From: Gregory Detal gregory.detal@gmail.com

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 --- net/mptcp/ctrl.c | 39 ++++++++++++++++++++++++++++++++++++++- 1 file changed, 38 insertions(+), 1 deletion(-)

diff --git a/net/mptcp/ctrl.c b/net/mptcp/ctrl.c index 13fe0748dde8..2963ba84e2ee 100644 --- a/net/mptcp/ctrl.c +++ b/net/mptcp/ctrl.c @@ -96,6 +96,43 @@ static void mptcp_pernet_set_defaults(struct mptcp_pernet *pernet) }

#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_table[] = { .procname = "scheduler", .maxlen = MPTCP_SCHED_NAME_MAX, .mode = 0644, - .proc_handler = proc_dostring, + .proc_handler = proc_scheduler, }, { .procname = "close_timeout",

--- base-commit: a26ff37e624d12e28077e5b24d2b264f62764ad6 change-id: 20240506-upstream-net-20240506-mptcp-sched-exist-6a1b91872a32

Best regards,