[PATCH v2] lsm: check size of writes

[Micah Morton]

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.

Micah

>
> Thanks everyone.
>
> --
> paul-moore.com