kernel.git/net/mptcp, branch linux-6.10.y

mptcp: pm: Fix uaf in __timer_delete_sync

2024-09-18T17:25:12Z

commit b4cd80b0338945a94972ac3ed54f8338d2da2076 upstream. There are two paths to access mptcp_pm_del_add_timer, result in a race condition: CPU1 CPU2 ==== ==== net_rx_action napi_poll netlink_sendmsg __napi_poll netlink_unicast process_backlog netlink_unicast_kernel __netif_receive_skb genl_rcv __netif_receive_skb_one_core netlink_rcv_skb NF_HOOK genl_rcv_msg ip_local_deliver_finish genl_family_rcv_msg ip_protocol_deliver_rcu genl_family_rcv_msg_doit tcp_v4_rcv mptcp_pm_nl_flush_addrs_doit tcp_v4_do_rcv mptcp_nl_remove_addrs_list tcp_rcv_established mptcp_pm_remove_addrs_and_subflows tcp_data_queue remove_anno_list_by_saddr mptcp_incoming_options mptcp_pm_del_add_timer mptcp_pm_del_add_timer kfree(entry) In remove_anno_list_by_saddr(running on CPU2), after leaving the critical zone protected by "pm.lock", the entry will be released, which leads to the occurrence of uaf in the mptcp_pm_del_add_timer(running on CPU1). Keeping a reference to add_timer inside the lock, and calling sk_stop_timer_sync() with this reference, instead of "entry->add_timer". Move list_del(&entry->list) to mptcp_pm_del_add_timer and inside the pm lock, do not directly access any members of the entry outside the pm lock, which can avoid similar "entry->x" uaf. Fixes: 00cfd77b9063 ("mptcp: retransmit ADD_ADDR when timeout") Cc: stable@vger.kernel.org Reported-and-tested-by: syzbot+f3a31fb909db9b2a5c4d@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=f3a31fb909db9b2a5c4d Signed-off-by: Matthieu Baerts (NGI0) Signed-off-by: Edward Adam Davis Acked-by: Paolo Abeni Link: https://patch.msgid.link/tencent_7142963A37944B4A74EF76CD66EA3C253609@qq.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

mptcp: pm: ADD_ADDR 0 is not a new address

2024-09-04T11:29:59Z

commit 57f86203b41c98b322119dfdbb1ec54ce5e3369b upstream. 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 Signed-off-by: Matthieu Baerts (NGI0) Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman

mptcp: avoid duplicated SUB_CLOSED events

2024-09-04T11:29:59Z

commit d82809b6c5f2676b382f77a5cbeb1a5d91ed2235 upstream. The initial subflow might have already been closed, but still in the connection list. When the worker is instructed to close the subflows that have been marked as closed, it might then try to close the initial subflow again. A consequence of that is that the SUB_CLOSED event can be seen twice: # ip mptcp endpoint 1.1.1.1 id 1 subflow dev eth0 2.2.2.2 id 2 subflow dev eth1 # ip mptcp monitor & [ CREATED] remid=0 locid=0 saddr4=1.1.1.1 daddr4=9.9.9.9 [ ESTABLISHED] remid=0 locid=0 saddr4=1.1.1.1 daddr4=9.9.9.9 [ SF_ESTABLISHED] remid=0 locid=2 saddr4=2.2.2.2 daddr4=9.9.9.9 # ip mptcp endpoint delete id 1 [ SF_CLOSED] remid=0 locid=0 saddr4=1.1.1.1 daddr4=9.9.9.9 [ SF_CLOSED] remid=0 locid=0 saddr4=1.1.1.1 daddr4=9.9.9.9 The first one is coming from mptcp_pm_nl_rm_subflow_received(), and the second one from __mptcp_close_subflow(). To avoid doing the post-closed processing twice, the subflow is now marked as closed the first time. Note that it is not enough to check if we are dealing with the first subflow and check its sk_state: the subflow might have been reset or closed before calling mptcp_close_ssk(). Fixes: b911c97c7dc7 ("mptcp: add netlink event support") Cc: stable@vger.kernel.org Tested-by: Arınç ÜNAL Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman

mptcp: pm: fix ID 0 endp usage after multiple re-creations

2024-09-04T11:29:58Z

commit 9366922adc6a71378ca01f898c41be295309f044 upstream. 'local_addr_used' and 'add_addr_accepted' are decremented for addresses not related to the initial subflow (ID0), because the source and destination addresses of the initial subflows are known from the beginning: they don't count as "additional local address being used" or "ADD_ADDR being accepted". It is then required not to increment them when the entrypoint used by the initial subflow is removed and re-added during a connection. Without this modification, this entrypoint cannot be removed and re-added more than once. Reported-by: Arınç ÜNAL Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/512 Fixes: 3ad14f54bd74 ("mptcp: more accurate MPC endpoint tracking") Reported-by: syzbot+455d38ecd5f655fc45cf@syzkaller.appspotmail.com Closes: https://lore.kernel.org/00000000000049861306209237f4@google.com Cc: stable@vger.kernel.org Tested-by: Arınç ÜNAL Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman

mptcp: pm: do not remove already closed subflows

2024-09-04T11:29:58Z

commit 58e1b66b4e4b8a602d3f2843e8eba00a969ecce2 upstream. It is possible to have in the list already closed subflows, e.g. the initial subflow has been already closed, but still in the list. No need to try to close it again, and increments the related counters again. Fixes: 0ee4261a3681 ("mptcp: implement mptcp_pm_remove_subflow") Cc: stable@vger.kernel.org Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman

mptcp: pm: fix RM_ADDR ID for the initial subflow

2024-09-04T11:29:58Z

commit 87b5896f3f7848130095656739b05881904e2697 upstream. The initial subflow has a special local ID: 0. When an endpoint is being deleted, it is then important to check if its address is not linked to the initial subflow to send the right ID. If there was an endpoint linked to the initial subflow, msk's mpc_endpoint_id field will be set. We can then use this info when an endpoint is being removed to see if it is linked to the initial subflow. So now, the correct IDs are passed to mptcp_pm_nl_rm_addr_or_subflow(), it is no longer needed to use mptcp_local_id_match(). Fixes: 3ad14f54bd74 ("mptcp: more accurate MPC endpoint tracking") Cc: stable@vger.kernel.org Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman

mptcp: pm: send ACK on an active subflow

2024-09-04T11:29:58Z

commit c07cc3ed895f9bfe0c53b5ed6be710c133b4271c upstream. Taking the first one on the list doesn't work in some cases, e.g. if the initial subflow is being removed. Pick another one instead of not sending anything. Fixes: 84dfe3677a6f ("mptcp: send out dedicated ADD_ADDR packet") Cc: stable@vger.kernel.org Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman

mptcp: pm: reset MPC endp ID when re-added

2024-09-04T11:29:58Z

commit dce1c6d1e92535f165219695a826caedcca4e9b9 upstream. The initial subflow has a special local ID: 0. It is specific per connection. When a global endpoint is deleted and re-added later, it can have a different ID -- most services managing the endpoints automatically don't force the ID to be the same as before. It is then important to track these modifications to be consistent with the ID being used for the address used by the initial subflow, not to confuse the other peer or to send the ID 0 for the wrong address. Now when removing an endpoint, msk->mpc_endpoint_id is reset if it corresponds to this endpoint. When adding a new endpoint, the same variable is updated if the address match the one of the initial subflow. Fixes: 3ad14f54bd74 ("mptcp: more accurate MPC endpoint tracking") Cc: stable@vger.kernel.org Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman

mptcp: pm: skip connecting to already established sf

2024-09-04T11:29:58Z

commit bc19ff57637ff563d2bdf2b385b48c41e6509e0d upstream. The lookup_subflow_by_daddr() helper checks if there is already a subflow connected to this address. But there could be a subflow that is closing, but taking time due to some reasons: latency, losses, data to process, etc. If an ADD_ADDR is received while the endpoint is being closed, it is better to try connecting to it, instead of rejecting it: the peer which has sent the ADD_ADDR will not be notified that the ADD_ADDR has been rejected for this reason, and the expected subflow will not be created at the end. This helper should then only look for subflows that are established, or going to be, but not the ones being closed. Fixes: d84ad04941c3 ("mptcp: skip connecting the connected address") Cc: stable@vger.kernel.org Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman

mptcp: pm: reuse ID 0 after delete and re-add

2024-09-04T11:29:58Z

commit 8b8ed1b429f8fa7ebd5632555e7b047bc0620075 upstream. When the endpoint used by the initial subflow is removed and re-added later, the PM has to force the ID 0, it is a special case imposed by the MPTCP specs. Note that the endpoint should then need to be re-added reusing the same ID. Fixes: 3ad14f54bd74 ("mptcp: more accurate MPC endpoint tracking") Cc: stable@vger.kernel.org Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman