The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 57f86203b41c98b322119dfdbb1ec54ce5e3369b # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2024083024-distort-gallantly-afea@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

57f86203b41c ("mptcp: pm: ADD_ADDR 0 is not a new address") 4d25247d3ae4 ("mptcp: bypass in-kernel PM restrictions for non-kernel PMs") 14b06811bec6 ("mptcp: Bypass kernel PM when userspace PM is enabled") a88c9e496937 ("mptcp: do not block subflows creation on errors") 86e39e04482b ("mptcp: keep track of local endpoint still available for each msk") f7d6a237d742 ("mptcp: fix per socket endpoint accounting") b29fcfb54cd7 ("mptcp: full disconnect implementation") 59060a47ca50 ("mptcp: clean up harmless false expressions") 3ce0852c86b9 ("mptcp: enforce HoL-blocking estimation") 6511882cdd82 ("mptcp: allocate fwd memory separately on the rx and tx path") 765ff425528f ("mptcp: use lockdep_assert_held_once() instead of open-coding it")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 57f86203b41c98b322119dfdbb1ec54ce5e3369b Mon Sep 17 00:00:00 2001 From: "Matthieu Baerts (NGI0)" matttbe@kernel.org Date: Wed, 28 Aug 2024 08:14:37 +0200 Subject: [PATCH] mptcp: pm: ADD_ADDR 0 is not a new address

The ADD_ADDR 0 with the address from the initial subflow should not be considered as a new address: this is not something new. If the host receives it, it simply means that the address is available again.

When receiving an ADD_ADDR for the ID 0, the PM already doesn't consider it as new by not incrementing the 'add_addr_accepted' counter. But the 'accept_addr' might not be set if the limit has already been reached: this can be bypassed in this case. But before, it is important to check that this ADD_ADDR for the ID 0 is for the same address as the initial subflow. If not, it is not something that should happen, and the ADD_ADDR can be ignored.

Note that if an ADD_ADDR is received while there is already a subflow opened using the same address, this ADD_ADDR is ignored as well. It means that if multiple ADD_ADDR for ID 0 are received, there will not be any duplicated subflows created by the client.

Fixes: d0876b2284cf ("mptcp: add the incoming RM_ADDR support") Cc: stable@vger.kernel.org Reviewed-by: Mat Martineau martineau@kernel.org Signed-off-by: Matthieu Baerts (NGI0) matttbe@kernel.org Signed-off-by: Paolo Abeni pabeni@redhat.com

diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c index 3f8dbde243f1..37f6dbcd8434 100644 --- a/net/mptcp/pm.c +++ b/net/mptcp/pm.c @@ -226,7 +226,9 @@ void mptcp_pm_add_addr_received(const struct sock *ssk, } else { __MPTCP_INC_STATS(sock_net((struct sock *)msk), MPTCP_MIB_ADDADDRDROP); } - } else if (!READ_ONCE(pm->accept_addr)) { + /* id0 should not have a different address */ + } else if ((addr->id == 0 && !mptcp_pm_nl_is_init_remote_addr(msk, addr)) || + (addr->id > 0 && !READ_ONCE(pm->accept_addr))) { mptcp_pm_announce_addr(msk, addr, true); mptcp_pm_add_addr_send_ack(msk); } else if (mptcp_pm_schedule_work(msk, MPTCP_PM_ADD_ADDR_RECEIVED)) { diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c index a93450ded50a..f891bc714668 100644 --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -760,6 +760,15 @@ static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk) } }

+bool mptcp_pm_nl_is_init_remote_addr(struct mptcp_sock *msk, + const struct mptcp_addr_info *remote) +{ + struct mptcp_addr_info mpc_remote; + + remote_address((struct sock_common *)msk, &mpc_remote); + return mptcp_addresses_equal(&mpc_remote, remote, remote->port); +} + void mptcp_pm_nl_addr_send_ack(struct mptcp_sock *msk) { struct mptcp_subflow_context *subflow; diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index 26eb898a202b..3b22313d1b86 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -993,6 +993,8 @@ void mptcp_pm_add_addr_received(const struct sock *ssk, void mptcp_pm_add_addr_echoed(struct mptcp_sock *msk, const struct mptcp_addr_info *addr); void mptcp_pm_add_addr_send_ack(struct mptcp_sock *msk); +bool mptcp_pm_nl_is_init_remote_addr(struct mptcp_sock *msk, + const struct mptcp_addr_info *remote); void mptcp_pm_nl_addr_send_ack(struct mptcp_sock *msk); void mptcp_pm_rm_addr_received(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list);