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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
rose_loopback.c 
/*
 * 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.
 *
 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
 */
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/socket.h>
#include <linux/timer.h>
#include <net/ax25.h>
#include <linux/skbuff.h>
#include <net/rose.h>
#include <linux/init.h>

static struct sk_buff_head loopback_queue;
static struct timer_list loopback_timer;

static void rose_set_loopback_timer(void);
static void rose_loopback_timer(struct timer_list *unused);

void rose_loopback_init(void)
{
	skb_queue_head_init(&loopback_queue);

	timer_setup(&loopback_timer, rose_loopback_timer, 0);
}

static int rose_loopback_running(void)
{
	return timer_pending(&loopback_timer);
}

int rose_loopback_queue(struct sk_buff *skb, struct rose_neigh *neigh)
{
	struct sk_buff *skbn;

	skbn = skb_clone(skb, GFP_ATOMIC);

	kfree_skb(skb);

	if (skbn != NULL) {
		skb_queue_tail(&loopback_queue, skbn);

		if (!rose_loopback_running())
			rose_set_loopback_timer();
	}

	return 1;
}


static void rose_set_loopback_timer(void)
{
	del_timer(&loopback_timer);

	loopback_timer.expires  = jiffies + 10;
	add_timer(&loopback_timer);
}

static void rose_loopback_timer(struct timer_list *unused)
{
	struct sk_buff *skb;
	struct net_device *dev;
	rose_address *dest;
	struct sock *sk;
	unsigned short frametype;
	unsigned int lci_i, lci_o;

	while ((skb = skb_dequeue(&loopback_queue)) != NULL) {
		if (skb->len < ROSE_MIN_LEN) {
			kfree_skb(skb);
			continue;
		}
		lci_i     = ((skb->data[0] << 8) & 0xF00) + ((skb->data[1] << 0) & 0x0FF);
		frametype = skb->data[2];
		if (frametype == ROSE_CALL_REQUEST &&
		    (skb->len <= ROSE_CALL_REQ_FACILITIES_OFF ||
		     skb->data[ROSE_CALL_REQ_ADDR_LEN_OFF] !=
		     ROSE_CALL_REQ_ADDR_LEN_VAL)) {
			kfree_skb(skb);
			continue;
		}
		dest      = (rose_address *)(skb->data + ROSE_CALL_REQ_DEST_ADDR_OFF);
		lci_o     = ROSE_DEFAULT_MAXVC + 1 - lci_i;

		skb_reset_transport_header(skb);

		sk = rose_find_socket(lci_o, rose_loopback_neigh);
		if (sk) {
			if (rose_process_rx_frame(sk, skb) == 0)
				kfree_skb(skb);
			continue;
		}

		if (frametype == ROSE_CALL_REQUEST) {
			if ((dev = rose_dev_get(dest)) != NULL) {
				if (rose_rx_call_request(skb, dev, rose_loopback_neigh, lci_o) == 0)
					kfree_skb(skb);
			} else {
				kfree_skb(skb);
			}
		} else {
			kfree_skb(skb);
		}
	}
}

void __exit rose_loopback_clear(void)
{
	struct sk_buff *skb;

	del_timer(&loopback_timer);

	while ((skb = skb_dequeue(&loopback_queue)) != NULL) {
		skb->sk = NULL;
		kfree_skb(skb);
	}
}
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