| From 9e8ed5086092eafdef689cc5a469371020012c53 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Thu, 5 May 2022 18:09:10 +0800 |
| Subject: vringh: Fix loop descriptors check in the indirect cases |
| |
| From: Xie Yongji <xieyongji@bytedance.com> |
| |
| [ Upstream commit dbd29e0752286af74243cf891accf472b2f3edd8 ] |
| |
| 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: f87d0fbb5798 ("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> |
| --- |
| drivers/vhost/vringh.c | 10 ++++++++-- |
| 1 file changed, 8 insertions(+), 2 deletions(-) |
| |
| diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c |
| index da47542496cc..63f0ab3e6f63 100644 |
| --- a/drivers/vhost/vringh.c |
| +++ b/drivers/vhost/vringh.c |
| @@ -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; |
| } |
| -- |
| 2.35.1 |
| |