[PATCH net 1/2] net: bpfilter: restart bpfilter_umh when error occurred
From: Taehee Yoo <ap420073@gmail.com>
Date: 2018-12-12 01:19:34
Subsystem:
bpf [core], bpf [general] (safe dynamic programs and tools), networking [general], the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
When bpfilter error occurred bpfilter_umh will be stopped via __stop_umh().
The bpfilter_umh() couldn't start again because there is no restart
routine.
The section of 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.
Test commands:
$ iptables -vnL
$ kill -9 <pid of bpfilter_umh>
$ iptables -vnL
[ 480.045136] bpfilter: write fail -32
$ iptables -vnL
iptables v1.8.1 (legacy): can't initialize iptables table `filter': No child processes
Perhaps iptables or your kernel needs to be upgraded.
Then, iptables command is always failed.
Fixes: d2ba09c17a06 ("net: add skeleton of bpfilter kernel module")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
---
include/linux/bpfilter.h | 2 ++
net/bpfilter/bpfilter_kern.c | 12 +++++++++++-
net/bpfilter/bpfilter_umh_blob.S | 2 +-
net/ipv4/bpfilter/sockopt.c | 6 +++++-
4 files changed, 19 insertions(+), 3 deletions(-)
diff --git a/include/linux/bpfilter.h b/include/linux/bpfilter.h
index f02cee0225d4..3039361cd65a 100644
--- a/include/linux/bpfilter.h
+++ b/include/linux/bpfilter.h@@ -12,4 +12,6 @@ int bpfilter_ip_get_sockopt(struct sock *sk, int optname, char __user *optval, extern int (*bpfilter_process_sockopt)(struct sock *sk, int optname, char __user *optval, unsigned int optlen, bool is_set); +extern int (*bpfilter_start_umh)(void); + #endif
diff --git a/net/bpfilter/bpfilter_kern.c b/net/bpfilter/bpfilter_kern.c
index 7acfc83087d5..7397f5e8da2f 100644
--- a/net/bpfilter/bpfilter_kern.c
+++ b/net/bpfilter/bpfilter_kern.c@@ -87,7 +87,7 @@ static int __bpfilter_process_sockopt(struct sock *sk, int optname, return ret; } -static int __init load_umh(void) +int start_umh(void) { int err;
@@ -111,8 +111,18 @@ static int __init load_umh(void) return 0; } +static int __init load_umh(void) +{ + if (IS_ENABLED(CONFIG_INET)) + bpfilter_start_umh = &start_umh; + + return start_umh(); +} + static void __exit fini_umh(void) { + if (IS_ENABLED(CONFIG_INET)) + bpfilter_start_umh = NULL; stop_umh(); } module_init(load_umh);
diff --git a/net/bpfilter/bpfilter_umh_blob.S b/net/bpfilter/bpfilter_umh_blob.S
index 40311d10d2f2..7f1c521dcc2f 100644
--- a/net/bpfilter/bpfilter_umh_blob.S
+++ b/net/bpfilter/bpfilter_umh_blob.S@@ -1,5 +1,5 @@ /* SPDX-License-Identifier: GPL-2.0 */ - .section .init.rodata, "a" + .section .bpfilter_umh, "a" .global bpfilter_umh_start bpfilter_umh_start: .incbin "net/bpfilter/bpfilter_umh"
diff --git a/net/ipv4/bpfilter/sockopt.c b/net/ipv4/bpfilter/sockopt.c
index 5e04ed25bc0e..f7efcff9634d 100644
--- a/net/ipv4/bpfilter/sockopt.c
+++ b/net/ipv4/bpfilter/sockopt.c@@ -10,6 +10,9 @@ int (*bpfilter_process_sockopt)(struct sock *sk, int optname, unsigned int optlen, bool is_set); EXPORT_SYMBOL_GPL(bpfilter_process_sockopt); +int (*bpfilter_start_umh)(void); +EXPORT_SYMBOL_GPL(bpfilter_start_umh); + static int bpfilter_mbox_request(struct sock *sk, int optname, char __user *optval, unsigned int optlen, bool is_set)
@@ -20,7 +23,8 @@ static int bpfilter_mbox_request(struct sock *sk, int optname, if (err) return err; if (!bpfilter_process_sockopt) - return -ECHILD; + if (!bpfilter_start_umh || bpfilter_start_umh()) + return -ECHILD; } return bpfilter_process_sockopt(sk, optname, optval, optlen, is_set); }
--
2.17.1