Commit f7ad318e authored by Xie Yongji's avatar Xie Yongji Committed by Michael S. Tsirkin
Browse files

vhost: Fix the calculation in vhost_overflow() 



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

Fixes: ec33d031 ("vhost: detect 32 bit integer wrap around")
Reported-by: default avatarJason Wang <jasowang@redhat.com>
Signed-off-by: default avatarXie Yongji <xieyongji@bytedance.com>
Acked-by: default avatarJason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20210728130756.97-2-xieyongji@bytedance.com


Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 0e398290

drivers/vhost/vhost.c

+8 −2
Original line number Diff line number Diff line
@@ -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. */