From: "Matthieu Baerts (NGI0)" matttbe@kernel.org

stable inclusion from stable-v6.6.48 commit d20bf2c96d7ffd171299b32f562f70e5bf5dc608 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAQOJM CVE: CVE-2024-45009

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

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commit 1c1f721375989579e46741f59523e39ec9b2a9bd upstream.

Adding the following warning ...

WARN_ON_ONCE(msk->pm.add_addr_accepted == 0)

... before decrementing the add_addr_accepted counter helped to find a bug when running the "remove single subflow" subtest from the mptcp_join.sh selftest.

Removing a 'subflow' endpoint will first trigger a RM_ADDR, then the subflow closure. Before this patch, and upon the reception of the RM_ADDR, the other peer will then try to decrement this add_addr_accepted. That's not correct because the attached subflows have not been created upon the reception of an ADD_ADDR.

A way to solve that is to decrement the counter only if the attached subflow was an MP_JOIN to a remote id that was not 0, and initiated by the host receiving the RM_ADDR.

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 Link: https://patch.msgid.link/20240819-net-mptcp-pm-reusing-id-v1-9-38035d40de5b@... Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Wang Liang wangliang74@huawei.com --- net/mptcp/pm_netlink.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c index aa56696cdc78..7fc4d7063c82 100644 --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -841,7 +841,7 @@ static void mptcp_pm_nl_rm_addr_or_subflow(struct mptcp_sock *msk, mptcp_close_ssk(sk, ssk, subflow); spin_lock_bh(&msk->pm.lock);

- removed = true; + removed |= subflow->request_join; if (rm_type == MPTCP_MIB_RMSUBFLOW) __MPTCP_INC_STATS(sock_net(sk), rm_type); } @@ -855,7 +855,11 @@ static void mptcp_pm_nl_rm_addr_or_subflow(struct mptcp_sock *msk, if (!mptcp_pm_is_kernel(msk)) continue;

- if (rm_type == MPTCP_MIB_RMADDR) { + if (rm_type == MPTCP_MIB_RMADDR && rm_id && + !WARN_ON_ONCE(msk->pm.add_addr_accepted == 0)) { + /* Note: if the subflow has been closed before, this + * add_addr_accepted counter will not be decremented. + */ msk->pm.add_addr_accepted--; WRITE_ONCE(msk->pm.accept_addr, true); } else if (rm_type == MPTCP_MIB_RMSUBFLOW) {