move_to_indirect() accepts an indirect descriptor with a zero length,
setting desc_max to 0. __vringh_iov() then reads descs[0] before
checking the descriptor bounds, resulting in an out-of-bounds read.
Reject a zero-length indirect table in move_to_indirect() so the
caller returns -EINVAL before dereferencing the table. Also use the
converted length in the warning to report invalid lengths correctly
when the vring byte order differs from the CPU byte order.
Fixes: f87d0fbb5798 ("vringh: host-side implementation of virtio rings.")
Cc: [email protected]
Reviewed-by: Guanglei Zhu <[email protected]>
Signed-off-by: Fang Xieyan <[email protected]>
---
drivers/vhost/vringh.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c
index 9066f9f12ba1..ce4f5a02c8d2 100644
--- a/drivers/vhost/vringh.c
+++ b/drivers/vhost/vringh.c
@@ -197,8 +197,8 @@ static int move_to_indirect(const struct vringh *vrh,
}
len = vringh32_to_cpu(vrh, desc->len);
- if (unlikely(len % sizeof(struct vring_desc))) {
- vringh_bad("Strange indirect len %u", desc->len);
+ if (unlikely(!len || len % sizeof(struct vring_desc))) {
+ vringh_bad("Strange indirect len %u", len);
return -EINVAL;
}
--
2.50.1
