From 61fbf5933d42b02f552123af5a87a06335a3b4db Mon Sep 17 00:00:00 2001 From: Taehee Yoo Date: Wed, 9 Jan 2019 02:24:53 +0900 Subject: net: bpfilter: restart bpfilter_umh when error occurred The bpfilter_umh will be stopped via __stop_umh() when the bpfilter error occurred. The bpfilter_umh() couldn't start again because there is no restart routine. The section of the bpfilter_umh_{start/end} is no longer .init.rodata because these area should be reused in the restart routine. hence the section name is changed to .bpfilter_umh. The bpfilter_ops->start() is restart callback. it will be called when bpfilter_umh is stopped. The stop bit means bpfilter_umh is stopped. this bit is set by both start and stop routine. Before this patch, Test commands: $ iptables -vnL $ kill -9 $ iptables -vnL [ 480.045136] bpfilter: write fail -32 $ iptables -vnL All iptables commands will fail. After this patch, Test commands: $ iptables -vnL $ kill -9 $ iptables -vnL $ iptables -vnL Now, all iptables commands will work. Fixes: d2ba09c17a06 ("net: add skeleton of bpfilter kernel module") Signed-off-by: Taehee Yoo Signed-off-by: David S. Miller --- net/ipv4/bpfilter/sockopt.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'net/ipv4/bpfilter') diff --git a/net/ipv4/bpfilter/sockopt.c b/net/ipv4/bpfilter/sockopt.c index c326cfbc0f62..de84ede4e765 100644 --- a/net/ipv4/bpfilter/sockopt.c +++ b/net/ipv4/bpfilter/sockopt.c @@ -14,6 +14,7 @@ EXPORT_SYMBOL_GPL(bpfilter_ops); static void bpfilter_umh_cleanup(struct umh_info *info) { + bpfilter_ops.stop = true; fput(info->pipe_to_umh); fput(info->pipe_from_umh); info->pid = 0; @@ -23,14 +24,21 @@ static int bpfilter_mbox_request(struct sock *sk, int optname, char __user *optval, unsigned int optlen, bool is_set) { + int err; + if (!bpfilter_ops.sockopt) { - int err = request_module("bpfilter"); + err = request_module("bpfilter"); if (err) return err; if (!bpfilter_ops.sockopt) return -ECHILD; } + if (bpfilter_ops.stop) { + err = bpfilter_ops.start(); + if (err) + return err; + } return bpfilter_ops.sockopt(sk, optname, optval, optlen, is_set); } @@ -53,6 +61,7 @@ int bpfilter_ip_get_sockopt(struct sock *sk, int optname, char __user *optval, static int __init bpfilter_sockopt_init(void) { + bpfilter_ops.stop = true; bpfilter_ops.info.cmdline = "bpfilter_umh"; bpfilter_ops.info.cleanup = &bpfilter_umh_cleanup; -- cgit v1.2.3-73-gaa49b