kernel_optimize_test/include/net/ip6_fib.h
Wei Wang e873e4b9cc ipv6: use fib6_info_hold_safe() when necessary
In the code path where only rcu read lock is held, e.g. in the route
lookup code path, it is not safe to directly call fib6_info_hold()
because the fib6_info may already have been deleted but still exists
in the rcu grace period. Holding reference to it could cause double
free and crash the kernel.

This patch adds a new function fib6_info_hold_safe() and replace
fib6_info_hold() in all necessary places.

Syzbot reported 3 crash traces because of this. One of them is:
8021q: adding VLAN 0 to HW filter on device team0
IPv6: ADDRCONF(NETDEV_CHANGE): team0: link becomes ready
dst_release: dst:(____ptrval____) refcnt:-1
dst_release: dst:(____ptrval____) refcnt:-2
WARNING: CPU: 1 PID: 4845 at include/net/dst.h:239 dst_hold include/net/dst.h:239 [inline]
WARNING: CPU: 1 PID: 4845 at include/net/dst.h:239 ip6_setup_cork+0xd66/0x1830 net/ipv6/ip6_output.c:1204
dst_release: dst:(____ptrval____) refcnt:-1
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 4845 Comm: syz-executor493 Not tainted 4.18.0-rc3+ #10
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113
 panic+0x238/0x4e7 kernel/panic.c:184
dst_release: dst:(____ptrval____) refcnt:-2
dst_release: dst:(____ptrval____) refcnt:-3
 __warn.cold.8+0x163/0x1ba kernel/panic.c:536
dst_release: dst:(____ptrval____) refcnt:-4
 report_bug+0x252/0x2d0 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:178 [inline]
 do_error_trap+0x1fc/0x4d0 arch/x86/kernel/traps.c:296
dst_release: dst:(____ptrval____) refcnt:-5
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:316
 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:992
RIP: 0010:dst_hold include/net/dst.h:239 [inline]
RIP: 0010:ip6_setup_cork+0xd66/0x1830 net/ipv6/ip6_output.c:1204
Code: c1 ed 03 89 9d 18 ff ff ff 48 b8 00 00 00 00 00 fc ff df 41 c6 44 05 00 f8 e9 2d 01 00 00 4c 8b a5 c8 fe ff ff e8 1a f6 e6 fa <0f> 0b e9 6a fc ff ff e8 0e f6 e6 fa 48 8b 85 d0 fe ff ff 48 8d 78
RSP: 0018:ffff8801a8fcf178 EFLAGS: 00010293
RAX: ffff8801a8eba5c0 RBX: 0000000000000000 RCX: ffffffff869511e6
RDX: 0000000000000000 RSI: ffffffff869515b6 RDI: 0000000000000005
RBP: ffff8801a8fcf2c8 R08: ffff8801a8eba5c0 R09: ffffed0035ac8338
R10: ffffed0035ac8338 R11: ffff8801ad6419c3 R12: ffff8801a8fcf720
R13: ffff8801a8fcf6a0 R14: ffff8801ad6419c0 R15: ffff8801ad641980
 ip6_make_skb+0x2c8/0x600 net/ipv6/ip6_output.c:1768
 udpv6_sendmsg+0x2c90/0x35f0 net/ipv6/udp.c:1376
 inet_sendmsg+0x1a1/0x690 net/ipv4/af_inet.c:798
 sock_sendmsg_nosec net/socket.c:641 [inline]
 sock_sendmsg+0xd5/0x120 net/socket.c:651
 ___sys_sendmsg+0x51d/0x930 net/socket.c:2125
 __sys_sendmmsg+0x240/0x6f0 net/socket.c:2220
 __do_sys_sendmmsg net/socket.c:2249 [inline]
 __se_sys_sendmmsg net/socket.c:2246 [inline]
 __x64_sys_sendmmsg+0x9d/0x100 net/socket.c:2246
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x446ba9
Code: e8 cc bb 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 eb 08 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fb39a469da8 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00000000006dcc54 RCX: 0000000000446ba9
RDX: 00000000000000b8 RSI: 0000000020001b00 RDI: 0000000000000003
RBP: 00000000006dcc50 R08: 00007fb39a46a700 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 45c828efc7a64843
R13: e6eeb815b9d8a477 R14: 5068caf6f713c6fc R15: 0000000000000001
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..

Fixes: 93531c6743 ("net/ipv6: separate handling of FIB entries from dst based routes")
Reported-by: syzbot+902e2a1bcd4f7808cef5@syzkaller.appspotmail.com
Reported-by: syzbot+8ae62d67f647abeeceb9@syzkaller.appspotmail.com
Reported-by: syzbot+3f08feb14086930677d0@syzkaller.appspotmail.com
Signed-off-by: Wei Wang <weiwan@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-23 11:19:02 -07:00

521 lines
12 KiB
C

/*
* Linux INET6 implementation
*
* Authors:
* Pedro Roque <roque@di.fc.ul.pt>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#ifndef _IP6_FIB_H
#define _IP6_FIB_H
#include <linux/ipv6_route.h>
#include <linux/rtnetlink.h>
#include <linux/spinlock.h>
#include <linux/notifier.h>
#include <net/dst.h>
#include <net/flow.h>
#include <net/netlink.h>
#include <net/inetpeer.h>
#include <net/fib_notifier.h>
#ifdef CONFIG_IPV6_MULTIPLE_TABLES
#define FIB6_TABLE_HASHSZ 256
#else
#define FIB6_TABLE_HASHSZ 1
#endif
#define RT6_DEBUG 2
#if RT6_DEBUG >= 3
#define RT6_TRACE(x...) pr_debug(x)
#else
#define RT6_TRACE(x...) do { ; } while (0)
#endif
struct rt6_info;
struct fib6_info;
struct fib6_config {
u32 fc_table;
u32 fc_metric;
int fc_dst_len;
int fc_src_len;
int fc_ifindex;
u32 fc_flags;
u32 fc_protocol;
u16 fc_type; /* only 8 bits are used */
u16 fc_delete_all_nh : 1,
__unused : 15;
struct in6_addr fc_dst;
struct in6_addr fc_src;
struct in6_addr fc_prefsrc;
struct in6_addr fc_gateway;
unsigned long fc_expires;
struct nlattr *fc_mx;
int fc_mx_len;
int fc_mp_len;
struct nlattr *fc_mp;
struct nl_info fc_nlinfo;
struct nlattr *fc_encap;
u16 fc_encap_type;
};
struct fib6_node {
struct fib6_node __rcu *parent;
struct fib6_node __rcu *left;
struct fib6_node __rcu *right;
#ifdef CONFIG_IPV6_SUBTREES
struct fib6_node __rcu *subtree;
#endif
struct fib6_info __rcu *leaf;
__u16 fn_bit; /* bit key */
__u16 fn_flags;
int fn_sernum;
struct fib6_info __rcu *rr_ptr;
struct rcu_head rcu;
};
struct fib6_gc_args {
int timeout;
int more;
};
#ifndef CONFIG_IPV6_SUBTREES
#define FIB6_SUBTREE(fn) NULL
#else
#define FIB6_SUBTREE(fn) (rcu_dereference_protected((fn)->subtree, 1))
#endif
/*
* routing information
*
*/
struct rt6key {
struct in6_addr addr;
int plen;
};
struct fib6_table;
struct rt6_exception_bucket {
struct hlist_head chain;
int depth;
};
struct rt6_exception {
struct hlist_node hlist;
struct rt6_info *rt6i;
unsigned long stamp;
struct rcu_head rcu;
};
#define FIB6_EXCEPTION_BUCKET_SIZE_SHIFT 10
#define FIB6_EXCEPTION_BUCKET_SIZE (1 << FIB6_EXCEPTION_BUCKET_SIZE_SHIFT)
#define FIB6_MAX_DEPTH 5
struct fib6_nh {
struct in6_addr nh_gw;
struct net_device *nh_dev;
struct lwtunnel_state *nh_lwtstate;
unsigned int nh_flags;
atomic_t nh_upper_bound;
int nh_weight;
};
struct fib6_info {
struct fib6_table *fib6_table;
struct fib6_info __rcu *fib6_next;
struct fib6_node __rcu *fib6_node;
/* Multipath routes:
* siblings is a list of fib6_info that have the the same metric/weight,
* destination, but not the same gateway. nsiblings is just a cache
* to speed up lookup.
*/
struct list_head fib6_siblings;
unsigned int fib6_nsiblings;
atomic_t fib6_ref;
unsigned long expires;
struct dst_metrics *fib6_metrics;
#define fib6_pmtu fib6_metrics->metrics[RTAX_MTU-1]
struct rt6key fib6_dst;
u32 fib6_flags;
struct rt6key fib6_src;
struct rt6key fib6_prefsrc;
struct rt6_info * __percpu *rt6i_pcpu;
struct rt6_exception_bucket __rcu *rt6i_exception_bucket;
u32 fib6_metric;
u8 fib6_protocol;
u8 fib6_type;
u8 exception_bucket_flushed:1,
should_flush:1,
dst_nocount:1,
dst_nopolicy:1,
dst_host:1,
unused:3;
struct fib6_nh fib6_nh;
struct rcu_head rcu;
};
struct rt6_info {
struct dst_entry dst;
struct fib6_info __rcu *from;
struct rt6key rt6i_dst;
struct rt6key rt6i_src;
struct in6_addr rt6i_gateway;
struct inet6_dev *rt6i_idev;
u32 rt6i_flags;
struct rt6key rt6i_prefsrc;
struct list_head rt6i_uncached;
struct uncached_list *rt6i_uncached_list;
/* more non-fragment space at head required */
unsigned short rt6i_nfheader_len;
};
#define for_each_fib6_node_rt_rcu(fn) \
for (rt = rcu_dereference((fn)->leaf); rt; \
rt = rcu_dereference(rt->fib6_next))
#define for_each_fib6_walker_rt(w) \
for (rt = (w)->leaf; rt; \
rt = rcu_dereference_protected(rt->fib6_next, 1))
static inline struct inet6_dev *ip6_dst_idev(struct dst_entry *dst)
{
return ((struct rt6_info *)dst)->rt6i_idev;
}
static inline void fib6_clean_expires(struct fib6_info *f6i)
{
f6i->fib6_flags &= ~RTF_EXPIRES;
f6i->expires = 0;
}
static inline void fib6_set_expires(struct fib6_info *f6i,
unsigned long expires)
{
f6i->expires = expires;
f6i->fib6_flags |= RTF_EXPIRES;
}
static inline bool fib6_check_expired(const struct fib6_info *f6i)
{
if (f6i->fib6_flags & RTF_EXPIRES)
return time_after(jiffies, f6i->expires);
return false;
}
/* Function to safely get fn->sernum for passed in rt
* and store result in passed in cookie.
* Return true if we can get cookie safely
* Return false if not
*/
static inline bool fib6_get_cookie_safe(const struct fib6_info *f6i,
u32 *cookie)
{
struct fib6_node *fn;
bool status = false;
fn = rcu_dereference(f6i->fib6_node);
if (fn) {
*cookie = fn->fn_sernum;
/* pairs with smp_wmb() in fib6_update_sernum_upto_root() */
smp_rmb();
status = true;
}
return status;
}
static inline u32 rt6_get_cookie(const struct rt6_info *rt)
{
struct fib6_info *from;
u32 cookie = 0;
rcu_read_lock();
from = rcu_dereference(rt->from);
if (from && (rt->rt6i_flags & RTF_PCPU ||
unlikely(!list_empty(&rt->rt6i_uncached))))
fib6_get_cookie_safe(from, &cookie);
rcu_read_unlock();
return cookie;
}
static inline void ip6_rt_put(struct rt6_info *rt)
{
/* dst_release() accepts a NULL parameter.
* We rely on dst being first structure in struct rt6_info
*/
BUILD_BUG_ON(offsetof(struct rt6_info, dst) != 0);
dst_release(&rt->dst);
}
struct fib6_info *fib6_info_alloc(gfp_t gfp_flags);
void fib6_info_destroy_rcu(struct rcu_head *head);
static inline void fib6_info_hold(struct fib6_info *f6i)
{
atomic_inc(&f6i->fib6_ref);
}
static inline bool fib6_info_hold_safe(struct fib6_info *f6i)
{
return atomic_inc_not_zero(&f6i->fib6_ref);
}
static inline void fib6_info_release(struct fib6_info *f6i)
{
if (f6i && atomic_dec_and_test(&f6i->fib6_ref))
call_rcu(&f6i->rcu, fib6_info_destroy_rcu);
}
enum fib6_walk_state {
#ifdef CONFIG_IPV6_SUBTREES
FWS_S,
#endif
FWS_L,
FWS_R,
FWS_C,
FWS_U
};
struct fib6_walker {
struct list_head lh;
struct fib6_node *root, *node;
struct fib6_info *leaf;
enum fib6_walk_state state;
unsigned int skip;
unsigned int count;
int (*func)(struct fib6_walker *);
void *args;
};
struct rt6_statistics {
__u32 fib_nodes; /* all fib6 nodes */
__u32 fib_route_nodes; /* intermediate nodes */
__u32 fib_rt_entries; /* rt entries in fib table */
__u32 fib_rt_cache; /* cached rt entries in exception table */
__u32 fib_discarded_routes; /* total number of routes delete */
/* The following stats are not protected by any lock */
atomic_t fib_rt_alloc; /* total number of routes alloced */
atomic_t fib_rt_uncache; /* rt entries in uncached list */
};
#define RTN_TL_ROOT 0x0001
#define RTN_ROOT 0x0002 /* tree root node */
#define RTN_RTINFO 0x0004 /* node with valid routing info */
/*
* priority levels (or metrics)
*
*/
struct fib6_table {
struct hlist_node tb6_hlist;
u32 tb6_id;
spinlock_t tb6_lock;
struct fib6_node tb6_root;
struct inet_peer_base tb6_peers;
unsigned int flags;
unsigned int fib_seq;
#define RT6_TABLE_HAS_DFLT_ROUTER BIT(0)
};
#define RT6_TABLE_UNSPEC RT_TABLE_UNSPEC
#define RT6_TABLE_MAIN RT_TABLE_MAIN
#define RT6_TABLE_DFLT RT6_TABLE_MAIN
#define RT6_TABLE_INFO RT6_TABLE_MAIN
#define RT6_TABLE_PREFIX RT6_TABLE_MAIN
#ifdef CONFIG_IPV6_MULTIPLE_TABLES
#define FIB6_TABLE_MIN 1
#define FIB6_TABLE_MAX RT_TABLE_MAX
#define RT6_TABLE_LOCAL RT_TABLE_LOCAL
#else
#define FIB6_TABLE_MIN RT_TABLE_MAIN
#define FIB6_TABLE_MAX FIB6_TABLE_MIN
#define RT6_TABLE_LOCAL RT6_TABLE_MAIN
#endif
typedef struct rt6_info *(*pol_lookup_t)(struct net *,
struct fib6_table *,
struct flowi6 *,
const struct sk_buff *, int);
struct fib6_entry_notifier_info {
struct fib_notifier_info info; /* must be first */
struct fib6_info *rt;
};
/*
* exported functions
*/
struct fib6_table *fib6_get_table(struct net *net, u32 id);
struct fib6_table *fib6_new_table(struct net *net, u32 id);
struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
const struct sk_buff *skb,
int flags, pol_lookup_t lookup);
/* called with rcu lock held; can return error pointer
* caller needs to select path
*/
struct fib6_info *fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
int flags);
/* called with rcu lock held; caller needs to select path */
struct fib6_info *fib6_table_lookup(struct net *net, struct fib6_table *table,
int oif, struct flowi6 *fl6, int strict);
struct fib6_info *fib6_multipath_select(const struct net *net,
struct fib6_info *match,
struct flowi6 *fl6, int oif,
const struct sk_buff *skb, int strict);
struct fib6_node *fib6_node_lookup(struct fib6_node *root,
const struct in6_addr *daddr,
const struct in6_addr *saddr);
struct fib6_node *fib6_locate(struct fib6_node *root,
const struct in6_addr *daddr, int dst_len,
const struct in6_addr *saddr, int src_len,
bool exact_match);
void fib6_clean_all(struct net *net, int (*func)(struct fib6_info *, void *arg),
void *arg);
int fib6_add(struct fib6_node *root, struct fib6_info *rt,
struct nl_info *info, struct netlink_ext_ack *extack);
int fib6_del(struct fib6_info *rt, struct nl_info *info);
static inline struct net_device *fib6_info_nh_dev(const struct fib6_info *f6i)
{
return f6i->fib6_nh.nh_dev;
}
static inline
struct lwtunnel_state *fib6_info_nh_lwt(const struct fib6_info *f6i)
{
return f6i->fib6_nh.nh_lwtstate;
}
void inet6_rt_notify(int event, struct fib6_info *rt, struct nl_info *info,
unsigned int flags);
void fib6_run_gc(unsigned long expires, struct net *net, bool force);
void fib6_gc_cleanup(void);
int fib6_init(void);
struct ipv6_route_iter {
struct seq_net_private p;
struct fib6_walker w;
loff_t skip;
struct fib6_table *tbl;
int sernum;
};
extern const struct seq_operations ipv6_route_seq_ops;
int call_fib6_notifier(struct notifier_block *nb, struct net *net,
enum fib_event_type event_type,
struct fib_notifier_info *info);
int call_fib6_notifiers(struct net *net, enum fib_event_type event_type,
struct fib_notifier_info *info);
int __net_init fib6_notifier_init(struct net *net);
void __net_exit fib6_notifier_exit(struct net *net);
unsigned int fib6_tables_seq_read(struct net *net);
int fib6_tables_dump(struct net *net, struct notifier_block *nb);
void fib6_update_sernum(struct net *net, struct fib6_info *rt);
void fib6_update_sernum_upto_root(struct net *net, struct fib6_info *rt);
void fib6_metric_set(struct fib6_info *f6i, int metric, u32 val);
static inline bool fib6_metric_locked(struct fib6_info *f6i, int metric)
{
return !!(f6i->fib6_metrics->metrics[RTAX_LOCK - 1] & (1 << metric));
}
#ifdef CONFIG_IPV6_MULTIPLE_TABLES
int fib6_rules_init(void);
void fib6_rules_cleanup(void);
bool fib6_rule_default(const struct fib_rule *rule);
int fib6_rules_dump(struct net *net, struct notifier_block *nb);
unsigned int fib6_rules_seq_read(struct net *net);
static inline bool fib6_rules_early_flow_dissect(struct net *net,
struct sk_buff *skb,
struct flowi6 *fl6,
struct flow_keys *flkeys)
{
unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
if (!net->ipv6.fib6_rules_require_fldissect)
return false;
skb_flow_dissect_flow_keys(skb, flkeys, flag);
fl6->fl6_sport = flkeys->ports.src;
fl6->fl6_dport = flkeys->ports.dst;
fl6->flowi6_proto = flkeys->basic.ip_proto;
return true;
}
#else
static inline int fib6_rules_init(void)
{
return 0;
}
static inline void fib6_rules_cleanup(void)
{
return ;
}
static inline bool fib6_rule_default(const struct fib_rule *rule)
{
return true;
}
static inline int fib6_rules_dump(struct net *net, struct notifier_block *nb)
{
return 0;
}
static inline unsigned int fib6_rules_seq_read(struct net *net)
{
return 0;
}
static inline bool fib6_rules_early_flow_dissect(struct net *net,
struct sk_buff *skb,
struct flowi6 *fl6,
struct flow_keys *flkeys)
{
return false;
}
#endif
#endif