From daad878a509d69da1761106cb48c091dfe9d522d Mon Sep 17 00:00:00 2001 From: Gregory Detal Date: Mon, 6 May 2024 17:35:28 +0200 Subject: mptcp: only allow set existing scheduler for net.mptcp.scheduler 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 Reviewed-by: Matthieu Baerts (NGI0) Tested-by: Geliang Tang Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Link: https://lore.kernel.org/r/20240506-upstream-net-20240506-mptcp-sched-exist-v1-1-2ed1529e521e@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- 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 e72b518c5d02..de75df904a00 100644 --- a/net/mptcp/ctrl.c +++ b/net/mptcp/ctrl.c @@ -87,6 +87,43 @@ 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", @@ -139,7 +176,7 @@ static struct ctl_table mptcp_sysctl_table[] = { .procname = "scheduler", .maxlen = MPTCP_SCHED_NAME_MAX, .mode = 0644, - .proc_handler = proc_dostring, + .proc_handler = proc_scheduler, }, {} }; -- cgit v1.2.3