This is a note to let you know that I've just added the patch titled
mptcp: fix duplicate subflow creation
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mptcp-fix-duplicate-subflow-creation.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit db1cb1b3347989a7492fd5e33c9597da8cc5194c
Author: Paolo Abeni <pabeni@xxxxxxxxxx>
Date: Thu Feb 15 19:25:33 2024 +0100
mptcp: fix duplicate subflow creation
[ Upstream commit 045e9d812868a2d80b7a57b224ce8009444b7bbc ]
Fullmesh endpoints could end-up unexpectedly generating duplicate
subflows - same local and remote addresses - when multiple incoming
ADD_ADDR are processed before the PM creates the subflow for the local
endpoints.
Address the issue explicitly checking for duplicates at subflow
creation time.
To avoid a quadratic computational complexity, track the unavailable
remote address ids in a temporary bitmap and initialize such bitmap
with the remote ids of all the existing subflows matching the local
address currently processed.
The above allows additionally replacing the existing code checking
for duplicate entry in the current set with a simple bit test
operation.
Fixes: 2843ff6f36db ("mptcp: remote addresses fullmesh")
Cc: stable@xxxxxxxxxxxxxxx
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/435
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Reviewed-by: Mat Martineau <martineau@xxxxxxxxxx>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index beacea4d5da51..4f8f8c27a59e9 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -396,19 +396,6 @@ void mptcp_pm_free_anno_list(struct mptcp_sock *msk)
}
}
-static bool lookup_address_in_vec(const struct mptcp_addr_info *addrs, unsigned int nr,
- const struct mptcp_addr_info *addr)
-{
- int i;
-
- for (i = 0; i < nr; i++) {
- if (addrs[i].id == addr->id)
- return true;
- }
-
- return false;
-}
-
/* Fill all the remote addresses into the array addrs[],
* and return the array size.
*/
@@ -440,6 +427,16 @@ static unsigned int fill_remote_addresses_vec(struct mptcp_sock *msk,
msk->pm.subflows++;
addrs[i++] = remote;
} else {
+ DECLARE_BITMAP(unavail_id, MPTCP_PM_MAX_ADDR_ID + 1);
+
+ /* Forbid creation of new subflows matching existing
+ * ones, possibly already created by incoming ADD_ADDR
+ */
+ bitmap_zero(unavail_id, MPTCP_PM_MAX_ADDR_ID + 1);
+ mptcp_for_each_subflow(msk, subflow)
+ if (READ_ONCE(subflow->local_id) == local->id)
+ __set_bit(subflow->remote_id, unavail_id);
+
mptcp_for_each_subflow(msk, subflow) {
ssk = mptcp_subflow_tcp_sock(subflow);
remote_address((struct sock_common *)ssk, &addrs[i]);
@@ -447,11 +444,17 @@ static unsigned int fill_remote_addresses_vec(struct mptcp_sock *msk,
if (deny_id0 && !addrs[i].id)
continue;
+ if (test_bit(addrs[i].id, unavail_id))
+ continue;
+
if (!mptcp_pm_addr_families_match(sk, local, &addrs[i]))
continue;
- if (!lookup_address_in_vec(addrs, i, &addrs[i]) &&
- msk->pm.subflows < subflows_max) {
+ if (msk->pm.subflows < subflows_max) {
+ /* forbid creating multiple address towards
+ * this id
+ */
+ __set_bit(addrs[i].id, unavail_id);
msk->pm.subflows++;
i++;
}
