kernel/git/stable/linux.git/net/vmw_vsock, branch linux-5.8.y

vsock: fix potential null pointer dereference in vsock_poll()

2020-08-19T06:26:59+00:00

[ Upstream commit 1980c05844830a44708c98c96d600833aa3fae08 ] syzbot reported this issue where in the vsock_poll() we find the socket state at TCP_ESTABLISHED, but 'transport' is null: general protection fault, probably for non-canonical address 0xdffffc0000000012: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000090-0x0000000000000097] CPU: 0 PID: 8227 Comm: syz-executor.2 Not tainted 5.8.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:vsock_poll+0x75a/0x8e0 net/vmw_vsock/af_vsock.c:1038 Call Trace: sock_poll+0x159/0x460 net/socket.c:1266 vfs_poll include/linux/poll.h:90 [inline] do_pollfd fs/select.c:869 [inline] do_poll fs/select.c:917 [inline] do_sys_poll+0x607/0xd40 fs/select.c:1011 __do_sys_poll fs/select.c:1069 [inline] __se_sys_poll fs/select.c:1057 [inline] __x64_sys_poll+0x18c/0x440 fs/select.c:1057 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384 entry_SYSCALL_64_after_hwframe+0x44/0xa9 This issue can happen if the TCP_ESTABLISHED state is set after we read the vsk->transport in the vsock_poll(). We could put barriers to synchronize, but this can only happen during connection setup, so we can simply check that 'transport' is valid. Fixes: c0cfa2d8a788 ("vsock: add multi-transports support") Reported-and-tested-by: syzbot+a61bac2fcc1a7c6623fe@syzkaller.appspotmail.com Signed-off-by: Stefano Garzarella Reviewed-by: Jorgen Hansen Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

vsock/virtio: annotate 'the_virtio_vsock' RCU pointer

2020-07-16T00:47:15+00:00

Commit 0deab087b16a ("vsock/virtio: use RCU to avoid use-after-free on the_virtio_vsock") starts to use RCU to protect 'the_virtio_vsock' pointer, but we forgot to annotate it. This patch adds the annotation to fix the following sparse errors: net/vmw_vsock/virtio_transport.c:73:17: error: incompatible types in comparison expression (different address spaces): net/vmw_vsock/virtio_transport.c:73:17: struct virtio_vsock [noderef] __rcu * net/vmw_vsock/virtio_transport.c:73:17: struct virtio_vsock * net/vmw_vsock/virtio_transport.c:171:17: error: incompatible types in comparison expression (different address spaces): net/vmw_vsock/virtio_transport.c:171:17: struct virtio_vsock [noderef] __rcu * net/vmw_vsock/virtio_transport.c:171:17: struct virtio_vsock * net/vmw_vsock/virtio_transport.c:207:17: error: incompatible types in comparison expression (different address spaces): net/vmw_vsock/virtio_transport.c:207:17: struct virtio_vsock [noderef] __rcu * net/vmw_vsock/virtio_transport.c:207:17: struct virtio_vsock * net/vmw_vsock/virtio_transport.c:561:13: error: incompatible types in comparison expression (different address spaces): net/vmw_vsock/virtio_transport.c:561:13: struct virtio_vsock [noderef] __rcu * net/vmw_vsock/virtio_transport.c:561:13: struct virtio_vsock * net/vmw_vsock/virtio_transport.c:612:9: error: incompatible types in comparison expression (different address spaces): net/vmw_vsock/virtio_transport.c:612:9: struct virtio_vsock [noderef] __rcu * net/vmw_vsock/virtio_transport.c:612:9: struct virtio_vsock * net/vmw_vsock/virtio_transport.c:631:9: error: incompatible types in comparison expression (different address spaces): net/vmw_vsock/virtio_transport.c:631:9: struct virtio_vsock [noderef] __rcu * net/vmw_vsock/virtio_transport.c:631:9: struct virtio_vsock * Fixes: 0deab087b16a ("vsock/virtio: use RCU to avoid use-after-free on the_virtio_vsock") Reported-by: Michael S. Tsirkin Signed-off-by: Stefano Garzarella Reviewed-by: Stefan Hajnoczi Acked-by: Michael S. Tsirkin Signed-off-by: Jakub Kicinski

vsock/vmci: make vmci_vsock_transport_cb() static

2020-06-05T20:18:26+00:00

Fix the following gcc-9.3 warning when building with 'make W=1': net/vmw_vsock/vmci_transport.c:2058:6: warning: no previous prototype for ‘vmci_vsock_transport_cb’ [-Wmissing-prototypes] 2058 | void vmci_vsock_transport_cb(bool is_host) | ^~~~~~~~~~~~~~~~~~~~~~~ Fixes: b1bba80a4376 ("vsock/vmci: register vmci_transport only when VMCI guest/host are active") Reported-by: kernel test robot Signed-off-by: Stefano Garzarella Signed-off-by: David S. Miller

virtio_vsock: Fix race condition in virtio_transport_recv_pkt

2020-05-31T00:44:01+00:00

When client on the host tries to connect(SOCK_STREAM, O_NONBLOCK) to the server on the guest, there will be a panic on a ThunderX2 (armv8a server): [ 463.718844] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 [ 463.718848] Mem abort info: [ 463.718849] ESR = 0x96000044 [ 463.718852] EC = 0x25: DABT (current EL), IL = 32 bits [ 463.718853] SET = 0, FnV = 0 [ 463.718854] EA = 0, S1PTW = 0 [ 463.718855] Data abort info: [ 463.718856] ISV = 0, ISS = 0x00000044 [ 463.718857] CM = 0, WnR = 1 [ 463.718859] user pgtable: 4k pages, 48-bit VAs, pgdp=0000008f6f6e9000 [ 463.718861] [0000000000000000] pgd=0000000000000000 [ 463.718866] Internal error: Oops: 96000044 [#1] SMP [...] [ 463.718977] CPU: 213 PID: 5040 Comm: vhost-5032 Tainted: G O 5.7.0-rc7+ #139 [ 463.718980] Hardware name: GIGABYTE R281-T91-00/MT91-FS1-00, BIOS F06 09/25/2018 [ 463.718982] pstate: 60400009 (nZCv daif +PAN -UAO) [ 463.718995] pc : virtio_transport_recv_pkt+0x4c8/0xd40 [vmw_vsock_virtio_transport_common] [ 463.718999] lr : virtio_transport_recv_pkt+0x1fc/0xd40 [vmw_vsock_virtio_transport_common] [ 463.719000] sp : ffff80002dbe3c40 [...] [ 463.719025] Call trace: [ 463.719030] virtio_transport_recv_pkt+0x4c8/0xd40 [vmw_vsock_virtio_transport_common] [ 463.719034] vhost_vsock_handle_tx_kick+0x360/0x408 [vhost_vsock] [ 463.719041] vhost_worker+0x100/0x1a0 [vhost] [ 463.719048] kthread+0x128/0x130 [ 463.719052] ret_from_fork+0x10/0x18 The race condition is as follows: Task1 Task2 ===== ===== __sock_release virtio_transport_recv_pkt __vsock_release vsock_find_bound_socket (found sk) lock_sock_nested vsock_remove_sock sock_orphan sk_set_socket(sk, NULL) sk->sk_shutdown = SHUTDOWN_MASK ... release_sock lock_sock virtio_transport_recv_connecting sk->sk_socket->state (panic!) The root cause is that vsock_find_bound_socket can't hold the lock_sock, so there is a small race window between vsock_find_bound_socket() and lock_sock(). If __vsock_release() is running in another task, sk->sk_socket will be set to NULL inadvertently. This fixes it by checking sk->sk_shutdown(suggested by Stefano) after lock_sock since sk->sk_shutdown is set to SHUTDOWN_MASK under the protection of lock_sock_nested. Signed-off-by: Jia He Reviewed-by: Stefano Garzarella Signed-off-by: David S. Miller

vsock: fix timeout in vsock_accept()

2020-05-27T18:20:23+00:00

The accept(2) is an "input" socket interface, so we should use SO_RCVTIMEO instead of SO_SNDTIMEO to set the timeout. So this patch replace sock_sndtimeo() with sock_rcvtimeo() to use the right timeout in the vsock_accept(). Fixes: d021c344051a ("VSOCK: Introduce VM Sockets") Signed-off-by: Stefano Garzarella Reviewed-by: Jorgen Hansen Signed-off-by: David S. Miller

vsock/virtio: fix multiple packet delivery to monitoring devices

2020-04-27T17:18:01+00:00

In virtio_transport.c, if the virtqueue is full, the transmitting packet is queued up and it will be sent in the next iteration. This causes the same packet to be delivered multiple times to monitoring devices. We want to continue to deliver packets to monitoring devices before it is put in the virtqueue, to avoid that replies can appear in the packet capture before the transmitted packet. This patch fixes the issue, adding a new flag (tap_delivered) in struct virtio_vsock_pkt, to check if the packet is already delivered to monitoring devices. In vhost/vsock.c, we are splitting packets, so we must set 'tap_delivered' to false when we queue up the same virtio_vsock_pkt to handle the remaining bytes. Signed-off-by: Stefano Garzarella Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2020-02-28T02:31:39+00:00

The mptcp conflict was overlapping additions. The SMC conflict was an additional and removal happening at the same time. Signed-off-by: David S. Miller

vsock: fix potential deadlock in transport->release()

2020-02-27T20:03:56+00:00

Some transports (hyperv, virtio) acquire the sock lock during the .release() callback. In the vsock_stream_connect() we call vsock_assign_transport(); if the socket was previously assigned to another transport, the vsk->transport->release() is called, but the sock lock is already held in the vsock_stream_connect(), causing a deadlock reported by syzbot: INFO: task syz-executor280:9768 blocked for more than 143 seconds. Not tainted 5.6.0-rc1-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor280 D27912 9768 9766 0x00000000 Call Trace: context_switch kernel/sched/core.c:3386 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4082 schedule+0xdc/0x2b0 kernel/sched/core.c:4156 __lock_sock+0x165/0x290 net/core/sock.c:2413 lock_sock_nested+0xfe/0x120 net/core/sock.c:2938 virtio_transport_release+0xc4/0xd60 net/vmw_vsock/virtio_transport_common.c:832 vsock_assign_transport+0xf3/0x3b0 net/vmw_vsock/af_vsock.c:454 vsock_stream_connect+0x2b3/0xc70 net/vmw_vsock/af_vsock.c:1288 __sys_connect_file+0x161/0x1c0 net/socket.c:1857 __sys_connect+0x174/0x1b0 net/socket.c:1874 __do_sys_connect net/socket.c:1885 [inline] __se_sys_connect net/socket.c:1882 [inline] __x64_sys_connect+0x73/0xb0 net/socket.c:1882 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe To avoid this issue, this patch remove the lock acquiring in the .release() callback of hyperv and virtio transports, and it holds the lock when we call vsk->transport->release() in the vsock core. Reported-by: syzbot+731710996d79d0d58fbc@syzkaller.appspotmail.com Fixes: 408624af4c89 ("vsock: use local transport when it is loaded") Signed-off-by: Stefano Garzarella Reviewed-by: Stefan Hajnoczi Signed-off-by: David S. Miller

net: virtio_vsock: Enhance connection semantics

2020-02-17T03:01:49+00:00

Whenever the vsock backend on the host sends a packet through the RX queue, it expects an answer on the TX queue. Unfortunately, there is one case where the host side will hang waiting for the answer and might effectively never recover if no timeout mechanism was implemented. This issue happens when the guest side starts binding to the socket, which insert a new bound socket into the list of already bound sockets. At this time, we expect the guest to also start listening, which will trigger the sk_state to move from TCP_CLOSE to TCP_LISTEN. The problem occurs if the host side queued a RX packet and triggered an interrupt right between the end of the binding process and the beginning of the listening process. In this specific case, the function processing the packet virtio_transport_recv_pkt() will find a bound socket, which means it will hit the switch statement checking for the sk_state, but the state won't be changed into TCP_LISTEN yet, which leads the code to pick the default statement. This default statement will only free the buffer, while it should also respond to the host side, by sending a packet on its TX queue. In order to simply fix this unfortunate chain of events, it is important that in case the default statement is entered, and because at this stage we know the host side is waiting for an answer, we must send back a packet containing the operation VIRTIO_VSOCK_OP_RST. One could say that a proper timeout mechanism on the host side will be enough to avoid the backend to hang. But the point of this patch is to ensure the normal use case will be provided with proper responsiveness when it comes to establishing the connection. Signed-off-by: Sebastien Boeuf Signed-off-by: David S. Miller

Merge ra.kernel.org:/pub/scm/linux/kernel/git/netdev/net

2020-01-19T21:10:04+00:00