* [PATCH] mptcp: fix msk traversal in mptcp_nl_cmd_set_flags()
@ 2022-02-05 1:02 Mat Martineau
2022-02-05 13:15 ` Greg KH
0 siblings, 1 reply; 2+ messages in thread
From: Mat Martineau @ 2022-02-05 1:02 UTC (permalink / raw)
To: stable; +Cc: Mat Martineau, mptcp, Paolo Abeni
commit 8e9eacad7ec7a9cbf262649ebf1fa6e6f6cc7d82 upstream.
The upstream commit had to handle a lookup_by_id variable that is only
present in 5.17. This version of the patch removes that variable, so the
__lookup_addr() function only handles the lookup as it is implemented in
5.15 and 5.16. It also removes one 'const' keyword to prevent a warning
due to differing const-ness in the 5.17 version of addresses_equal().
The MPTCP endpoint list is under RCU protection, guarded by the
pernet spinlock. mptcp_nl_cmd_set_flags() traverses the list
without acquiring the spin-lock nor under the RCU critical section.
This change addresses the issue performing the lookup and the endpoint
update under the pernet spinlock.
Cc: <stable@vger.kernel.org> # 5.15.x
Cc: <stable@vger.kernel.org> # 5.16.x
Fixes: 0f9f696a502e ("mptcp: add set_flags command in PM netlink")
Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---
net/mptcp/pm_netlink.c | 34 +++++++++++++++++++++++++---------
1 file changed, 25 insertions(+), 9 deletions(-)
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index 65764c8171b3..5d305fafd0e9 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -459,6 +459,18 @@ static unsigned int fill_remote_addresses_vec(struct mptcp_sock *msk, bool fullm
return i;
}
+static struct mptcp_pm_addr_entry *
+__lookup_addr(struct pm_nl_pernet *pernet, struct mptcp_addr_info *info)
+{
+ struct mptcp_pm_addr_entry *entry;
+
+ list_for_each_entry(entry, &pernet->local_addr_list, list) {
+ if (addresses_equal(&entry->addr, info, true))
+ return entry;
+ }
+ return NULL;
+}
+
static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
{
struct sock *sk = (struct sock *)msk;
@@ -1725,17 +1737,21 @@ static int mptcp_nl_cmd_set_flags(struct sk_buff *skb, struct genl_info *info)
if (addr.flags & MPTCP_PM_ADDR_FLAG_BACKUP)
bkup = 1;
- list_for_each_entry(entry, &pernet->local_addr_list, list) {
- if (addresses_equal(&entry->addr, &addr.addr, true)) {
- mptcp_nl_addr_backup(net, &entry->addr, bkup);
-
- if (bkup)
- entry->flags |= MPTCP_PM_ADDR_FLAG_BACKUP;
- else
- entry->flags &= ~MPTCP_PM_ADDR_FLAG_BACKUP;
- }
+ spin_lock_bh(&pernet->lock);
+ entry = __lookup_addr(pernet, &addr.addr);
+ if (!entry) {
+ spin_unlock_bh(&pernet->lock);
+ return -EINVAL;
}
+ if (bkup)
+ entry->flags |= MPTCP_PM_ADDR_FLAG_BACKUP;
+ else
+ entry->flags &= ~MPTCP_PM_ADDR_FLAG_BACKUP;
+ addr = *entry;
+ spin_unlock_bh(&pernet->lock);
+
+ mptcp_nl_addr_backup(net, &addr.addr, bkup);
return 0;
}
--
2.35.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] mptcp: fix msk traversal in mptcp_nl_cmd_set_flags()
2022-02-05 1:02 [PATCH] mptcp: fix msk traversal in mptcp_nl_cmd_set_flags() Mat Martineau
@ 2022-02-05 13:15 ` Greg KH
0 siblings, 0 replies; 2+ messages in thread
From: Greg KH @ 2022-02-05 13:15 UTC (permalink / raw)
To: Mat Martineau; +Cc: stable, mptcp, Paolo Abeni
On Fri, Feb 04, 2022 at 05:02:31PM -0800, Mat Martineau wrote:
> commit 8e9eacad7ec7a9cbf262649ebf1fa6e6f6cc7d82 upstream.
>
> The upstream commit had to handle a lookup_by_id variable that is only
> present in 5.17. This version of the patch removes that variable, so the
> __lookup_addr() function only handles the lookup as it is implemented in
> 5.15 and 5.16. It also removes one 'const' keyword to prevent a warning
> due to differing const-ness in the 5.17 version of addresses_equal().
>
> The MPTCP endpoint list is under RCU protection, guarded by the
> pernet spinlock. mptcp_nl_cmd_set_flags() traverses the list
> without acquiring the spin-lock nor under the RCU critical section.
>
> This change addresses the issue performing the lookup and the endpoint
> update under the pernet spinlock.
>
> Cc: <stable@vger.kernel.org> # 5.15.x
> Cc: <stable@vger.kernel.org> # 5.16.x
> Fixes: 0f9f696a502e ("mptcp: add set_flags command in PM netlink")
> Acked-by: Paolo Abeni <pabeni@redhat.com>
> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
> ---
> net/mptcp/pm_netlink.c | 34 +++++++++++++++++++++++++---------
> 1 file changed, 25 insertions(+), 9 deletions(-)
Now queued up, thanks.
greg k-h
^ permalink raw reply [flat|nested] 2+ messages in thread
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2022-02-05 1:02 [PATCH] mptcp: fix msk traversal in mptcp_nl_cmd_set_flags() Mat Martineau
2022-02-05 13:15 ` Greg KH
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