Revision c300aa64ddf57d9c5d9c898a64b36877345dd4a9 authored by Andy Honig on 11 March 2013, 16:34:52 UTC, committed by Marcelo Tosatti on 19 March 2013, 17:17:31 UTC
If the guest sets the GPA of the time_page so that the request to update the time straddles a page then KVM will write onto an incorrect page. The write is done byusing kmap atomic to get a pointer to the page for the time structure and then performing a memcpy to that page starting at an offset that the guest controls. Well behaved guests always provide a 32-byte aligned address, however a malicious guest could use this to corrupt host kernel memory. Tested: Tested against kvmclock unit test. Signed-off-by: Andrew Honig <ahonig@google.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
1 parent c09664b
direct.h
/*
* direct.h - NILFS direct block pointer.
*
* Copyright (C) 2006-2008 Nippon Telegraph and Telephone Corporation.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* Written by Koji Sato <koji@osrg.net>.
*/
#ifndef _NILFS_DIRECT_H
#define _NILFS_DIRECT_H
#include <linux/types.h>
#include <linux/buffer_head.h>
#include "bmap.h"
/**
* struct nilfs_direct_node - direct node
* @dn_flags: flags
* @dn_pad: padding
*/
struct nilfs_direct_node {
__u8 dn_flags;
__u8 pad[7];
};
#define NILFS_DIRECT_NBLOCKS (NILFS_BMAP_SIZE / sizeof(__le64) - 1)
#define NILFS_DIRECT_KEY_MIN 0
#define NILFS_DIRECT_KEY_MAX (NILFS_DIRECT_NBLOCKS - 1)
int nilfs_direct_init(struct nilfs_bmap *);
int nilfs_direct_delete_and_convert(struct nilfs_bmap *, __u64, __u64 *,
__u64 *, int);
#endif /* _NILFS_DIRECT_H */
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