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| author | Xie Yongji <xieyongji@bytedance.com> | 2021-07-28 21:07:56 +0800 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2021-08-11 06:44:15 -0400 |
| commit | f7ad318ea0ad58ebe0e595e59aed270bb643b29b (patch) | |
| tree | 1f9b72676673a8a42c252b8947fd26f59b789388 /drivers/vhost/vhost.c | |
| parent | 0e398290cff997610b66e73573faaee70c9a700e (diff) | |
| download | linux-f7ad318ea0ad58ebe0e595e59aed270bb643b29b.tar.gz linux-f7ad318ea0ad58ebe0e595e59aed270bb643b29b.tar.bz2 linux-f7ad318ea0ad58ebe0e595e59aed270bb643b29b.zip | |
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: ec33d031a14b ("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>
Diffstat (limited to 'drivers/vhost/vhost.c')
| -rw-r--r-- | drivers/vhost/vhost.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index b9e853e6094d..59edb5a1ffe2 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -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. */ |