Unexpected WDCMSG_TARGET_START replay can lead to null-ptr-deref
when ar->tx_cmd->odata is NULL. The patch adds a null check to
prevent such case.
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
ar5523_cmd+0x46a/0x581 [ar5523]
ar5523_probe.cold+0x1b7/0x18da [ar5523]
? ar5523_cmd_rx_cb+0x7a0/0x7a0 [ar5523]
? __pm_runtime_set_status+0x54a/0x8f0
? _raw_spin_trylock_bh+0x120/0x120
? pm_runtime_barrier+0x220/0x220
? __pm_runtime_resume+0xb1/0xf0
usb_probe_interface+0x25b/0x710
really_probe+0x209/0x5d0
driver_probe_device+0xc6/0x1b0
device_driver_attach+0xe2/0x120
Signed-off-by: Zekun Shen <[email protected]>
---
drivers/net/wireless/ath/ar5523/ar5523.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/net/wireless/ath/ar5523/ar5523.c b/drivers/net/wireless/ath/ar5523/ar5523.c
index 49cc4b7ed..1baec4b41 100644
--- a/drivers/net/wireless/ath/ar5523/ar5523.c
+++ b/drivers/net/wireless/ath/ar5523/ar5523.c
@@ -153,6 +153,10 @@ static void ar5523_cmd_rx_cb(struct urb *urb)
ar5523_err(ar, "Invalid reply to WDCMSG_TARGET_START");
return;
}
+ if (!cmd->odata) {
+ ar5523_err(ar, "Unexpected WDCMSG_TARGET_START reply");
+ return;
+ }
memcpy(cmd->odata, hdr + 1, sizeof(u32));
cmd->olen = sizeof(u32);
cmd->res = 0;
--
2.25.1
Zekun Shen <[email protected]> writes:
> Unexpected WDCMSG_TARGET_START replay can lead to null-ptr-deref
> when ar->tx_cmd->odata is NULL. The patch adds a null check to
> prevent such case.
>
> KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
> ar5523_cmd+0x46a/0x581 [ar5523]
> ar5523_probe.cold+0x1b7/0x18da [ar5523]
> ? ar5523_cmd_rx_cb+0x7a0/0x7a0 [ar5523]
> ? __pm_runtime_set_status+0x54a/0x8f0
> ? _raw_spin_trylock_bh+0x120/0x120
> ? pm_runtime_barrier+0x220/0x220
> ? __pm_runtime_resume+0xb1/0xf0
> usb_probe_interface+0x25b/0x710
> really_probe+0x209/0x5d0
> driver_probe_device+0xc6/0x1b0
> device_driver_attach+0xe2/0x120
>
> Signed-off-by: Zekun Shen <[email protected]>
How did you test this?
--
https://patchwork.kernel.org/project/linux-wireless/list/
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
On Fri, Oct 29, 2021 at 06:53:30AM +0300, Kalle Valo wrote:
> Zekun Shen <[email protected]> writes:
>
> > Unexpected WDCMSG_TARGET_START replay can lead to null-ptr-deref
> > when ar->tx_cmd->odata is NULL. The patch adds a null check to
> > prevent such case.
> >
> > KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
> > ar5523_cmd+0x46a/0x581 [ar5523]
> > ar5523_probe.cold+0x1b7/0x18da [ar5523]
> > ? ar5523_cmd_rx_cb+0x7a0/0x7a0 [ar5523]
> > ? __pm_runtime_set_status+0x54a/0x8f0
> > ? _raw_spin_trylock_bh+0x120/0x120
> > ? pm_runtime_barrier+0x220/0x220
> > ? __pm_runtime_resume+0xb1/0xf0
> > usb_probe_interface+0x25b/0x710
> > really_probe+0x209/0x5d0
> > driver_probe_device+0xc6/0x1b0
> > device_driver_attach+0xe2/0x120
> >
> > Signed-off-by: Zekun Shen <[email protected]>
>
> How did you test this?
I found the bug using a custome USBFuzz port. It's a research work
to fuzz USB stack/drivers. I modified it to fuzz ath9k driver only,
providing hand-crafted usb descriptors to QEMU.
After fixing the code (fourth byte in usb packet) to WDCMSG_TARGET_START,
I got the null-ptr-deref bug. I believe the bug is triggerable whenever
cmd->odata is NULL. After patching, I tested with the same input and no
longer see the KASAN report.
>
> --
> https://patchwork.kernel.org/project/linux-wireless/list/
>
> https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
Zekun Shen <[email protected]> writes:
> On Fri, Oct 29, 2021 at 06:53:30AM +0300, Kalle Valo wrote:
>> Zekun Shen <[email protected]> writes:
>>
>> > Unexpected WDCMSG_TARGET_START replay can lead to null-ptr-deref
>> > when ar->tx_cmd->odata is NULL. The patch adds a null check to
>> > prevent such case.
>> >
>> > KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
>> > ar5523_cmd+0x46a/0x581 [ar5523]
>> > ar5523_probe.cold+0x1b7/0x18da [ar5523]
>> > ? ar5523_cmd_rx_cb+0x7a0/0x7a0 [ar5523]
>> > ? __pm_runtime_set_status+0x54a/0x8f0
>> > ? _raw_spin_trylock_bh+0x120/0x120
>> > ? pm_runtime_barrier+0x220/0x220
>> > ? __pm_runtime_resume+0xb1/0xf0
>> > usb_probe_interface+0x25b/0x710
>> > really_probe+0x209/0x5d0
>> > driver_probe_device+0xc6/0x1b0
>> > device_driver_attach+0xe2/0x120
>> >
>> > Signed-off-by: Zekun Shen <[email protected]>
>>
>> How did you test this?
>
> I found the bug using a custome USBFuzz port. It's a research work
> to fuzz USB stack/drivers. I modified it to fuzz ath9k driver only,
> providing hand-crafted usb descriptors to QEMU.
>
> After fixing the code (fourth byte in usb packet) to WDCMSG_TARGET_START,
> I got the null-ptr-deref bug. I believe the bug is triggerable whenever
> cmd->odata is NULL. After patching, I tested with the same input and no
> longer see the KASAN report.
Ok, so you didn't test this on a real device at all. I'll mention that
in the commit log and also copy what you wrote above.
--
https://patchwork.kernel.org/project/linux-wireless/list/
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
Zekun Shen <[email protected]> wrote:
> Unexpected WDCMSG_TARGET_START replay can lead to null-ptr-deref
> when ar->tx_cmd->odata is NULL. The patch adds a null check to
> prevent such case.
>
> KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
> ar5523_cmd+0x46a/0x581 [ar5523]
> ar5523_probe.cold+0x1b7/0x18da [ar5523]
> ? ar5523_cmd_rx_cb+0x7a0/0x7a0 [ar5523]
> ? __pm_runtime_set_status+0x54a/0x8f0
> ? _raw_spin_trylock_bh+0x120/0x120
> ? pm_runtime_barrier+0x220/0x220
> ? __pm_runtime_resume+0xb1/0xf0
> usb_probe_interface+0x25b/0x710
> really_probe+0x209/0x5d0
> driver_probe_device+0xc6/0x1b0
> device_driver_attach+0xe2/0x120
>
> I found the bug using a custome USBFuzz port. It's a research work
> to fuzz USB stack/drivers. I modified it to fuzz ath9k driver only,
> providing hand-crafted usb descriptors to QEMU.
>
> After fixing the code (fourth byte in usb packet) to WDCMSG_TARGET_START,
> I got the null-ptr-deref bug. I believe the bug is triggerable whenever
> cmd->odata is NULL. After patching, I tested with the same input and no
> longer see the KASAN report.
>
> This was NOT tested on a real device.
>
> Signed-off-by: Zekun Shen <[email protected]>
> Signed-off-by: Kalle Valo <[email protected]>
Patch applied to ath-next branch of ath.git, thanks.
ae80b6033834 ar5523: Fix null-ptr-deref with unexpected WDCMSG_TARGET_START reply
--
https://patchwork.kernel.org/project/linux-wireless/patch/[email protected]/
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches