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vhost: Fix the calculation in vhost_overflow()

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

Fixes: ec33d031a1 ("vhost: detect 32 bit integer wrap around")
Reported-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20210728130756.97-2-xieyongji@bytedance.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Xie Yongji 2021-07-28 21:07:56 +08:00 committed by Michael S. Tsirkin
parent 0e398290cf
commit f7ad318ea0
1 changed files with 8 additions and 2 deletions
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10
drivers/vhost/vhost.c
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@ -735,10 +735,16 @@ static bool log_access_ok(void __user *log_base, u64 addr, unsigned long sz)
(sz + VHOST_PAGE_SIZE * 8 - 1) / VHOST_PAGE_SIZE / 8);
}
/* Make sure 64 bit math will not overflow. */
static bool vhost_overflow(u64 uaddr, u64 size)
{
/* Make sure 64 bit math will not overflow. */
return uaddr > ULONG_MAX || size > ULONG_MAX || uaddr > ULONG_MAX - size;
if (uaddr > ULONG_MAX || size > ULONG_MAX)
return true;
if (!size)
return false;
return uaddr > ULONG_MAX - size + 1;
}
/* Caller should have vq mutex and device mutex. */