Re: [PATCH 54/64] ipv6: Use struct_group() to zero rt6_info
From: Jakub Kicinski <kuba@kernel.org>
Date: 2021-07-29 18:58:58
Also in:
dri-devel, linux-block, linux-hardening, linux-kbuild, linux-staging, linux-wireless, lkml
On Tue, 27 Jul 2021 13:58:45 -0700 Kees Cook wrote:
In preparation for FORTIFY_SOURCE performing compile-time and run-time field bounds checking for memset(), avoid intentionally writing across neighboring fields. Add struct_group() to mark region of struct rt6_info that should be initialized to zero.
memset_after() ?
quoted hunk ↗ jump to hunk
diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h index 15b7fbe6b15c..9816e7444918 100644 --- a/include/net/ip6_fib.h +++ b/include/net/ip6_fib.h@@ -205,20 +205,22 @@ struct fib6_info { struct rt6_info { struct dst_entry dst; - struct fib6_info __rcu *from; - int sernum; - - struct rt6key rt6i_dst; - struct rt6key rt6i_src; - struct in6_addr rt6i_gateway; - struct inet6_dev *rt6i_idev; - u32 rt6i_flags; - - struct list_head rt6i_uncached; - struct uncached_list *rt6i_uncached_list; - - /* more non-fragment space at head required */ - unsigned short rt6i_nfheader_len; + struct_group(init, + struct fib6_info __rcu *from; + int sernum; + + struct rt6key rt6i_dst; + struct rt6key rt6i_src; + struct in6_addr rt6i_gateway; + struct inet6_dev *rt6i_idev; + u32 rt6i_flags; + + struct list_head rt6i_uncached; + struct uncached_list *rt6i_uncached_list; + + /* more non-fragment space at head required */ + unsigned short rt6i_nfheader_len; + ); }; struct fib6_result {diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 6b8051106aba..bbcc605bab57 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c@@ -327,9 +327,7 @@ static const struct rt6_info ip6_blk_hole_entry_template = { static void rt6_info_init(struct rt6_info *rt) { - struct dst_entry *dst = &rt->dst; - - memset(dst + 1, 0, sizeof(*rt) - sizeof(*dst)); + memset(&rt->init, 0, sizeof(rt->init)); INIT_LIST_HEAD(&rt->rt6i_uncached); }