diff options
| -rw-r--r-- | include/linux/netlink.h | 7 | ||||
| -rw-r--r-- | include/uapi/linux/netlink.h | 4 | ||||
| -rw-r--r-- | net/netlink/af_netlink.c | 33 |
3 files changed, 33 insertions, 11 deletions
diff --git a/include/linux/netlink.h b/include/linux/netlink.h index 60e7137f840d..8d2a8924705c 100644 --- a/include/linux/netlink.h +++ b/include/linux/netlink.h @@ -62,15 +62,22 @@ netlink_kernel_create(struct net *net, int unit, struct netlink_kernel_cfg *cfg) return __netlink_kernel_create(net, unit, THIS_MODULE, cfg); } +/* this can be increased when necessary - don't expose to userland */ +#define NETLINK_MAX_COOKIE_LEN 20 + /** * struct netlink_ext_ack - netlink extended ACK report struct * @_msg: message string to report - don't access directly, use * %NL_SET_ERR_MSG * @bad_attr: attribute with error + * @cookie: cookie data to return to userspace (for success) + * @cookie_len: actual cookie data length */ struct netlink_ext_ack { const char *_msg; const struct nlattr *bad_attr; + u8 cookie[NETLINK_MAX_COOKIE_LEN]; + u8 cookie_len; }; /* Always use this macro, this allows later putting the diff --git a/include/uapi/linux/netlink.h b/include/uapi/linux/netlink.h index 7df88770e029..f86127a46cfc 100644 --- a/include/uapi/linux/netlink.h +++ b/include/uapi/linux/netlink.h @@ -122,6 +122,9 @@ struct nlmsgerr { * @NLMSGERR_ATTR_MSG: error message string (string) * @NLMSGERR_ATTR_OFFS: offset of the invalid attribute in the original * message, counting from the beginning of the header (u32) + * @NLMSGERR_ATTR_COOKIE: arbitrary subsystem specific cookie to + * be used - in the success case - to identify a created + * object or operation or similar (binary) * @__NLMSGERR_ATTR_MAX: number of attributes * @NLMSGERR_ATTR_MAX: highest attribute number */ @@ -129,6 +132,7 @@ enum nlmsgerr_attrs { NLMSGERR_ATTR_UNUSED, NLMSGERR_ATTR_MSG, NLMSGERR_ATTR_OFFS, + NLMSGERR_ATTR_COOKIE, __NLMSGERR_ATTR_MAX, NLMSGERR_ATTR_MAX = __NLMSGERR_ATTR_MAX - 1 diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index c1564768000e..ee841f00a6ec 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -2311,6 +2311,10 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err, } } else { flags |= NLM_F_CAPPED; + + if (nlk->flags & NETLINK_F_EXT_ACK && + extack && extack->cookie_len) + tlvlen += nla_total_size(extack->cookie_len); } if (tlvlen) @@ -2337,17 +2341,24 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err, errmsg->error = err; memcpy(&errmsg->msg, nlh, payload > sizeof(*errmsg) ? nlh->nlmsg_len : sizeof(*nlh)); - if (err && nlk->flags & NETLINK_F_EXT_ACK && extack) { - if (extack->_msg) - WARN_ON(nla_put_string(skb, NLMSGERR_ATTR_MSG, - extack->_msg)); - 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 - - in_skb->data)); + if (nlk->flags & NETLINK_F_EXT_ACK && extack) { + if (err) { + if (extack->_msg) + WARN_ON(nla_put_string(skb, NLMSGERR_ATTR_MSG, + extack->_msg)); + 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 - + in_skb->data)); + } else { + if (extack->cookie_len) + WARN_ON(nla_put(skb, NLMSGERR_ATTR_COOKIE, + extack->cookie_len, + extack->cookie)); + } } nlmsg_end(skb, rep); |