libvhost-user: Support across-memory-boundary access

The sg list/indirect descriptor table may be contigious
in GPA but not in HVA address space. But libvhost-user
wasn't aware of that. This would cause out-of-bounds
access. Even a malicious guest could use it to get
information from the vhost-user backend.

Introduce a plen parameter in vu_gpa_to_va() so we can
handle this case, returning the actual mapped length.

Signed-off-by: Yongji Xie <xieyongji@baidu.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
This commit is contained in:
Yongji Xie 2018-01-19 00:04:05 +08:00 committed by Michael S. Tsirkin
parent bb102d1da1
commit 293084a719
2 changed files with 122 additions and 14 deletions

View file

@ -327,11 +327,12 @@ bool vu_dispatch(VuDev *dev);
/**
* vu_gpa_to_va:
* @dev: a VuDev context
* @plen: guest memory size
* @guest_addr: guest address
*
* Translate a guest address to a pointer. Returns NULL on failure.
*/
void *vu_gpa_to_va(VuDev *dev, uint64_t guest_addr);
void *vu_gpa_to_va(VuDev *dev, uint64_t *plen, uint64_t guest_addr);
/**
* vu_get_queue: