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/bpfilter/bpfilter_kern.c | 37 +++++++++++++++++++++++++++---------- net/bpfilter/bpfilter_umh_blob.S | 2 +- 2 files changed, 28 insertions(+), 11 deletions(-) (limited to 'net/bpfilter') diff --git a/net/bpfilter/bpfilter_kern.c b/net/bpfilter/bpfilter_kern.c index a68940b74c01..c0fcde910a7a 100644 --- a/net/bpfilter/bpfilter_kern.c +++ b/net/bpfilter/bpfilter_kern.c @@ -16,13 +16,14 @@ extern char bpfilter_umh_end; /* since ip_getsockopt() can run in parallel, serialize access to umh */ static DEFINE_MUTEX(bpfilter_lock); -static void shutdown_umh(struct umh_info *info) +static void shutdown_umh(void) { struct task_struct *tsk; - if (!info->pid) + if (bpfilter_ops.stop) return; - tsk = get_pid_task(find_vpid(info->pid), PIDTYPE_PID); + + tsk = get_pid_task(find_vpid(bpfilter_ops.info.pid), PIDTYPE_PID); if (tsk) { force_sig(SIGKILL, tsk); put_task_struct(tsk); @@ -31,10 +32,8 @@ static void shutdown_umh(struct umh_info *info) static void __stop_umh(void) { - if (IS_ENABLED(CONFIG_INET)) { - bpfilter_ops.sockopt = NULL; - shutdown_umh(&bpfilter_ops.info); - } + if (IS_ENABLED(CONFIG_INET)) + shutdown_umh(); } static void stop_umh(void) @@ -85,7 +84,7 @@ out: return ret; } -static int __init load_umh(void) +static int start_umh(void) { int err; @@ -95,6 +94,7 @@ static int __init load_umh(void) &bpfilter_ops.info); if (err) return err; + bpfilter_ops.stop = false; pr_info("Loaded bpfilter_umh pid %d\n", bpfilter_ops.info.pid); /* health check that usermode process started correctly */ @@ -102,14 +102,31 @@ static int __init load_umh(void) stop_umh(); return -EFAULT; } - if (IS_ENABLED(CONFIG_INET)) - bpfilter_ops.sockopt = &__bpfilter_process_sockopt; return 0; } +static int __init load_umh(void) +{ + int err; + + if (!bpfilter_ops.stop) + return -EFAULT; + err = start_umh(); + if (!err && IS_ENABLED(CONFIG_INET)) { + bpfilter_ops.sockopt = &__bpfilter_process_sockopt; + bpfilter_ops.start = &start_umh; + } + + return err; +} + static void __exit fini_umh(void) { + if (IS_ENABLED(CONFIG_INET)) { + bpfilter_ops.start = NULL; + bpfilter_ops.sockopt = 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" -- cgit v1.2.3-59-g8ed1b