Revision 048f49809c526348775425420fb5b8e84fd9a133 authored by Sean Christopherson on 25 March 2021, 20:01:18 UTC, committed by Paolo Bonzini on 30 March 2021, 17:19:55 UTC
Honor the "flush needed" return from kvm_tdp_mmu_zap_gfn_range(), which
does the flush itself if and only if it yields (which it will never do in
this particular scenario), and otherwise expects the caller to do the
flush.  If pages are zapped from the TDP MMU but not the legacy MMU, then
no flush will occur.

Fixes: 29cf0f5007a2 ("kvm: x86/mmu: NX largepage recovery for TDP MMU")
Cc: stable@vger.kernel.org
Cc: Ben Gardon <bgardon@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210325200119.1359384-3-seanjc@google.com>
Reviewed-by: Ben Gardon <bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
1 parent a835429
Raw File
ax25_in.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *
 * Copyright (C) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
 * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
 * Copyright (C) Hans-Joachim Hetscher DD8NE (dd8ne@bnv-bamberg.de)
 */
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/slab.h>
#include <net/ax25.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <net/tcp_states.h>
#include <linux/uaccess.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/interrupt.h>

/*
 *	Given a fragment, queue it on the fragment queue and if the fragment
 *	is complete, send it back to ax25_rx_iframe.
 */
static int ax25_rx_fragment(ax25_cb *ax25, struct sk_buff *skb)
{
	struct sk_buff *skbn, *skbo;

	if (ax25->fragno != 0) {
		if (!(*skb->data & AX25_SEG_FIRST)) {
			if ((ax25->fragno - 1) == (*skb->data & AX25_SEG_REM)) {
				/* Enqueue fragment */
				ax25->fragno = *skb->data & AX25_SEG_REM;
				skb_pull(skb, 1);	/* skip fragno */
				ax25->fraglen += skb->len;
				skb_queue_tail(&ax25->frag_queue, skb);

				/* Last fragment received ? */
				if (ax25->fragno == 0) {
					skbn = alloc_skb(AX25_MAX_HEADER_LEN +
							 ax25->fraglen,
							 GFP_ATOMIC);
					if (!skbn) {
						skb_queue_purge(&ax25->frag_queue);
						return 1;
					}

					skb_reserve(skbn, AX25_MAX_HEADER_LEN);

					skbn->dev   = ax25->ax25_dev->dev;
					skb_reset_network_header(skbn);
					skb_reset_transport_header(skbn);

					/* Copy data from the fragments */
					while ((skbo = skb_dequeue(&ax25->frag_queue)) != NULL) {
						skb_copy_from_linear_data(skbo,
							  skb_put(skbn, skbo->len),
									  skbo->len);
						kfree_skb(skbo);
					}

					ax25->fraglen = 0;

					if (ax25_rx_iframe(ax25, skbn) == 0)
						kfree_skb(skbn);
				}

				return 1;
			}
		}
	} else {
		/* First fragment received */
		if (*skb->data & AX25_SEG_FIRST) {
			skb_queue_purge(&ax25->frag_queue);
			ax25->fragno = *skb->data & AX25_SEG_REM;
			skb_pull(skb, 1);		/* skip fragno */
			ax25->fraglen = skb->len;
			skb_queue_tail(&ax25->frag_queue, skb);
			return 1;
		}
	}

	return 0;
}

/*
 *	This is where all valid I frames are sent to, to be dispatched to
 *	whichever protocol requires them.
 */
int ax25_rx_iframe(ax25_cb *ax25, struct sk_buff *skb)
{
	int (*func)(struct sk_buff *, ax25_cb *);
	unsigned char pid;
	int queued = 0;

	if (skb == NULL) return 0;

	ax25_start_idletimer(ax25);

	pid = *skb->data;

	if (pid == AX25_P_IP) {
		/* working around a TCP bug to keep additional listeners
		 * happy. TCP re-uses the buffer and destroys the original
		 * content.
		 */
		struct sk_buff *skbn = skb_copy(skb, GFP_ATOMIC);
		if (skbn != NULL) {
			kfree_skb(skb);
			skb = skbn;
		}

		skb_pull(skb, 1);	/* Remove PID */
		skb->mac_header = skb->network_header;
		skb_reset_network_header(skb);
		skb->dev      = ax25->ax25_dev->dev;
		skb->pkt_type = PACKET_HOST;
		skb->protocol = htons(ETH_P_IP);
		netif_rx(skb);
		return 1;
	}
	if (pid == AX25_P_SEGMENT) {
		skb_pull(skb, 1);	/* Remove PID */
		return ax25_rx_fragment(ax25, skb);
	}

	if ((func = ax25_protocol_function(pid)) != NULL) {
		skb_pull(skb, 1);	/* Remove PID */
		return (*func)(skb, ax25);
	}

	if (ax25->sk != NULL && ax25->ax25_dev->values[AX25_VALUES_CONMODE] == 2) {
		if ((!ax25->pidincl && ax25->sk->sk_protocol == pid) ||
		    ax25->pidincl) {
			if (sock_queue_rcv_skb(ax25->sk, skb) == 0)
				queued = 1;
			else
				ax25->condition |= AX25_COND_OWN_RX_BUSY;
		}
	}

	return queued;
}

/*
 *	Higher level upcall for a LAPB frame
 */
static int ax25_process_rx_frame(ax25_cb *ax25, struct sk_buff *skb, int type, int dama)
{
	int queued = 0;

	if (ax25->state == AX25_STATE_0)
		return 0;

	switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
	case AX25_PROTO_STD_SIMPLEX:
	case AX25_PROTO_STD_DUPLEX:
		queued = ax25_std_frame_in(ax25, skb, type);
		break;

#ifdef CONFIG_AX25_DAMA_SLAVE
	case AX25_PROTO_DAMA_SLAVE:
		if (dama || ax25->ax25_dev->dama.slave)
			queued = ax25_ds_frame_in(ax25, skb, type);
		else
			queued = ax25_std_frame_in(ax25, skb, type);
		break;
#endif
	}

	return queued;
}

static int ax25_rcv(struct sk_buff *skb, struct net_device *dev,
	ax25_address *dev_addr, struct packet_type *ptype)
{
	ax25_address src, dest, *next_digi = NULL;
	int type = 0, mine = 0, dama;
	struct sock *make, *sk;
	ax25_digi dp, reverse_dp;
	ax25_cb *ax25;
	ax25_dev *ax25_dev;

	/*
	 *	Process the AX.25/LAPB frame.
	 */

	skb_reset_transport_header(skb);

	if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL)
		goto free;

	/*
	 *	Parse the address header.
	 */

	if (ax25_addr_parse(skb->data, skb->len, &src, &dest, &dp, &type, &dama) == NULL)
		goto free;

	/*
	 *	Ours perhaps ?
	 */
	if (dp.lastrepeat + 1 < dp.ndigi)		/* Not yet digipeated completely */
		next_digi = &dp.calls[dp.lastrepeat + 1];

	/*
	 *	Pull of the AX.25 headers leaving the CTRL/PID bytes
	 */
	skb_pull(skb, ax25_addr_size(&dp));

	/* For our port addresses ? */
	if (ax25cmp(&dest, dev_addr) == 0 && dp.lastrepeat + 1 == dp.ndigi)
		mine = 1;

	/* Also match on any registered callsign from L3/4 */
	if (!mine && ax25_listen_mine(&dest, dev) && dp.lastrepeat + 1 == dp.ndigi)
		mine = 1;

	/* UI frame - bypass LAPB processing */
	if ((*skb->data & ~0x10) == AX25_UI && dp.lastrepeat + 1 == dp.ndigi) {
		skb_set_transport_header(skb, 2); /* skip control and pid */

		ax25_send_to_raw(&dest, skb, skb->data[1]);

		if (!mine && ax25cmp(&dest, (ax25_address *)dev->broadcast) != 0)
			goto free;

		/* Now we are pointing at the pid byte */
		switch (skb->data[1]) {
		case AX25_P_IP:
			skb_pull(skb,2);		/* drop PID/CTRL */
			skb_reset_transport_header(skb);
			skb_reset_network_header(skb);
			skb->dev      = dev;
			skb->pkt_type = PACKET_HOST;
			skb->protocol = htons(ETH_P_IP);
			netif_rx(skb);
			break;

		case AX25_P_ARP:
			skb_pull(skb,2);
			skb_reset_transport_header(skb);
			skb_reset_network_header(skb);
			skb->dev      = dev;
			skb->pkt_type = PACKET_HOST;
			skb->protocol = htons(ETH_P_ARP);
			netif_rx(skb);
			break;
		case AX25_P_TEXT:
			/* Now find a suitable dgram socket */
			sk = ax25_get_socket(&dest, &src, SOCK_DGRAM);
			if (sk != NULL) {
				bh_lock_sock(sk);
				if (atomic_read(&sk->sk_rmem_alloc) >=
				    sk->sk_rcvbuf) {
					kfree_skb(skb);
				} else {
					/*
					 *	Remove the control and PID.
					 */
					skb_pull(skb, 2);
					if (sock_queue_rcv_skb(sk, skb) != 0)
						kfree_skb(skb);
				}
				bh_unlock_sock(sk);
				sock_put(sk);
			} else {
				kfree_skb(skb);
			}
			break;

		default:
			kfree_skb(skb);	/* Will scan SOCK_AX25 RAW sockets */
			break;
		}

		return 0;
	}

	/*
	 *	Is connected mode supported on this device ?
	 *	If not, should we DM the incoming frame (except DMs) or
	 *	silently ignore them. For now we stay quiet.
	 */
	if (ax25_dev->values[AX25_VALUES_CONMODE] == 0)
		goto free;

	/* LAPB */

	/* AX.25 state 1-4 */

	ax25_digi_invert(&dp, &reverse_dp);

	if ((ax25 = ax25_find_cb(&dest, &src, &reverse_dp, dev)) != NULL) {
		/*
		 *	Process the frame. If it is queued up internally it
		 *	returns one otherwise we free it immediately. This
		 *	routine itself wakes the user context layers so we do
		 *	no further work
		 */
		if (ax25_process_rx_frame(ax25, skb, type, dama) == 0)
			kfree_skb(skb);

		ax25_cb_put(ax25);
		return 0;
	}

	/* AX.25 state 0 (disconnected) */

	/* a) received not a SABM(E) */

	if ((*skb->data & ~AX25_PF) != AX25_SABM &&
	    (*skb->data & ~AX25_PF) != AX25_SABME) {
		/*
		 *	Never reply to a DM. Also ignore any connects for
		 *	addresses that are not our interfaces and not a socket.
		 */
		if ((*skb->data & ~AX25_PF) != AX25_DM && mine)
			ax25_return_dm(dev, &src, &dest, &dp);

		goto free;
	}

	/* b) received SABM(E) */

	if (dp.lastrepeat + 1 == dp.ndigi)
		sk = ax25_find_listener(&dest, 0, dev, SOCK_SEQPACKET);
	else
		sk = ax25_find_listener(next_digi, 1, dev, SOCK_SEQPACKET);

	if (sk != NULL) {
		bh_lock_sock(sk);
		if (sk_acceptq_is_full(sk) ||
		    (make = ax25_make_new(sk, ax25_dev)) == NULL) {
			if (mine)
				ax25_return_dm(dev, &src, &dest, &dp);
			kfree_skb(skb);
			bh_unlock_sock(sk);
			sock_put(sk);

			return 0;
		}

		ax25 = sk_to_ax25(make);
		skb_set_owner_r(skb, make);
		skb_queue_head(&sk->sk_receive_queue, skb);

		make->sk_state = TCP_ESTABLISHED;

		sk_acceptq_added(sk);
		bh_unlock_sock(sk);
	} else {
		if (!mine)
			goto free;

		if ((ax25 = ax25_create_cb()) == NULL) {
			ax25_return_dm(dev, &src, &dest, &dp);
			goto free;
		}

		ax25_fillin_cb(ax25, ax25_dev);
	}

	ax25->source_addr = dest;
	ax25->dest_addr   = src;

	/*
	 *	Sort out any digipeated paths.
	 */
	if (dp.ndigi && !ax25->digipeat &&
	    (ax25->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
		kfree_skb(skb);
		ax25_destroy_socket(ax25);
		if (sk)
			sock_put(sk);
		return 0;
	}

	if (dp.ndigi == 0) {
		kfree(ax25->digipeat);
		ax25->digipeat = NULL;
	} else {
		/* Reverse the source SABM's path */
		memcpy(ax25->digipeat, &reverse_dp, sizeof(ax25_digi));
	}

	if ((*skb->data & ~AX25_PF) == AX25_SABME) {
		ax25->modulus = AX25_EMODULUS;
		ax25->window  = ax25_dev->values[AX25_VALUES_EWINDOW];
	} else {
		ax25->modulus = AX25_MODULUS;
		ax25->window  = ax25_dev->values[AX25_VALUES_WINDOW];
	}

	ax25_send_control(ax25, AX25_UA, AX25_POLLON, AX25_RESPONSE);

#ifdef CONFIG_AX25_DAMA_SLAVE
	if (dama && ax25->ax25_dev->values[AX25_VALUES_PROTOCOL] == AX25_PROTO_DAMA_SLAVE)
		ax25_dama_on(ax25);
#endif

	ax25->state = AX25_STATE_3;

	ax25_cb_add(ax25);

	ax25_start_heartbeat(ax25);
	ax25_start_t3timer(ax25);
	ax25_start_idletimer(ax25);

	if (sk) {
		if (!sock_flag(sk, SOCK_DEAD))
			sk->sk_data_ready(sk);
		sock_put(sk);
	} else {
free:
		kfree_skb(skb);
	}
	return 0;
}

/*
 *	Receive an AX.25 frame via a SLIP interface.
 */
int ax25_kiss_rcv(struct sk_buff *skb, struct net_device *dev,
		  struct packet_type *ptype, struct net_device *orig_dev)
{
	skb_orphan(skb);

	if (!net_eq(dev_net(dev), &init_net)) {
		kfree_skb(skb);
		return 0;
	}

	if ((*skb->data & 0x0F) != 0) {
		kfree_skb(skb);	/* Not a KISS data frame */
		return 0;
	}

	skb_pull(skb, AX25_KISS_HEADER_LEN);	/* Remove the KISS byte */

	return ax25_rcv(skb, dev, (ax25_address *)dev->dev_addr, ptype);
}
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