Re: Fwd: UBSAN: array-index-out-of-bounds in net/wireless/nl80211.c and net/mac80211/scan.c

[Johannes Berg <johannes@sipsolutions.net>]

On Thu, 2024-05-09 at 07:07 +0700, Bagas Sanjaya wrote:
> Hi,
> 
> Jannik Glückert <jannik.glueckert@gmail.com> reported on Bugzilla array index
> out-of-bounds catched by ubsan along with full kernel trace dump (see
> https://bugzilla.kernel.org/show_bug.cgi?id=218810):
> 
> > I am seeing multiple array-index-out-of-bounds related to `ieee80211_channel[]` iteration.
> > 
> > This is with a Mediatek MT7921 chipset.
> > I have only tested with kernel 6.8.9, but I don't see any channel index related fixes in master.
> > 
> > This was discovered as part of Gentoo Hardened enabling CONFIG_UBSAN_ARRAY_BOUNDS
> > 
> > 
> > [  106.194465] UBSAN: array-index-out-of-bounds in /var/tmp/portage/sys-kernel/gentoo-kernel-6.8.9/work/linux-6.8/net/wireless/nl80211.c:9203:29
> > [  106.195063] index 42 is out of range for type 'struct ieee80211_channel *[]'

> > [  106.200924] UBSAN: array-index-out-of-bounds in /var/tmp/portage/sys-kernel/gentoo-kernel-6.8.9/work/linux-6.8/net/wireless/nl80211.c:9252:5
> > [  106.200926] index 0 is out of range for type 'struct ieee80211_channel *[]'

At least one of these should be fixed by
https://git.kernel.org/pub/scm/linux/kernel/git/wireless/wireless.git/commit/?id=838c7b8f1f278404d9d684c34a8cb26dc41aaaa1

> > [  106.201036] UBSAN: array-index-out-of-bounds in /var/tmp/portage/sys-kernel/gentoo-kernel-6.8.9/work/linux-6.8/net/mac80211/scan.c:364:4
> > [  106.201037] index 0 is out of range for type 'struct ieee80211_channel *[]'

No idea about that one. Send patches.

(Seriously. If you're running with bleeding edge toolchains that pretty
much nobody has yet, send patches.)

johannes