diff mbox series

[procd] hotplug.c: set nl_pid to zero

Message ID 20210124225849.659106-1-eichest@gmail.com
State Accepted
Delegated to: John Crispin
Headers show
Series [procd] hotplug.c: set nl_pid to zero | expand

Commit Message

Stefan Eichenberger Jan. 24, 2021, 10:58 p.m. UTC 
From: Stefan Eichenberger <eichest@gmail.com>

With the current solution where nl_pid is set through getpid we run into
problems when running procd in a different PID namespace (e.g.
container). The PID number inside the active PID namespace will be set
which doesn't match the global PID. Therefore, procd will never receive
any netlink messages.

By setting nl_pid to zero the kernel will assign the global PID
automatically and fixes the issue.

Signed-off-by: Stefan Eichenberger <eichest@gmail.com>
---
 plug/hotplug.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

John Crispin Jan. 25, 2021, 1:14 p.m. UTC | #1 
On 24.01.21 23:58, eichest@gmail.com wrote:
> From: Stefan Eichenberger <eichest@gmail.com>
>
> With the current solution where nl_pid is set through getpid we run into
> problems when running procd in a different PID namespace (e.g.
> container). The PID number inside the active PID namespace will be set
> which doesn't match the global PID. Therefore, procd will never receive
> any netlink messages.
>
> By setting nl_pid to zero the kernel will assign the global PID
> automatically and fixes the issue.
>
> Signed-off-by: Stefan Eichenberger <eichest@gmail.com>
> ---
>   plug/hotplug.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/plug/hotplug.c b/plug/hotplug.c
> index 9aeb1c1..beff38a 100644
> --- a/plug/hotplug.c
> +++ b/plug/hotplug.c
> @@ -612,7 +612,7 @@ void hotplug(char *rules)
>   
>   	rule_file = strdup(rules);
>   	nls.nl_family = AF_NETLINK;
> -	nls.nl_pid = getpid();
> +	nls.nl_pid = 0;
>   	nls.nl_groups = -1;
>   
>   	if ((hotplug_fd.fd = socket(PF_NETLINK, SOCK_DGRAM | SOCK_CLOEXEC, NETLINK_KOBJECT_UEVENT)) == -1) {

Acked-by: John Crispin <john@phrozen.org>

Just tested this locally outside a pid namespace.
diff mbox series

Patch

diff --git a/plug/hotplug.c b/plug/hotplug.c
index 9aeb1c1..beff38a 100644
--- a/plug/hotplug.c
+++ b/plug/hotplug.c
@@ -612,7 +612,7 @@  void hotplug(char *rules)
 
 	rule_file = strdup(rules);
 	nls.nl_family = AF_NETLINK;
-	nls.nl_pid = getpid();
+	nls.nl_pid = 0;
 	nls.nl_groups = -1;
 
 	if ((hotplug_fd.fd = socket(PF_NETLINK, SOCK_DGRAM | SOCK_CLOEXEC, NETLINK_KOBJECT_UEVENT)) == -1) {