* [PATCH v2 net] octeontx2-pf: Fix use-after-free bugs in otx2_sync_tstamp()
@ 2025-09-17 6:38 Duoming Zhou
2025-09-17 11:18 ` Vadim Fedorenko
2025-09-18 15:00 ` patchwork-bot+netdevbpf
0 siblings, 2 replies; 3+ messages in thread
From: Duoming Zhou @ 2025-09-17 6:38 UTC (permalink / raw)
To: netdev
Cc: linux-kernel, pabeni, kuba, edumazet, davem, sgoutham, gakula,
sbhatta, hkelam, bbhushan2, andrew+netdev, richardcochran,
naveenm, Duoming Zhou
The original code relies on cancel_delayed_work() in otx2_ptp_destroy(),
which does not ensure that the delayed work item synctstamp_work has fully
completed if it was already running. This leads to use-after-free scenarios
where otx2_ptp is deallocated by otx2_ptp_destroy(), while synctstamp_work
remains active and attempts to dereference otx2_ptp in otx2_sync_tstamp().
Furthermore, the synctstamp_work is cyclic, the likelihood of triggering
the bug is nonnegligible.
A typical race condition is illustrated below:
CPU 0 (cleanup) | CPU 1 (delayed work callback)
otx2_remove() |
otx2_ptp_destroy() | otx2_sync_tstamp()
cancel_delayed_work() |
kfree(ptp) |
| ptp = container_of(...); //UAF
| ptp-> //UAF
This is confirmed by a KASAN report:
BUG: KASAN: slab-use-after-free in __run_timer_base.part.0+0x7d7/0x8c0
Write of size 8 at addr ffff88800aa09a18 by task bash/136
...
Call Trace:
<IRQ>
dump_stack_lvl+0x55/0x70
print_report+0xcf/0x610
? __run_timer_base.part.0+0x7d7/0x8c0
kasan_report+0xb8/0xf0
? __run_timer_base.part.0+0x7d7/0x8c0
__run_timer_base.part.0+0x7d7/0x8c0
? __pfx___run_timer_base.part.0+0x10/0x10
? __pfx_read_tsc+0x10/0x10
? ktime_get+0x60/0x140
? lapic_next_event+0x11/0x20
? clockevents_program_event+0x1d4/0x2a0
run_timer_softirq+0xd1/0x190
handle_softirqs+0x16a/0x550
irq_exit_rcu+0xaf/0xe0
sysvec_apic_timer_interrupt+0x70/0x80
</IRQ>
...
Allocated by task 1:
kasan_save_stack+0x24/0x50
kasan_save_track+0x14/0x30
__kasan_kmalloc+0x7f/0x90
otx2_ptp_init+0xb1/0x860
otx2_probe+0x4eb/0xc30
local_pci_probe+0xdc/0x190
pci_device_probe+0x2fe/0x470
really_probe+0x1ca/0x5c0
__driver_probe_device+0x248/0x310
driver_probe_device+0x44/0x120
__driver_attach+0xd2/0x310
bus_for_each_dev+0xed/0x170
bus_add_driver+0x208/0x500
driver_register+0x132/0x460
do_one_initcall+0x89/0x300
kernel_init_freeable+0x40d/0x720
kernel_init+0x1a/0x150
ret_from_fork+0x10c/0x1a0
ret_from_fork_asm+0x1a/0x30
Freed by task 136:
kasan_save_stack+0x24/0x50
kasan_save_track+0x14/0x30
kasan_save_free_info+0x3a/0x60
__kasan_slab_free+0x3f/0x50
kfree+0x137/0x370
otx2_ptp_destroy+0x38/0x80
otx2_remove+0x10d/0x4c0
pci_device_remove+0xa6/0x1d0
device_release_driver_internal+0xf8/0x210
pci_stop_bus_device+0x105/0x150
pci_stop_and_remove_bus_device_locked+0x15/0x30
remove_store+0xcc/0xe0
kernfs_fop_write_iter+0x2c3/0x440
vfs_write+0x871/0xd70
ksys_write+0xee/0x1c0
do_syscall_64+0xac/0x280
entry_SYSCALL_64_after_hwframe+0x77/0x7f
...
Replace cancel_delayed_work() with cancel_delayed_work_sync() to ensure
that the delayed work item is properly canceled before the otx2_ptp is
deallocated.
This bug was initially identified through static analysis. To reproduce
and test it, I simulated the OcteonTX2 PCI device in QEMU and introduced
artificial delays within the otx2_sync_tstamp() function to increase the
likelihood of triggering the bug.
Fixes: 2958d17a8984 ("octeontx2-pf: Add support for ptp 1-step mode on CN10K silicon")
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
---
Changes in v2:
- Describe how the issue was discovered and how the patch was tested.
drivers/net/ethernet/marvell/octeontx2/nic/otx2_ptp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_ptp.c b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_ptp.c
index e52cc6b1a26c..dedd586ed310 100644
--- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_ptp.c
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_ptp.c
@@ -491,7 +491,7 @@ void otx2_ptp_destroy(struct otx2_nic *pfvf)
if (!ptp)
return;
- cancel_delayed_work(&pfvf->ptp->synctstamp_work);
+ cancel_delayed_work_sync(&pfvf->ptp->synctstamp_work);
ptp_clock_unregister(ptp->ptp_clock);
kfree(ptp);
--
2.34.1
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH v2 net] octeontx2-pf: Fix use-after-free bugs in otx2_sync_tstamp()
2025-09-17 6:38 [PATCH v2 net] octeontx2-pf: Fix use-after-free bugs in otx2_sync_tstamp() Duoming Zhou
@ 2025-09-17 11:18 ` Vadim Fedorenko
2025-09-18 15:00 ` patchwork-bot+netdevbpf
1 sibling, 0 replies; 3+ messages in thread
From: Vadim Fedorenko @ 2025-09-17 11:18 UTC (permalink / raw)
To: Duoming Zhou, netdev
Cc: linux-kernel, pabeni, kuba, edumazet, davem, sgoutham, gakula,
sbhatta, hkelam, bbhushan2, andrew+netdev, richardcochran,
naveenm
On 17/09/2025 07:38, Duoming Zhou wrote:
> The original code relies on cancel_delayed_work() in otx2_ptp_destroy(),
> which does not ensure that the delayed work item synctstamp_work has fully
> completed if it was already running. This leads to use-after-free scenarios
> where otx2_ptp is deallocated by otx2_ptp_destroy(), while synctstamp_work
> remains active and attempts to dereference otx2_ptp in otx2_sync_tstamp().
> Furthermore, the synctstamp_work is cyclic, the likelihood of triggering
> the bug is nonnegligible.
>
> A typical race condition is illustrated below:
>
> CPU 0 (cleanup) | CPU 1 (delayed work callback)
> otx2_remove() |
> otx2_ptp_destroy() | otx2_sync_tstamp()
> cancel_delayed_work() |
> kfree(ptp) |
> | ptp = container_of(...); //UAF
> | ptp-> //UAF
>
> This is confirmed by a KASAN report:
>
> BUG: KASAN: slab-use-after-free in __run_timer_base.part.0+0x7d7/0x8c0
> Write of size 8 at addr ffff88800aa09a18 by task bash/136
> ...
> Call Trace:
> <IRQ>
> dump_stack_lvl+0x55/0x70
> print_report+0xcf/0x610
> ? __run_timer_base.part.0+0x7d7/0x8c0
> kasan_report+0xb8/0xf0
> ? __run_timer_base.part.0+0x7d7/0x8c0
> __run_timer_base.part.0+0x7d7/0x8c0
> ? __pfx___run_timer_base.part.0+0x10/0x10
> ? __pfx_read_tsc+0x10/0x10
> ? ktime_get+0x60/0x140
> ? lapic_next_event+0x11/0x20
> ? clockevents_program_event+0x1d4/0x2a0
> run_timer_softirq+0xd1/0x190
> handle_softirqs+0x16a/0x550
> irq_exit_rcu+0xaf/0xe0
> sysvec_apic_timer_interrupt+0x70/0x80
> </IRQ>
> ...
> Allocated by task 1:
> kasan_save_stack+0x24/0x50
> kasan_save_track+0x14/0x30
> __kasan_kmalloc+0x7f/0x90
> otx2_ptp_init+0xb1/0x860
> otx2_probe+0x4eb/0xc30
> local_pci_probe+0xdc/0x190
> pci_device_probe+0x2fe/0x470
> really_probe+0x1ca/0x5c0
> __driver_probe_device+0x248/0x310
> driver_probe_device+0x44/0x120
> __driver_attach+0xd2/0x310
> bus_for_each_dev+0xed/0x170
> bus_add_driver+0x208/0x500
> driver_register+0x132/0x460
> do_one_initcall+0x89/0x300
> kernel_init_freeable+0x40d/0x720
> kernel_init+0x1a/0x150
> ret_from_fork+0x10c/0x1a0
> ret_from_fork_asm+0x1a/0x30
>
> Freed by task 136:
> kasan_save_stack+0x24/0x50
> kasan_save_track+0x14/0x30
> kasan_save_free_info+0x3a/0x60
> __kasan_slab_free+0x3f/0x50
> kfree+0x137/0x370
> otx2_ptp_destroy+0x38/0x80
> otx2_remove+0x10d/0x4c0
> pci_device_remove+0xa6/0x1d0
> device_release_driver_internal+0xf8/0x210
> pci_stop_bus_device+0x105/0x150
> pci_stop_and_remove_bus_device_locked+0x15/0x30
> remove_store+0xcc/0xe0
> kernfs_fop_write_iter+0x2c3/0x440
> vfs_write+0x871/0xd70
> ksys_write+0xee/0x1c0
> do_syscall_64+0xac/0x280
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
> ...
>
> Replace cancel_delayed_work() with cancel_delayed_work_sync() to ensure
> that the delayed work item is properly canceled before the otx2_ptp is
> deallocated.
>
> This bug was initially identified through static analysis. To reproduce
> and test it, I simulated the OcteonTX2 PCI device in QEMU and introduced
> artificial delays within the otx2_sync_tstamp() function to increase the
> likelihood of triggering the bug.
>
> Fixes: 2958d17a8984 ("octeontx2-pf: Add support for ptp 1-step mode on CN10K silicon")
> Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
> ---
> Changes in v2:
> - Describe how the issue was discovered and how the patch was tested.
>
> drivers/net/ethernet/marvell/octeontx2/nic/otx2_ptp.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_ptp.c b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_ptp.c
> index e52cc6b1a26c..dedd586ed310 100644
> --- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_ptp.c
> +++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_ptp.c
> @@ -491,7 +491,7 @@ void otx2_ptp_destroy(struct otx2_nic *pfvf)
> if (!ptp)
> return;
>
> - cancel_delayed_work(&pfvf->ptp->synctstamp_work);
> + cancel_delayed_work_sync(&pfvf->ptp->synctstamp_work);
>
> ptp_clock_unregister(ptp->ptp_clock);
> kfree(ptp);
Reviewed-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH v2 net] octeontx2-pf: Fix use-after-free bugs in otx2_sync_tstamp()
2025-09-17 6:38 [PATCH v2 net] octeontx2-pf: Fix use-after-free bugs in otx2_sync_tstamp() Duoming Zhou
2025-09-17 11:18 ` Vadim Fedorenko
@ 2025-09-18 15:00 ` patchwork-bot+netdevbpf
1 sibling, 0 replies; 3+ messages in thread
From: patchwork-bot+netdevbpf @ 2025-09-18 15:00 UTC (permalink / raw)
To: Duoming Zhou
Cc: netdev, linux-kernel, pabeni, kuba, edumazet, davem, sgoutham,
gakula, sbhatta, hkelam, bbhushan2, andrew+netdev, richardcochran,
naveenm
Hello:
This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:
On Wed, 17 Sep 2025 14:38:53 +0800 you wrote:
> The original code relies on cancel_delayed_work() in otx2_ptp_destroy(),
> which does not ensure that the delayed work item synctstamp_work has fully
> completed if it was already running. This leads to use-after-free scenarios
> where otx2_ptp is deallocated by otx2_ptp_destroy(), while synctstamp_work
> remains active and attempts to dereference otx2_ptp in otx2_sync_tstamp().
> Furthermore, the synctstamp_work is cyclic, the likelihood of triggering
> the bug is nonnegligible.
>
> [...]
Here is the summary with links:
- [v2,net] octeontx2-pf: Fix use-after-free bugs in otx2_sync_tstamp()
https://git.kernel.org/netdev/net/c/f8b468715102
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
^ permalink raw reply [flat|nested] 3+ messages in thread
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2025-09-17 6:38 [PATCH v2 net] octeontx2-pf: Fix use-after-free bugs in otx2_sync_tstamp() Duoming Zhou
2025-09-17 11:18 ` Vadim Fedorenko
2025-09-18 15:00 ` patchwork-bot+netdevbpf
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