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cb9f1b7838
linux/include/net/ip_tunnels.h
Willem de Bruijn cb9f1b7838 ip: validate header length on virtual device xmit 
KMSAN detected read beyond end of buffer in vti and sit devices when
passing truncated packets with PF_PACKET. The issue affects additional
ip tunnel devices.

Extend commit 76c0ddd8c3 ("ip6_tunnel: be careful when accessing the
inner header") and commit ccfec9e5cb ("ip_tunnel: be careful when
accessing the inner header").

Move the check to a separate helper and call at the start of each
ndo_start_xmit function in net/ipv4 and net/ipv6.

Minor changes:
- convert dev_kfree_skb to kfree_skb on error path,
  as dev_kfree_skb calls consume_skb which is not for error paths.
- use pskb_network_may_pull even though that is pedantic here,
  as the same as pskb_may_pull for devices without llheaders.
- do not cache ipv6 hdrs if used only once
  (unsafe across pskb_may_pull, was more relevant to earlier patch)

Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-01-01 12:05:02 -08:00

528 lines
13 KiB
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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __NET_IP_TUNNELS_H
#define __NET_IP_TUNNELS_H 1
#include <linux/if_tunnel.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/socket.h>
#include <linux/types.h>
#include <linux/u64_stats_sync.h>
#include <linux/bitops.h>
#include <net/dsfield.h>
#include <net/gro_cells.h>
#include <net/inet_ecn.h>
#include <net/netns/generic.h>
#include <net/rtnetlink.h>
#include <net/lwtunnel.h>
#include <net/dst_cache.h>
#if IS_ENABLED(CONFIG_IPV6)
#include <net/ipv6.h>
#include <net/ip6_fib.h>
#include <net/ip6_route.h>
#endif
/* Keep error state on tunnel for 30 sec */
#define IPTUNNEL_ERR_TIMEO (30*HZ)
/* Used to memset ip_tunnel padding. */
#define IP_TUNNEL_KEY_SIZE offsetofend(struct ip_tunnel_key, tp_dst)
/* Used to memset ipv4 address padding. */
#define IP_TUNNEL_KEY_IPV4_PAD offsetofend(struct ip_tunnel_key, u.ipv4.dst)
#define IP_TUNNEL_KEY_IPV4_PAD_LEN \
(FIELD_SIZEOF(struct ip_tunnel_key, u) - \
FIELD_SIZEOF(struct ip_tunnel_key, u.ipv4))
struct ip_tunnel_key {
__be64 tun_id;
union {
struct {
__be32 src;
__be32 dst;
} ipv4;
struct {
struct in6_addr src;
struct in6_addr dst;
} ipv6;
} u;
__be16 tun_flags;
u8 tos; /* TOS for IPv4, TC for IPv6 */
u8 ttl; /* TTL for IPv4, HL for IPv6 */
__be32 label; /* Flow Label for IPv6 */
__be16 tp_src;
__be16 tp_dst;
};
/* Flags for ip_tunnel_info mode. */
#define IP_TUNNEL_INFO_TX 0x01 /* represents tx tunnel parameters */
#define IP_TUNNEL_INFO_IPV6 0x02 /* key contains IPv6 addresses */
#define IP_TUNNEL_INFO_BRIDGE 0x04 /* represents a bridged tunnel id */
/* Maximum tunnel options length. */
#define IP_TUNNEL_OPTS_MAX \
GENMASK((FIELD_SIZEOF(struct ip_tunnel_info, \
options_len) * BITS_PER_BYTE) - 1, 0)
struct ip_tunnel_info {
struct ip_tunnel_key key;
#ifdef CONFIG_DST_CACHE
struct dst_cache dst_cache;
#endif
u8 options_len;
u8 mode;
};
/* 6rd prefix/relay information */
#ifdef CONFIG_IPV6_SIT_6RD
struct ip_tunnel_6rd_parm {
struct in6_addr prefix;
__be32 relay_prefix;
u16 prefixlen;
u16 relay_prefixlen;
};
#endif
struct ip_tunnel_encap {
u16 type;
u16 flags;
__be16 sport;
__be16 dport;
};
struct ip_tunnel_prl_entry {
struct ip_tunnel_prl_entry __rcu *next;
__be32 addr;
u16 flags;
struct rcu_head rcu_head;
};
struct metadata_dst;
struct ip_tunnel {
struct ip_tunnel __rcu *next;
struct hlist_node hash_node;
struct net_device *dev;
struct net *net; /* netns for packet i/o */
unsigned long err_time; /* Time when the last ICMP error
* arrived */
int err_count; /* Number of arrived ICMP errors */
/* These four fields used only by GRE */
u32 i_seqno; /* The last seen seqno */
u32 o_seqno; /* The last output seqno */
int tun_hlen; /* Precalculated header length */
/* These four fields used only by ERSPAN */
u32 index; /* ERSPAN type II index */
u8 erspan_ver; /* ERSPAN version */
u8 dir; /* ERSPAN direction */
u16 hwid; /* ERSPAN hardware ID */
struct dst_cache dst_cache;
struct ip_tunnel_parm parms;
int mlink;
int encap_hlen; /* Encap header length (FOU,GUE) */
int hlen; /* tun_hlen + encap_hlen */
struct ip_tunnel_encap encap;
/* for SIT */
#ifdef CONFIG_IPV6_SIT_6RD
struct ip_tunnel_6rd_parm ip6rd;
#endif
struct ip_tunnel_prl_entry __rcu *prl; /* potential router list */
unsigned int prl_count; /* # of entries in PRL */
unsigned int ip_tnl_net_id;
struct gro_cells gro_cells;
__u32 fwmark;
bool collect_md;
bool ignore_df;
};
struct tnl_ptk_info {
__be16 flags;
__be16 proto;
__be32 key;
__be32 seq;
int hdr_len;
};
#define PACKET_RCVD 0
#define PACKET_REJECT 1
#define PACKET_NEXT 2
#define IP_TNL_HASH_BITS 7
#define IP_TNL_HASH_SIZE (1 << IP_TNL_HASH_BITS)
struct ip_tunnel_net {
struct net_device *fb_tunnel_dev;
struct rtnl_link_ops *rtnl_link_ops;
struct hlist_head tunnels[IP_TNL_HASH_SIZE];
struct ip_tunnel __rcu *collect_md_tun;
int type;
};
static inline void ip_tunnel_key_init(struct ip_tunnel_key *key,
__be32 saddr, __be32 daddr,
u8 tos, u8 ttl, __be32 label,
__be16 tp_src, __be16 tp_dst,
__be64 tun_id, __be16 tun_flags)
{
key->tun_id = tun_id;
key->u.ipv4.src = saddr;
key->u.ipv4.dst = daddr;
memset((unsigned char *)key + IP_TUNNEL_KEY_IPV4_PAD,
0, IP_TUNNEL_KEY_IPV4_PAD_LEN);
key->tos = tos;
key->ttl = ttl;
key->label = label;
key->tun_flags = tun_flags;
/* For the tunnel types on the top of IPsec, the tp_src and tp_dst of
* the upper tunnel are used.
* E.g: GRE over IPSEC, the tp_src and tp_port are zero.
*/
key->tp_src = tp_src;
key->tp_dst = tp_dst;
/* Clear struct padding. */
if (sizeof(*key) != IP_TUNNEL_KEY_SIZE)
memset((unsigned char *)key + IP_TUNNEL_KEY_SIZE,
0, sizeof(*key) - IP_TUNNEL_KEY_SIZE);
}
static inline bool
ip_tunnel_dst_cache_usable(const struct sk_buff *skb,
const struct ip_tunnel_info *info)
{
if (skb->mark)
return false;
if (!info)
return true;
if (info->key.tun_flags & TUNNEL_NOCACHE)
return false;
return true;
}
static inline unsigned short ip_tunnel_info_af(const struct ip_tunnel_info
*tun_info)
{
return tun_info->mode & IP_TUNNEL_INFO_IPV6 ? AF_INET6 : AF_INET;
}
static inline __be64 key32_to_tunnel_id(__be32 key)
{
#ifdef __BIG_ENDIAN
return (__force __be64)key;
#else
return (__force __be64)((__force u64)key << 32);
#endif
}
/* Returns the least-significant 32 bits of a __be64. */
static inline __be32 tunnel_id_to_key32(__be64 tun_id)
{
#ifdef __BIG_ENDIAN
return (__force __be32)tun_id;
#else
return (__force __be32)((__force u64)tun_id >> 32);
#endif
}
#ifdef CONFIG_INET
static inline void ip_tunnel_init_flow(struct flowi4 *fl4,
int proto,
__be32 daddr, __be32 saddr,
__be32 key, __u8 tos, int oif,
__u32 mark)
{
memset(fl4, 0, sizeof(*fl4));
fl4->flowi4_oif = oif;
fl4->daddr = daddr;
fl4->saddr = saddr;
fl4->flowi4_tos = tos;
fl4->flowi4_proto = proto;
fl4->fl4_gre_key = key;
fl4->flowi4_mark = mark;
}
int ip_tunnel_init(struct net_device *dev);
void ip_tunnel_uninit(struct net_device *dev);
void ip_tunnel_dellink(struct net_device *dev, struct list_head *head);
struct net *ip_tunnel_get_link_net(const struct net_device *dev);
int ip_tunnel_get_iflink(const struct net_device *dev);
int ip_tunnel_init_net(struct net *net, unsigned int ip_tnl_net_id,
struct rtnl_link_ops *ops, char *devname);
void ip_tunnel_delete_nets(struct list_head *list_net, unsigned int id,
struct rtnl_link_ops *ops);
void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
const struct iphdr *tnl_params, const u8 protocol);
void ip_md_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
const u8 proto);
int ip_tunnel_ioctl(struct net_device *dev, struct ip_tunnel_parm *p, int cmd);
int __ip_tunnel_change_mtu(struct net_device *dev, int new_mtu, bool strict);
int ip_tunnel_change_mtu(struct net_device *dev, int new_mtu);
void ip_tunnel_get_stats64(struct net_device *dev,
struct rtnl_link_stats64 *tot);
struct ip_tunnel *ip_tunnel_lookup(struct ip_tunnel_net *itn,
int link, __be16 flags,
__be32 remote, __be32 local,
__be32 key);
int ip_tunnel_rcv(struct ip_tunnel *tunnel, struct sk_buff *skb,
const struct tnl_ptk_info *tpi, struct metadata_dst *tun_dst,
bool log_ecn_error);
int ip_tunnel_changelink(struct net_device *dev, struct nlattr *tb[],
struct ip_tunnel_parm *p, __u32 fwmark);
int ip_tunnel_newlink(struct net_device *dev, struct nlattr *tb[],
struct ip_tunnel_parm *p, __u32 fwmark);
void ip_tunnel_setup(struct net_device *dev, unsigned int net_id);
struct ip_tunnel_encap_ops {
size_t (*encap_hlen)(struct ip_tunnel_encap *e);
int (*build_header)(struct sk_buff *skb, struct ip_tunnel_encap *e,
u8 *protocol, struct flowi4 *fl4);
int (*err_handler)(struct sk_buff *skb, u32 info);
};
#define MAX_IPTUN_ENCAP_OPS 8
extern const struct ip_tunnel_encap_ops __rcu *
iptun_encaps[MAX_IPTUN_ENCAP_OPS];
int ip_tunnel_encap_add_ops(const struct ip_tunnel_encap_ops *op,
unsigned int num);
int ip_tunnel_encap_del_ops(const struct ip_tunnel_encap_ops *op,
unsigned int num);
int ip_tunnel_encap_setup(struct ip_tunnel *t,
struct ip_tunnel_encap *ipencap);
static inline bool pskb_inet_may_pull(struct sk_buff *skb)
{
int nhlen;
switch (skb->protocol) {
#if IS_ENABLED(CONFIG_IPV6)
case htons(ETH_P_IPV6):
nhlen = sizeof(struct ipv6hdr);
break;
#endif
case htons(ETH_P_IP):
nhlen = sizeof(struct iphdr);
break;
default:
nhlen = 0;
}
return pskb_network_may_pull(skb, nhlen);
}
static inline int ip_encap_hlen(struct ip_tunnel_encap *e)
{
const struct ip_tunnel_encap_ops *ops;
int hlen = -EINVAL;
if (e->type == TUNNEL_ENCAP_NONE)
return 0;
if (e->type >= MAX_IPTUN_ENCAP_OPS)
return -EINVAL;
rcu_read_lock();
ops = rcu_dereference(iptun_encaps[e->type]);
if (likely(ops && ops->encap_hlen))
hlen = ops->encap_hlen(e);
rcu_read_unlock();
return hlen;
}
static inline int ip_tunnel_encap(struct sk_buff *skb, struct ip_tunnel *t,
u8 *protocol, struct flowi4 *fl4)
{
const struct ip_tunnel_encap_ops *ops;
int ret = -EINVAL;
if (t->encap.type == TUNNEL_ENCAP_NONE)
return 0;
if (t->encap.type >= MAX_IPTUN_ENCAP_OPS)
return -EINVAL;
rcu_read_lock();
ops = rcu_dereference(iptun_encaps[t->encap.type]);
if (likely(ops && ops->build_header))
ret = ops->build_header(skb, &t->encap, protocol, fl4);
rcu_read_unlock();
return ret;
}
/* Extract dsfield from inner protocol */
static inline u8 ip_tunnel_get_dsfield(const struct iphdr *iph,
const struct sk_buff *skb)
{
if (skb->protocol == htons(ETH_P_IP))
return iph->tos;
else if (skb->protocol == htons(ETH_P_IPV6))
return ipv6_get_dsfield((const struct ipv6hdr *)iph);
else
return 0;
}
static inline u8 ip_tunnel_get_ttl(const struct iphdr *iph,
const struct sk_buff *skb)
{
if (skb->protocol == htons(ETH_P_IP))
return iph->ttl;
else if (skb->protocol == htons(ETH_P_IPV6))
return ((const struct ipv6hdr *)iph)->hop_limit;
else
return 0;
}
/* Propogate ECN bits out */
static inline u8 ip_tunnel_ecn_encap(u8 tos, const struct iphdr *iph,
const struct sk_buff *skb)
{
u8 inner = ip_tunnel_get_dsfield(iph, skb);
return INET_ECN_encapsulate(tos, inner);
}
int __iptunnel_pull_header(struct sk_buff *skb, int hdr_len,
__be16 inner_proto, bool raw_proto, bool xnet);
static inline int iptunnel_pull_header(struct sk_buff *skb, int hdr_len,
__be16 inner_proto, bool xnet)
{
return __iptunnel_pull_header(skb, hdr_len, inner_proto, false, xnet);
}
void iptunnel_xmit(struct sock *sk, struct rtable *rt, struct sk_buff *skb,
__be32 src, __be32 dst, u8 proto,
u8 tos, u8 ttl, __be16 df, bool xnet);
struct metadata_dst *iptunnel_metadata_reply(struct metadata_dst *md,
gfp_t flags);
int iptunnel_handle_offloads(struct sk_buff *skb, int gso_type_mask);
static inline int iptunnel_pull_offloads(struct sk_buff *skb)
{
if (skb_is_gso(skb)) {
int err;
err = skb_unclone(skb, GFP_ATOMIC);
if (unlikely(err))
return err;
skb_shinfo(skb)->gso_type &= ~(NETIF_F_GSO_ENCAP_ALL >>
NETIF_F_GSO_SHIFT);
}
skb->encapsulation = 0;
return 0;
}
static inline void iptunnel_xmit_stats(struct net_device *dev, int pkt_len)
{
if (pkt_len > 0) {
struct pcpu_sw_netstats *tstats = get_cpu_ptr(dev->tstats);
u64_stats_update_begin(&tstats->syncp);
tstats->tx_bytes += pkt_len;
tstats->tx_packets++;
u64_stats_update_end(&tstats->syncp);
put_cpu_ptr(tstats);
} else {
struct net_device_stats *err_stats = &dev->stats;
if (pkt_len < 0) {
err_stats->tx_errors++;
err_stats->tx_aborted_errors++;
} else {
err_stats->tx_dropped++;
}
}
}
static inline void *ip_tunnel_info_opts(struct ip_tunnel_info *info)
{
return info + 1;
}
static inline void ip_tunnel_info_opts_get(void *to,
const struct ip_tunnel_info *info)
{
memcpy(to, info + 1, info->options_len);
}
static inline void ip_tunnel_info_opts_set(struct ip_tunnel_info *info,
const void *from, int len,
__be16 flags)
{
memcpy(ip_tunnel_info_opts(info), from, len);
info->options_len = len;
info->key.tun_flags |= flags;
}
static inline struct ip_tunnel_info *lwt_tun_info(struct lwtunnel_state *lwtstate)
{
return (struct ip_tunnel_info *)lwtstate->data;
}
DECLARE_STATIC_KEY_FALSE(ip_tunnel_metadata_cnt);
/* Returns > 0 if metadata should be collected */
static inline int ip_tunnel_collect_metadata(void)
{
return static_branch_unlikely(&ip_tunnel_metadata_cnt);
}
void __init ip_tunnel_core_init(void);
void ip_tunnel_need_metadata(void);
void ip_tunnel_unneed_metadata(void);
#else /* CONFIG_INET */
static inline struct ip_tunnel_info *lwt_tun_info(struct lwtunnel_state *lwtstate)
{
return NULL;
}
static inline void ip_tunnel_need_metadata(void)
{
}
static inline void ip_tunnel_unneed_metadata(void)
{
}
static inline void ip_tunnel_info_opts_get(void *to,
const struct ip_tunnel_info *info)
{
}
static inline void ip_tunnel_info_opts_set(struct ip_tunnel_info *info,
const void *from, int len,
__be16 flags)
{
info->options_len = 0;
info->key.tun_flags |= flags;
}
#endif /* CONFIG_INET */
#endif /* __NET_IP_TUNNELS_H */
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