linux/net, branch v6.13

netdev: avoid CFI problems with sock priv helpers

2025-01-16T12:15:40Z

Li Li reports that casting away callback type may cause issues for CFI. Let's generate a small wrapper for each callback, to make sure compiler sees the anticipated types. Reported-by: Li Li Link: https://lore.kernel.org/CANBPYPjQVqmzZ4J=rVQX87a9iuwmaetULwbK_5_3YWk2eGzkaA@mail.gmail.com Fixes: 170aafe35cb9 ("netdev: support binding dma-buf to netdevice") Signed-off-by: Jakub Kicinski Reviewed-by: Mina Almasry Link: https://patch.msgid.link/20250115161436.648646-1-kuba@kernel.org Signed-off-by: Paolo Abeni

net: netpoll: ensure skb_pool list is always initialized

2025-01-15T01:45:14Z

When __netpoll_setup() is called directly, instead of through netpoll_setup(), the np->skb_pool list head isn't initialized. If skb_pool_flush() is later called, then we hit a NULL pointer in skb_queue_purge_reason(). This can be seen with this repro, when CONFIG_NETCONSOLE is enabled as a module: ip tuntap add mode tap tap0 ip link add name br0 type bridge ip link set dev tap0 master br0 modprobe netconsole netconsole=4444@10.0.0.1/br0,9353@10.0.0.2/ rmmod netconsole The backtrace is: BUG: kernel NULL pointer dereference, address: 0000000000000008 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page ... ... ... Call Trace: __netpoll_free+0xa5/0xf0 br_netpoll_cleanup+0x43/0x50 [bridge] do_netpoll_cleanup+0x43/0xc0 netconsole_netdev_event+0x1e3/0x300 [netconsole] unregister_netdevice_notifier+0xd9/0x150 cleanup_module+0x45/0x920 [netconsole] __se_sys_delete_module+0x205/0x290 do_syscall_64+0x70/0x150 entry_SYSCALL_64_after_hwframe+0x76/0x7e Move the skb_pool list setup and initial skb fill into __netpoll_setup(). Fixes: 221a9c1df790 ("net: netpoll: Individualize the skb pool") Signed-off-by: John Sperbeck Reviewed-by: Breno Leitao Link: https://patch.msgid.link/20250114011354.2096812-1-jsperbeck@google.com Signed-off-by: Jakub Kicinski

mptcp: fix spurious wake-up on under memory pressure

2025-01-14T21:32:11Z

The wake-up condition currently implemented by mptcp_epollin_ready() is wrong, as it could mark the MPTCP socket as readable even when no data are present and the system is under memory pressure. Explicitly check for some data being available in the receive queue. Fixes: 5684ab1a0eff ("mptcp: give rcvlowat some love") Cc: stable@vger.kernel.org Signed-off-by: Paolo Abeni Reviewed-by: Matthieu Baerts (NGI0) Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20250113-net-mptcp-connect-st-flakes-v1-2-0d986ee7b1b6@kernel.org Signed-off-by: Jakub Kicinski

mptcp: be sure to send ack when mptcp-level window re-opens

2025-01-14T21:32:11Z

mptcp_cleanup_rbuf() is responsible to send acks when the user-space reads enough data to update the receive windows significantly. It tries hard to avoid acquiring the subflow sockets locks by checking conditions similar to the ones implemented at the TCP level. To avoid too much code duplication - the MPTCP protocol can't reuse the TCP helpers as part of the relevant status is maintained into the msk socket - and multiple costly window size computation, mptcp_cleanup_rbuf uses a rough estimate for the most recently advertised window size: the MPTCP receive free space, as recorded as at last-ack time. Unfortunately the above does not allow mptcp_cleanup_rbuf() to detect a zero to non-zero win change in some corner cases, skipping the tcp_cleanup_rbuf call and leaving the peer stuck. After commit ea66758c1795 ("tcp: allow MPTCP to update the announced window"), MPTCP has actually cheap access to the announced window value. Use it in mptcp_cleanup_rbuf() for a more accurate ack generation. Fixes: e3859603ba13 ("mptcp: better msk receive window updates") Cc: stable@vger.kernel.org Reported-by: Jakub Kicinski Closes: https://lore.kernel.org/20250107131845.5e5de3c5@kernel.org Signed-off-by: Paolo Abeni Reviewed-by: Matthieu Baerts (NGI0) Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20250113-net-mptcp-connect-st-flakes-v1-1-0d986ee7b1b6@kernel.org Signed-off-by: Jakub Kicinski

vsock: prevent null-ptr-deref in vsock_*[has_data|has_space]

2025-01-14T11:29:37Z

Recent reports have shown how we sometimes call vsock_*_has_data() when a vsock socket has been de-assigned from a transport (see attached links), but we shouldn't. Previous commits should have solved the real problems, but we may have more in the future, so to avoid null-ptr-deref, we can return 0 (no space, no data available) but with a warning. This way the code should continue to run in a nearly consistent state and have a warning that allows us to debug future problems. Fixes: c0cfa2d8a788 ("vsock: add multi-transports support") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/netdev/Z2K%2FI4nlHdfMRTZC@v4bel-B760M-AORUS-ELITE-AX/ Link: https://lore.kernel.org/netdev/5ca20d4c-1017-49c2-9516-f6f75fd331e9@rbox.co/ Link: https://lore.kernel.org/netdev/677f84a8.050a0220.25a300.01b3.GAE@google.com/ Co-developed-by: Hyunwoo Kim Signed-off-by: Hyunwoo Kim Co-developed-by: Wongi Lee Signed-off-by: Wongi Lee Signed-off-by: Stefano Garzarella Reviewed-by: Luigi Leonardi Reviewed-by: Hyunwoo Kim Signed-off-by: Paolo Abeni

vsock: reset socket state when de-assigning the transport

2025-01-14T11:29:37Z

Transport's release() and destruct() are called when de-assigning the vsock transport. These callbacks can touch some socket state like sock flags, sk_state, and peer_shutdown. Since we are reassigning the socket to a new transport during vsock_connect(), let's reset these fields to have a clean state with the new transport. Fixes: c0cfa2d8a788 ("vsock: add multi-transports support") Cc: stable@vger.kernel.org Signed-off-by: Stefano Garzarella Reviewed-by: Luigi Leonardi Signed-off-by: Paolo Abeni

vsock/virtio: cancel close work in the destructor

2025-01-14T11:29:37Z

During virtio_transport_release() we can schedule a delayed work to perform the closing of the socket before destruction. The destructor is called either when the socket is really destroyed (reference counter to zero), or it can also be called when we are de-assigning the transport. In the former case, we are sure the delayed work has completed, because it holds a reference until it completes, so the destructor will definitely be called after the delayed work is finished. But in the latter case, the destructor is called by AF_VSOCK core, just after the release(), so there may still be delayed work scheduled. Refactor the code, moving the code to delete the close work already in the do_close() to a new function. Invoke it during destruction to make sure we don't leave any pending work. Fixes: c0cfa2d8a788 ("vsock: add multi-transports support") Cc: stable@vger.kernel.org Reported-by: Hyunwoo Kim Closes: https://lore.kernel.org/netdev/Z37Sh+utS+iV3+eb@v4bel-B760M-AORUS-ELITE-AX/ Signed-off-by: Stefano Garzarella Reviewed-by: Luigi Leonardi Tested-by: Hyunwoo Kim Signed-off-by: Paolo Abeni

vsock/bpf: return early if transport is not assigned

2025-01-14T11:29:37Z

Some of the core functions can only be called if the transport has been assigned. As Michal reported, a socket might have the transport at NULL, for example after a failed connect(), causing the following trace: BUG: kernel NULL pointer dereference, address: 00000000000000a0 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 12faf8067 P4D 12faf8067 PUD 113670067 PMD 0 Oops: Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 15 UID: 0 PID: 1198 Comm: a.out Not tainted 6.13.0-rc2+ RIP: 0010:vsock_connectible_has_data+0x1f/0x40 Call Trace: vsock_bpf_recvmsg+0xca/0x5e0 sock_recvmsg+0xb9/0xc0 __sys_recvfrom+0xb3/0x130 __x64_sys_recvfrom+0x20/0x30 do_syscall_64+0x93/0x180 entry_SYSCALL_64_after_hwframe+0x76/0x7e So we need to check the `vsk->transport` in vsock_bpf_recvmsg(), especially for connected sockets (stream/seqpacket) as we already do in __vsock_connectible_recvmsg(). Fixes: 634f1a7110b4 ("vsock: support sockmap") Cc: stable@vger.kernel.org Reported-by: Michal Luczaj Closes: https://lore.kernel.org/netdev/5ca20d4c-1017-49c2-9516-f6f75fd331e9@rbox.co/ Tested-by: Michal Luczaj Reported-by: syzbot+3affdbfc986ecd9200fd@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/677f84a8.050a0220.25a300.01b3.GAE@google.com/ Tested-by: syzbot+3affdbfc986ecd9200fd@syzkaller.appspotmail.com Reviewed-by: Hyunwoo Kim Acked-by: Michael S. Tsirkin Reviewed-by: Luigi Leonardi Signed-off-by: Stefano Garzarella Signed-off-by: Paolo Abeni

vsock/virtio: discard packets if the transport changes

2025-01-14T11:29:36Z

If the socket has been de-assigned or assigned to another transport, we must discard any packets received because they are not expected and would cause issues when we access vsk->transport. A possible scenario is described by Hyunwoo Kim in the attached link, where after a first connect() interrupted by a signal, and a second connect() failed, we can find `vsk->transport` at NULL, leading to a NULL pointer dereference. Fixes: c0cfa2d8a788 ("vsock: add multi-transports support") Cc: stable@vger.kernel.org Reported-by: Hyunwoo Kim Reported-by: Wongi Lee Closes: https://lore.kernel.org/netdev/Z2LvdTTQR7dBmPb5@v4bel-B760M-AORUS-ELITE-AX/ Signed-off-by: Stefano Garzarella Reviewed-by: Hyunwoo Kim Signed-off-by: Paolo Abeni

udp: Make rehash4 independent in udp_lib_rehash()

2025-01-14T09:44:10Z

As discussed in [0], rehash4 could be missed in udp_lib_rehash() when udp hash4 changes while hash2 doesn't change. This patch fixes this by moving rehash4 codes out of rehash2 checking, and then rehash2 and rehash4 are done separately. By doing this, we no longer need to call rehash4 explicitly in udp_lib_hash4(), as the rehash callback in __ip4_datagram_connect takes it. Thus, now udp_lib_hash4() returns directly if the sk is already hashed. Note that uhash4 may fail to work under consecutive connect() calls because rehash() is not called with every connect(). To overcome this, connect() needs to be called after the next connect to a new destination. [0] https://lore.kernel.org/all/4761e466ab9f7542c68cdc95f248987d127044d2.1733499715.git.pabeni@redhat.com/ Fixes: 78c91ae2c6de ("ipv4/udp: Add 4-tuple hash for connected socket") Suggested-by: Paolo Abeni Signed-off-by: Philo Lu Link: https://patch.msgid.link/20250110010810.107145-1-lulie@linux.alibaba.com Signed-off-by: Paolo Abeni