In preparation for FORTIFY_SOURCE performing compile-time and run-time field bounds checking for memset(), avoid intentionally writing across neighboring fields.
Clear trailing padding bytes using the new helper so that memset() doesn't get confused about writing "past the end" of the last struct member. There is no change to the resulting machine code.
Cc: Steffen Klassert steffen.klassert@secunet.com Cc: Herbert Xu herbert@gondor.apana.org.au Cc: "David S. Miller" davem@davemloft.net Cc: Jakub Kicinski kuba@kernel.org Cc: netdev@vger.kernel.org Signed-off-by: Kees Cook keescook@chromium.org --- net/xfrm/xfrm_policy.c | 4 +--- net/xfrm/xfrm_user.c | 2 +- 2 files changed, 2 insertions(+), 4 deletions(-)
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c index 37d17a79617c..1a06585022ab 100644 --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -2486,9 +2486,7 @@ static inline struct xfrm_dst *xfrm_alloc_dst(struct net *net, int family) xdst = dst_alloc(dst_ops, NULL, 1, DST_OBSOLETE_NONE, 0);
if (likely(xdst)) { - struct dst_entry *dst = &xdst->u.dst; - - memset(dst + 1, 0, sizeof(*xdst) - sizeof(*dst)); + memset_after(xdst, 0, u.dst); } else xdst = ERR_PTR(-ENOBUFS);
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c index 03b66d154b2b..b7b986520dc7 100644 --- a/net/xfrm/xfrm_user.c +++ b/net/xfrm/xfrm_user.c @@ -2912,7 +2912,7 @@ static int build_expire(struct sk_buff *skb, struct xfrm_state *x, const struct copy_to_user_state(x, &ue->state); ue->hard = (c->data.hard != 0) ? 1 : 0; /* clear the padding bytes */ - memset(&ue->hard + 1, 0, sizeof(*ue) - offsetofend(typeof(*ue), hard)); + memset_after(ue, 0, hard);
err = xfrm_mark_put(skb, &x->mark); if (err)