* [PATCH v2] net: nfc: Fix use-after-free in local_cleanup()
@ 2023-01-06 5:50 Jisoo Jang
2023-01-07 19:02 ` Saeed Mahameed
0 siblings, 1 reply; 2+ messages in thread
From: Jisoo Jang @ 2023-01-06 5:50 UTC (permalink / raw)
To: pabeni, krzysztof.kozlowski, netdev
Cc: edumazet, kuba, dokyungs, linuxlovemin
local_cleanup(). When detaching an nfc device, local_cleanup()
called from nfc_llcp_unregister_device() frees local->rx_pending
and cancels local->rx_work. So the socket allocated before
unregister is not set null by nfc_llcp_rx_work().
local_cleanup() called from local_release() frees local->rx_pending
again, which leads to the bug.
Set local->rx_pending to NULL in local_cleanup()
Found by a modified version of syzkaller.
BUG: KASAN: use-after-free in kfree_skb
Call Trace:
kfree_skb
local_cleanup
nfc_llcp_local_put
llcp_sock_destruct
__sk_destruct
sk_destruct
__sk_free
sk_free
llcp_sock_release
__sock_release
sock_close
__fput
task_work_run
exit_to_user_mode_prepare
syscall_exit_to_user_mode
do_syscall_64
entry_SYSCALL_64_after_hwframe
Allocate by:
__alloc_skb
pn533_recv_response
__usb_hcd_giveback_urb
usb_hcd_giveback_urb
dummy_timer
call_timer_fn
run_timer_softirq
__do_softirq
Freed by:
kfree_skbmem
kfree_skb
local_cleanup
nfc_llcp_unregister_device
nfc_unregister_device
pn53x_unregister_nfc
pn533_usb_disconnect
usb_unbind_interface
device_release_driver_internal
bus_remove_device
device_del
usb_disable_device
usb_disconnect
hub_event
process_one_work
worker_thread
kthread
ret_from_fork
Signed-off-by: Jisoo Jang <jisoo.jang@yonsei.ac.kr>
---
v1->v2: set local->rx_pending to NULL instead move kfree_skb()
net/nfc/llcp_core.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/net/nfc/llcp_core.c b/net/nfc/llcp_core.c
index 3364caabef8b..a27e1842b2a0 100644
--- a/net/nfc/llcp_core.c
+++ b/net/nfc/llcp_core.c
@@ -157,6 +157,7 @@ static void local_cleanup(struct nfc_llcp_local *local)
cancel_work_sync(&local->rx_work);
cancel_work_sync(&local->timeout_work);
kfree_skb(local->rx_pending);
+ local->rx_pending = NULL;
del_timer_sync(&local->sdreq_timer);
cancel_work_sync(&local->sdreq_timeout_work);
nfc_llcp_free_sdp_tlv_list(&local->pending_sdreqs);
--
2.25.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v2] net: nfc: Fix use-after-free in local_cleanup()
2023-01-06 5:50 [PATCH v2] net: nfc: Fix use-after-free in local_cleanup() Jisoo Jang
@ 2023-01-07 19:02 ` Saeed Mahameed
0 siblings, 0 replies; 2+ messages in thread
From: Saeed Mahameed @ 2023-01-07 19:02 UTC (permalink / raw)
To: Jisoo Jang
Cc: pabeni, krzysztof.kozlowski, netdev, edumazet, kuba, dokyungs,
linuxlovemin
On 06 Jan 14:50, Jisoo Jang wrote:
>local_cleanup(). When detaching an nfc device, local_cleanup()
>called from nfc_llcp_unregister_device() frees local->rx_pending
>and cancels local->rx_work. So the socket allocated before
>unregister is not set null by nfc_llcp_rx_work().
>local_cleanup() called from local_release() frees local->rx_pending
>again, which leads to the bug.
>
>Set local->rx_pending to NULL in local_cleanup()
>
>Found by a modified version of syzkaller.
>
>BUG: KASAN: use-after-free in kfree_skb
>Call Trace:
> kfree_skb
> local_cleanup
> nfc_llcp_local_put
> llcp_sock_destruct
> __sk_destruct
> sk_destruct
> __sk_free
> sk_free
> llcp_sock_release
> __sock_release
> sock_close
> __fput
> task_work_run
> exit_to_user_mode_prepare
> syscall_exit_to_user_mode
> do_syscall_64
> entry_SYSCALL_64_after_hwframe
>
>Allocate by:
> __alloc_skb
> pn533_recv_response
> __usb_hcd_giveback_urb
> usb_hcd_giveback_urb
> dummy_timer
> call_timer_fn
> run_timer_softirq
> __do_softirq
>
>Freed by:
> kfree_skbmem
> kfree_skb
> local_cleanup
Why local_cleanup is called explicitly here ?
The next thing nfc_llcp_unregister_device() will call is
nfc_llcp_local_put()->kref_put->local_release()->local_cleanup()
> nfc_llcp_unregister_device
> nfc_unregister_device
> pn53x_unregister_nfc
> pn533_usb_disconnect
> usb_unbind_interface
> device_release_driver_internal
> bus_remove_device
> device_del
> usb_disable_device
> usb_disconnect
> hub_event
> process_one_work
> worker_thread
> kthread
> ret_from_fork
>
>
>Signed-off-by: Jisoo Jang <jisoo.jang@yonsei.ac.kr>
>---
>v1->v2: set local->rx_pending to NULL instead move kfree_skb()
>
> net/nfc/llcp_core.c | 1 +
> 1 file changed, 1 insertion(+)
>
>diff --git a/net/nfc/llcp_core.c b/net/nfc/llcp_core.c
>index 3364caabef8b..a27e1842b2a0 100644
>--- a/net/nfc/llcp_core.c
>+++ b/net/nfc/llcp_core.c
>@@ -157,6 +157,7 @@ static void local_cleanup(struct nfc_llcp_local *local)
> cancel_work_sync(&local->rx_work);
> cancel_work_sync(&local->timeout_work);
> kfree_skb(local->rx_pending);
>+ local->rx_pending = NULL;
> del_timer_sync(&local->sdreq_timer);
> cancel_work_sync(&local->sdreq_timeout_work);
> nfc_llcp_free_sdp_tlv_list(&local->pending_sdreqs);
>--
>2.25.1
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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2023-01-06 5:50 [PATCH v2] net: nfc: Fix use-after-free in local_cleanup() Jisoo Jang
2023-01-07 19:02 ` Saeed Mahameed
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