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Revision 0447378a4a793da008451fad50bc0f93e9675ae6 authored by Marc Orr on 21 June 2018, 00:21:29 UTC, committed by Radim Krčmář on 22 June 2018, 14:46:26 UTC 
kvm: vmx: Nested VM-entry prereqs for event inj.
 
This patch extends the checks done prior to a nested VM entry.
Specifically, it extends the check_vmentry_prereqs function with checks
for fields relevant to the VM-entry event injection information, as
described in the Intel SDM, volume 3.

This patch is motivated by a syzkaller bug, where a bad VM-entry
interruption information field is generated in the VMCS02, which causes
the nested VM launch to fail. Then, KVM fails to resume L1.

While KVM should be improved to correctly resume L1 execution after a
failed nested launch, this change is justified because the existing code
to resume L1 is flaky/ad-hoc and the test coverage for resuming L1 is
sparse.

Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Marc Orr <marcorr@google.com>
[Removed comment whose parts were describing previous revisions and the
 rest was obvious from function/variable naming. - Radim]
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
1 parent 5f9077c
Raw File
auth_none.c 
// SPDX-License-Identifier: GPL-2.0

#include <linux/ceph/ceph_debug.h>

#include <linux/err.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/slab.h>

#include <linux/ceph/decode.h>
#include <linux/ceph/auth.h>

#include "auth_none.h"

static void reset(struct ceph_auth_client *ac)
{
	struct ceph_auth_none_info *xi = ac->private;

	xi->starting = true;
}

static void destroy(struct ceph_auth_client *ac)
{
	kfree(ac->private);
	ac->private = NULL;
}

static int is_authenticated(struct ceph_auth_client *ac)
{
	struct ceph_auth_none_info *xi = ac->private;

	return !xi->starting;
}

static int should_authenticate(struct ceph_auth_client *ac)
{
	struct ceph_auth_none_info *xi = ac->private;

	return xi->starting;
}

static int ceph_auth_none_build_authorizer(struct ceph_auth_client *ac,
					   struct ceph_none_authorizer *au)
{
	void *p = au->buf;
	void *const end = p + sizeof(au->buf);
	int ret;

	ceph_encode_8_safe(&p, end, 1, e_range);
	ret = ceph_auth_entity_name_encode(ac->name, &p, end);
	if (ret < 0)
		return ret;

	ceph_encode_64_safe(&p, end, ac->global_id, e_range);
	au->buf_len = p - (void *)au->buf;
	dout("%s built authorizer len %d\n", __func__, au->buf_len);
	return 0;

e_range:
	return -ERANGE;
}

static int build_request(struct ceph_auth_client *ac, void *buf, void *end)
{
	return 0;
}

/*
 * the generic auth code decode the global_id, and we carry no actual
 * authenticate state, so nothing happens here.
 */
static int handle_reply(struct ceph_auth_client *ac, int result,
			void *buf, void *end)
{
	struct ceph_auth_none_info *xi = ac->private;

	xi->starting = false;
	return result;
}

static void ceph_auth_none_destroy_authorizer(struct ceph_authorizer *a)
{
	kfree(a);
}

/*
 * build an 'authorizer' with our entity_name and global_id.  it is
 * identical for all services we connect to.
 */
static int ceph_auth_none_create_authorizer(
	struct ceph_auth_client *ac, int peer_type,
	struct ceph_auth_handshake *auth)
{
	struct ceph_none_authorizer *au;
	int ret;

	au = kmalloc(sizeof(*au), GFP_NOFS);
	if (!au)
		return -ENOMEM;

	au->base.destroy = ceph_auth_none_destroy_authorizer;

	ret = ceph_auth_none_build_authorizer(ac, au);
	if (ret) {
		kfree(au);
		return ret;
	}

	auth->authorizer = (struct ceph_authorizer *) au;
	auth->authorizer_buf = au->buf;
	auth->authorizer_buf_len = au->buf_len;
	auth->authorizer_reply_buf = au->reply_buf;
	auth->authorizer_reply_buf_len = sizeof (au->reply_buf);

	return 0;
}

static const struct ceph_auth_client_ops ceph_auth_none_ops = {
	.name = "none",
	.reset = reset,
	.destroy = destroy,
	.is_authenticated = is_authenticated,
	.should_authenticate = should_authenticate,
	.build_request = build_request,
	.handle_reply = handle_reply,
	.create_authorizer = ceph_auth_none_create_authorizer,
};

int ceph_auth_none_init(struct ceph_auth_client *ac)
{
	struct ceph_auth_none_info *xi;

	dout("ceph_auth_none_init %p\n", ac);
	xi = kzalloc(sizeof(*xi), GFP_NOFS);
	if (!xi)
		return -ENOMEM;

	xi->starting = true;

	ac->protocol = CEPH_AUTH_NONE;
	ac->private = xi;
	ac->ops = &ceph_auth_none_ops;
	return 0;
}
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