diff mbox

[V2,1/3] brcmfmac: Avoid possible out-of-bounds read

Message ID 20170909193020.19061-1-cernekee@chromium.org (mailing list archive)
State Superseded
Delegated to: Kalle Valo
Headers show

Commit Message

Kevin Cernekee Sept. 9, 2017, 7:30 p.m. UTC
In brcmf_p2p_notify_rx_mgmt_p2p_probereq(), chanspec is assigned before
the length of rxframe is validated.  This could lead to uninitialized
data being accessed (but not printed).  Since we already have a
perfectly good endian-swapped copy of rxframe->chanspec in ch.chspec,
and ch.chspec is not modified by decchspec(), avoid the extra
assignment and use ch.chspec in the debug print.

Suggested-by: Mattias Nissler <mnissler@chromium.org>
Signed-off-by: Kevin Cernekee <cernekee@chromium.org>
Reviewed-by: Arend van Spriel <arend.vanspriel@broadcom.com>
---
 drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)


V1->V2: Clarify changelog re: whether the uninitialized data is printed.

Comments

Arend van Spriel Sept. 10, 2017, 6:50 p.m. UTC | #1
On 09-09-17 21:30, Kevin Cernekee wrote:
> In brcmf_p2p_notify_rx_mgmt_p2p_probereq(), chanspec is assigned before
> the length of rxframe is validated.  This could lead to uninitialized
> data being accessed (but not printed).  Since we already have a
> perfectly good endian-swapped copy of rxframe->chanspec in ch.chspec,
> and ch.chspec is not modified by decchspec(), avoid the extra
> assignment and use ch.chspec in the debug print.
> 
> Suggested-by: Mattias Nissler <mnissler@chromium.org>
> Signed-off-by: Kevin Cernekee <cernekee@chromium.org>
> Reviewed-by: Arend van Spriel <arend.vanspriel@broadcom.com>
> ---
>   drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c | 3 +--
>   1 file changed, 1 insertion(+), 2 deletions(-)
> 
> 
> V1->V2: Clarify changelog re: whether the uninitialized data is printed.

This patch and the others in this series look fine to me.

Thanks,
Arend
Kalle Valo Sept. 12, 2017, 5:48 a.m. UTC | #2
Arend van Spriel <arend.vanspriel@broadcom.com> writes:

> On 09-09-17 21:30, Kevin Cernekee wrote:
>> In brcmf_p2p_notify_rx_mgmt_p2p_probereq(), chanspec is assigned before
>> the length of rxframe is validated.  This could lead to uninitialized
>> data being accessed (but not printed).  Since we already have a
>> perfectly good endian-swapped copy of rxframe->chanspec in ch.chspec,
>> and ch.chspec is not modified by decchspec(), avoid the extra
>> assignment and use ch.chspec in the debug print.
>>
>> Suggested-by: Mattias Nissler <mnissler@chromium.org>
>> Signed-off-by: Kevin Cernekee <cernekee@chromium.org>
>> Reviewed-by: Arend van Spriel <arend.vanspriel@broadcom.com>
>> ---
>>   drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c | 3 +--
>>   1 file changed, 1 insertion(+), 2 deletions(-)
>>
>>
>> V1->V2: Clarify changelog re: whether the uninitialized data is printed.
>
> This patch and the others in this series look fine to me.

Should these go to v4.14?
Arend van Spriel Sept. 12, 2017, 7:36 a.m. UTC | #3
On 9/12/2017 7:48 AM, Kalle Valo wrote:
> Arend van Spriel <arend.vanspriel@broadcom.com> writes:
>
>> On 09-09-17 21:30, Kevin Cernekee wrote:
>>> In brcmf_p2p_notify_rx_mgmt_p2p_probereq(), chanspec is assigned before
>>> the length of rxframe is validated.  This could lead to uninitialized
>>> data being accessed (but not printed).  Since we already have a
>>> perfectly good endian-swapped copy of rxframe->chanspec in ch.chspec,
>>> and ch.chspec is not modified by decchspec(), avoid the extra
>>> assignment and use ch.chspec in the debug print.
>>>
>>> Suggested-by: Mattias Nissler <mnissler@chromium.org>
>>> Signed-off-by: Kevin Cernekee <cernekee@chromium.org>
>>> Reviewed-by: Arend van Spriel <arend.vanspriel@broadcom.com>
>>> ---
>>>    drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c | 3 +--
>>>    1 file changed, 1 insertion(+), 2 deletions(-)
>>>
>>>
>>> V1->V2: Clarify changelog re: whether the uninitialized data is printed.
>>
>> This patch and the others in this series look fine to me.
>
> Should these go to v4.14?

I have no strong opinion. These are certainly improvements, but it does 
not seem an -rc fix to me. Within this series I would say patch 3/3 adds 
an additional sanity check in the event processing against an attack so 
you may consider adding just that one to v4.14 and tag it for stable, ie.:

Cc: stable@vger.kernel.org # v3.8.x

Regards,
Arend
Kalle Valo Sept. 12, 2017, 7:47 a.m. UTC | #4
Arend van Spriel <arend.vanspriel@broadcom.com> writes:

> On 9/12/2017 7:48 AM, Kalle Valo wrote:
>> Arend van Spriel <arend.vanspriel@broadcom.com> writes:
>>
>>> On 09-09-17 21:30, Kevin Cernekee wrote:
>>>> In brcmf_p2p_notify_rx_mgmt_p2p_probereq(), chanspec is assigned before
>>>> the length of rxframe is validated.  This could lead to uninitialized
>>>> data being accessed (but not printed).  Since we already have a
>>>> perfectly good endian-swapped copy of rxframe->chanspec in ch.chspec,
>>>> and ch.chspec is not modified by decchspec(), avoid the extra
>>>> assignment and use ch.chspec in the debug print.
>>>>
>>>> Suggested-by: Mattias Nissler <mnissler@chromium.org>
>>>> Signed-off-by: Kevin Cernekee <cernekee@chromium.org>
>>>> Reviewed-by: Arend van Spriel <arend.vanspriel@broadcom.com>
>>>> ---
>>>>    drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c | 3 +--
>>>>    1 file changed, 1 insertion(+), 2 deletions(-)
>>>>
>>>>
>>>> V1->V2: Clarify changelog re: whether the uninitialized data is printed.
>>>
>>> This patch and the others in this series look fine to me.
>>
>> Should these go to v4.14?
>
> I have no strong opinion. These are certainly improvements, but it
> does not seem an -rc fix to me. Within this series I would say patch
> 3/3 adds an additional sanity check in the event processing against an
> attack so you may consider adding just that one to v4.14

Ok, I'll queue patch 3 to v4.14.

> and tag it for stable, ie.:
>
> Cc: stable@vger.kernel.org # v3.8.x

But why v3.8.x? I admit that I haven't fully figured out the stable tags
yet, but doesn't that mean that it will be only applied to v3.8.x and
nothing else? I was expecting it to be:

Cc: stable@vger.kernel.org # v3.8+
Arend van Spriel Sept. 12, 2017, 7:59 a.m. UTC | #5
On 9/12/2017 9:47 AM, Kalle Valo wrote:
> Arend van Spriel <arend.vanspriel@broadcom.com> writes:
>
>> On 9/12/2017 7:48 AM, Kalle Valo wrote:
>>> Arend van Spriel <arend.vanspriel@broadcom.com> writes:
>>>
>>>> On 09-09-17 21:30, Kevin Cernekee wrote:
>>>>> In brcmf_p2p_notify_rx_mgmt_p2p_probereq(), chanspec is assigned before
>>>>> the length of rxframe is validated.  This could lead to uninitialized
>>>>> data being accessed (but not printed).  Since we already have a
>>>>> perfectly good endian-swapped copy of rxframe->chanspec in ch.chspec,
>>>>> and ch.chspec is not modified by decchspec(), avoid the extra
>>>>> assignment and use ch.chspec in the debug print.
>>>>>
>>>>> Suggested-by: Mattias Nissler <mnissler@chromium.org>
>>>>> Signed-off-by: Kevin Cernekee <cernekee@chromium.org>
>>>>> Reviewed-by: Arend van Spriel <arend.vanspriel@broadcom.com>
>>>>> ---
>>>>>     drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c | 3 +--
>>>>>     1 file changed, 1 insertion(+), 2 deletions(-)
>>>>>
>>>>>
>>>>> V1->V2: Clarify changelog re: whether the uninitialized data is printed.
>>>>
>>>> This patch and the others in this series look fine to me.
>>>
>>> Should these go to v4.14?
>>
>> I have no strong opinion. These are certainly improvements, but it
>> does not seem an -rc fix to me. Within this series I would say patch
>> 3/3 adds an additional sanity check in the event processing against an
>> attack so you may consider adding just that one to v4.14
>
> Ok, I'll queue patch 3 to v4.14.
>
>> and tag it for stable, ie.:
>>
>> Cc: stable@vger.kernel.org # v3.8.x
>
> But why v3.8.x? I admit that I haven't fully figured out the stable tags
> yet, but doesn't that mean that it will be only applied to v3.8.x and
> nothing else? I was expecting it to be:
>
> Cc: stable@vger.kernel.org # v3.8+
>

It is actually in the stable-kernel-rules documentation [1]:

"""
Also, some patches may have kernel version prerequisites.  This can be
specified in the following format in the sign-off area:

.. code-block:: none

      Cc: <stable@vger.kernel.org> # 3.3.x

The tag has the meaning of:

.. code-block:: none

      git cherry-pick <this commit>

For each "-stable" tree starting with the specified version.
"""

The event handling code was added in v3.8.

Regards,
Arend

[1] https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
Kalle Valo Sept. 12, 2017, 8:05 a.m. UTC | #6
Arend van Spriel <arend.vanspriel@broadcom.com> writes:

> On 9/12/2017 9:47 AM, Kalle Valo wrote:
>> Arend van Spriel <arend.vanspriel@broadcom.com> writes:
>>
>>> On 9/12/2017 7:48 AM, Kalle Valo wrote:
>>>> Arend van Spriel <arend.vanspriel@broadcom.com> writes:
>>>>
>>>>> On 09-09-17 21:30, Kevin Cernekee wrote:
>>>>>> In brcmf_p2p_notify_rx_mgmt_p2p_probereq(), chanspec is assigned before
>>>>>> the length of rxframe is validated.  This could lead to uninitialized
>>>>>> data being accessed (but not printed).  Since we already have a
>>>>>> perfectly good endian-swapped copy of rxframe->chanspec in ch.chspec,
>>>>>> and ch.chspec is not modified by decchspec(), avoid the extra
>>>>>> assignment and use ch.chspec in the debug print.
>>>>>>
>>>>>> Suggested-by: Mattias Nissler <mnissler@chromium.org>
>>>>>> Signed-off-by: Kevin Cernekee <cernekee@chromium.org>
>>>>>> Reviewed-by: Arend van Spriel <arend.vanspriel@broadcom.com>
>>>>>> ---
>>>>>>     drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c | 3 +--
>>>>>>     1 file changed, 1 insertion(+), 2 deletions(-)
>>>>>>
>>>>>>
>>>>>> V1->V2: Clarify changelog re: whether the uninitialized data is printed.
>>>>>
>>>>> This patch and the others in this series look fine to me.
>>>>
>>>> Should these go to v4.14?
>>>
>>> I have no strong opinion. These are certainly improvements, but it
>>> does not seem an -rc fix to me. Within this series I would say patch
>>> 3/3 adds an additional sanity check in the event processing against an
>>> attack so you may consider adding just that one to v4.14
>>
>> Ok, I'll queue patch 3 to v4.14.
>>
>>> and tag it for stable, ie.:
>>>
>>> Cc: stable@vger.kernel.org # v3.8.x
>>
>> But why v3.8.x? I admit that I haven't fully figured out the stable tags
>> yet, but doesn't that mean that it will be only applied to v3.8.x and
>> nothing else? I was expecting it to be:
>>
>> Cc: stable@vger.kernel.org # v3.8+
>>
>
> It is actually in the stable-kernel-rules documentation [1]:
>
> """
> Also, some patches may have kernel version prerequisites.  This can be
> specified in the following format in the sign-off area:
>
> .. code-block:: none
>
>      Cc: <stable@vger.kernel.org> # 3.3.x
>
> The tag has the meaning of:
>
> .. code-block:: none
>
>      git cherry-pick <this commit>
>
> For each "-stable" tree starting with the specified version.
> """

Yeah, but it says "starting with" which I interpret as "starting with
string '3.3'". For example the commit here would be applied to 3.3.1,
3.3.2 and 3.3.3 etc but _not_ to 3.4, 3.4.1, 3.5 or any later release.

Of course I can be way off here, wouldn't be the first :)
Arend van Spriel Sept. 12, 2017, 8:18 a.m. UTC | #7
+ Greg KH

On 9/12/2017 10:05 AM, Kalle Valo wrote:
> Arend van Spriel <arend.vanspriel@broadcom.com> writes:
>
>> On 9/12/2017 9:47 AM, Kalle Valo wrote:
>>> Arend van Spriel <arend.vanspriel@broadcom.com> writes:
>>>
>>>> On 9/12/2017 7:48 AM, Kalle Valo wrote:
>>>>> Arend van Spriel <arend.vanspriel@broadcom.com> writes:
>>>>>
>>>>>> On 09-09-17 21:30, Kevin Cernekee wrote:
>>>>>>> In brcmf_p2p_notify_rx_mgmt_p2p_probereq(), chanspec is assigned before
>>>>>>> the length of rxframe is validated.  This could lead to uninitialized
>>>>>>> data being accessed (but not printed).  Since we already have a
>>>>>>> perfectly good endian-swapped copy of rxframe->chanspec in ch.chspec,
>>>>>>> and ch.chspec is not modified by decchspec(), avoid the extra
>>>>>>> assignment and use ch.chspec in the debug print.
>>>>>>>
>>>>>>> Suggested-by: Mattias Nissler <mnissler@chromium.org>
>>>>>>> Signed-off-by: Kevin Cernekee <cernekee@chromium.org>
>>>>>>> Reviewed-by: Arend van Spriel <arend.vanspriel@broadcom.com>
>>>>>>> ---
>>>>>>>      drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c | 3 +--
>>>>>>>      1 file changed, 1 insertion(+), 2 deletions(-)
>>>>>>>
>>>>>>>
>>>>>>> V1->V2: Clarify changelog re: whether the uninitialized data is printed.
>>>>>>
>>>>>> This patch and the others in this series look fine to me.
>>>>>
>>>>> Should these go to v4.14?
>>>>
>>>> I have no strong opinion. These are certainly improvements, but it
>>>> does not seem an -rc fix to me. Within this series I would say patch
>>>> 3/3 adds an additional sanity check in the event processing against an
>>>> attack so you may consider adding just that one to v4.14
>>>
>>> Ok, I'll queue patch 3 to v4.14.
>>>
>>>> and tag it for stable, ie.:
>>>>
>>>> Cc: stable@vger.kernel.org # v3.8.x
>>>
>>> But why v3.8.x? I admit that I haven't fully figured out the stable tags
>>> yet, but doesn't that mean that it will be only applied to v3.8.x and
>>> nothing else? I was expecting it to be:
>>>
>>> Cc: stable@vger.kernel.org # v3.8+
>>>
>>
>> It is actually in the stable-kernel-rules documentation [1]:
>>
>> """
>> Also, some patches may have kernel version prerequisites.  This can be
>> specified in the following format in the sign-off area:
>>
>> .. code-block:: none
>>
>>       Cc: <stable@vger.kernel.org> # 3.3.x
>>
>> The tag has the meaning of:
>>
>> .. code-block:: none
>>
>>       git cherry-pick <this commit>
>>
>> For each "-stable" tree starting with the specified version.
>> """
>
> Yeah, but it says "starting with" which I interpret as "starting with
> string '3.3'". For example the commit here would be applied to 3.3.1,
> 3.3.2 and 3.3.3 etc but _not_ to 3.4, 3.4.1, 3.5 or any later release.
>
> Of course I can be way off here, wouldn't be the first :)

Dito. I interpret "each -stable tree" as each stable branch in the 
stable repository. Would Greg know?

Regards,
Arend
Greg KH Sept. 12, 2017, 12:33 p.m. UTC | #8
On Tue, Sep 12, 2017 at 10:18:00AM +0200, Arend van Spriel wrote:
> + Greg KH
> 
> On 9/12/2017 10:05 AM, Kalle Valo wrote:
> > Arend van Spriel <arend.vanspriel@broadcom.com> writes:
> > 
> > > On 9/12/2017 9:47 AM, Kalle Valo wrote:
> > > > Arend van Spriel <arend.vanspriel@broadcom.com> writes:
> > > > 
> > > > > On 9/12/2017 7:48 AM, Kalle Valo wrote:
> > > > > > Arend van Spriel <arend.vanspriel@broadcom.com> writes:
> > > > > > 
> > > > > > > On 09-09-17 21:30, Kevin Cernekee wrote:
> > > > > > > > In brcmf_p2p_notify_rx_mgmt_p2p_probereq(), chanspec is assigned before
> > > > > > > > the length of rxframe is validated.  This could lead to uninitialized
> > > > > > > > data being accessed (but not printed).  Since we already have a
> > > > > > > > perfectly good endian-swapped copy of rxframe->chanspec in ch.chspec,
> > > > > > > > and ch.chspec is not modified by decchspec(), avoid the extra
> > > > > > > > assignment and use ch.chspec in the debug print.
> > > > > > > > 
> > > > > > > > Suggested-by: Mattias Nissler <mnissler@chromium.org>
> > > > > > > > Signed-off-by: Kevin Cernekee <cernekee@chromium.org>
> > > > > > > > Reviewed-by: Arend van Spriel <arend.vanspriel@broadcom.com>
> > > > > > > > ---
> > > > > > > >      drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c | 3 +--
> > > > > > > >      1 file changed, 1 insertion(+), 2 deletions(-)
> > > > > > > > 
> > > > > > > > 
> > > > > > > > V1->V2: Clarify changelog re: whether the uninitialized data is printed.
> > > > > > > 
> > > > > > > This patch and the others in this series look fine to me.
> > > > > > 
> > > > > > Should these go to v4.14?
> > > > > 
> > > > > I have no strong opinion. These are certainly improvements, but it
> > > > > does not seem an -rc fix to me. Within this series I would say patch
> > > > > 3/3 adds an additional sanity check in the event processing against an
> > > > > attack so you may consider adding just that one to v4.14
> > > > 
> > > > Ok, I'll queue patch 3 to v4.14.
> > > > 
> > > > > and tag it for stable, ie.:
> > > > > 
> > > > > Cc: stable@vger.kernel.org # v3.8.x
> > > > 
> > > > But why v3.8.x? I admit that I haven't fully figured out the stable tags
> > > > yet, but doesn't that mean that it will be only applied to v3.8.x and
> > > > nothing else? I was expecting it to be:
> > > > 
> > > > Cc: stable@vger.kernel.org # v3.8+
> > > > 
> > > 
> > > It is actually in the stable-kernel-rules documentation [1]:
> > > 
> > > """
> > > Also, some patches may have kernel version prerequisites.  This can be
> > > specified in the following format in the sign-off area:
> > > 
> > > .. code-block:: none
> > > 
> > >       Cc: <stable@vger.kernel.org> # 3.3.x
> > > 
> > > The tag has the meaning of:
> > > 
> > > .. code-block:: none
> > > 
> > >       git cherry-pick <this commit>
> > > 
> > > For each "-stable" tree starting with the specified version.
> > > """
> > 
> > Yeah, but it says "starting with" which I interpret as "starting with
> > string '3.3'". For example the commit here would be applied to 3.3.1,
> > 3.3.2 and 3.3.3 etc but _not_ to 3.4, 3.4.1, 3.5 or any later release.
> > 
> > Of course I can be way off here, wouldn't be the first :)
> 
> Dito. I interpret "each -stable tree" as each stable branch in the stable
> repository. Would Greg know?

"# 3.8+" and "# 3.8" mean the same thing to me, we would never backport
something to only a very specific kernel version, and leave newer kernel
versions to not have that fix.  That would be crazy, and would break our
"no regressions" rule (i.e. newer kernels should always work as good as
older kernels.)

Don't get hung up on the semantics here people, it's not all that
complicated, and I do it all by hand anyway :)

thanks,

greg k-h
Kalle Valo Sept. 13, 2017, 4:20 a.m. UTC | #9
Greg KH <greg@kroah.com> writes:

> On Tue, Sep 12, 2017 at 10:18:00AM +0200, Arend van Spriel wrote:
>> + Greg KH
>> 
>> On 9/12/2017 10:05 AM, Kalle Valo wrote:
>> > Arend van Spriel <arend.vanspriel@broadcom.com> writes:
>> > 
>> > > It is actually in the stable-kernel-rules documentation [1]:
>> > > 
>> > > """
>> > > Also, some patches may have kernel version prerequisites.  This can be
>> > > specified in the following format in the sign-off area:
>> > > 
>> > > .. code-block:: none
>> > > 
>> > >       Cc: <stable@vger.kernel.org> # 3.3.x
>> > > 
>> > > The tag has the meaning of:
>> > > 
>> > > .. code-block:: none
>> > > 
>> > >       git cherry-pick <this commit>
>> > > 
>> > > For each "-stable" tree starting with the specified version.
>> > > """
>> > 
>> > Yeah, but it says "starting with" which I interpret as "starting with
>> > string '3.3'". For example the commit here would be applied to 3.3.1,
>> > 3.3.2 and 3.3.3 etc but _not_ to 3.4, 3.4.1, 3.5 or any later release.
>> > 
>> > Of course I can be way off here, wouldn't be the first :)
>> 
>> Dito. I interpret "each -stable tree" as each stable branch in the stable
>> repository. Would Greg know?
>
> "# 3.8+" and "# 3.8" mean the same thing to me, we would never backport
> something to only a very specific kernel version, and leave newer kernel
> versions to not have that fix.  That would be crazy, and would break our
> "no regressions" rule (i.e. newer kernels should always work as good as
> older kernels.)

Indeed, that would be crazy. Didn't think it like that, thanks for the
clarification.

> Don't get hung up on the semantics here people, it's not all that
> complicated, and I do it all by hand anyway :)

Manually? Oh man, that has to be so hard. I cannot understand how you
can do it.
diff mbox

Patch

diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c
index 2ce675ab40ef..1c450c0727cb 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c
@@ -1853,7 +1853,6 @@  s32 brcmf_p2p_notify_rx_mgmt_p2p_probereq(struct brcmf_if *ifp,
 	struct afx_hdl *afx_hdl = &p2p->afx_hdl;
 	struct brcmf_cfg80211_vif *vif = ifp->vif;
 	struct brcmf_rx_mgmt_data *rxframe = (struct brcmf_rx_mgmt_data *)data;
-	u16 chanspec = be16_to_cpu(rxframe->chanspec);
 	struct brcmu_chan ch;
 	u8 *mgmt_frame;
 	u32 mgmt_frame_len;
@@ -1906,7 +1905,7 @@  s32 brcmf_p2p_notify_rx_mgmt_p2p_probereq(struct brcmf_if *ifp,
 	cfg80211_rx_mgmt(&vif->wdev, freq, 0, mgmt_frame, mgmt_frame_len, 0);
 
 	brcmf_dbg(INFO, "mgmt_frame_len (%d) , e->datalen (%d), chanspec (%04x), freq (%d)\n",
-		  mgmt_frame_len, e->datalen, chanspec, freq);
+		  mgmt_frame_len, e->datalen, ch.chspec, freq);
 
 	return 0;
 }