[PATCH 6.8 270/336] mptcp: only allow set existing scheduler for net.mptcp.scheduler

Greg Kroah-Hartman
2024-05-14T10:49:25Z

From: Gregory Detal <gregory.detal@gmail.com>

commit 6963c508fd7ab66ae0b7ae3db9a62ca6267f1ae8 upstream.

The current behavior is to accept any strings as inputs, this results in
an inconsistent result where an unexisting scheduler can be set:

# sysctl -w net.mptcp.scheduler=notdefault
net.mptcp.scheduler = notdefault

This patch changes this behavior by checking for existing scheduler
before accepting the input.

Fixes: e3b2870b6d22 ("mptcp: add a new sysctl scheduler")
Cc: stable@vger.kernel.org
Signed-off-by: Gregory Detal <gregory.detal@gmail.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Tested-by: Geliang Tang <geliang@kernel.org>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://lore.kernel.org/r/20240506-upstream-net-20240506-mptcp-sched-exist-v1-1-2ed1529e521e@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/mptcp/ctrl.c | 39 ++++++++++++++++++++++++++++++++++++++-
1 file changed, 38 insertions(+), 1 deletion(-)

--- a/net/mptcp/ctrl.c
+++ b/net/mptcp/ctrl.c
@@ -96,6 +96,43 @@ static void mptcp_pernet_set_defaults(st
}

#ifdef CONFIG_SYSCTL
+static int mptcp_set_scheduler(const struct net *net, const char *name)
+{
+ struct mptcp_pernet *pernet = mptcp_get_pernet(net);
+ struct mptcp_sched_ops *sched;
+ int ret = 0;
+
+ rcu_read_lock();
+ sched = mptcp_sched_find(name);
+ if (sched)
+ strscpy(pernet->scheduler, name, MPTCP_SCHED_NAME_MAX);
+ else
+ ret = -ENOENT;
+ rcu_read_unlock();
+
+ return ret;
+}
+
+static int proc_scheduler(struct ctl_table *ctl, int write,
+ void *buffer, size_t *lenp, loff_t *ppos)
+{
+ const struct net *net = current->nsproxy->net_ns;
+ char val[MPTCP_SCHED_NAME_MAX];
+ struct ctl_table tbl = {
+ .data = val,
+ .maxlen = MPTCP_SCHED_NAME_MAX,
+ };
+ int ret;
+
+ strscpy(val, mptcp_get_scheduler(net), MPTCP_SCHED_NAME_MAX);
+
+ ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
+ if (write && ret == 0)
+ ret = mptcp_set_scheduler(net, val);
+
+ return ret;
+}
+
static struct ctl_table mptcp_sysctl_table[] = {
{
.procname = "enabled",
@@ -148,7 +185,7 @@ static struct ctl_table mptcp_sysctl_tab
.procname = "scheduler",
.maxlen = MPTCP_SCHED_NAME_MAX,
.mode = 0644,
- .proc_handler = proc_dostring,
+ .proc_handler = proc_scheduler,
},
{
.procname = "close_timeout",