From: Jia He justin.he@arm.com

mainline inclusion from mainline-v5.7 commit 8692cefc433f282228fd44938dd4d26ed38254a2 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I94J63 CVE: CVE-2021-47024

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...

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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 justin.he@arm.com Reviewed-by: Stefano Garzarella sgarzare@redhat.com Signed-off-by: David S. Miller davem@davemloft.net Conflicts: net/vmw_vsock/virtio_transport_common.c Signed-off-by: Ziyang Xuan william.xuanziyang@huawei.com --- net/vmw_vsock/virtio_transport_common.c | 8 ++++++++ 1 file changed, 8 insertions(+)

diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c index 52242a148c70..723ea42d7a40 100644 --- a/net/vmw_vsock/virtio_transport_common.c +++ b/net/vmw_vsock/virtio_transport_common.c @@ -1037,6 +1037,14 @@ void virtio_transport_recv_pkt(struct virtio_vsock_pkt *pkt)

lock_sock(sk);

+ /* Check if sk has been released before lock_sock */ + if (sk->sk_shutdown == SHUTDOWN_MASK) { + (void)virtio_transport_reset_no_sock(pkt); + release_sock(sk); + sock_put(sk); + goto free_pkt; + } + /* Update CID in case it has changed after a transport reset event */ vsk->local_addr.svm_cid = dst.svm_cid;

From: Stefano Garzarella sgarzare@redhat.com

mainline inclusion from mainline-v5.13-rc1 commit 8432b8114957235f42e070a16118a7f750de9d39 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I94J63 CVE: CVE-2021-47024

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...

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As reported by syzbot [1], there is a memory leak while closing the socket. We partially solved this issue with commit ac03046ece2b ("vsock/virtio: free packets during the socket release"), but we forgot to drain the RX queue when the socket is definitely closed by the scheduled work.

To avoid future issues, let's use the new virtio_transport_remove_sock() to drain the RX queue before removing the socket from the af_vsock lists calling vsock_remove_sock().

[1] https://syzkaller.appspot.com/bug?extid=24452624fc4c571eedd9

Fixes: ac03046ece2b ("vsock/virtio: free packets during the socket release") Reported-and-tested-by: syzbot+24452624fc4c571eedd9@syzkaller.appspotmail.com Signed-off-by: Stefano Garzarella sgarzare@redhat.com Signed-off-by: David S. Miller davem@davemloft.net Conflicts: net/vmw_vsock/virtio_transport_common.c Signed-off-by: Ziyang Xuan william.xuanziyang@huawei.com --- net/vmw_vsock/virtio_transport_common.c | 30 ++++++++++++++++--------- 1 file changed, 20 insertions(+), 10 deletions(-)

diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c index ff46c0fcc02b..6db562d9569d 100644 --- a/net/vmw_vsock/virtio_transport_common.c +++ b/net/vmw_vsock/virtio_transport_common.c @@ -700,6 +700,23 @@ static int virtio_transport_reset_no_sock(struct virtio_vsock_pkt *pkt) return t->send_pkt(reply); }

+/* This function should be called with sk_lock held and SOCK_DONE set */ +static void virtio_transport_remove_sock(struct vsock_sock *vsk) +{ + struct virtio_vsock_sock *vvs = vsk->trans; + struct virtio_vsock_pkt *pkt, *tmp; + + /* We don't need to take rx_lock, as the socket is closing and we are + * removing it. + */ + list_for_each_entry_safe(pkt, tmp, &vvs->rx_queue, list) { + list_del(&pkt->list); + virtio_transport_free_pkt(pkt); + } + + vsock_remove_sock(vsk); +} + static void virtio_transport_wait_close(struct sock *sk, long timeout) { if (timeout) { @@ -732,7 +749,7 @@ static void virtio_transport_do_close(struct vsock_sock *vsk, (!cancel_timeout || cancel_delayed_work(&vsk->close_work))) { vsk->close_work_scheduled = false;

- vsock_remove_sock(vsk); + virtio_transport_remove_sock(vsk);

/* Release refcnt obtained when we scheduled the timeout */ sock_put(sk); @@ -795,8 +812,6 @@ static bool virtio_transport_close(struct vsock_sock *vsk)

void virtio_transport_release(struct vsock_sock *vsk) { - struct virtio_vsock_sock *vvs = vsk->trans; - struct virtio_vsock_pkt *pkt, *tmp; struct sock *sk = &vsk->sk; bool remove_sock = true;

@@ -804,16 +819,11 @@ void virtio_transport_release(struct vsock_sock *vsk) if (sk->sk_type == SOCK_STREAM) remove_sock = virtio_transport_close(vsk);

- list_for_each_entry_safe(pkt, tmp, &vvs->rx_queue, list) { - list_del(&pkt->list); - virtio_transport_free_pkt(pkt); - } - release_sock(sk); - if (remove_sock) { sock_set_flag(sk, SOCK_DONE); - vsock_remove_sock(vsk); + virtio_transport_remove_sock(vsk); } + release_sock(sk); } EXPORT_SYMBOL_GPL(virtio_transport_release);