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authorKees Cook <keescook@chromium.org>2022-11-07 21:58:52 +0100
committerJozsef Kadlecsik <kadlec@netfilter.org>2022-11-07 21:58:52 +0100
commit67e1c031e8bae91764ecd100538753c3dabdedb0 (patch)
treea3971fbc03ef8d24b42b071ee999b86258d984f2 /kernel/net
parent6aa65d00f6a7305310eec05218b9ab9dea396658 (diff)
netlink: Bounds-check struct nlmsgerr creation
In preparation for FORTIFY_SOURCE doing bounds-check on memcpy(), switch from __nlmsg_put to nlmsg_put(), and explain the bounds check for dealing with the memcpy() across a composite flexible array struct. Avoids this future run-time warning: memcpy: detected field-spanning write (size 32) of single field "&errmsg->msg" at net/netlink/af_netlink.c:2447 (size 16) Cc: Jakub Kicinski <kuba@kernel.org> Cc: Pablo Neira Ayuso <pablo@netfilter.org> Cc: Jozsef Kadlecsik <kadlec@netfilter.org> Cc: Florian Westphal <fw@strlen.de> Cc: "David S. Miller" <davem@davemloft.net> Cc: Eric Dumazet <edumazet@google.com> Cc: Paolo Abeni <pabeni@redhat.com> Cc: syzbot <syzkaller@googlegroups.com> Cc: netfilter-devel@vger.kernel.org Cc: coreteam@netfilter.org Cc: netdev@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220901071336.1418572-1-keescook@chromium.org Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel/net')
-rw-r--r--kernel/net/netfilter/ipset/ip_set_core.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/kernel/net/netfilter/ipset/ip_set_core.c b/kernel/net/netfilter/ipset/ip_set_core.c
index 0fdafb7..037b2ce 100644
--- a/kernel/net/netfilter/ipset/ip_set_core.c
+++ b/kernel/net/netfilter/ipset/ip_set_core.c
@@ -1775,11 +1775,12 @@ CALL_AD(struct net *net, struct sock *ctnl, struct sk_buff *skb,
skb2 = nlmsg_new(payload, GFP_KERNEL);
if (!skb2)
return -ENOMEM;
- rep = __nlmsg_put(skb2, NETLINK_PORTID(skb),
- nlh->nlmsg_seq, NLMSG_ERROR, payload, 0);
+ rep = nlmsg_put(skb2, NETLINK_PORTID(skb),
+ nlh->nlmsg_seq, NLMSG_ERROR, payload, 0);
errmsg = nlmsg_data(rep);
errmsg->error = ret;
- memcpy(&errmsg->msg, nlh, nlh->nlmsg_len);
+ unsafe_memcpy(&errmsg->msg, nlh, nlh->nlmsg_len,
+ /* Bounds checked by the skb layer. */);
cmdattr = (void *)&errmsg->msg + min_len;
ret = NLA_PARSE(cda, IPSET_ATTR_CMD_MAX, cmdattr,