freebsd-dev/sys/netinet6/scope6.c
Gleb Smirnoff d74b7baeb0 ifnet_byindex() actually requires network epoch
Sweep over potentially unsafe calls to ifnet_byindex() and wrap them
in epoch.  Most of the code touched remains unsafe, as the returned
pointer is being used after epoch exit.  Mark that with a comment.

Validate the index argument inside the function, reducing argument
validation requirement from the callers and making V_if_index
private to if.c.

Reviewed by:		melifaro
Differential revision:	https://reviews.freebsd.org/D33263
2021-12-06 09:32:31 -08:00

611 lines
15 KiB
C

/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (C) 2000 WIDE Project.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the project nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $KAME: scope6.c,v 1.10 2000/07/24 13:29:31 itojun Exp $
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/systm.h>
#include <sys/queue.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <net/if.h>
#include <net/if_var.h>
#include <net/vnet.h>
#include <netinet/in.h>
#include <netinet/ip6.h>
#include <netinet6/in6_var.h>
#include <netinet6/ip6_var.h>
#include <netinet6/scope6_var.h>
#ifdef ENABLE_DEFAULT_SCOPE
VNET_DEFINE(int, ip6_use_defzone) = 1;
#else
VNET_DEFINE(int, ip6_use_defzone) = 0;
#endif
SYSCTL_DECL(_net_inet6_ip6);
/*
* The scope6_lock protects the global sid default stored in
* sid_default below.
*/
static struct mtx scope6_lock;
#define SCOPE6_LOCK_INIT() mtx_init(&scope6_lock, "scope6_lock", NULL, MTX_DEF)
#define SCOPE6_LOCK() mtx_lock(&scope6_lock)
#define SCOPE6_UNLOCK() mtx_unlock(&scope6_lock)
#define SCOPE6_LOCK_ASSERT() mtx_assert(&scope6_lock, MA_OWNED)
VNET_DEFINE_STATIC(struct scope6_id, sid_default);
#define V_sid_default VNET(sid_default)
#define SID(ifp) \
(((struct in6_ifextra *)(ifp)->if_afdata[AF_INET6])->scope6_id)
static int scope6_get(struct ifnet *, struct scope6_id *);
static int scope6_set(struct ifnet *, struct scope6_id *);
void
scope6_init(void)
{
bzero(&V_sid_default, sizeof(V_sid_default));
if (!IS_DEFAULT_VNET(curvnet))
return;
SCOPE6_LOCK_INIT();
}
struct scope6_id *
scope6_ifattach(struct ifnet *ifp)
{
struct scope6_id *sid;
sid = malloc(sizeof(*sid), M_IFADDR, M_WAITOK | M_ZERO);
/*
* XXX: IPV6_ADDR_SCOPE_xxx macros are not standard.
* Should we rather hardcode here?
*/
sid->s6id_list[IPV6_ADDR_SCOPE_INTFACELOCAL] = ifp->if_index;
sid->s6id_list[IPV6_ADDR_SCOPE_LINKLOCAL] = ifp->if_index;
return (sid);
}
void
scope6_ifdetach(struct scope6_id *sid)
{
free(sid, M_IFADDR);
}
int
scope6_ioctl(u_long cmd, caddr_t data, struct ifnet *ifp)
{
struct in6_ifreq *ifr;
if (ifp->if_afdata[AF_INET6] == NULL)
return (EPFNOSUPPORT);
ifr = (struct in6_ifreq *)data;
switch (cmd) {
case SIOCSSCOPE6:
return (scope6_set(ifp,
(struct scope6_id *)ifr->ifr_ifru.ifru_scope_id));
case SIOCGSCOPE6:
return (scope6_get(ifp,
(struct scope6_id *)ifr->ifr_ifru.ifru_scope_id));
case SIOCGSCOPE6DEF:
return (scope6_get_default(
(struct scope6_id *)ifr->ifr_ifru.ifru_scope_id));
default:
return (EOPNOTSUPP);
}
}
static int
scope6_set(struct ifnet *ifp, struct scope6_id *idlist)
{
int i;
int error = 0;
struct scope6_id *sid = NULL;
IF_AFDATA_WLOCK(ifp);
sid = SID(ifp);
if (!sid) { /* paranoid? */
IF_AFDATA_WUNLOCK(ifp);
return (EINVAL);
}
/*
* XXX: We need more consistency checks of the relationship among
* scopes (e.g. an organization should be larger than a site).
*/
/*
* TODO(XXX): after setting, we should reflect the changes to
* interface addresses, routing table entries, PCB entries...
*/
for (i = 0; i < 16; i++) {
if (idlist->s6id_list[i] &&
idlist->s6id_list[i] != sid->s6id_list[i]) {
/*
* An interface zone ID must be the corresponding
* interface index by definition.
*/
if (i == IPV6_ADDR_SCOPE_INTFACELOCAL &&
idlist->s6id_list[i] != ifp->if_index) {
IF_AFDATA_WUNLOCK(ifp);
return (EINVAL);
}
if (i == IPV6_ADDR_SCOPE_LINKLOCAL) {
struct epoch_tracker et;
NET_EPOCH_ENTER(et);
if (!ifnet_byindex(idlist->s6id_list[i])) {
/*
* XXX: theoretically, there should be
* no relationship between link IDs and
* interface IDs, but we check the
* consistency for safety in later use.
*/
NET_EPOCH_EXIT(et);
IF_AFDATA_WUNLOCK(ifp);
return (EINVAL);
}
NET_EPOCH_EXIT(et);
}
/*
* XXX: we must need lots of work in this case,
* but we simply set the new value in this initial
* implementation.
*/
sid->s6id_list[i] = idlist->s6id_list[i];
}
}
IF_AFDATA_WUNLOCK(ifp);
return (error);
}
static int
scope6_get(struct ifnet *ifp, struct scope6_id *idlist)
{
struct epoch_tracker et;
struct scope6_id *sid;
/* We only need to lock the interface's afdata for SID() to work. */
NET_EPOCH_ENTER(et);
sid = SID(ifp);
if (sid == NULL) { /* paranoid? */
NET_EPOCH_EXIT(et);
return (EINVAL);
}
*idlist = *sid;
NET_EPOCH_EXIT(et);
return (0);
}
/*
* Get a scope of the address. Node-local, link-local, site-local or global.
*/
int
in6_addrscope(const struct in6_addr *addr)
{
if (IN6_IS_ADDR_MULTICAST(addr)) {
/*
* Addresses with reserved value F must be treated as
* global multicast addresses.
*/
if (IPV6_ADDR_MC_SCOPE(addr) == 0x0f)
return (IPV6_ADDR_SCOPE_GLOBAL);
return (IPV6_ADDR_MC_SCOPE(addr));
}
if (IN6_IS_ADDR_LINKLOCAL(addr) ||
IN6_IS_ADDR_LOOPBACK(addr))
return (IPV6_ADDR_SCOPE_LINKLOCAL);
if (IN6_IS_ADDR_SITELOCAL(addr))
return (IPV6_ADDR_SCOPE_SITELOCAL);
return (IPV6_ADDR_SCOPE_GLOBAL);
}
/*
* ifp - note that this might be NULL
*/
void
scope6_setdefault(struct ifnet *ifp)
{
/*
* Currently, this function just sets the default "interfaces"
* and "links" according to the given interface.
* We might eventually have to separate the notion of "link" from
* "interface" and provide a user interface to set the default.
*/
SCOPE6_LOCK();
if (ifp) {
V_sid_default.s6id_list[IPV6_ADDR_SCOPE_INTFACELOCAL] =
ifp->if_index;
V_sid_default.s6id_list[IPV6_ADDR_SCOPE_LINKLOCAL] =
ifp->if_index;
} else {
V_sid_default.s6id_list[IPV6_ADDR_SCOPE_INTFACELOCAL] = 0;
V_sid_default.s6id_list[IPV6_ADDR_SCOPE_LINKLOCAL] = 0;
}
SCOPE6_UNLOCK();
}
int
scope6_get_default(struct scope6_id *idlist)
{
SCOPE6_LOCK();
*idlist = V_sid_default;
SCOPE6_UNLOCK();
return (0);
}
u_int32_t
scope6_addr2default(struct in6_addr *addr)
{
u_int32_t id;
/*
* special case: The loopback address should be considered as
* link-local, but there's no ambiguity in the syntax.
*/
if (IN6_IS_ADDR_LOOPBACK(addr))
return (0);
/*
* XXX: 32-bit read is atomic on all our platforms, is it OK
* not to lock here?
*/
SCOPE6_LOCK();
id = V_sid_default.s6id_list[in6_addrscope(addr)];
SCOPE6_UNLOCK();
return (id);
}
/*
* Validate the specified scope zone ID in the sin6_scope_id field. If the ID
* is unspecified (=0), needs to be specified, and the default zone ID can be
* used, the default value will be used.
* This routine then generates the kernel-internal form: if the address scope
* of is interface-local or link-local, embed the interface index in the
* address.
*/
int
sa6_embedscope(struct sockaddr_in6 *sin6, int defaultok)
{
u_int32_t zoneid;
if ((zoneid = sin6->sin6_scope_id) == 0 && defaultok)
zoneid = scope6_addr2default(&sin6->sin6_addr);
if (zoneid != 0 &&
(IN6_IS_SCOPE_LINKLOCAL(&sin6->sin6_addr) ||
IN6_IS_ADDR_MC_INTFACELOCAL(&sin6->sin6_addr))) {
struct epoch_tracker et;
/*
* At this moment, we only check interface-local and
* link-local scope IDs, and use interface indices as the
* zone IDs assuming a one-to-one mapping between interfaces
* and links.
*/
NET_EPOCH_ENTER(et);
if (ifnet_byindex(zoneid) == NULL) {
NET_EPOCH_EXIT(et);
return (ENXIO);
}
NET_EPOCH_EXIT(et);
/* XXX assignment to 16bit from 32bit variable */
sin6->sin6_addr.s6_addr16[1] = htons(zoneid & 0xffff);
sin6->sin6_scope_id = 0;
}
return 0;
}
/*
* generate standard sockaddr_in6 from embedded form.
*/
int
sa6_recoverscope(struct sockaddr_in6 *sin6)
{
char ip6buf[INET6_ADDRSTRLEN];
u_int32_t zoneid;
if (IN6_IS_SCOPE_LINKLOCAL(&sin6->sin6_addr) ||
IN6_IS_ADDR_MC_INTFACELOCAL(&sin6->sin6_addr)) {
/*
* KAME assumption: link id == interface id
*/
zoneid = ntohs(sin6->sin6_addr.s6_addr16[1]);
if (zoneid) {
struct epoch_tracker et;
NET_EPOCH_ENTER(et);
/* sanity check */
if (!ifnet_byindex(zoneid)) {
NET_EPOCH_EXIT(et);
return (ENXIO);
}
NET_EPOCH_EXIT(et);
if (sin6->sin6_scope_id != 0 &&
zoneid != sin6->sin6_scope_id) {
log(LOG_NOTICE,
"%s: embedded scope mismatch: %s%%%d. "
"sin6_scope_id was overridden\n", __func__,
ip6_sprintf(ip6buf, &sin6->sin6_addr),
sin6->sin6_scope_id);
}
sin6->sin6_addr.s6_addr16[1] = 0;
sin6->sin6_scope_id = zoneid;
}
}
return 0;
}
/*
* Determine the appropriate scope zone ID for in6 and ifp. If ret_id is
* non NULL, it is set to the zone ID. If the zone ID needs to be embedded
* in the in6_addr structure, in6 will be modified.
*
* ret_id - unnecessary?
*/
int
in6_setscope(struct in6_addr *in6, struct ifnet *ifp, u_int32_t *ret_id)
{
int scope;
u_int32_t zoneid = 0;
struct scope6_id *sid;
/*
* special case: the loopback address can only belong to a loopback
* interface.
*/
if (IN6_IS_ADDR_LOOPBACK(in6)) {
if (!(ifp->if_flags & IFF_LOOPBACK))
return (EINVAL);
} else {
scope = in6_addrscope(in6);
if (scope == IPV6_ADDR_SCOPE_INTFACELOCAL ||
scope == IPV6_ADDR_SCOPE_LINKLOCAL) {
/*
* Currently we use interface indices as the
* zone IDs for interface-local and link-local
* scopes.
*/
zoneid = ifp->if_index;
in6->s6_addr16[1] = htons(zoneid & 0xffff); /* XXX */
} else if (scope != IPV6_ADDR_SCOPE_GLOBAL) {
struct epoch_tracker et;
NET_EPOCH_ENTER(et);
if (ifp->if_afdata[AF_INET6] == NULL) {
NET_EPOCH_EXIT(et);
return (ENETDOWN);
}
sid = SID(ifp);
zoneid = sid->s6id_list[scope];
NET_EPOCH_EXIT(et);
}
}
if (ret_id != NULL)
*ret_id = zoneid;
return (0);
}
/*
* Just clear the embedded scope identifier. Return 0 if the original address
* is intact; return non 0 if the address is modified.
*/
int
in6_clearscope(struct in6_addr *in6)
{
int modified = 0;
if (IN6_IS_SCOPE_LINKLOCAL(in6) || IN6_IS_ADDR_MC_INTFACELOCAL(in6)) {
if (in6->s6_addr16[1] != 0)
modified = 1;
in6->s6_addr16[1] = 0;
}
return (modified);
}
/*
* Return the scope identifier or zero.
*/
uint16_t
in6_getscope(const struct in6_addr *in6)
{
if (IN6_IS_SCOPE_LINKLOCAL(in6) || IN6_IS_ADDR_MC_INTFACELOCAL(in6))
return (in6->s6_addr16[1]);
return (0);
}
/*
* Returns scope zone id for the unicast address @in6.
*
* Returns 0 for global unicast and loopback addresses.
* Returns interface index for the link-local addresses.
*/
uint32_t
in6_get_unicast_scopeid(const struct in6_addr *in6, const struct ifnet *ifp)
{
if (IN6_IS_SCOPE_LINKLOCAL(in6))
return (ifp->if_index);
return (0);
}
void
in6_set_unicast_scopeid(struct in6_addr *in6, uint32_t scopeid)
{
in6->s6_addr16[1] = htons(scopeid & 0xffff);
}
/*
* Return pointer to ifnet structure, corresponding to the zone id of
* link-local scope.
*/
struct ifnet*
in6_getlinkifnet(uint32_t zoneid)
{
return (ifnet_byindex((u_short)zoneid));
}
/*
* Return zone id for the specified scope.
*/
uint32_t
in6_getscopezone(const struct ifnet *ifp, int scope)
{
if (scope == IPV6_ADDR_SCOPE_INTFACELOCAL ||
scope == IPV6_ADDR_SCOPE_LINKLOCAL)
return (ifp->if_index);
if (scope >= 0 && scope < IPV6_ADDR_SCOPES_COUNT)
return (SID(ifp)->s6id_list[scope]);
return (0);
}
/*
* Extracts scope from adddress @dst, stores cleared address
* inside @dst and zone inside @scopeid
*/
void
in6_splitscope(const struct in6_addr *src, struct in6_addr *dst,
uint32_t *scopeid)
{
uint32_t zoneid;
*dst = *src;
zoneid = ntohs(in6_getscope(dst));
in6_clearscope(dst);
*scopeid = zoneid;
}
/*
* This function is for checking sockaddr_in6 structure passed
* from the application level (usually).
*
* sin6_scope_id should be set for link-local unicast, link-local and
* interface-local multicast addresses.
*
* If it is zero, then look into default zone ids. If default zone id is
* not set or disabled, then return error.
*/
int
sa6_checkzone(struct sockaddr_in6 *sa6)
{
int scope;
scope = in6_addrscope(&sa6->sin6_addr);
if (scope == IPV6_ADDR_SCOPE_GLOBAL)
return (sa6->sin6_scope_id ? EINVAL: 0);
if (IN6_IS_ADDR_MULTICAST(&sa6->sin6_addr) &&
scope != IPV6_ADDR_SCOPE_LINKLOCAL &&
scope != IPV6_ADDR_SCOPE_INTFACELOCAL) {
if (sa6->sin6_scope_id == 0 && V_ip6_use_defzone != 0)
sa6->sin6_scope_id = V_sid_default.s6id_list[scope];
return (0);
}
/*
* Since ::1 address always configured on the lo0, we can
* automatically set its zone id, when it is not specified.
* Return error, when specified zone id doesn't match with
* actual value.
*/
if (IN6_IS_ADDR_LOOPBACK(&sa6->sin6_addr)) {
if (sa6->sin6_scope_id == 0)
sa6->sin6_scope_id = in6_getscopezone(V_loif, scope);
else if (sa6->sin6_scope_id != in6_getscopezone(V_loif, scope))
return (EADDRNOTAVAIL);
}
/* XXX: we can validate sin6_scope_id here */
if (sa6->sin6_scope_id != 0)
return (0);
if (V_ip6_use_defzone != 0)
sa6->sin6_scope_id = V_sid_default.s6id_list[scope];
/* Return error if we can't determine zone id */
return (sa6->sin6_scope_id ? 0: EADDRNOTAVAIL);
}
/*
* This function is similar to sa6_checkzone, but it uses given ifp
* to initialize sin6_scope_id.
*/
int
sa6_checkzone_ifp(struct ifnet *ifp, struct sockaddr_in6 *sa6)
{
int scope;
scope = in6_addrscope(&sa6->sin6_addr);
if (scope == IPV6_ADDR_SCOPE_LINKLOCAL ||
scope == IPV6_ADDR_SCOPE_INTFACELOCAL) {
if (sa6->sin6_scope_id == 0) {
sa6->sin6_scope_id = in6_getscopezone(ifp, scope);
return (0);
} else if (sa6->sin6_scope_id != in6_getscopezone(ifp, scope))
return (EADDRNOTAVAIL);
}
return (sa6_checkzone(sa6));
}