[PATCH v2] lsm: check size of writes

[Micah Morton]

On Fri, Jan 24, 2025 at 11:42 AM Paul Moore <paul at paul-moore.com> wrote:
>
> On Fri, Jan 24, 2025 at 2:24 PM Micah Morton <mortonm at chromium.org> wrote:
> > On Sat, Jan 4, 2025 at 7:49 PM Paul Moore <paul at paul-moore.com> wrote:
> > >
> > > On Wed, Dec 18, 2024 at 4:51 PM Paul Moore <paul at paul-moore.com> wrote:
> > > > On Tue, Dec 17, 2024 at 1:27 PM Leo Stone <leocstone at gmail.com> wrote:
> > > > >
> > > > > syzbot attempts to write a buffer with a large size to a sysfs entry
> > > > > with writes handled by handle_policy_update(), triggering a warning
> > > > > in kmalloc.
> > > > >
> > > > > Check the size specified for write buffers before allocating.
> > > > >
> > > > > Reported-by: syzbot+4eb7a741b3216020043a at syzkaller.appspotmail.com
> > > > > Closes: https://syzkaller.appspot.com/bug?extid=4eb7a741b3216020043a
> > > > > Signed-off-by: Leo Stone <leocstone at gmail.com>
> > > > > ---
> > > > > v2: Make the check in handle_policy_update() to also cover
> > > > > safesetid_uid_file_write(). Thanks for your feedback.
> > > > > v1: https://lore.kernel.org/all/20241216030213.246804-2-leocstone@gmail.com/
> > > > > ---
> > > > >  security/safesetid/securityfs.c | 3 +++
> > > > >  1 file changed, 3 insertions(+)
> > > >
> > > > Looks okay to me.  Micah, are you planning to merge this patch, or
> > > > would you like me to take it via the LSM tree?
> > > >
> > > > Reviewed-by: Paul Moore <paul at paul-moore.com>
> > > >
> > > > I'm going to tag this to come back to it in a week or so in case we
> > > > don't hear from Micah, but if you don't see any further replies Leo,
> > > > feel free to send a gentle nudge ;)
> > >
> > > I'm going to go ahead and merge this into lsm/dev, if Micah has a
> > > problem with that I can always remove/revert if needed.
> > >
> > > We may need to revisit safesetid's documented support status, but
> > > that's a topic for another day.
> >
> > Sorry guys, I missed this one. I usually just check in weekly on my
> > linux-security-users filter in my email inbox and see if any
> > discussions include 'SafeSetID'.
> >
> > I must have skimmed over 'lsm: check size of writes' thinking it was a
> > generic LSM patch rather than something specific to SafeSetID.
> >
> > I'll have to adjust my email settings so that emails which directly
> > list me on the CC are sent to a specific folder for me to check more
> > closely.
>
> No worries, I'm just happy to hear you're still around and looking out
> for patches :)
>
> I'm assuming you are okay with that patch?  If not we still have time
> to fix it up.

Yes, looks good to me!

>
> --
> paul-moore.com