Re: [PATCH] dell-wmi: Fix access out of memory

Re: [PATCH] dell-wmi: Fix access out of memory

[Darren Hart]

On Mon, Sep 29, 2014 at 03:10:51PM +0200, Pali Rohár wrote:
> Without this patch driver dell-wmi is trying to access elements of dynamically
> allocated array without checking array size. This can lead to memory corruption
> or kernel panic. This patch adds missing checks for array size.
> 
> Signed-off-by: Pali Rohár <pali.rohar@gmail.com>

Looks good to me. Rafael, any concerns?

Cc: linux-acpi

> ---
> This patch should be probably applied to stable kernel trees as it fixing
> possible memory corruption.
> ---
>  drivers/platform/x86/dell-wmi.c |   12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/platform/x86/dell-wmi.c b/drivers/platform/x86/dell-wmi.c
> index 390e8e3..25721bf 100644
> --- a/drivers/platform/x86/dell-wmi.c
> +++ b/drivers/platform/x86/dell-wmi.c
> @@ -163,18 +163,24 @@ static void dell_wmi_notify(u32 value, void *context)
>  		const struct key_entry *key;
>  		int reported_key;
>  		u16 *buffer_entry = (u16 *)obj->buffer.pointer;
> +		int buffer_size = obj->buffer.length/2;
>  
> -		if (dell_new_hk_type && (buffer_entry[1] != 0x10)) {
> +		if (buffer_size >= 2 && dell_new_hk_type && buffer_entry[1] != 0x10) {
>  			pr_info("Received unknown WMI event (0x%x)\n",
>  				buffer_entry[1]);
>  			kfree(obj);
>  			return;
>  		}
>  
> -		if (dell_new_hk_type || buffer_entry[1] == 0x0)
> +		if (buffer_size >= 3 && (dell_new_hk_type || buffer_entry[1] == 0x0))
>  			reported_key = (int)buffer_entry[2];
> -		else
> +		else if (buffer_size >= 2)
>  			reported_key = (int)buffer_entry[1] & 0xffff;
> +		else {
> +			pr_info("Received unknown WMI event\n");
> +			kfree(obj);
> +			return;
> +		}
>  
>  		key = sparse_keymap_entry_from_scancode(dell_wmi_input_dev,
>  							reported_key);
> -- 
> 1.7.9.5
> 
> 

-- 
Darren Hart
Intel Open Source Technology Center

Re: [PATCH] dell-wmi: Fix access out of memory

[Darren Hart]

On September 29, 2014 4:26:03 PM PDT, "Rafael J. Wysocki" <rjw@rjwysocki.net> wrote:
>On Monday, September 29, 2014 02:30:29 PM Darren Hart wrote:
>> On Mon, Sep 29, 2014 at 03:10:51PM +0200, Pali Rohár wrote:
>> > Without this patch driver dell-wmi is trying to access elements of
>dynamically
>> > allocated array without checking array size. This can lead to
>memory corruption
>> > or kernel panic. This patch adds missing checks for array size.
>> > 
>> > Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
>> 
>> Looks good to me. Rafael, any concerns?
>
>Not anything obvious.

Queued, thanks.

>
>> 
>> Cc: linux-acpi
>
>Thanks!
>
>
>> > ---
>> > This patch should be probably applied to stable kernel trees as it
>fixing
>> > possible memory corruption.
>> > ---
>> >  drivers/platform/x86/dell-wmi.c |   12 +++++++++---
>> >  1 file changed, 9 insertions(+), 3 deletions(-)
>> > 
>> > diff --git a/drivers/platform/x86/dell-wmi.c
>b/drivers/platform/x86/dell-wmi.c
>> > index 390e8e3..25721bf 100644
>> > --- a/drivers/platform/x86/dell-wmi.c
>> > +++ b/drivers/platform/x86/dell-wmi.c
>> > @@ -163,18 +163,24 @@ static void dell_wmi_notify(u32 value, void
>*context)
>> >  		const struct key_entry *key;
>> >  		int reported_key;
>> >  		u16 *buffer_entry = (u16 *)obj->buffer.pointer;
>> > +		int buffer_size = obj->buffer.length/2;
>> >  
>> > -		if (dell_new_hk_type && (buffer_entry[1] != 0x10)) {
>> > +		if (buffer_size >= 2 && dell_new_hk_type && buffer_entry[1] !=
>0x10) {
>> >  			pr_info("Received unknown WMI event (0x%x)\n",
>> >  				buffer_entry[1]);
>> >  			kfree(obj);
>> >  			return;
>> >  		}
>> >  
>> > -		if (dell_new_hk_type || buffer_entry[1] == 0x0)
>> > +		if (buffer_size >= 3 && (dell_new_hk_type || buffer_entry[1] ==
>0x0))
>> >  			reported_key = (int)buffer_entry[2];
>> > -		else
>> > +		else if (buffer_size >= 2)
>> >  			reported_key = (int)buffer_entry[1] & 0xffff;
>> > +		else {
>> > +			pr_info("Received unknown WMI event\n");
>> > +			kfree(obj);
>> > +			return;
>> > +		}
>> >  
>> >  		key = sparse_keymap_entry_from_scancode(dell_wmi_input_dev,
>> >  							reported_key);
>> 
>> 

-- 
Sent from my Android device with K-9 Mail. Please excuse my brevity.

Re: [PATCH] dell-wmi: Fix access out of memory

[Rafael J. Wysocki]

On Monday, September 29, 2014 02:30:29 PM Darren Hart wrote:
> On Mon, Sep 29, 2014 at 03:10:51PM +0200, Pali Rohár wrote:
> > Without this patch driver dell-wmi is trying to access elements of dynamically
> > allocated array without checking array size. This can lead to memory corruption
> > or kernel panic. This patch adds missing checks for array size.
> > 
> > Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
> 
> Looks good to me. Rafael, any concerns?

Not anything obvious.

> 
> Cc: linux-acpi

Thanks!


> > ---
> > This patch should be probably applied to stable kernel trees as it fixing
> > possible memory corruption.
> > ---
> >  drivers/platform/x86/dell-wmi.c |   12 +++++++++---
> >  1 file changed, 9 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/platform/x86/dell-wmi.c b/drivers/platform/x86/dell-wmi.c
> > index 390e8e3..25721bf 100644
> > --- a/drivers/platform/x86/dell-wmi.c
> > +++ b/drivers/platform/x86/dell-wmi.c
> > @@ -163,18 +163,24 @@ static void dell_wmi_notify(u32 value, void *context)
> >  		const struct key_entry *key;
> >  		int reported_key;
> >  		u16 *buffer_entry = (u16 *)obj->buffer.pointer;
> > +		int buffer_size = obj->buffer.length/2;
> >  
> > -		if (dell_new_hk_type && (buffer_entry[1] != 0x10)) {
> > +		if (buffer_size >= 2 && dell_new_hk_type && buffer_entry[1] != 0x10) {
> >  			pr_info("Received unknown WMI event (0x%x)\n",
> >  				buffer_entry[1]);
> >  			kfree(obj);
> >  			return;
> >  		}
> >  
> > -		if (dell_new_hk_type || buffer_entry[1] == 0x0)
> > +		if (buffer_size >= 3 && (dell_new_hk_type || buffer_entry[1] == 0x0))
> >  			reported_key = (int)buffer_entry[2];
> > -		else
> > +		else if (buffer_size >= 2)
> >  			reported_key = (int)buffer_entry[1] & 0xffff;
> > +		else {
> > +			pr_info("Received unknown WMI event\n");
> > +			kfree(obj);
> > +			return;
> > +		}
> >  
> >  		key = sparse_keymap_entry_from_scancode(dell_wmi_input_dev,
> >  							reported_key);
> 
> 

-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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Re: [PATCH] dell-wmi: Fix access out of memory

[Pali Rohár]

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On Tuesday 30 September 2014 01:16:23 Darren Hart wrote:
> On September 29, 2014 4:26:03 PM PDT, "Rafael J. Wysocki" 
<rjw@rjwysocki.net> wrote:
> >On Monday, September 29, 2014 02:30:29 PM Darren Hart wrote:
> >> On Mon, Sep 29, 2014 at 03:10:51PM +0200, Pali Rohár wrote:
> >> > Without this patch driver dell-wmi is trying to access
> >> > elements of
> >
> >dynamically
> >
> >> > allocated array without checking array size. This can
> >> > lead to
> >
> >memory corruption
> >
> >> > or kernel panic. This patch adds missing checks for array
> >> > size.
> >> > 
> >> > Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
> >> 
> >> Looks good to me. Rafael, any concerns?
> >
> >Not anything obvious.
> 
> Queued, thanks.
> 
> >> Cc: linux-acpi
> >
> >Thanks!
> >

Now I see that this patch is in linus tree. Can you sent it to 
stable trees too?

-- 
Pali Rohár
pali.rohar@gmail.com

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Re: [PATCH] dell-wmi: Fix access out of memory

[Darren Hart]

On Sun, Oct 12, 2014 at 06:45:06PM +0200, Pali Rohár wrote:
> On Tuesday 30 September 2014 01:16:23 Darren Hart wrote:
> > On September 29, 2014 4:26:03 PM PDT, "Rafael J. Wysocki" 
> <rjw@rjwysocki.net> wrote:
> > >On Monday, September 29, 2014 02:30:29 PM Darren Hart wrote:
> > >> On Mon, Sep 29, 2014 at 03:10:51PM +0200, Pali Rohár wrote:
> > >> > Without this patch driver dell-wmi is trying to access
> > >> > elements of
> > >
> > >dynamically
> > >
> > >> > allocated array without checking array size. This can
> > >> > lead to
> > >
> > >memory corruption
> > >
> > >> > or kernel panic. This patch adds missing checks for array
> > >> > size.
> > >> > 
> > >> > Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
> > >> 
> > >> Looks good to me. Rafael, any concerns?
> > >
> > >Not anything obvious.
> > 
> > Queued, thanks.
> > 
> > >> Cc: linux-acpi
> > >
> > >Thanks!
> > >
> 
> Now I see that this patch is in linus tree. Can you sent it to 
> stable trees too?

Hi Pali,

Please see Documentation/stable_kernel_rules.txt for details on how to mark
patches for stable when you submit them. Now that it is in mainline, the process
is a bit more manual, you'll find instructions for how to go about that in the
same document.

Thanks,

-- 
Darren Hart
Intel Open Source Technology Center