On Mon, Jun 15, 2020 at 08:25:23PM -0700, Kees Cook wrote: > This patch is based on discussions[1] with Sargun Dhillon, Christian > Brauner, and David Laight. Instead of building size into the addfd > structure, make it a function of the ioctl command (which is how sizes are > normally passed to ioctls). To support forward and backward compatibility, > just mask out the direction and size, and match everything. The size (and > any future direction) checks are done along with copy_struct_from_user() > logic. Also update the selftests to check size bounds. > > [1] https://lore.kernel.org/lkml/20200612104629.GA15814@ircssh-2.c.rugged-nimbus-611.internal > > Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> > --- > include/uapi/linux/seccomp.h | 2 - > kernel/seccomp.c | 21 ++++++---- > tools/testing/selftests/seccomp/seccomp_bpf.c | 40 ++++++++++++++++--- > 3 files changed, 49 insertions(+), 14 deletions(-) > > diff --git a/include/uapi/linux/seccomp.h b/include/uapi/linux/seccomp.h > index c347160378e5..473a61695ac3 100644 > --- a/include/uapi/linux/seccomp.h > +++ b/include/uapi/linux/seccomp.h > @@ -118,7 +118,6 @@ struct seccomp_notif_resp { > > /** > * struct seccomp_notif_addfd > - * @size: The size of the seccomp_notif_addfd structure > * @id: The ID of the seccomp notification > * @flags: SECCOMP_ADDFD_FLAG_* > * @srcfd: The local fd number > @@ -126,7 +125,6 @@ struct seccomp_notif_resp { > * @newfd_flags: The O_* flags the remote FD should have applied > */ > struct seccomp_notif_addfd { > - __u64 size; Huh? Won't this break builds? Tycho
