Please backport 2ae5c9248e06 ("wifi: mac80211: Use flexible array in struct ieee80211_tim_ie")

Please backport 2ae5c9248e06 ("wifi: mac80211: Use flexible array in struct ieee80211_tim_ie")

[Jeff Johnson]

Refer to:
https://lore.kernel.org/all/CAPh3n83zb1PwFBFijJKChBqY95zzpYh=2iPf8tmh=YTS6e3xPw@mail.gmail.com/

Looks like this should be backported to all LTS kernels where FORTIFY_SOURCE
is expected to be enabled.

/jeff

Re: Please backport 2ae5c9248e06 ("wifi: mac80211: Use flexible array in struct ieee80211_tim_ie")

[Greg KH]

On Wed, Jun 26, 2024 at 11:32:22AM -0700, Jeff Johnson wrote:
> Refer to:
> https://lore.kernel.org/all/CAPh3n83zb1PwFBFijJKChBqY95zzpYh=2iPf8tmh=YTS6e3xPw@mail.gmail.com/

Please provide the information in the email, for those of us traveling
with store-and-forward email systems, links don't always work.

> Looks like this should be backported to all LTS kernels where FORTIFY_SOURCE
> is expected to be enabled.

And where would that exactly be?  Have you verified that it will apply
properly to those unnamed kernel trees?

thanks,

greg k-h

Re: Please backport 2ae5c9248e06 ("wifi: mac80211: Use flexible array in struct ieee80211_tim_ie")

[Jeff Johnson]

On 6/27/2024 12:18 AM, Greg KH wrote:
> On Wed, Jun 26, 2024 at 11:32:22AM -0700, Jeff Johnson wrote:
>> Refer to:
>> https://lore.kernel.org/all/CAPh3n83zb1PwFBFijJKChBqY95zzpYh=2iPf8tmh=YTS6e3xPw@mail.gmail.com/
> 
> Please provide the information in the email, for those of us traveling
> with store-and-forward email systems, links don't always work.

Apologies. I was trying to be concise, but over did it.

The issue reported is a splat in 6.6 due to FORTIFY_SOURCE complaining about
access to an "old style" variable array declared with size 1:
            u8 virtual_map[1];

>> Looks like this should be backported to all LTS kernels where FORTIFY_SOURCE
>> is expected to be enabled.
> 
> And where would that exactly be?  Have you verified that it will apply
> properly to those unnamed kernel trees?

I don't know which trees are actively enabling FORTIFY_SOURCE. Since the
report is coming from 6.6, I would expect we should backport at least to there.

I've cc'd Kees in case he has more definite information, as well as the
wireless maintainers and the reporter in case they have anything else to add.

The actual fix is trivial, containing just a change to a data structure along
with a related documentation change. Any conflicts would more likely occur due
to the documentation rather than the code, since that code definition had been
unchanged since 2012 but the documentation has been refined over time.

/jeff

Re: Please backport 2ae5c9248e06 ("wifi: mac80211: Use flexible array in struct ieee80211_tim_ie")

[Kees Cook]

On Thu, Jun 27, 2024 at 07:44:48AM -0700, Jeff Johnson wrote:
> On 6/27/2024 12:18 AM, Greg KH wrote:
> > On Wed, Jun 26, 2024 at 11:32:22AM -0700, Jeff Johnson wrote:
> >> Refer to:
> >> https://lore.kernel.org/all/CAPh3n83zb1PwFBFijJKChBqY95zzpYh=2iPf8tmh=YTS6e3xPw@mail.gmail.com/
> > 
> > Please provide the information in the email, for those of us traveling
> > with store-and-forward email systems, links don't always work.
> 
> Apologies. I was trying to be concise, but over did it.
> 
> The issue reported is a splat in 6.6 due to FORTIFY_SOURCE complaining about
> access to an "old style" variable array declared with size 1:
>             u8 virtual_map[1];
> 
> >> Looks like this should be backported to all LTS kernels where FORTIFY_SOURCE
> >> is expected to be enabled.
> > 
> > And where would that exactly be?  Have you verified that it will apply
> > properly to those unnamed kernel trees?
> 
> I don't know which trees are actively enabling FORTIFY_SOURCE. Since the
> report is coming from 6.6, I would expect we should backport at least to there.

FWIW, FORTIFY_SOURCE is enabled in every distro kernel config I know of
(and has been for a very long time).

> I've cc'd Kees in case he has more definite information, as well as the
> wireless maintainers and the reporter in case they have anything else to add.
> 
> The actual fix is trivial, containing just a change to a data structure along
> with a related documentation change. Any conflicts would more likely occur due
> to the documentation rather than the code, since that code definition had been
> unchanged since 2012 but the documentation has been refined over time.

Right, this is fixing the splat -- no other behavioral changes were
seen.

-Kees

-- 
Kees Cook

Re: Please backport 2ae5c9248e06 ("wifi: mac80211: Use flexible array in struct ieee80211_tim_ie")

[Greg KH]

On Thu, Jun 27, 2024 at 07:44:48AM -0700, Jeff Johnson wrote:
> On 6/27/2024 12:18 AM, Greg KH wrote:
> > On Wed, Jun 26, 2024 at 11:32:22AM -0700, Jeff Johnson wrote:
> >> Refer to:
> >> https://lore.kernel.org/all/CAPh3n83zb1PwFBFijJKChBqY95zzpYh=2iPf8tmh=YTS6e3xPw@mail.gmail.com/
> > 
> > Please provide the information in the email, for those of us traveling
> > with store-and-forward email systems, links don't always work.
> 
> Apologies. I was trying to be concise, but over did it.
> 
> The issue reported is a splat in 6.6 due to FORTIFY_SOURCE complaining about
> access to an "old style" variable array declared with size 1:
>             u8 virtual_map[1];
> 
> >> Looks like this should be backported to all LTS kernels where FORTIFY_SOURCE
> >> is expected to be enabled.
> > 
> > And where would that exactly be?  Have you verified that it will apply
> > properly to those unnamed kernel trees?
> 
> I don't know which trees are actively enabling FORTIFY_SOURCE. Since the
> report is coming from 6.6, I would expect we should backport at least to there.

It does not apply to 6.6.y, sorry, please provide a working backport for
any tree you wish to see this applied to.

thanks,

greg k-h