On Sat, Dec 28, 2019 at 07:10:29PM -0500, Sargun Dhillon wrote: > On Sat, Dec 28, 2019 at 1:18 PM Tycho Andersen <tycho@xxxxxxxx> wrote: > > > > On Sat, Dec 28, 2019 at 01:48:39AM +0000, Sargun Dhillon wrote: > > > The seccomp_notif structure should be zeroed out prior to calling the > > > SECCOMP_IOCTL_NOTIF_RECV ioctl. Previously, the kernel did not check > > > whether these structures were zeroed out or not, so these worked. > > > > > > Signed-off-by: Sargun Dhillon <sargun@xxxxxxxxx> > > > Cc: Kees Cook <keescook@xxxxxxxxxxxx> > > > --- > > > samples/seccomp/user-trap.c | 2 +- > > > tools/testing/selftests/seccomp/seccomp_bpf.c | 2 ++ > > > 2 files changed, 3 insertions(+), 1 deletion(-) > > > > > > diff --git a/samples/seccomp/user-trap.c b/samples/seccomp/user-trap.c > > > index 6d0125ca8af7..0ca8fb37cd79 100644 > > > --- a/samples/seccomp/user-trap.c > > > +++ b/samples/seccomp/user-trap.c > > > @@ -298,7 +298,6 @@ int main(void) > > > req = malloc(sizes.seccomp_notif); > > > if (!req) > > > goto out_close; > > > - memset(req, 0, sizeof(*req)); > > > > > > resp = malloc(sizes.seccomp_notif_resp); > > > if (!resp) > > > @@ -306,6 +305,7 @@ int main(void) > > > memset(resp, 0, sizeof(*resp)); > > > > I know it's unrelated, but it's probably worth sending a patch to fix > > this to be sizes.seccomp_notif_resp instead of sizeof(*resp), since if > > the kernel is older this will over-zero things. I can do that, or you > > can add the patch to this series, just let me know which. > > I was thinking about this, and initially, I chose to make the smaller > change. I think it might make more sense to combine the patch, > given that the memset behaviour is "incorrect" if we do it based on > sizeof(*req), or sizeof(*resp). > > I'll go ahead and respin this patch with the change to call memset > based on sizes. I think it would be good to keep it as a separate patch, since it's an unrelated bug fix. That way if we have to revert these because of some breakage, we won't lose the fix. Cheers, Tycho
