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linux/include/net/addrconf.h
Ziyang Xuan 85f0173df3 ipv6/addrconf: fix a null-ptr-deref bug for ip6_ptr 
Change net device's MTU to smaller than IPV6_MIN_MTU or unregister
device while matching route. That may trigger null-ptr-deref bug
for ip6_ptr probability as following.

=========================================================
BUG: KASAN: null-ptr-deref in find_match.part.0+0x70/0x134
Read of size 4 at addr 0000000000000308 by task ping6/263

CPU: 2 PID: 263 Comm: ping6 Not tainted 5.19.0-rc7+ #14
Call trace:
 dump_backtrace+0x1a8/0x230
 show_stack+0x20/0x70
 dump_stack_lvl+0x68/0x84
 print_report+0xc4/0x120
 kasan_report+0x84/0x120
 __asan_load4+0x94/0xd0
 find_match.part.0+0x70/0x134
 __find_rr_leaf+0x408/0x470
 fib6_table_lookup+0x264/0x540
 ip6_pol_route+0xf4/0x260
 ip6_pol_route_output+0x58/0x70
 fib6_rule_lookup+0x1a8/0x330
 ip6_route_output_flags_noref+0xd8/0x1a0
 ip6_route_output_flags+0x58/0x160
 ip6_dst_lookup_tail+0x5b4/0x85c
 ip6_dst_lookup_flow+0x98/0x120
 rawv6_sendmsg+0x49c/0xc70
 inet_sendmsg+0x68/0x94

Reproducer as following:
Firstly, prepare conditions:
$ip netns add ns1
$ip netns add ns2
$ip link add veth1 type veth peer name veth2
$ip link set veth1 netns ns1
$ip link set veth2 netns ns2
$ip netns exec ns1 ip -6 addr add 2001:0db8:0:f101::1/64 dev veth1
$ip netns exec ns2 ip -6 addr add 2001:0db8:0:f101::2/64 dev veth2
$ip netns exec ns1 ifconfig veth1 up
$ip netns exec ns2 ifconfig veth2 up
$ip netns exec ns1 ip -6 route add 2000::/64 dev veth1 metric 1
$ip netns exec ns2 ip -6 route add 2001::/64 dev veth2 metric 1

Secondly, execute the following two commands in two ssh windows
respectively:
$ip netns exec ns1 sh
$while true; do ip -6 addr add 2001:0db8:0:f101::1/64 dev veth1; ip -6 route add 2000::/64 dev veth1 metric 1; ping6 2000::2; done

$ip netns exec ns1 sh
$while true; do ip link set veth1 mtu 1000; ip link set veth1 mtu 1500; sleep 5; done

It is because ip6_ptr has been assigned to NULL in addrconf_ifdown() firstly,
then ip6_ignore_linkdown() accesses ip6_ptr directly without NULL check.

	cpu0			cpu1
fib6_table_lookup
__find_rr_leaf
			addrconf_notify [ NETDEV_CHANGEMTU ]
			addrconf_ifdown
			RCU_INIT_POINTER(dev->ip6_ptr, NULL)
find_match
ip6_ignore_linkdown

So we can add NULL check for ip6_ptr before using in ip6_ignore_linkdown() to
fix the null-ptr-deref bug.

Fixes: dcd1f57295 ("net/ipv6: Remove fib6_idev")
Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20220728013307.656257-1-william.xuanziyang@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-07-28 10:42:44 -07:00

510 lines
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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ADDRCONF_H
#define _ADDRCONF_H
#define MAX_RTR_SOLICITATIONS -1 /* unlimited */
#define RTR_SOLICITATION_INTERVAL (4*HZ)
#define RTR_SOLICITATION_MAX_INTERVAL (3600*HZ) /* 1 hour */
#define MIN_VALID_LIFETIME (2*3600) /* 2 hours */
#define TEMP_VALID_LIFETIME (7*86400)
#define TEMP_PREFERRED_LIFETIME (86400)
#define REGEN_MAX_RETRY (3)
#define MAX_DESYNC_FACTOR (600)
#define ADDR_CHECK_FREQUENCY (120*HZ)
#define IPV6_MAX_ADDRESSES 16
#define ADDRCONF_TIMER_FUZZ_MINUS (HZ > 50 ? HZ / 50 : 1)
#define ADDRCONF_TIMER_FUZZ (HZ / 4)
#define ADDRCONF_TIMER_FUZZ_MAX (HZ)
#define ADDRCONF_NOTIFY_PRIORITY 0
#include <linux/in.h>
#include <linux/in6.h>
struct prefix_info {
__u8 type;
__u8 length;
__u8 prefix_len;
#if defined(__BIG_ENDIAN_BITFIELD)
__u8 onlink : 1,
autoconf : 1,
reserved : 6;
#elif defined(__LITTLE_ENDIAN_BITFIELD)
__u8 reserved : 6,
autoconf : 1,
onlink : 1;
#else
#error "Please fix <asm/byteorder.h>"
#endif
__be32 valid;
__be32 prefered;
__be32 reserved2;
struct in6_addr prefix;
};
#include <linux/ipv6.h>
#include <linux/netdevice.h>
#include <net/if_inet6.h>
#include <net/ipv6.h>
struct in6_validator_info {
struct in6_addr i6vi_addr;
struct inet6_dev *i6vi_dev;
struct netlink_ext_ack *extack;
};
struct ifa6_config {
const struct in6_addr *pfx;
unsigned int plen;
u8 ifa_proto;
const struct in6_addr *peer_pfx;
u32 rt_priority;
u32 ifa_flags;
u32 preferred_lft;
u32 valid_lft;
u16 scope;
};
int addrconf_init(void);
void addrconf_cleanup(void);
int addrconf_add_ifaddr(struct net *net, void __user *arg);
int addrconf_del_ifaddr(struct net *net, void __user *arg);
int addrconf_set_dstaddr(struct net *net, void __user *arg);
int ipv6_chk_addr(struct net *net, const struct in6_addr *addr,
const struct net_device *dev, int strict);
int ipv6_chk_addr_and_flags(struct net *net, const struct in6_addr *addr,
const struct net_device *dev, bool skip_dev_check,
int strict, u32 banned_flags);
#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
int ipv6_chk_home_addr(struct net *net, const struct in6_addr *addr);
#endif
int ipv6_chk_rpl_srh_loop(struct net *net, const struct in6_addr *segs,
unsigned char nsegs);
bool ipv6_chk_custom_prefix(const struct in6_addr *addr,
const unsigned int prefix_len,
struct net_device *dev);
int ipv6_chk_prefix(const struct in6_addr *addr, struct net_device *dev);
struct net_device *ipv6_dev_find(struct net *net, const struct in6_addr *addr,
struct net_device *dev);
struct inet6_ifaddr *ipv6_get_ifaddr(struct net *net,
const struct in6_addr *addr,
struct net_device *dev, int strict);
int ipv6_dev_get_saddr(struct net *net, const struct net_device *dev,
const struct in6_addr *daddr, unsigned int srcprefs,
struct in6_addr *saddr);
int ipv6_get_lladdr(struct net_device *dev, struct in6_addr *addr,
u32 banned_flags);
bool inet_rcv_saddr_equal(const struct sock *sk, const struct sock *sk2,
bool match_wildcard);
bool inet_rcv_saddr_any(const struct sock *sk);
void addrconf_join_solict(struct net_device *dev, const struct in6_addr *addr);
void addrconf_leave_solict(struct inet6_dev *idev, const struct in6_addr *addr);
void addrconf_add_linklocal(struct inet6_dev *idev,
const struct in6_addr *addr, u32 flags);
int addrconf_prefix_rcv_add_addr(struct net *net, struct net_device *dev,
const struct prefix_info *pinfo,
struct inet6_dev *in6_dev,
const struct in6_addr *addr, int addr_type,
u32 addr_flags, bool sllao, bool tokenized,
__u32 valid_lft, u32 prefered_lft);
static inline void addrconf_addr_eui48_base(u8 *eui, const char *const addr)
{
memcpy(eui, addr, 3);
eui[3] = 0xFF;
eui[4] = 0xFE;
memcpy(eui + 5, addr + 3, 3);
}
static inline void addrconf_addr_eui48(u8 *eui, const char *const addr)
{
addrconf_addr_eui48_base(eui, addr);
eui[0] ^= 2;
}
static inline int addrconf_ifid_eui48(u8 *eui, struct net_device *dev)
{
if (dev->addr_len != ETH_ALEN)
return -1;
/*
* The zSeries OSA network cards can be shared among various
* OS instances, but the OSA cards have only one MAC address.
* This leads to duplicate address conflicts in conjunction
* with IPv6 if more than one instance uses the same card.
*
* The driver for these cards can deliver a unique 16-bit
* identifier for each instance sharing the same card. It is
* placed instead of 0xFFFE in the interface identifier. The
* "u" bit of the interface identifier is not inverted in this
* case. Hence the resulting interface identifier has local
* scope according to RFC2373.
*/
addrconf_addr_eui48_base(eui, dev->dev_addr);
if (dev->dev_id) {
eui[3] = (dev->dev_id >> 8) & 0xFF;
eui[4] = dev->dev_id & 0xFF;
} else {
eui[0] ^= 2;
}
return 0;
}
static inline unsigned long addrconf_timeout_fixup(u32 timeout,
unsigned int unit)
{
if (timeout == 0xffffffff)
return ~0UL;
/*
* Avoid arithmetic overflow.
* Assuming unit is constant and non-zero, this "if" statement
* will go away on 64bit archs.
*/
if (0xfffffffe > LONG_MAX / unit && timeout > LONG_MAX / unit)
return LONG_MAX / unit;
return timeout;
}
static inline int addrconf_finite_timeout(unsigned long timeout)
{
return ~timeout;
}
/*
* IPv6 Address Label subsystem (addrlabel.c)
*/
int ipv6_addr_label_init(void);
void ipv6_addr_label_cleanup(void);
int ipv6_addr_label_rtnl_register(void);
u32 ipv6_addr_label(struct net *net, const struct in6_addr *addr,
int type, int ifindex);
/*
* multicast prototypes (mcast.c)
*/
static inline bool ipv6_mc_may_pull(struct sk_buff *skb,
unsigned int len)
{
if (skb_transport_offset(skb) + ipv6_transport_len(skb) < len)
return false;
return pskb_may_pull(skb, len);
}
int ipv6_sock_mc_join(struct sock *sk, int ifindex,
const struct in6_addr *addr);
int ipv6_sock_mc_drop(struct sock *sk, int ifindex,
const struct in6_addr *addr);
void __ipv6_sock_mc_close(struct sock *sk);
void ipv6_sock_mc_close(struct sock *sk);
bool inet6_mc_check(struct sock *sk, const struct in6_addr *mc_addr,
const struct in6_addr *src_addr);
int ipv6_dev_mc_inc(struct net_device *dev, const struct in6_addr *addr);
int __ipv6_dev_mc_dec(struct inet6_dev *idev, const struct in6_addr *addr);
int ipv6_dev_mc_dec(struct net_device *dev, const struct in6_addr *addr);
void ipv6_mc_up(struct inet6_dev *idev);
void ipv6_mc_down(struct inet6_dev *idev);
void ipv6_mc_unmap(struct inet6_dev *idev);
void ipv6_mc_remap(struct inet6_dev *idev);
void ipv6_mc_init_dev(struct inet6_dev *idev);
void ipv6_mc_destroy_dev(struct inet6_dev *idev);
int ipv6_mc_check_mld(struct sk_buff *skb);
void addrconf_dad_failure(struct sk_buff *skb, struct inet6_ifaddr *ifp);
bool ipv6_chk_mcast_addr(struct net_device *dev, const struct in6_addr *group,
const struct in6_addr *src_addr);
void ipv6_mc_dad_complete(struct inet6_dev *idev);
/*
* identify MLD packets for MLD filter exceptions
*/
static inline bool ipv6_is_mld(struct sk_buff *skb, int nexthdr, int offset)
{
struct icmp6hdr *hdr;
if (nexthdr != IPPROTO_ICMPV6 ||
!pskb_network_may_pull(skb, offset + sizeof(struct icmp6hdr)))
return false;
hdr = (struct icmp6hdr *)(skb_network_header(skb) + offset);
switch (hdr->icmp6_type) {
case ICMPV6_MGM_QUERY:
case ICMPV6_MGM_REPORT:
case ICMPV6_MGM_REDUCTION:
case ICMPV6_MLD2_REPORT:
return true;
default:
break;
}
return false;
}
void addrconf_prefix_rcv(struct net_device *dev,
u8 *opt, int len, bool sllao);
/*
* anycast prototypes (anycast.c)
*/
int ipv6_sock_ac_join(struct sock *sk, int ifindex,
const struct in6_addr *addr);
int ipv6_sock_ac_drop(struct sock *sk, int ifindex,
const struct in6_addr *addr);
void __ipv6_sock_ac_close(struct sock *sk);
void ipv6_sock_ac_close(struct sock *sk);
int __ipv6_dev_ac_inc(struct inet6_dev *idev, const struct in6_addr *addr);
int __ipv6_dev_ac_dec(struct inet6_dev *idev, const struct in6_addr *addr);
void ipv6_ac_destroy_dev(struct inet6_dev *idev);
bool ipv6_chk_acast_addr(struct net *net, struct net_device *dev,
const struct in6_addr *addr);
bool ipv6_chk_acast_addr_src(struct net *net, struct net_device *dev,
const struct in6_addr *addr);
int ipv6_anycast_init(void);
void ipv6_anycast_cleanup(void);
/* Device notifier */
int register_inet6addr_notifier(struct notifier_block *nb);
int unregister_inet6addr_notifier(struct notifier_block *nb);
int inet6addr_notifier_call_chain(unsigned long val, void *v);
int register_inet6addr_validator_notifier(struct notifier_block *nb);
int unregister_inet6addr_validator_notifier(struct notifier_block *nb);
int inet6addr_validator_notifier_call_chain(unsigned long val, void *v);
void inet6_netconf_notify_devconf(struct net *net, int event, int type,
int ifindex, struct ipv6_devconf *devconf);
/**
* __in6_dev_get - get inet6_dev pointer from netdevice
* @dev: network device
*
* Caller must hold rcu_read_lock or RTNL, because this function
* does not take a reference on the inet6_dev.
*/
static inline struct inet6_dev *__in6_dev_get(const struct net_device *dev)
{
return rcu_dereference_rtnl(dev->ip6_ptr);
}
/**
* __in6_dev_stats_get - get inet6_dev pointer for stats
* @dev: network device
* @skb: skb for original incoming interface if neeeded
*
* Caller must hold rcu_read_lock or RTNL, because this function
* does not take a reference on the inet6_dev.
*/
static inline struct inet6_dev *__in6_dev_stats_get(const struct net_device *dev,
const struct sk_buff *skb)
{
if (netif_is_l3_master(dev))
dev = dev_get_by_index_rcu(dev_net(dev), inet6_iif(skb));
return __in6_dev_get(dev);
}
/**
* __in6_dev_get_safely - get inet6_dev pointer from netdevice
* @dev: network device
*
* This is a safer version of __in6_dev_get
*/
static inline struct inet6_dev *__in6_dev_get_safely(const struct net_device *dev)
{
if (likely(dev))
return rcu_dereference_rtnl(dev->ip6_ptr);
else
return NULL;
}
/**
* in6_dev_get - get inet6_dev pointer from netdevice
* @dev: network device
*
* This version can be used in any context, and takes a reference
* on the inet6_dev. Callers must use in6_dev_put() later to
* release this reference.
*/
static inline struct inet6_dev *in6_dev_get(const struct net_device *dev)
{
struct inet6_dev *idev;
rcu_read_lock();
idev = rcu_dereference(dev->ip6_ptr);
if (idev)
refcount_inc(&idev->refcnt);
rcu_read_unlock();
return idev;
}
static inline struct neigh_parms *__in6_dev_nd_parms_get_rcu(const struct net_device *dev)
{
struct inet6_dev *idev = __in6_dev_get(dev);
return idev ? idev->nd_parms : NULL;
}
void in6_dev_finish_destroy(struct inet6_dev *idev);
static inline void in6_dev_put(struct inet6_dev *idev)
{
if (refcount_dec_and_test(&idev->refcnt))
in6_dev_finish_destroy(idev);
}
static inline void in6_dev_put_clear(struct inet6_dev **pidev)
{
struct inet6_dev *idev = *pidev;
if (idev) {
in6_dev_put(idev);
*pidev = NULL;
}
}
static inline void __in6_dev_put(struct inet6_dev *idev)
{
refcount_dec(&idev->refcnt);
}
static inline void in6_dev_hold(struct inet6_dev *idev)
{
refcount_inc(&idev->refcnt);
}
/* called with rcu_read_lock held */
static inline bool ip6_ignore_linkdown(const struct net_device *dev)
{
const struct inet6_dev *idev = __in6_dev_get(dev);
if (unlikely(!idev))
return true;
return !!idev->cnf.ignore_routes_with_linkdown;
}
void inet6_ifa_finish_destroy(struct inet6_ifaddr *ifp);
static inline void in6_ifa_put(struct inet6_ifaddr *ifp)
{
if (refcount_dec_and_test(&ifp->refcnt))
inet6_ifa_finish_destroy(ifp);
}
static inline void __in6_ifa_put(struct inet6_ifaddr *ifp)
{
refcount_dec(&ifp->refcnt);
}
static inline void in6_ifa_hold(struct inet6_ifaddr *ifp)
{
refcount_inc(&ifp->refcnt);
}
/*
* compute link-local solicited-node multicast address
*/
static inline void addrconf_addr_solict_mult(const struct in6_addr *addr,
struct in6_addr *solicited)
{
ipv6_addr_set(solicited,
htonl(0xFF020000), 0,
htonl(0x1),
htonl(0xFF000000) | addr->s6_addr32[3]);
}
static inline bool ipv6_addr_is_ll_all_nodes(const struct in6_addr *addr)
{
#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
__be64 *p = (__force __be64 *)addr;
return ((p[0] ^ cpu_to_be64(0xff02000000000000UL)) | (p[1] ^ cpu_to_be64(1))) == 0UL;
#else
return ((addr->s6_addr32[0] ^ htonl(0xff020000)) |
addr->s6_addr32[1] | addr->s6_addr32[2] |
(addr->s6_addr32[3] ^ htonl(0x00000001))) == 0;
#endif
}
static inline bool ipv6_addr_is_ll_all_routers(const struct in6_addr *addr)
{
#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
__be64 *p = (__force __be64 *)addr;
return ((p[0] ^ cpu_to_be64(0xff02000000000000UL)) | (p[1] ^ cpu_to_be64(2))) == 0UL;
#else
return ((addr->s6_addr32[0] ^ htonl(0xff020000)) |
addr->s6_addr32[1] | addr->s6_addr32[2] |
(addr->s6_addr32[3] ^ htonl(0x00000002))) == 0;
#endif
}
static inline bool ipv6_addr_is_isatap(const struct in6_addr *addr)
{
return (addr->s6_addr32[2] | htonl(0x02000000)) == htonl(0x02005EFE);
}
static inline bool ipv6_addr_is_solict_mult(const struct in6_addr *addr)
{
#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
__be64 *p = (__force __be64 *)addr;
return ((p[0] ^ cpu_to_be64(0xff02000000000000UL)) |
((p[1] ^ cpu_to_be64(0x00000001ff000000UL)) &
cpu_to_be64(0xffffffffff000000UL))) == 0UL;
#else
return ((addr->s6_addr32[0] ^ htonl(0xff020000)) |
addr->s6_addr32[1] |
(addr->s6_addr32[2] ^ htonl(0x00000001)) |
(addr->s6_addr[12] ^ 0xff)) == 0;
#endif
}
static inline bool ipv6_addr_is_all_snoopers(const struct in6_addr *addr)
{
#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
__be64 *p = (__force __be64 *)addr;
return ((p[0] ^ cpu_to_be64(0xff02000000000000UL)) |
(p[1] ^ cpu_to_be64(0x6a))) == 0UL;
#else
return ((addr->s6_addr32[0] ^ htonl(0xff020000)) |
addr->s6_addr32[1] | addr->s6_addr32[2] |
(addr->s6_addr32[3] ^ htonl(0x0000006a))) == 0;
#endif
}
#ifdef CONFIG_PROC_FS
int if6_proc_init(void);
void if6_proc_exit(void);
#endif
#endif
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