On Thu, Oct 20, 2022 at 11:10 AM Paul Moore <paul@xxxxxxxxxxxxxx> wrote:
> On Thu, Oct 20, 2022 at 9:16 AM Casey Schaufler <casey@xxxxxxxxxxxxxxxx> wrote:
> > On 10/10/2022 2:58 PM, Paul Moore wrote:
> > > Commit 4ff09db1b79b ("bpf: net: Change sk_getsockopt() to take the
> > > sockptr_t argument") made it possible to call sk_getsockopt()
> > > with both user and kernel address space buffers through the use of
> > > the sockptr_t type. Unfortunately at the time of conversion the
> > > security_socket_getpeersec_stream() LSM hook was written to only
> > > accept userspace buffers, and in a desire to avoid having to change
> > > the LSM hook the commit author simply passed the sockptr_t's
> > > userspace buffer pointer. Since the only sk_getsockopt() callers
> > > at the time of conversion which used kernel sockptr_t buffers did
> > > not allow SO_PEERSEC, and hence the
> > > security_socket_getpeersec_stream() hook, this was acceptable but
> > > also very fragile as future changes presented the possibility of
> > > silently passing kernel space pointers to the LSM hook.
> > >
> > > There are several ways to protect against this, including careful
> > > code review of future commits, but since relying on code review to
> > > catch bugs is a recipe for disaster and the upstream eBPF maintainer
> > > is "strongly against defensive programming", this patch updates the
> > > LSM hook, and all of the implementations to support sockptr_t and
> > > safely handle both user and kernel space buffers.
> > >
> > > Signed-off-by: Paul Moore <paul@xxxxxxxxxxxxxx>
> >
> > Smack part looks ok, I haven't had the opportunity to test it.
> > Will do so as I crunch through the backlog.
> >
> > Acked-by: Casey Schaufler <casey@xxxxxxxxxxxxxxxx>
>
> Thanks Casey.
>
> John, how do the AppArmor parts look?
Hey John - can you weigh in on the AppArmor bits?
> > > ---
> > > include/linux/lsm_hook_defs.h | 2 +-
> > > include/linux/lsm_hooks.h | 4 ++--
> > > include/linux/security.h | 11 +++++++----
> > > net/core/sock.c | 3 ++-
> > > security/apparmor/lsm.c | 29 +++++++++++++----------------
> > > security/security.c | 6 +++---
> > > security/selinux/hooks.c | 13 ++++++-------
> > > security/smack/smack_lsm.c | 19 ++++++++++---------
> > > 8 files changed, 44 insertions(+), 43 deletions(-)
--
paul-moore.com
