From: Joanne Koong <joannekoong@fb.com>
To: <netdev@vger.kernel.org>
Cc: <davem@davemloft.net>, <kuba@kernel.org>, <kafai@fb.com>,
<Kernel-team@fb.com>, Joanne Koong <joannekoong@fb.com>
Subject: [PATCH net-next] net: Enable unix sysctls to be configurable by non-init user namespaces
Date: Tue, 7 Dec 2021 12:21:01 -0800 [thread overview]
Message-ID: <20211207202101.2457994-1-joannekoong@fb.com> (raw)
Currently, when a networking namespace is initialized, its unix sysctls
are exposed only if the user namespace that "owns" it is the init user
namespace.
If there is a non-init user namespace that "owns" a networking
namespace (for example, in the case after we call clone() with both
CLONE_NEWUSER and CLONE_NEWNET set), the sysctls are hidden from view
and not configurable.
This patch enables the unix networking sysctls (there is currently only
1, "sysctl_max_dgram_qlen", which is used as the default
"sk_max_ack_backlog" value when a unix socket is created) to be exposed
to non-init user namespaces.
This is safe because any changes made to these sysctls will be limited
in scope to the networking namespace the non-init user namespace "owns"
and has privileges over.
Signed-off-by: Joanne Koong <joannekoong@fb.com>
---
net/unix/sysctl_net_unix.c | 4 ----
1 file changed, 4 deletions(-)
diff --git a/net/unix/sysctl_net_unix.c b/net/unix/sysctl_net_unix.c
index c09bea89151b..01d44e2598e2 100644
--- a/net/unix/sysctl_net_unix.c
+++ b/net/unix/sysctl_net_unix.c
@@ -30,10 +30,6 @@ int __net_init unix_sysctl_register(struct net *net)
if (table == NULL)
goto err_alloc;
- /* Don't export sysctls to unprivileged users */
- if (net->user_ns != &init_user_ns)
- table[0].procname = NULL;
-
table[0].data = &net->unx.sysctl_max_dgram_qlen;
net->unx.ctl = register_net_sysctl(net, "net/unix", table);
if (net->unx.ctl == NULL)
--
2.30.2
next reply other threads:[~2021-12-07 20:21 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-07 20:21 Joanne Koong [this message]
2021-12-08 5:49 ` [PATCH net-next] net: Enable unix sysctls to be configurable by non-init user namespaces Jakub Kicinski
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