| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <23fe0fe3-f330-b58e-c366-3ac5bd80fe22@linux.intel.com>
Date: Thu, 22 Dec 2022 13:08:47 +0200
From: Mathias Nyman <mathias.nyman@...ux.intel.com>
To: Ladislav Michl <oss-lists@...ops.cz>, Jimmy Hu <hhhuuu@...gle.com>
Cc: mathias.nyman@...el.com, gregkh@...uxfoundation.org,
badhri@...gle.com, linux-usb@...r.kernel.org,
linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH v2] usb: xhci: Check endpoint is valid before
dereferencing it
On 22.12.2022 11.01, Ladislav Michl wrote:
> On Thu, Dec 22, 2022 at 07:29:12AM +0000, Jimmy Hu wrote:
>> When the host controller is not responding, all URBs queued to all
>> endpoints need to be killed. This can cause a kernel panic if we
>> dereference an invalid endpoint.
>>
>> Fix this by using xhci_get_virt_ep() helper to find the endpoint and
>> checking if the endpoint is valid before dereferencing it.
>>
>> [233311.853271] xhci-hcd xhci-hcd.1.auto: xHCI host controller not responding, assume dead
>> [233311.853393] Unable to handle kernel NULL pointer dereference at virtual address 00000000000000e8
>>
>> [233311.853964] pc : xhci_hc_died+0x10c/0x270
>> [233311.853971] lr : xhci_hc_died+0x1ac/0x270
>>
>> [233311.854077] Call trace:
>> [233311.854085] xhci_hc_died+0x10c/0x270
>> [233311.854093] xhci_stop_endpoint_command_watchdog+0x100/0x1a4
>> [233311.854105] call_timer_fn+0x50/0x2d4
>> [233311.854112] expire_timers+0xac/0x2e4
>> [233311.854118] run_timer_softirq+0x300/0xabc
>> [233311.854127] __do_softirq+0x148/0x528
>> [233311.854135] irq_exit+0x194/0x1a8
>> [233311.854143] __handle_domain_irq+0x164/0x1d0
>> [233311.854149] gic_handle_irq.22273+0x10c/0x188
>> [233311.854156] el1_irq+0xfc/0x1a8
>> [233311.854175] lpm_cpuidle_enter+0x25c/0x418 [msm_pm]
>> [233311.854185] cpuidle_enter_state+0x1f0/0x764
>> [233311.854194] do_idle+0x594/0x6ac
>> [233311.854201] cpu_startup_entry+0x7c/0x80
>> [233311.854209] secondary_start_kernel+0x170/0x198
>>
>> Fixes: 50e8725e7c42 ("xhci: Refactor command watchdog and fix split string.")
>> Cc: stable@...r.kernel.org
>> Signed-off-by: Jimmy Hu <hhhuuu@...gle.com>
>> ---
>> drivers/usb/host/xhci-ring.c | 5 ++++-
>> 1 file changed, 4 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
>> index ddc30037f9ce..f5b0e1ce22af 100644
>> --- a/drivers/usb/host/xhci-ring.c
>> +++ b/drivers/usb/host/xhci-ring.c
>> @@ -1169,7 +1169,10 @@ static void xhci_kill_endpoint_urbs(struct xhci_hcd *xhci,
>> struct xhci_virt_ep *ep;
>> struct xhci_ring *ring;
>>
>> - ep = &xhci->devs[slot_id]->eps[ep_index];
>> + ep = xhci_get_virt_ep(xhci, slot_id, ep_index);
>> + if (!ep)
>> + return;
>> +
>
> xhci_get_virt_ep also adds check for slot_id == 0. It changes behaviour,
> do we really want to skip that slot? Original code went from 0 to
> MAX_HC_SLOTS-1.
>
> It seems to be off by one to me. Am I missing anything?
slot_id 0 is always invalid, so this is a good change.
> Also, what about passing ep directly to xhci_kill_endpoint_urbs
> and do the check in xhci_hc_died? Not even compile tested:
passing ep to a function named kill_endpoint_urbs() sound like the
right thing to do, but as a generic change.
I think its a good idea to first do a targeted fix for this null pointer
issue that we can send to stable fist.
>
> diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
> index ddc30037f9ce..5dac483c562a 100644
> --- a/drivers/usb/host/xhci-ring.c
> +++ b/drivers/usb/host/xhci-ring.c
> @@ -1162,14 +1162,12 @@ static void xhci_kill_ring_urbs(struct xhci_hcd *xhci, struct xhci_ring *ring)
> }
>
> static void xhci_kill_endpoint_urbs(struct xhci_hcd *xhci,
> - int slot_id, int ep_index)
> + struct xhci_virt_ep *ep)
> {
> struct xhci_td *cur_td;
> struct xhci_td *tmp;
> - struct xhci_virt_ep *ep;
> struct xhci_ring *ring;
>
> - ep = &xhci->devs[slot_id]->eps[ep_index];
> if ((ep->ep_state & EP_HAS_STREAMS) ||
> (ep->ep_state & EP_GETTING_NO_STREAMS)) {
> int stream_id;
> @@ -1180,18 +1178,12 @@ static void xhci_kill_endpoint_urbs(struct xhci_hcd *xhci,
> if (!ring)
> continue;
>
> - xhci_dbg_trace(xhci, trace_xhci_dbg_cancel_urb,
> - "Killing URBs for slot ID %u, ep index %u, stream %u",
> - slot_id, ep_index, stream_id);
> xhci_kill_ring_urbs(xhci, ring);
> }
> } else {
> ring = ep->ring;
> if (!ring)
> return;
> - xhci_dbg_trace(xhci, trace_xhci_dbg_cancel_urb,
> - "Killing URBs for slot ID %u, ep index %u",
> - slot_id, ep_index);
> xhci_kill_ring_urbs(xhci, ring);
> }
>
> @@ -1217,6 +1209,7 @@ static void xhci_kill_endpoint_urbs(struct xhci_hcd *xhci,
> void xhci_hc_died(struct xhci_hcd *xhci)
> {
> int i, j;
> + struct xhci_virt_ep *ep;
>
> if (xhci->xhc_state & XHCI_STATE_DYING)
> return;
> @@ -1227,11 +1220,14 @@ void xhci_hc_died(struct xhci_hcd *xhci)
> xhci_cleanup_command_queue(xhci);
>
> /* return any pending urbs, remove may be waiting for them */
> - for (i = 0; i <= HCS_MAX_SLOTS(xhci->hcs_params1); i++) {
> + for (i = 0; i < HCS_MAX_SLOTS(xhci->hcs_params1); i++) {
> if (!xhci->devs[i])
> continue;
> - for (j = 0; j < 31; j++)
> - xhci_kill_endpoint_urbs(xhci, i, j);
> + for (j = 0; j < EP_CTX_PER_DEV; j++) {
> + ep = &xhci->devs[i]->eps[j];
> + if (ep)
> + xhci_kill_endpoint_urbs(xhci, ep);
> + }
This does loop a bit more than the existing code.
With this change its always HCS_MAX_SLOTS * EP_CTX_PER_DEV.
Previously best case was just HCS_MAX_SLOTS.
-Mathias
Powered by blists - more mailing lists