linux-stable.git/drivers/vhost/vhost.c, branch linux-4.19.y

vhost: Add smp_rmb() in vhost_vq_avail_empty()

2024-05-02T14:17:08+00:00

commit 22e1992cf7b034db5325660e98c41ca5afa5f519 upstream.

A smp_rmb() has been missed in vhost_vq_avail_empty(), spotted by
Will. Otherwise, it's not ensured the available ring entries pushed
by guest can be observed by vhost in time, leading to stale available
ring entries fetched by vhost in vhost_get_vq_desc(), as reported by
Yihuang Yu on NVidia's grace-hopper (ARM64) platform.

  /home/gavin/sandbox/qemu.main/build/qemu-system-aarch64      \
  -accel kvm -machine virt,gic-version=host -cpu host          \
  -smp maxcpus=1,cpus=1,sockets=1,clusters=1,cores=1,threads=1 \
  -m 4096M,slots=16,maxmem=64G                                 \
  -object memory-backend-ram,id=mem0,size=4096M                \
   :                                                           \
  -netdev tap,id=vnet0,vhost=true                              \
  -device virtio-net-pci,bus=pcie.8,netdev=vnet0,mac=52:54:00:f1:26:b0
   :
  guest# netperf -H 10.26.1.81 -l 60 -C -c -t UDP_STREAM
  virtio_net virtio0: output.0:id 100 is not a head!

Add the missed smp_rmb() in vhost_vq_avail_empty(). When tx_can_batch()
returns true, it means there's still pending tx buffers. Since it might
read indices, so it still can bypass the smp_rmb() in vhost_get_vq_desc().
Note that it should be safe until vq->avail_idx is changed by commit
275bf960ac697 ("vhost: better detection of available buffers").

Fixes: 275bf960ac69 ("vhost: better detection of available buffers")
Cc:  # v4.11+
Reported-by: Yihuang Yu 
Suggested-by: Will Deacon 
Signed-off-by: Gavin Shan 
Acked-by: Jason Wang 
Message-Id: <20240328002149.1141302-2-gshan@redhat.com>
Signed-off-by: Michael S. Tsirkin 
Reviewed-by: Stefano Garzarella 
Signed-off-by: Greg Kroah-Hartman

vhost: use kzalloc() instead of kmalloc() followed by memset()

2024-02-23T07:12:55+00:00

commit 4d8df0f5f79f747d75a7d356d9b9ea40a4e4c8a9 upstream.

Use kzalloc() to allocate new zeroed out msg node instead of
memsetting a node allocated with kmalloc().

Signed-off-by: Prathu Baronia 
Message-Id: <20230522085019.42914-1-prathubaronia2011@gmail.com>
Signed-off-by: Michael S. Tsirkin 
Reviewed-by: Stefano Garzarella 
Signed-off-by: Ajay Kaher 
Signed-off-by: Greg Kroah-Hartman

vhost: Fix the calculation in vhost_overflow()

2021-08-26T12:36:45+00:00

[ Upstream commit f7ad318ea0ad58ebe0e595e59aed270bb643b29b ]

This fixes the incorrect calculation for integer overflow
when the last address of iova range is 0xffffffff.

Fixes: ec33d031a14b ("vhost: detect 32 bit integer wrap around")
Reported-by: Jason Wang 
Signed-off-by: Xie Yongji 
Acked-by: Jason Wang 
Link: https://lore.kernel.org/r/20210728130756.97-2-xieyongji@bytedance.com
Signed-off-by: Michael S. Tsirkin 
Signed-off-by: Sasha Levin

vhost: Fix vhost_vq_reset()

2021-04-07T10:48:48+00:00

[ Upstream commit beb691e69f4dec7bfe8b81b509848acfd1f0dbf9 ]

vhost_reset_is_le() is vhost_init_is_le(), and in the case of
cross-endian legacy, vhost_init_is_le() depends on vq->user_be.

vq->user_be is set by vhost_disable_cross_endian().

But in vhost_vq_reset(), we have:

    vhost_reset_is_le(vq);
    vhost_disable_cross_endian(vq);

And so user_be is used before being set.

To fix that, reverse the lines order as there is no other dependency
between them.

Signed-off-by: Laurent Vivier 
Link: https://lore.kernel.org/r/20210312140913.788592-1-lvivier@redhat.com
Signed-off-by: Michael S. Tsirkin 
Signed-off-by: Sasha Levin

vhost: make sure log_num < in_num

2019-09-16T06:22:25+00:00

commit 060423bfdee3f8bc6e2c1bac97de24d5415e2bc4 upstream.

The code assumes log_num < in_num everywhere, and that is true as long as
in_num is incremented by descriptor iov count, and log_num by 1. However
this breaks if there's a zero sized descriptor.

As a result, if a malicious guest creates a vring desc with desc.len = 0,
it may cause the host kernel to crash by overflowing the log array. This
bug can be triggered during the VM migration.

There's no need to log when desc.len = 0, so just don't increment log_num
in this case.

Fixes: 3a4d5c94e959 ("vhost_net: a kernel-level virtio server")
Cc: stable@vger.kernel.org
Reviewed-by: Lidong Chen 
Signed-off-by: ruippan 
Signed-off-by: yongduan 
Acked-by: Michael S. Tsirkin 
Reviewed-by: Tyler Hicks 
Signed-off-by: Michael S. Tsirkin 
Signed-off-by: Greg Kroah-Hartman

vhost: introduce vhost_exceeds_weight()

2019-08-04T07:30:55+00:00

commit e82b9b0727ff6d665fff2d326162b460dded554d upstream.

We used to have vhost_exceeds_weight() for vhost-net to:

- prevent vhost kthread from hogging the cpu
- balance the time spent between TX and RX

This function could be useful for vsock and scsi as well. So move it
to vhost.c. Device must specify a weight which counts the number of
requests, or it can also specific a byte_weight which counts the
number of bytes that has been processed.

Signed-off-by: Jason Wang 
Reviewed-by: Stefan Hajnoczi 
Signed-off-by: Michael S. Tsirkin 
[jwang: backport to 4.19, fix conflict in net.c]
Signed-off-by: Jack Wang 
Signed-off-by: Greg Kroah-Hartman

vhost: reject zero size iova range

2019-04-27T07:36:31+00:00

[ Upstream commit 813dbeb656d6c90266f251d8bd2b02d445afa63f ]

We used to accept zero size iova range which will lead a infinite loop
in translate_desc(). Fixing this by failing the request in this case.

Reported-by: syzbot+d21e6e297322a900c128@syzkaller.appspotmail.com
Fixes: 6b1e6cc7 ("vhost: new device IOTLB API")
Signed-off-by: Jason Wang 
Acked-by: Michael S. Tsirkin 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

vhost: return EINVAL if iovecs size does not match the message size

2019-02-27T09:08:56+00:00

[ Upstream commit 74ad7419489ddade8044e3c9ab064ad656520306 ]

We've failed to copy and process vhost_iotlb_msg so let userspace at
least know about it. For instance before these patch the code below runs
without any error:

int main()
{
  struct vhost_msg msg;
  struct iovec iov;
  int fd;

  fd = open("/dev/vhost-net", O_RDWR);
  if (fd == -1) {
    perror("open");
    return 1;
  }

  iov.iov_base = &msg;
  iov.iov_len = sizeof(msg)-4;

  if (writev(fd, &iov,1) == -1) {
    perror("writev");
    return 1;
  }

  return 0;
}

Signed-off-by: Pavel Tikhomirov 
Signed-off-by: Michael S. Tsirkin 
Signed-off-by: Sasha Levin

vhost: correctly check the return value of translate_desc() in log_used()

2019-02-23T08:07:25+00:00

[ Upstream commit 816db7663565cd23f74ed3d5c9240522e3fb0dda ]

When fail, translate_desc() returns negative value, otherwise the
number of iovs. So we should fail when the return value is negative
instead of a blindly check against zero.

Detected by CoverityScan, CID# 1442593:  Control flow issues  (DEADCODE)

Fixes: cc5e71075947 ("vhost: log dirty page correctly")
Acked-by: Michael S. Tsirkin 
Reported-by: Stephen Hemminger 
Signed-off-by: Jason Wang 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

vhost: fix OOB in get_rx_bufs()

2019-02-06T16:30:08+00:00

[ Upstream commit b46a0bf78ad7b150ef5910da83859f7f5a514ffd ]

After batched used ring updating was introduced in commit e2b3b35eb989
("vhost_net: batch used ring update in rx"). We tend to batch heads in
vq->heads for more than one packet. But the quota passed to
get_rx_bufs() was not correctly limited, which can result a OOB write
in vq->heads.

        headcount = get_rx_bufs(vq, vq->heads + nvq->done_idx,
                    vhost_len, &in, vq_log, &log,
                    likely(mergeable) ? UIO_MAXIOV : 1);

UIO_MAXIOV was still used which is wrong since we could have batched
used in vq->heads, this will cause OOB if the next buffer needs more
than 960 (1024 (UIO_MAXIOV) - 64 (VHOST_NET_BATCH)) heads after we've
batched 64 (VHOST_NET_BATCH) heads:
Acked-by: Stefan Hajnoczi 

=============================================================================
BUG kmalloc-8k (Tainted: G    B            ): Redzone overwritten
-----------------------------------------------------------------------------

INFO: 0x00000000fd93b7a2-0x00000000f0713384. First byte 0xa9 instead of 0xcc
INFO: Allocated in alloc_pd+0x22/0x60 age=3933677 cpu=2 pid=2674
    kmem_cache_alloc_trace+0xbb/0x140
    alloc_pd+0x22/0x60
    gen8_ppgtt_create+0x11d/0x5f0
    i915_ppgtt_create+0x16/0x80
    i915_gem_create_context+0x248/0x390
    i915_gem_context_create_ioctl+0x4b/0xe0
    drm_ioctl_kernel+0xa5/0xf0
    drm_ioctl+0x2ed/0x3a0
    do_vfs_ioctl+0x9f/0x620
    ksys_ioctl+0x6b/0x80
    __x64_sys_ioctl+0x11/0x20
    do_syscall_64+0x43/0xf0
    entry_SYSCALL_64_after_hwframe+0x44/0xa9
INFO: Slab 0x00000000d13e87af objects=3 used=3 fp=0x          (null) flags=0x200000000010201
INFO: Object 0x0000000003278802 @offset=17064 fp=0x00000000e2e6652b

Fixing this by allocating UIO_MAXIOV + VHOST_NET_BATCH iovs for
vhost-net. This is done through set the limitation through
vhost_dev_init(), then set_owner can allocate the number of iov in a
per device manner.

This fixes CVE-2018-16880.

Fixes: e2b3b35eb989 ("vhost_net: batch used ring update in rx")
Signed-off-by: Jason Wang 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman