From ae0be8de9a53cda3505865c11826d8ff0640237c Mon Sep 17 00:00:00 2001 From: Michal Kubecek Date: Fri, 26 Apr 2019 11:13:06 +0200 Subject: netlink: make nla_nest_start() add NLA_F_NESTED flag Even if the NLA_F_NESTED flag was introduced more than 11 years ago, most netlink based interfaces (including recently added ones) are still not setting it in kernel generated messages. Without the flag, message parsers not aware of attribute semantics (e.g. wireshark dissector or libmnl's mnl_nlmsg_fprintf()) cannot recognize nested attributes and won't display the structure of their contents. Unfortunately we cannot just add the flag everywhere as there may be userspace applications which check nlattr::nla_type directly rather than through a helper masking out the flags. Therefore the patch renames nla_nest_start() to nla_nest_start_noflag() and introduces nla_nest_start() as a wrapper adding NLA_F_NESTED. The calls which add NLA_F_NESTED manually are rewritten to use nla_nest_start(). Except for changes in include/net/netlink.h, the patch was generated using this semantic patch: @@ expression E1, E2; @@ -nla_nest_start(E1, E2) +nla_nest_start_noflag(E1, E2) @@ expression E1, E2; @@ -nla_nest_start_noflag(E1, E2 | NLA_F_NESTED) +nla_nest_start(E1, E2) Signed-off-by: Michal Kubecek Acked-by: Jiri Pirko Acked-by: David Ahern Signed-off-by: David S. Miller --- net/decnet/dn_table.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/decnet') diff --git a/net/decnet/dn_table.c b/net/decnet/dn_table.c index f0710b5d037d..2fb764321b97 100644 --- a/net/decnet/dn_table.c +++ b/net/decnet/dn_table.c @@ -348,7 +348,7 @@ static int dn_fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event, struct rtnexthop *nhp; struct nlattr *mp_head; - if (!(mp_head = nla_nest_start(skb, RTA_MULTIPATH))) + if (!(mp_head = nla_nest_start_noflag(skb, RTA_MULTIPATH))) goto errout; for_nexthops(fi) { -- cgit v1.2.3