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vringh: Fix loop descriptors check in the indirect cases 

[ Upstream commit dbd29e0752 ]

We should use size of descriptor chain to test loop condition
in the indirect case. And another statistical count is also introduced
for indirect descriptors to avoid conflict with the statistical count
of direct descriptors.

Fixes: f87d0fbb57 ("vringh: host-side implementation of virtio rings.")
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Signed-off-by: Fam Zheng <fam.zheng@bytedance.com>
Message-Id: <20220505100910.137-1-xieyongji@bytedance.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Xie Yongji 2022-05-05 18:09:10 +08:00 committed by Greg Kroah-Hartman
parent 2811cda7d2
commit 45984b3ae9
1 changed files with 8 additions and 2 deletions
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10
drivers/vhost/vringh.c
View File

@ -262,7 +262,7 @@ __vringh_iov(struct vringh *vrh, u16 i,
gfp_t gfp,
int (*copy)(void *dst, const void *src, size_t len))
{
int err, count = 0, up_next, desc_max;
int err, count = 0, indirect_count = 0, up_next, desc_max;
struct vring_desc desc, *descs;
struct vringh_range range = { -1ULL, 0 }, slowrange;
bool slow = false;
@ -319,7 +319,12 @@ __vringh_iov(struct vringh *vrh, u16 i,
continue;
}
if (count++ == vrh->vring.num) {
if (up_next == -1)
count++;
else
indirect_count++;
if (count > vrh->vring.num || indirect_count > desc_max) {
vringh_bad("Descriptor loop in %p", descs);
err = -ELOOP;
goto fail;
@ -381,6 +386,7 @@ __vringh_iov(struct vringh *vrh, u16 i,
i = return_from_indirect(vrh, &up_next,
&descs, &desc_max);
slow = false;
indirect_count = 0;
} else
break;
}