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?
> > ---
> > 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
