* [PATCH] thunderbolt: Fix use-after-free in remove_unplugged_switch()
@ 2020-11-18 13:37 Mika Westerberg
2020-11-18 13:47 ` Greg KH
0 siblings, 1 reply; 3+ messages in thread
From: Mika Westerberg @ 2020-11-18 13:37 UTC (permalink / raw)
To: linux-usb
Cc: Yehezkel Bernat, Michael Jamet, Paulian Bogdan Marinca,
Andreas Noever, Lukas Wunner, Mika Westerberg
Paulian reported a crash that happens when a dock is unplugged during
hibernation:
[78436.228217] thunderbolt 0-1: device disconnected
[78436.228365] BUG: kernel NULL pointer dereference, address: 00000000000001e0
...
[78436.228397] RIP: 0010:icm_free_unplugged_children+0x109/0x1a0
...
[78436.228432] Call Trace:
[78436.228439] icm_rescan_work+0x24/0x30
[78436.228444] process_one_work+0x1a3/0x3a0
[78436.228449] worker_thread+0x30/0x370
[78436.228454] ? process_one_work+0x3a0/0x3a0
[78436.228457] kthread+0x13d/0x160
[78436.228461] ? kthread_park+0x90/0x90
[78436.228465] ret_from_fork+0x1f/0x30
This happens because remove_unplugged_switch() calls tb_switch_remove()
that releases the memory pointed by sw so the following lines reference
to a memory that might be released already.
Fix this by saving pointer to the parent device before calling
tb_switch_remove().
Reported-by: Paulian Bogdan Marinca <paulian@marinca.net>
Fixes: 4f7c2e0d8765 ("thunderbolt: Make sure device runtime resume completes before taking domain lock")
Cc: stable@vger.kernel.org
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
drivers/thunderbolt/icm.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/drivers/thunderbolt/icm.c b/drivers/thunderbolt/icm.c
index b51fc3f62b1f..05323c442b56 100644
--- a/drivers/thunderbolt/icm.c
+++ b/drivers/thunderbolt/icm.c
@@ -1976,7 +1976,9 @@ static int complete_rpm(struct device *dev, void *data)
static void remove_unplugged_switch(struct tb_switch *sw)
{
- pm_runtime_get_sync(sw->dev.parent);
+ struct device *parent = sw->dev.parent;
+
+ pm_runtime_get_sync(parent);
/*
* Signal this and switches below for rpm_complete because
@@ -1987,8 +1989,8 @@ static void remove_unplugged_switch(struct tb_switch *sw)
bus_for_each_dev(&tb_bus_type, &sw->dev, NULL, complete_rpm);
tb_switch_remove(sw);
- pm_runtime_mark_last_busy(sw->dev.parent);
- pm_runtime_put_autosuspend(sw->dev.parent);
+ pm_runtime_mark_last_busy(parent);
+ pm_runtime_put_autosuspend(parent);
}
static void icm_free_unplugged_children(struct tb_switch *sw)
--
2.29.2
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] thunderbolt: Fix use-after-free in remove_unplugged_switch()
2020-11-18 13:37 [PATCH] thunderbolt: Fix use-after-free in remove_unplugged_switch() Mika Westerberg
@ 2020-11-18 13:47 ` Greg KH
2020-11-18 13:55 ` Mika Westerberg
0 siblings, 1 reply; 3+ messages in thread
From: Greg KH @ 2020-11-18 13:47 UTC (permalink / raw)
To: Mika Westerberg
Cc: linux-usb, Yehezkel Bernat, Michael Jamet, Paulian Bogdan Marinca,
Andreas Noever, Lukas Wunner
On Wed, Nov 18, 2020 at 04:37:45PM +0300, Mika Westerberg wrote:
> Paulian reported a crash that happens when a dock is unplugged during
> hibernation:
>
> [78436.228217] thunderbolt 0-1: device disconnected
> [78436.228365] BUG: kernel NULL pointer dereference, address: 00000000000001e0
> ...
> [78436.228397] RIP: 0010:icm_free_unplugged_children+0x109/0x1a0
> ...
> [78436.228432] Call Trace:
> [78436.228439] icm_rescan_work+0x24/0x30
> [78436.228444] process_one_work+0x1a3/0x3a0
> [78436.228449] worker_thread+0x30/0x370
> [78436.228454] ? process_one_work+0x3a0/0x3a0
> [78436.228457] kthread+0x13d/0x160
> [78436.228461] ? kthread_park+0x90/0x90
> [78436.228465] ret_from_fork+0x1f/0x30
>
> This happens because remove_unplugged_switch() calls tb_switch_remove()
> that releases the memory pointed by sw so the following lines reference
> to a memory that might be released already.
>
> Fix this by saving pointer to the parent device before calling
> tb_switch_remove().
>
> Reported-by: Paulian Bogdan Marinca <paulian@marinca.net>
> Fixes: 4f7c2e0d8765 ("thunderbolt: Make sure device runtime resume completes before taking domain lock")
> Cc: stable@vger.kernel.org
> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> ---
> drivers/thunderbolt/icm.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/thunderbolt/icm.c b/drivers/thunderbolt/icm.c
> index b51fc3f62b1f..05323c442b56 100644
> --- a/drivers/thunderbolt/icm.c
> +++ b/drivers/thunderbolt/icm.c
> @@ -1976,7 +1976,9 @@ static int complete_rpm(struct device *dev, void *data)
>
> static void remove_unplugged_switch(struct tb_switch *sw)
> {
> - pm_runtime_get_sync(sw->dev.parent);
> + struct device *parent = sw->dev.parent;
> +
> + pm_runtime_get_sync(parent);
If you are saving a pointer to a structure, shouldn't you increment the
reference count?
struct device *parent = get_device(sw->dev.parent);
Then you know it is valid when you use it later on.
Just remember to call put_device() when you are done.
thanks,
greg k-h
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] thunderbolt: Fix use-after-free in remove_unplugged_switch()
2020-11-18 13:47 ` Greg KH
@ 2020-11-18 13:55 ` Mika Westerberg
0 siblings, 0 replies; 3+ messages in thread
From: Mika Westerberg @ 2020-11-18 13:55 UTC (permalink / raw)
To: Greg KH
Cc: linux-usb, Yehezkel Bernat, Michael Jamet, Paulian Bogdan Marinca,
Andreas Noever, Lukas Wunner
On Wed, Nov 18, 2020 at 02:47:27PM +0100, Greg KH wrote:
> On Wed, Nov 18, 2020 at 04:37:45PM +0300, Mika Westerberg wrote:
> > Paulian reported a crash that happens when a dock is unplugged during
> > hibernation:
> >
> > [78436.228217] thunderbolt 0-1: device disconnected
> > [78436.228365] BUG: kernel NULL pointer dereference, address: 00000000000001e0
> > ...
> > [78436.228397] RIP: 0010:icm_free_unplugged_children+0x109/0x1a0
> > ...
> > [78436.228432] Call Trace:
> > [78436.228439] icm_rescan_work+0x24/0x30
> > [78436.228444] process_one_work+0x1a3/0x3a0
> > [78436.228449] worker_thread+0x30/0x370
> > [78436.228454] ? process_one_work+0x3a0/0x3a0
> > [78436.228457] kthread+0x13d/0x160
> > [78436.228461] ? kthread_park+0x90/0x90
> > [78436.228465] ret_from_fork+0x1f/0x30
> >
> > This happens because remove_unplugged_switch() calls tb_switch_remove()
> > that releases the memory pointed by sw so the following lines reference
> > to a memory that might be released already.
> >
> > Fix this by saving pointer to the parent device before calling
> > tb_switch_remove().
> >
> > Reported-by: Paulian Bogdan Marinca <paulian@marinca.net>
> > Fixes: 4f7c2e0d8765 ("thunderbolt: Make sure device runtime resume completes before taking domain lock")
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> > ---
> > drivers/thunderbolt/icm.c | 8 +++++---
> > 1 file changed, 5 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/thunderbolt/icm.c b/drivers/thunderbolt/icm.c
> > index b51fc3f62b1f..05323c442b56 100644
> > --- a/drivers/thunderbolt/icm.c
> > +++ b/drivers/thunderbolt/icm.c
> > @@ -1976,7 +1976,9 @@ static int complete_rpm(struct device *dev, void *data)
> >
> > static void remove_unplugged_switch(struct tb_switch *sw)
> > {
> > - pm_runtime_get_sync(sw->dev.parent);
> > + struct device *parent = sw->dev.parent;
> > +
> > + pm_runtime_get_sync(parent);
>
> If you are saving a pointer to a structure, shouldn't you increment the
> reference count?
>
> struct device *parent = get_device(sw->dev.parent);
>
> Then you know it is valid when you use it later on.
Indeed, I missed that.
> Just remember to call put_device() when you are done.
Sure I'll do this in v2. Thanks!
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2020-11-18 13:58 UTC | newest]
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2020-11-18 13:37 [PATCH] thunderbolt: Fix use-after-free in remove_unplugged_switch() Mika Westerberg
2020-11-18 13:47 ` Greg KH
2020-11-18 13:55 ` Mika Westerberg
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