netlink: allow extack cookie also for error messages

Commit 3fe968eff6dd ("netlink: allow sending extended ACK with cookie on
success") introduced a cookie which can be sent to userspace as part of
extended ack message in the form of NLMSGERR_ATTR_COOKIE attribute.
Currently the cookie is ignored if error code is non-zero but there is
no technical reason for such limitation and it can be useful to provide
machine parseable information as part of an error message.

Include NLMSGERR_ATTR_COOKIE whenever the cookie has been set,
regardless of error code.

Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 5313f1cec17063fb048ad80fdf0a567c4dc7357f..2f234791b879f03ee4ab655a545d34996adfb501 100644 (file)
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -2392,19 +2392,14 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err,
        if (nlk_has_extack && extack && extack->_msg)
                tlvlen += nla_total_size(strlen(extack->_msg) + 1);
 
-       if (err) {
-               if (!(nlk->flags & NETLINK_F_CAP_ACK))
-                       payload += nlmsg_len(nlh);
-               else
-                       flags |= NLM_F_CAPPED;
-               if (nlk_has_extack && extack && extack->bad_attr)
-                       tlvlen += nla_total_size(sizeof(u32));
-       } else {
+       if (err && !(nlk->flags & NETLINK_F_CAP_ACK))
+               payload += nlmsg_len(nlh);
+       else
                flags |= NLM_F_CAPPED;
-
-               if (nlk_has_extack && extack && extack->cookie_len)
-                       tlvlen += nla_total_size(extack->cookie_len);
-       }
+       if (err && nlk_has_extack && extack && extack->bad_attr)
+               tlvlen += nla_total_size(sizeof(u32));
+       if (nlk_has_extack && extack && extack->cookie_len)
+               tlvlen += nla_total_size(extack->cookie_len);
 
        if (tlvlen)
                flags |= NLM_F_ACK_TLVS;
@@ -2427,20 +2422,16 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err,
                        WARN_ON(nla_put_string(skb, NLMSGERR_ATTR_MSG,
                                               extack->_msg));
                }
-               if (err) {
-                       if (extack->bad_attr &&
-                           !WARN_ON((u8 *)extack->bad_attr < in_skb->data ||
-                                    (u8 *)extack->bad_attr >= in_skb->data +
-                                                              in_skb->len))
-                               WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_OFFS,
-                                                   (u8 *)extack->bad_attr -
-                                                   (u8 *)nlh));
-               } else {
-                       if (extack->cookie_len)
-                               WARN_ON(nla_put(skb, NLMSGERR_ATTR_COOKIE,
-                                               extack->cookie_len,
-                                               extack->cookie));
-               }
+               if (err && extack->bad_attr &&
+                   !WARN_ON((u8 *)extack->bad_attr < in_skb->data ||
+                            (u8 *)extack->bad_attr >= in_skb->data +
+                                                      in_skb->len))
+                       WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_OFFS,
+                                           (u8 *)extack->bad_attr -
+                                           (u8 *)nlh));
+               if (extack->cookie_len)
+                       WARN_ON(nla_put(skb, NLMSGERR_ATTR_COOKIE,
+                                       extack->cookie_len, extack->cookie));
        }
 
        nlmsg_end(skb, rep);