On Tue, Jun 16, 2020 at 08:55:46AM -0600, Tycho Andersen wrote: > 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? Only if they use addfd without this patch? :) Are you saying I should collapse this patch into the main addfd and test patches? -- Kees Cook
