Merge branch 'mptcp-misc-fixes-for-v6-7'

Matthieu Baerts says:

====================
mptcp: misc. fixes for v6.7

Here are a few fixes related to MPTCP:

- Patch 1 limits GSO max size to ~64K when MPTCP is being used due to a
  spec limit. 'gso_max_size' can exceed the max value supported by MPTCP
  since v5.19.

- Patch 2 fixes a possible NULL pointer dereference on close that can
  happen since v6.7-rc1.

- Patch 3 avoids sending a RM_ADDR when the corresponding address is no
  longer tracked locally. A regression for a fix backported to v5.19.

- Patch 4 adds a missing lock when changing the IP TOS with setsockopt().
  A fix for v5.17.

- Patch 5 fixes an expectation when running MPTCP Join selftest with the
  checksum option (-C). An issue present since v6.1.
====================

Link: https://lore.kernel.org/r/20231114-upstream-net-20231113-mptcp-misc-fixes-6-7-rc2-v1-0-7b9cd6a7b7f4@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: kuba-moo

net/mptcp/pm_netlink.c

@@ -1515,8 +1515,9 @@ void mptcp_pm_remove_addrs(struct mptcp_sock *msk, struct list_head *rm_list)
 	struct mptcp_pm_addr_entry *entry;
 
 	list_for_each_entry(entry, rm_list, list) {
-		remove_anno_list_by_saddr(msk, &entry->addr);
-		if (alist.nr < MPTCP_RM_IDS_MAX)
+		if ((remove_anno_list_by_saddr(msk, &entry->addr) ||
+		     lookup_subflow_by_saddr(&msk->conn_list, &entry->addr)) &&
+		    alist.nr < MPTCP_RM_IDS_MAX)
 			alist.ids[alist.nr++] = entry->addr.id;
 	}
 

net/mptcp/protocol.c

@@ -1230,6 +1230,8 @@ static void mptcp_update_infinite_map(struct mptcp_sock *msk,
 	mptcp_do_fallback(ssk);
 }
 
+#define MPTCP_MAX_GSO_SIZE (GSO_LEGACY_MAX_SIZE - (MAX_TCP_HEADER + 1))
+
 static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
 			      struct mptcp_data_frag *dfrag,
 			      struct mptcp_sendmsg_info *info)
@@ -1256,6 +1258,8 @@ static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
 		return -EAGAIN;
 
 	/* compute send limit */
+	if (unlikely(ssk->sk_gso_max_size > MPTCP_MAX_GSO_SIZE))
+		ssk->sk_gso_max_size = MPTCP_MAX_GSO_SIZE;
 	info->mss_now = tcp_send_mss(ssk, &info->size_goal, info->flags);
 	copy = info->size_goal;
 
@@ -3398,10 +3402,11 @@ static void mptcp_release_cb(struct sock *sk)
 	if (__test_and_clear_bit(MPTCP_CLEAN_UNA, &msk->cb_flags))
 		__mptcp_clean_una_wakeup(sk);
 	if (unlikely(msk->cb_flags)) {
-		/* be sure to set the current sk state before tacking actions
-		 * depending on sk_state, that is processing MPTCP_ERROR_REPORT
+		/* be sure to set the current sk state before taking actions
+		 * depending on sk_state (MPTCP_ERROR_REPORT)
+		 * On sk release avoid actions depending on the first subflow
 		 */
-		if (__test_and_clear_bit(MPTCP_CONNECTED, &msk->cb_flags))
+		if (__test_and_clear_bit(MPTCP_CONNECTED, &msk->cb_flags) && msk->first)
 			__mptcp_set_connected(sk);
 		if (__test_and_clear_bit(MPTCP_ERROR_REPORT, &msk->cb_flags))
 			__mptcp_error_report(sk);

net/mptcp/sockopt.c

@@ -738,8 +738,11 @@ static int mptcp_setsockopt_v4_set_tos(struct mptcp_sock *msk, int optname,
 	val = READ_ONCE(inet_sk(sk)->tos);
 	mptcp_for_each_subflow(msk, subflow) {
 		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+		bool slow;
 
+		slow = lock_sock_fast(ssk);
 		__ip_sock_set_tos(ssk, val);
+		unlock_sock_fast(ssk, slow);
 	}
 	release_sock(sk);
 

tools/testing/selftests/net/mptcp/mptcp_join.sh

@@ -3240,7 +3240,7 @@ fastclose_tests()
 	if reset_check_counter "fastclose server test" "MPTcpExtMPFastcloseRx"; then
 		test_linkfail=1024 fastclose=server \
 			run_tests $ns1 $ns2 10.0.1.1
-		chk_join_nr 0 0 0
+		chk_join_nr 0 0 0 0 0 0 1
 		chk_fclose_nr 1 1 invert
 		chk_rst_nr 1 1
 	fi