diff mbox series

[net-next,01/20] netlink: Pass extack to dump handlers

Message ID 20181004213355.14899-2-dsahern@kernel.org
State Changes Requested, archived
Delegated to: David Miller
Headers show
Series rtnetlink: Add support for rigid checking of data in dump request | expand

Commit Message

David Ahern Oct. 4, 2018, 9:33 p.m. UTC 
From: David Ahern <dsahern@gmail.com>

Declare extack in netlink_dump and pass to dump handlers via
netlink_callback. Add any extack message after the dump_done_errno
allowing error messages to be returned. This will be useful when
strict checking is done on dump requests, returning why the dump
fails EINVAL.

Signed-off-by: David Ahern <dsahern@gmail.com>
---
 include/linux/netlink.h  |  1 +
 net/netlink/af_netlink.c | 12 +++++++++++-
 2 files changed, 12 insertions(+), 1 deletion(-)

Comments

Christian Brauner Oct. 5, 2018, 5:41 p.m. UTC | #1 
On Thu, Oct 04, 2018 at 02:33:36PM -0700, David Ahern wrote:
> From: David Ahern <dsahern@gmail.com>
> 
> Declare extack in netlink_dump and pass to dump handlers via
> netlink_callback. Add any extack message after the dump_done_errno
> allowing error messages to be returned. This will be useful when
> strict checking is done on dump requests, returning why the dump
> fails EINVAL.
> 
> Signed-off-by: David Ahern <dsahern@gmail.com>

Acked-by: Christian Brauner <christian@brauner.io>

> ---
>  include/linux/netlink.h  |  1 +
>  net/netlink/af_netlink.c | 12 +++++++++++-
>  2 files changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/include/linux/netlink.h b/include/linux/netlink.h
> index 71f121b66ca8..88c8a2d83eb3 100644
> --- a/include/linux/netlink.h
> +++ b/include/linux/netlink.h
> @@ -176,6 +176,7 @@ struct netlink_callback {
>  	void			*data;
>  	/* the module that dump function belong to */
>  	struct module		*module;
> +	struct netlink_ext_ack	*extack;
>  	u16			family;
>  	u16			min_dump_alloc;
>  	unsigned int		prev_seq, seq;
> diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
> index e3a0538ec0be..7ac585f33a9e 100644
> --- a/net/netlink/af_netlink.c
> +++ b/net/netlink/af_netlink.c
> @@ -2171,6 +2171,7 @@ EXPORT_SYMBOL(__nlmsg_put);
>  static int netlink_dump(struct sock *sk)
>  {
>  	struct netlink_sock *nlk = nlk_sk(sk);
> +	struct netlink_ext_ack extack = {};
>  	struct netlink_callback *cb;
>  	struct sk_buff *skb = NULL;
>  	struct nlmsghdr *nlh;
> @@ -2222,8 +2223,11 @@ static int netlink_dump(struct sock *sk)
>  	skb_reserve(skb, skb_tailroom(skb) - alloc_size);
>  	netlink_skb_set_owner_r(skb, sk);
>  
> -	if (nlk->dump_done_errno > 0)
> +	if (nlk->dump_done_errno > 0) {
> +		cb->extack = &extack;
>  		nlk->dump_done_errno = cb->dump(skb, cb);
> +		cb->extack = NULL;
> +	}
>  
>  	if (nlk->dump_done_errno > 0 ||
>  	    skb_tailroom(skb) < nlmsg_total_size(sizeof(nlk->dump_done_errno))) {
> @@ -2246,6 +2250,12 @@ static int netlink_dump(struct sock *sk)
>  	memcpy(nlmsg_data(nlh), &nlk->dump_done_errno,
>  	       sizeof(nlk->dump_done_errno));
>  
> +	if (extack._msg && nlk->flags & NETLINK_F_EXT_ACK) {
> +		nlh->nlmsg_flags |= NLM_F_ACK_TLVS;
> +		if (!nla_put_string(skb, NLMSGERR_ATTR_MSG, extack._msg))
> +			nlmsg_end(skb, nlh);
> +	}
> +
>  	if (sk_filter(sk, skb))
>  		kfree_skb(skb);
>  	else
> -- 
> 2.11.0
>
diff mbox series

Patch

diff --git a/include/linux/netlink.h b/include/linux/netlink.h
index 71f121b66ca8..88c8a2d83eb3 100644
--- a/include/linux/netlink.h
+++ b/include/linux/netlink.h
@@ -176,6 +176,7 @@  struct netlink_callback {
 	void			*data;
 	/* the module that dump function belong to */
 	struct module		*module;
+	struct netlink_ext_ack	*extack;
 	u16			family;
 	u16			min_dump_alloc;
 	unsigned int		prev_seq, seq;
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index e3a0538ec0be..7ac585f33a9e 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -2171,6 +2171,7 @@  EXPORT_SYMBOL(__nlmsg_put);
 static int netlink_dump(struct sock *sk)
 {
 	struct netlink_sock *nlk = nlk_sk(sk);
+	struct netlink_ext_ack extack = {};
 	struct netlink_callback *cb;
 	struct sk_buff *skb = NULL;
 	struct nlmsghdr *nlh;
@@ -2222,8 +2223,11 @@  static int netlink_dump(struct sock *sk)
 	skb_reserve(skb, skb_tailroom(skb) - alloc_size);
 	netlink_skb_set_owner_r(skb, sk);
 
-	if (nlk->dump_done_errno > 0)
+	if (nlk->dump_done_errno > 0) {
+		cb->extack = &extack;
 		nlk->dump_done_errno = cb->dump(skb, cb);
+		cb->extack = NULL;
+	}
 
 	if (nlk->dump_done_errno > 0 ||
 	    skb_tailroom(skb) < nlmsg_total_size(sizeof(nlk->dump_done_errno))) {
@@ -2246,6 +2250,12 @@  static int netlink_dump(struct sock *sk)
 	memcpy(nlmsg_data(nlh), &nlk->dump_done_errno,
 	       sizeof(nlk->dump_done_errno));
 
+	if (extack._msg && nlk->flags & NETLINK_F_EXT_ACK) {
+		nlh->nlmsg_flags |= NLM_F_ACK_TLVS;
+		if (!nla_put_string(skb, NLMSGERR_ATTR_MSG, extack._msg))
+			nlmsg_end(skb, nlh);
+	}
+
 	if (sk_filter(sk, skb))
 		kfree_skb(skb);
 	else