netfilter: nfnetlink: nfnetlink_unicast() reports EAGAIN instead of ENOBUFS

Frontend callback reports EAGAIN to nfnetlink to retry a command, this
is used to signal that module autoloading is required. Unfortunately,
nlmsg_unicast() reports EAGAIN in case the receiver socket buffer gets
full, so it enters a busy-loop.

This patch updates nfnetlink_unicast() to turn EAGAIN into ENOBUFS and
to use nlmsg_unicast(). Remove the flags field in nfnetlink_unicast()
since this is always MSG_DONTWAIT in the existing code which is exactly
what nlmsg_unicast() passes to netlink_unicast() as parameter.

Fixes: 96518518cc ("netfilter: add nftables")
Reported-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Pablo Neira Ayuso
2020-08-23 13:55:36 +02:00
parent 4b7ddc58e6
commit ee92118355
5 changed files with 40 additions and 40 deletions

View File

@@ -43,8 +43,7 @@ int nfnetlink_has_listeners(struct net *net, unsigned int group);
int nfnetlink_send(struct sk_buff *skb, struct net *net, u32 portid,
unsigned int group, int echo, gfp_t flags);
int nfnetlink_set_err(struct net *net, u32 portid, u32 group, int error);
int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u32 portid,
int flags);
int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u32 portid);
static inline u16 nfnl_msg_type(u8 subsys, u8 msg_type)
{