* [PATCH] staging: greybus: spilib: fix use-after-free after deregistration
@ 2017-10-29 12:01 Johan Hovold
2017-10-29 12:43 ` Viresh Kumar
2017-10-29 17:44 ` Rui Miguel Silva
0 siblings, 2 replies; 5+ messages in thread
From: Johan Hovold @ 2017-10-29 12:01 UTC (permalink / raw)
To: Rui Miguel Silva, Viresh Kumar
Cc: Johan Hovold, Alex Elder, Greg Kroah-Hartman, greybus-dev, devel,
linux-kernel, stable
Remove erroneous spi_master_put() after controller deregistration which
would access the already freed spi controller.
Note that spi_unregister_master() drops our only controller reference.
Fixes: ba3e67001b42 ("greybus: SPI: convert to a gpbridge driver")
Cc: stable <stable@vger.kernel.org> # 4.9
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
drivers/staging/greybus/spilib.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/drivers/staging/greybus/spilib.c b/drivers/staging/greybus/spilib.c
index e97b19148497..1e7321a1404c 100644
--- a/drivers/staging/greybus/spilib.c
+++ b/drivers/staging/greybus/spilib.c
@@ -544,11 +544,14 @@ int gb_spilib_master_init(struct gb_connection *connection, struct device *dev,
return 0;
-exit_spi_unregister:
- spi_unregister_master(master);
exit_spi_put:
spi_master_put(master);
+ return ret;
+
+exit_spi_unregister:
+ spi_unregister_master(master);
+
return ret;
}
EXPORT_SYMBOL_GPL(gb_spilib_master_init);
@@ -558,7 +561,6 @@ void gb_spilib_master_exit(struct gb_connection *connection)
struct spi_master *master = gb_connection_get_data(connection);
spi_unregister_master(master);
- spi_master_put(master);
}
EXPORT_SYMBOL_GPL(gb_spilib_master_exit);
--
2.14.3
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH] staging: greybus: spilib: fix use-after-free after deregistration
2017-10-29 12:01 [PATCH] staging: greybus: spilib: fix use-after-free after deregistration Johan Hovold
@ 2017-10-29 12:43 ` Viresh Kumar
2017-10-29 12:51 ` Johan Hovold
2017-10-29 17:44 ` Rui Miguel Silva
1 sibling, 1 reply; 5+ messages in thread
From: Viresh Kumar @ 2017-10-29 12:43 UTC (permalink / raw)
To: Johan Hovold
Cc: Rui Miguel Silva, Viresh Kumar, Alex Elder, Greg Kroah-Hartman,
greybus-dev, devel, linux-kernel, stable
On 29-10-17, 13:01, Johan Hovold wrote:
> Remove erroneous spi_master_put() after controller deregistration which
> would access the already freed spi controller.
>
> Note that spi_unregister_master() drops our only controller reference.
>
> Fixes: ba3e67001b42 ("greybus: SPI: convert to a gpbridge driver")
> Cc: stable <stable@vger.kernel.org> # 4.9
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Signed-off-by: Johan Hovold <johan@kernel.org>
> ---
> drivers/staging/greybus/spilib.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/staging/greybus/spilib.c b/drivers/staging/greybus/spilib.c
> index e97b19148497..1e7321a1404c 100644
> --- a/drivers/staging/greybus/spilib.c
> +++ b/drivers/staging/greybus/spilib.c
> @@ -544,11 +544,14 @@ int gb_spilib_master_init(struct gb_connection *connection, struct device *dev,
>
> return 0;
>
> -exit_spi_unregister:
> - spi_unregister_master(master);
> exit_spi_put:
> spi_master_put(master);
>
> + return ret;
> +
> +exit_spi_unregister:
> + spi_unregister_master(master);
> +
> return ret;
> }
> EXPORT_SYMBOL_GPL(gb_spilib_master_init);
> @@ -558,7 +561,6 @@ void gb_spilib_master_exit(struct gb_connection *connection)
> struct spi_master *master = gb_connection_get_data(connection);
>
> spi_unregister_master(master);
> - spi_master_put(master);
> }
> EXPORT_SYMBOL_GPL(gb_spilib_master_exit);
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
While looking at this I think I found another problem (I will send it as a
separate patch later on) and this fixes it:
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 6e65524cbfd9..af7ca751b4f7 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -2261,11 +2261,11 @@ void spi_unregister_controller(struct spi_controller *ctlr)
mutex_unlock(&board_lock);
dummy = device_for_each_child(&ctlr->dev, NULL, __unregister);
- device_unregister(&ctlr->dev);
/* free bus id */
mutex_lock(&board_lock);
idr_remove(&spi_master_idr, ctlr->bus_num);
mutex_unlock(&board_lock);
+ device_unregister(&ctlr->dev);
}
EXPORT_SYMBOL_GPL(spi_unregister_controller);
--
viresh
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH] staging: greybus: spilib: fix use-after-free after deregistration
2017-10-29 12:43 ` Viresh Kumar
@ 2017-10-29 12:51 ` Johan Hovold
2017-10-29 12:53 ` Viresh Kumar
0 siblings, 1 reply; 5+ messages in thread
From: Johan Hovold @ 2017-10-29 12:51 UTC (permalink / raw)
To: Viresh Kumar
Cc: Johan Hovold, Rui Miguel Silva, Viresh Kumar, Alex Elder,
Greg Kroah-Hartman, greybus-dev, devel, linux-kernel, stable
On Sun, Oct 29, 2017 at 06:13:28PM +0530, Viresh Kumar wrote:
> On 29-10-17, 13:01, Johan Hovold wrote:
> > Remove erroneous spi_master_put() after controller deregistration which
> > would access the already freed spi controller.
> >
> > Note that spi_unregister_master() drops our only controller reference.
> >
> > Fixes: ba3e67001b42 ("greybus: SPI: convert to a gpbridge driver")
> > Cc: stable <stable@vger.kernel.org> # 4.9
> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > Signed-off-by: Johan Hovold <johan@kernel.org>
> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
>
> While looking at this I think I found another problem (I will send it as a
> separate patch later on) and this fixes it:
That's right, and I already posted a fix for that use-after-free:
https://lkml.kernel.org/r/20171029115625.32385-1-johan@kernel.org
Thanks,
Johan
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] staging: greybus: spilib: fix use-after-free after deregistration
2017-10-29 12:51 ` Johan Hovold
@ 2017-10-29 12:53 ` Viresh Kumar
0 siblings, 0 replies; 5+ messages in thread
From: Viresh Kumar @ 2017-10-29 12:53 UTC (permalink / raw)
To: Johan Hovold
Cc: Rui Miguel Silva, Viresh Kumar, Alex Elder, Greg Kroah-Hartman,
greybus-dev, devel, linux-kernel, stable
On 29-10-17, 13:51, Johan Hovold wrote:
> That's right, and I already posted a fix for that use-after-free:
>
> https://lkml.kernel.org/r/20171029115625.32385-1-johan@kernel.org
Great :)
--
viresh
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] staging: greybus: spilib: fix use-after-free after deregistration
2017-10-29 12:01 [PATCH] staging: greybus: spilib: fix use-after-free after deregistration Johan Hovold
2017-10-29 12:43 ` Viresh Kumar
@ 2017-10-29 17:44 ` Rui Miguel Silva
1 sibling, 0 replies; 5+ messages in thread
From: Rui Miguel Silva @ 2017-10-29 17:44 UTC (permalink / raw)
To: Johan Hovold
Cc: Rui Miguel Silva, Viresh Kumar, Alex Elder, Greg Kroah-Hartman,
greybus-dev, devel, linux-kernel, stable
Hi Johan,
Thanks for the patch.
On Sun 29 Oct 2017 at 12:01, Johan Hovold <johan@kernel.org> wrote:
> Remove erroneous spi_master_put() after controller deregistration which
> would access the already freed spi controller.
>
> Note that spi_unregister_master() drops our only controller reference.
>
> Fixes: ba3e67001b42 ("greybus: SPI: convert to a gpbridge driver")
> Cc: stable <stable@vger.kernel.org> # 4.9
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Rui Miguel Silva <rmfrfs@gmail.com>
---
Cheers,
Rui
> ---
> drivers/staging/greybus/spilib.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/staging/greybus/spilib.c b/drivers/staging/greybus/spilib.c
> index e97b19148497..1e7321a1404c 100644
> --- a/drivers/staging/greybus/spilib.c
> +++ b/drivers/staging/greybus/spilib.c
> @@ -544,11 +544,14 @@ int gb_spilib_master_init(struct gb_connection *connection, struct device *dev,
>
> return 0;
>
> -exit_spi_unregister:
> - spi_unregister_master(master);
> exit_spi_put:
> spi_master_put(master);
>
> + return ret;
> +
> +exit_spi_unregister:
> + spi_unregister_master(master);
> +
> return ret;
> }
> EXPORT_SYMBOL_GPL(gb_spilib_master_init);
> @@ -558,7 +561,6 @@ void gb_spilib_master_exit(struct gb_connection *connection)
> struct spi_master *master = gb_connection_get_data(connection);
>
> spi_unregister_master(master);
> - spi_master_put(master);
> }
> EXPORT_SYMBOL_GPL(gb_spilib_master_exit);
^ permalink raw reply [flat|nested] 5+ messages in thread
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2017-10-29 12:01 [PATCH] staging: greybus: spilib: fix use-after-free after deregistration Johan Hovold
2017-10-29 12:43 ` Viresh Kumar
2017-10-29 12:51 ` Johan Hovold
2017-10-29 12:53 ` Viresh Kumar
2017-10-29 17:44 ` Rui Miguel Silva
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