linux-stable/net/ipv4/fib_lookup.h
Eric Dumazet 9fcf986cc4 ipv4: fix data races in fib_alias_hw_flags_set
fib_alias_hw_flags_set() can be used by concurrent threads,
and is only RCU protected.

We need to annotate accesses to following fields of struct fib_alias:

    offload, trap, offload_failed

Because of READ_ONCE()WRITE_ONCE() limitations, make these
field u8.

BUG: KCSAN: data-race in fib_alias_hw_flags_set / fib_alias_hw_flags_set

read to 0xffff888134224a6a of 1 bytes by task 2013 on cpu 1:
 fib_alias_hw_flags_set+0x28a/0x470 net/ipv4/fib_trie.c:1050
 nsim_fib4_rt_hw_flags_set drivers/net/netdevsim/fib.c:350 [inline]
 nsim_fib4_rt_add drivers/net/netdevsim/fib.c:367 [inline]
 nsim_fib4_rt_insert drivers/net/netdevsim/fib.c:429 [inline]
 nsim_fib4_event drivers/net/netdevsim/fib.c:461 [inline]
 nsim_fib_event drivers/net/netdevsim/fib.c:881 [inline]
 nsim_fib_event_work+0x1852/0x2cf0 drivers/net/netdevsim/fib.c:1477
 process_one_work+0x3f6/0x960 kernel/workqueue.c:2307
 process_scheduled_works kernel/workqueue.c:2370 [inline]
 worker_thread+0x7df/0xa70 kernel/workqueue.c:2456
 kthread+0x1bf/0x1e0 kernel/kthread.c:377
 ret_from_fork+0x1f/0x30

write to 0xffff888134224a6a of 1 bytes by task 4872 on cpu 0:
 fib_alias_hw_flags_set+0x2d5/0x470 net/ipv4/fib_trie.c:1054
 nsim_fib4_rt_hw_flags_set drivers/net/netdevsim/fib.c:350 [inline]
 nsim_fib4_rt_add drivers/net/netdevsim/fib.c:367 [inline]
 nsim_fib4_rt_insert drivers/net/netdevsim/fib.c:429 [inline]
 nsim_fib4_event drivers/net/netdevsim/fib.c:461 [inline]
 nsim_fib_event drivers/net/netdevsim/fib.c:881 [inline]
 nsim_fib_event_work+0x1852/0x2cf0 drivers/net/netdevsim/fib.c:1477
 process_one_work+0x3f6/0x960 kernel/workqueue.c:2307
 process_scheduled_works kernel/workqueue.c:2370 [inline]
 worker_thread+0x7df/0xa70 kernel/workqueue.c:2456
 kthread+0x1bf/0x1e0 kernel/kthread.c:377
 ret_from_fork+0x1f/0x30

value changed: 0x00 -> 0x02

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 4872 Comm: kworker/0:0 Not tainted 5.17.0-rc3-syzkaller-00188-g1d41d2e82623-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events nsim_fib_event_work

Fixes: 90b93f1b31 ("ipv4: Add "offload" and "trap" indications to routes")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://lore.kernel.org/r/20220216173217.3792411-1-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-17 09:48:24 -08:00

62 lines
1.6 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _FIB_LOOKUP_H
#define _FIB_LOOKUP_H
#include <linux/types.h>
#include <linux/list.h>
#include <net/ip_fib.h>
#include <net/nexthop.h>
struct fib_alias {
struct hlist_node fa_list;
struct fib_info *fa_info;
u8 fa_tos;
u8 fa_type;
u8 fa_state;
u8 fa_slen;
u32 tb_id;
s16 fa_default;
u8 offload;
u8 trap;
u8 offload_failed;
struct rcu_head rcu;
};
#define FA_S_ACCESSED 0x01
/* Don't write on fa_state unless needed, to keep it shared on all cpus */
static inline void fib_alias_accessed(struct fib_alias *fa)
{
if (!(fa->fa_state & FA_S_ACCESSED))
fa->fa_state |= FA_S_ACCESSED;
}
/* Exported by fib_semantics.c */
void fib_release_info(struct fib_info *);
struct fib_info *fib_create_info(struct fib_config *cfg,
struct netlink_ext_ack *extack);
int fib_nh_match(struct net *net, struct fib_config *cfg, struct fib_info *fi,
struct netlink_ext_ack *extack);
bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi);
int fib_dump_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
const struct fib_rt_info *fri, unsigned int flags);
void rtmsg_fib(int event, __be32 key, struct fib_alias *fa, int dst_len,
u32 tb_id, const struct nl_info *info, unsigned int nlm_flags);
size_t fib_nlmsg_size(struct fib_info *fi);
static inline void fib_result_assign(struct fib_result *res,
struct fib_info *fi)
{
/* we used to play games with refcounts, but we now use RCU */
res->fi = fi;
res->nhc = fib_info_nhc(fi, 0);
}
struct fib_prop {
int error;
u8 scope;
};
extern const struct fib_prop fib_props[RTN_MAX + 1];
#endif /* _FIB_LOOKUP_H */