-- | drivers/isdn/mISDN/l1oip_core.c | 13 |
2 files changed, 8 insertions, 6 deletions
diff --git a/drivers/isdn/mISDN/l1oip.h b/drivers/isdn/mISDN/l1oip.h index 7ea10db20e3a..48133d022812 100644 --- a/drivers/isdn/mISDN/l1oip.h +++ b/drivers/isdn/mISDN/l1oip.h @@ -59,6 +59,7 @@ struct l1oip { int bundle; /* bundle channels in one frm */ int codec; /* codec to use for transmis. */ int limit; /* limit number of bchannels */ + bool shutdown; /* if card is released */ /* timer */ struct timer_list keep_tl; diff --git a/drivers/isdn/mISDN/l1oip_core.c b/drivers/isdn/mISDN/l1oip_core.c index b05022f94f18..2f4a01ab25e8 100644 --- a/drivers/isdn/mISDN/l1oip_core.c +++ b/drivers/isdn/mISDN/l1oip_core.c @@ -289,7 +289,7 @@ l1oip_socket_send(struct l1oip *hc, u8 localcodec, u8 channel, u32 chanmask, p = frame; /* restart timer */ - if (time_before(hc->keep_tl.expires, jiffies + 5 * HZ)) + if (time_before(hc->keep_tl.expires, jiffies + 5 * HZ) && !hc->shutdown) mod_timer(&hc->keep_tl, jiffies + L1OIP_KEEPALIVE * HZ); else hc->keep_tl.expires = jiffies + L1OIP_KEEPALIVE * HZ; @@ -615,7 +615,9 @@ multiframe: goto multiframe; /* restart timer */ - if (time_before(hc->timeout_tl.expires, jiffies + 5 * HZ) || !hc->timeout_on) { + if ((time_before(hc->timeout_tl.expires, jiffies + 5 * HZ) || + !hc->timeout_on) && + !hc->shutdown) { hc->timeout_on = 1; mod_timer(&hc->timeout_tl, jiffies + L1OIP_TIMEOUT * HZ); } else /* only adjust timer */ @@ -1247,11 +1249,10 @@ release_card(struct l1oip *hc) { int ch; - if (timer_pending(&hc->keep_tl)) - del_timer(&hc->keep_tl); + hc->shutdown = true; - if (timer_pending(&hc->timeout_tl)) - del_timer(&hc->timeout_tl); + del_timer_sync(&hc->keep_tl); + del_timer_sync(&hc->timeout_tl); cancel_work_sync(&hc->workq); |