From d3e38fdf9e1016897c897ea0d22af34e915b1219 Mon Sep 17 00:00:00 2001 From: Xie Yongji Date: Thu, 5 May 2022 18:09:10 +0800 Subject: [PATCH] vringh: Fix loop descriptors check in the indirect cases [ 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 Signed-off-by: Fam Zheng Message-Id: <20220505100910.137-1-xieyongji@bytedance.com> Signed-off-by: Michael S. Tsirkin Acked-by: Jason Wang Signed-off-by: Sasha Levin --- 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 14e2043..eab55ac 100644 --- a/drivers/vhost/vringh.c +++ b/drivers/vhost/vringh.c @@ -292,7 +292,7 @@ __vringh_iov(struct vringh *vrh, u16 i, int (*copy)(const struct vringh *vrh, 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; @@ -349,7 +349,12 @@ __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; @@ -411,6 +416,7 @@ __vringh_iov(struct vringh *vrh, u16 i, i = return_from_indirect(vrh, &up_next, &descs, &desc_max); slow = false; + indirect_count = 0; } else break; } -- 2.7.4