[PATCH] vhost: handle zero regions in vhost_set_memory
From: Anirudh Rayabharam <hidden>
Date: 2022-02-21 07:45:10
Also in:
kvm, lkml
Subsystem:
the rest, virtio host (vhost) · Maintainers:
Linus Torvalds, "Michael S. Tsirkin", Jason Wang
Return early when userspace sends zero regions in the VHOST_SET_MEM_TABLE ioctl. Otherwise, this causes an erroneous entry to be added to the iotlb. This entry has a range size of 0 (due to u64 overflow). This then causes iotlb_access_ok() to loop indefinitely resulting in a hung thread. Syzbot has reported this here: https://syzkaller.appspot.com/bug?extid=0abd373e2e50d704db87 Reported-and-tested-by: syzbot+0abd373e2e50d704db87@syzkaller.appspotmail.com Signed-off-by: Anirudh Rayabharam <redacted> --- drivers/vhost/vhost.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 59edb5a1ffe2..821aba60eac2 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c@@ -1428,6 +1428,8 @@ static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m) return -EFAULT; if (mem.padding) return -EOPNOTSUPP; + if (mem.nregions == 0) + return 0; if (mem.nregions > max_mem_regions) return -E2BIG; newmem = kvzalloc(struct_size(newmem, regions, mem.nregions),
--
2.35.1