* [PATCH] spi: spidev: fix possible NULL dereference
@ 2015-09-10 11:18 Sudip Mukherjee
[not found] ` <1441883893-20596-1-git-send-email-sudipm.mukherjee-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
0 siblings, 1 reply; 5+ messages in thread
From: Sudip Mukherjee @ 2015-09-10 11:18 UTC (permalink / raw)
To: Mark Brown
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA,
linux-spi-u79uwXL29TY76Z2rM5mHXA, Sudip Mukherjee
During the last close we are freeing spidev if spidev->spi is NULL, but
just before checking if spidev->spi is NULL we are dereferencing it.
Lets add a check there to avoid the NULL dereference.
Signed-off-by: Sudip Mukherjee <sudip-ofJRbWXBVFamYgehrs7/Lw@public.gmane.org>
---
drivers/spi/spidev.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c
index fba92a5..ef008e5 100644
--- a/drivers/spi/spidev.c
+++ b/drivers/spi/spidev.c
@@ -651,7 +651,8 @@ static int spidev_release(struct inode *inode, struct file *filp)
kfree(spidev->rx_buffer);
spidev->rx_buffer = NULL;
- spidev->speed_hz = spidev->spi->max_speed_hz;
+ if (spidev->spi)
+ spidev->speed_hz = spidev->spi->max_speed_hz;
/* ... after we unbound from the underlying device? */
spin_lock_irq(&spidev->spi_lock);
--
1.9.1
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^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] spi: spidev: fix possible NULL dereference
[not found] ` <1441883893-20596-1-git-send-email-sudipm.mukherjee-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
@ 2015-09-11 12:11 ` Jarkko Nikula
[not found] ` <55F2C4F4.3090704-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
0 siblings, 1 reply; 5+ messages in thread
From: Jarkko Nikula @ 2015-09-11 12:11 UTC (permalink / raw)
To: Sudip Mukherjee, Mark Brown
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA, linux-spi-u79uwXL29TY76Z2rM5mHXA
Hi
On 09/10/2015 02:18 PM, Sudip Mukherjee wrote:
> During the last close we are freeing spidev if spidev->spi is NULL, but
> just before checking if spidev->spi is NULL we are dereferencing it.
> Lets add a check there to avoid the NULL dereference.
>
> Signed-off-by: Sudip Mukherjee <sudip-ofJRbWXBVFamYgehrs7/Lw@public.gmane.org>
> ---
> drivers/spi/spidev.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c
> index fba92a5..ef008e5 100644
> --- a/drivers/spi/spidev.c
> +++ b/drivers/spi/spidev.c
> @@ -651,7 +651,8 @@ static int spidev_release(struct inode *inode, struct file *filp)
> kfree(spidev->rx_buffer);
> spidev->rx_buffer = NULL;
>
> - spidev->speed_hz = spidev->spi->max_speed_hz;
> + if (spidev->spi)
> + spidev->speed_hz = spidev->spi->max_speed_hz;
>
> /* ... after we unbound from the underlying device? */
> spin_lock_irq(&spidev->spi_lock);
Actually this fixes a *real* NULL dereference case but it is not related
to normal open/close life cycle of spidev. It requires that spidev is
kept open when SPI master is removed.
spidev->spi is set to NULL in spidev_remove() and it is called before
spidev_release() in case master is removed while spidev is in use
It would be good to update this to commit log, add a tag below and Cc
<stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Fixes: 9169051617df ("spi: spidev: Don't mangle max_speed_hz in
underlying spi device")
You can add these too:
Reviewed-by: Jarkko Nikula <jarkko.nikula-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
Tested-by: Jarkko Nikula <jarkko.nikula-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] spi: spidev: fix possible NULL dereference
[not found] ` <55F2C4F4.3090704-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
@ 2015-09-11 12:25 ` Mark Brown
[not found] ` <20150911122513.GT12027-GFdadSzt00ze9xe1eoZjHA@public.gmane.org>
0 siblings, 1 reply; 5+ messages in thread
From: Mark Brown @ 2015-09-11 12:25 UTC (permalink / raw)
To: Jarkko Nikula
Cc: Sudip Mukherjee, linux-kernel-u79uwXL29TY76Z2rM5mHXA,
linux-spi-u79uwXL29TY76Z2rM5mHXA
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On Fri, Sep 11, 2015 at 03:11:32PM +0300, Jarkko Nikula wrote:
> Actually this fixes a *real* NULL dereference case but it is not related to
> normal open/close life cycle of spidev. It requires that spidev is kept open
> when SPI master is removed.
> spidev->spi is set to NULL in spidev_remove() and it is called before
> spidev_release() in case master is removed while spidev is in use
> It would be good to update this to commit log, add a tag below and Cc
> <stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
> Fixes: 9169051617df ("spi: spidev: Don't mangle max_speed_hz in underlying
> spi device")
The patch was already applied :(
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] spi: spidev: fix possible NULL dereference
[not found] ` <20150911122513.GT12027-GFdadSzt00ze9xe1eoZjHA@public.gmane.org>
@ 2015-09-11 12:49 ` Sudip Mukherjee
2015-09-11 14:21 ` Mark Brown
0 siblings, 1 reply; 5+ messages in thread
From: Sudip Mukherjee @ 2015-09-11 12:49 UTC (permalink / raw)
To: Mark Brown
Cc: Jarkko Nikula, linux-kernel-u79uwXL29TY76Z2rM5mHXA,
linux-spi-u79uwXL29TY76Z2rM5mHXA
On Fri, Sep 11, 2015 at 01:25:13PM +0100, Mark Brown wrote:
> On Fri, Sep 11, 2015 at 03:11:32PM +0300, Jarkko Nikula wrote:
>
> > Actually this fixes a *real* NULL dereference case but it is not related to
> > normal open/close life cycle of spidev. It requires that spidev is kept open
> > when SPI master is removed.
>
> > spidev->spi is set to NULL in spidev_remove() and it is called before
> > spidev_release() in case master is removed while spidev is in use
>
> > It would be good to update this to commit log, add a tag below and Cc
> > <stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
>
> > Fixes: 9169051617df ("spi: spidev: Don't mangle max_speed_hz in underlying
> > spi device")
>
> The patch was already applied :(
Applied? But usually I will receive an auto mail from you after applying.
I dont think I have received any.
regards
sudip
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] spi: spidev: fix possible NULL dereference
2015-09-11 12:49 ` Sudip Mukherjee
@ 2015-09-11 14:21 ` Mark Brown
0 siblings, 0 replies; 5+ messages in thread
From: Mark Brown @ 2015-09-11 14:21 UTC (permalink / raw)
To: Sudip Mukherjee
Cc: Jarkko Nikula, linux-kernel-u79uwXL29TY76Z2rM5mHXA,
linux-spi-u79uwXL29TY76Z2rM5mHXA
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On Fri, Sep 11, 2015 at 06:19:45PM +0530, Sudip Mukherjee wrote:
> On Fri, Sep 11, 2015 at 01:25:13PM +0100, Mark Brown wrote:
> > The patch was already applied :(
> Applied? But usually I will receive an auto mail from you after applying.
> I dont think I have received any.
You get a mail when the changes are pushed, which had happened by the
time I replied.
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^ permalink raw reply [flat|nested] 5+ messages in thread
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2015-09-10 11:18 [PATCH] spi: spidev: fix possible NULL dereference Sudip Mukherjee
[not found] ` <1441883893-20596-1-git-send-email-sudipm.mukherjee-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2015-09-11 12:11 ` Jarkko Nikula
[not found] ` <55F2C4F4.3090704-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
2015-09-11 12:25 ` Mark Brown
[not found] ` <20150911122513.GT12027-GFdadSzt00ze9xe1eoZjHA@public.gmane.org>
2015-09-11 12:49 ` Sudip Mukherjee
2015-09-11 14:21 ` Mark Brown
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