Support for handling the PPPOEIOCSFWD ioctl in compat mode was added in
linux-2.5.69 along with hundreds of other commands, but was always broken
sincen only the structure is compatible, but the command number is not,
due to the size being sizeof(size_t), or at first sizeof(sizeof((struct
sockaddr_pppox)), which is different on 64-bit architectures.
Guillaume Nault adds:
  And the implementation was broken until 2016 (see 29e73269aa ("pppoe:
  fix reference counting in PPPoE proxy")), and nobody ever noticed. I
  should probably have removed this ioctl entirely instead of fixing it.
  Clearly, it has never been used.
Fix it by adding a compat_ioctl handler for all pppoe variants that
translates the command number and then calls the regular ioctl function.
All other ioctl commands handled by pppoe are compatible between 32-bit
and 64-bit, and require compat_ptr() conversion.
This should apply to all stable kernels.
Acked-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
		
	
			
		
			
				
	
	
		
			159 lines
		
	
	
		
			3.4 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			159 lines
		
	
	
		
			3.4 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| // SPDX-License-Identifier: GPL-2.0-or-later
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| /** -*- linux-c -*- ***********************************************************
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|  * Linux PPP over X/Ethernet (PPPoX/PPPoE) Sockets
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|  *
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|  * PPPoX --- Generic PPP encapsulation socket family
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|  * PPPoE --- PPP over Ethernet (RFC 2516)
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|  *
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|  * Version:	0.5.2
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|  *
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|  * Author:	Michal Ostrowski <mostrows@speakeasy.net>
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|  *
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|  * 051000 :	Initialization cleanup
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|  *
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|  * License:
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|  */
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| 
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| #include <linux/string.h>
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| #include <linux/module.h>
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| #include <linux/kernel.h>
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| #include <linux/compat.h>
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| #include <linux/errno.h>
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| #include <linux/netdevice.h>
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| #include <linux/net.h>
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| #include <linux/init.h>
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| #include <linux/if_pppox.h>
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| #include <linux/ppp_defs.h>
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| #include <linux/ppp-ioctl.h>
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| #include <linux/ppp_channel.h>
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| #include <linux/kmod.h>
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| 
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| #include <net/sock.h>
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| 
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| #include <linux/uaccess.h>
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| 
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| static const struct pppox_proto *pppox_protos[PX_MAX_PROTO + 1];
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| 
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| int register_pppox_proto(int proto_num, const struct pppox_proto *pp)
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| {
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| 	if (proto_num < 0 || proto_num > PX_MAX_PROTO)
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| 		return -EINVAL;
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| 	if (pppox_protos[proto_num])
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| 		return -EALREADY;
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| 	pppox_protos[proto_num] = pp;
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| 	return 0;
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| }
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| 
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| void unregister_pppox_proto(int proto_num)
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| {
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| 	if (proto_num >= 0 && proto_num <= PX_MAX_PROTO)
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| 		pppox_protos[proto_num] = NULL;
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| }
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| 
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| void pppox_unbind_sock(struct sock *sk)
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| {
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| 	/* Clear connection to ppp device, if attached. */
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| 
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| 	if (sk->sk_state & (PPPOX_BOUND | PPPOX_CONNECTED)) {
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| 		ppp_unregister_channel(&pppox_sk(sk)->chan);
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| 		sk->sk_state = PPPOX_DEAD;
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| 	}
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| }
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| 
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| EXPORT_SYMBOL(register_pppox_proto);
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| EXPORT_SYMBOL(unregister_pppox_proto);
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| EXPORT_SYMBOL(pppox_unbind_sock);
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| 
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| int pppox_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
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| {
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| 	struct sock *sk = sock->sk;
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| 	struct pppox_sock *po = pppox_sk(sk);
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| 	int rc;
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| 
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| 	lock_sock(sk);
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| 
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| 	switch (cmd) {
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| 	case PPPIOCGCHAN: {
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| 		int index;
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| 		rc = -ENOTCONN;
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| 		if (!(sk->sk_state & PPPOX_CONNECTED))
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| 			break;
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| 
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| 		rc = -EINVAL;
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| 		index = ppp_channel_index(&po->chan);
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| 		if (put_user(index , (int __user *) arg))
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| 			break;
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| 
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| 		rc = 0;
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| 		sk->sk_state |= PPPOX_BOUND;
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| 		break;
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| 	}
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| 	default:
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| 		rc = pppox_protos[sk->sk_protocol]->ioctl ?
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| 			pppox_protos[sk->sk_protocol]->ioctl(sock, cmd, arg) : -ENOTTY;
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| 	}
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| 
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| 	release_sock(sk);
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| 	return rc;
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| }
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| 
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| EXPORT_SYMBOL(pppox_ioctl);
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| 
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| #ifdef CONFIG_COMPAT
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| int pppox_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
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| {
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| 	if (cmd == PPPOEIOCSFWD32)
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| 		cmd = PPPOEIOCSFWD;
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| 
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| 	return pppox_ioctl(sock, cmd, (unsigned long)compat_ptr(arg));
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| }
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| 
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| EXPORT_SYMBOL(pppox_compat_ioctl);
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| #endif
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| 
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| static int pppox_create(struct net *net, struct socket *sock, int protocol,
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| 			int kern)
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| {
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| 	int rc = -EPROTOTYPE;
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| 
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| 	if (protocol < 0 || protocol > PX_MAX_PROTO)
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| 		goto out;
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| 
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| 	rc = -EPROTONOSUPPORT;
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| 	if (!pppox_protos[protocol])
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| 		request_module("net-pf-%d-proto-%d", PF_PPPOX, protocol);
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| 	if (!pppox_protos[protocol] ||
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| 	    !try_module_get(pppox_protos[protocol]->owner))
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| 		goto out;
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| 
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| 	rc = pppox_protos[protocol]->create(net, sock, kern);
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| 
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| 	module_put(pppox_protos[protocol]->owner);
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| out:
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| 	return rc;
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| }
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| 
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| static const struct net_proto_family pppox_proto_family = {
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| 	.family	= PF_PPPOX,
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| 	.create	= pppox_create,
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| 	.owner	= THIS_MODULE,
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| };
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| 
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| static int __init pppox_init(void)
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| {
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| 	return sock_register(&pppox_proto_family);
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| }
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| 
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| static void __exit pppox_exit(void)
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| {
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| 	sock_unregister(PF_PPPOX);
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| }
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| 
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| module_init(pppox_init);
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| module_exit(pppox_exit);
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| 
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| MODULE_AUTHOR("Michal Ostrowski <mostrows@speakeasy.net>");
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| MODULE_DESCRIPTION("PPP over Ethernet driver (generic socket layer)");
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| MODULE_LICENSE("GPL");
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| MODULE_ALIAS_NETPROTO(PF_PPPOX);
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