diff options
| author | Eric Dumazet <edumazet@google.com> | 2022-02-16 18:32:17 +0100 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2022-02-17 18:48:24 +0100 |
| commit | d95d6320ba7a51d61c097ffc3bcafcf70283414e (patch) | |
| tree | ba13ddf538388cf15198abf5de1d1cfae36dbc38 /net | |
| parent | ipv4: fix data races in fib_alias_hw_flags_set (diff) | |
| download | linux-d95d6320ba7a51d61c097ffc3bcafcf70283414e.tar.xz linux-d95d6320ba7a51d61c097ffc3bcafcf70283414e.zip | |
ipv6: fix data-race in fib6_info_hw_flags_set / fib6_purge_rt
Because fib6_info_hw_flags_set() is called without any synchronization,
all accesses to gi6->offload, fi->trap and fi->offload_failed
need some basic protection like READ_ONCE()/WRITE_ONCE().
BUG: KCSAN: data-race in fib6_info_hw_flags_set / fib6_purge_rt
read to 0xffff8881087d5886 of 1 bytes by task 13953 on cpu 0:
fib6_drop_pcpu_from net/ipv6/ip6_fib.c:1007 [inline]
fib6_purge_rt+0x4f/0x580 net/ipv6/ip6_fib.c:1033
fib6_del_route net/ipv6/ip6_fib.c:1983 [inline]
fib6_del+0x696/0x890 net/ipv6/ip6_fib.c:2028
__ip6_del_rt net/ipv6/route.c:3876 [inline]
ip6_del_rt+0x83/0x140 net/ipv6/route.c:3891
__ipv6_dev_ac_dec+0x2b5/0x370 net/ipv6/anycast.c:374
ipv6_dev_ac_dec net/ipv6/anycast.c:387 [inline]
__ipv6_sock_ac_close+0x141/0x200 net/ipv6/anycast.c:207
ipv6_sock_ac_close+0x79/0x90 net/ipv6/anycast.c:220
inet6_release+0x32/0x50 net/ipv6/af_inet6.c:476
__sock_release net/socket.c:650 [inline]
sock_close+0x6c/0x150 net/socket.c:1318
__fput+0x295/0x520 fs/file_table.c:280
____fput+0x11/0x20 fs/file_table.c:313
task_work_run+0x8e/0x110 kernel/task_work.c:164
tracehook_notify_resume include/linux/tracehook.h:189 [inline]
exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
exit_to_user_mode_prepare+0x160/0x190 kernel/entry/common.c:207
__syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:300
do_syscall_64+0x50/0xd0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x44/0xae
write to 0xffff8881087d5886 of 1 bytes by task 1912 on cpu 1:
fib6_info_hw_flags_set+0x155/0x3b0 net/ipv6/route.c:6230
nsim_fib6_rt_hw_flags_set drivers/net/netdevsim/fib.c:668 [inline]
nsim_fib6_rt_add drivers/net/netdevsim/fib.c:691 [inline]
nsim_fib6_rt_insert drivers/net/netdevsim/fib.c:756 [inline]
nsim_fib6_event drivers/net/netdevsim/fib.c:853 [inline]
nsim_fib_event drivers/net/netdevsim/fib.c:886 [inline]
nsim_fib_event_work+0x284f/0x2cf0 drivers/net/netdevsim/fib.c:1477
process_one_work+0x3f6/0x960 kernel/workqueue.c:2307
worker_thread+0x616/0xa70 kernel/workqueue.c:2454
kthread+0x2c7/0x2e0 kernel/kthread.c:327
ret_from_fork+0x1f/0x30
value changed: 0x22 -> 0x2a
Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 1912 Comm: kworker/1:3 Not tainted 5.16.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events nsim_fib_event_work
Fixes: 0c5fcf9e249e ("IPv6: Add "offload failed" indication to routes")
Fixes: bb3c4ab93e44 ("ipv6: Add "offload" and "trap" indications to routes")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Amit Cohen <amcohen@nvidia.com>
Cc: Ido Schimmel <idosch@nvidia.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Link: https://lore.kernel.org/r/20220216173217.3792411-2-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv6/route.c | 19 |
1 files changed, 10 insertions, 9 deletions
diff --git a/net/ipv6/route.c b/net/ipv6/route.c index f4884cda13b9..ea1cf414a92e 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -5753,11 +5753,11 @@ static int rt6_fill_node(struct net *net, struct sk_buff *skb, } if (!dst) { - if (rt->offload) + if (READ_ONCE(rt->offload)) rtm->rtm_flags |= RTM_F_OFFLOAD; - if (rt->trap) + if (READ_ONCE(rt->trap)) rtm->rtm_flags |= RTM_F_TRAP; - if (rt->offload_failed) + if (READ_ONCE(rt->offload_failed)) rtm->rtm_flags |= RTM_F_OFFLOAD_FAILED; } @@ -6215,19 +6215,20 @@ void fib6_info_hw_flags_set(struct net *net, struct fib6_info *f6i, struct sk_buff *skb; int err; - if (f6i->offload == offload && f6i->trap == trap && - f6i->offload_failed == offload_failed) + if (READ_ONCE(f6i->offload) == offload && + READ_ONCE(f6i->trap) == trap && + READ_ONCE(f6i->offload_failed) == offload_failed) return; - f6i->offload = offload; - f6i->trap = trap; + WRITE_ONCE(f6i->offload, offload); + WRITE_ONCE(f6i->trap, trap); /* 2 means send notifications only if offload_failed was changed. */ if (net->ipv6.sysctl.fib_notify_on_flag_change == 2 && - f6i->offload_failed == offload_failed) + READ_ONCE(f6i->offload_failed) == offload_failed) return; - f6i->offload_failed = offload_failed; + WRITE_ONCE(f6i->offload_failed, offload_failed); if (!rcu_access_pointer(f6i->fib6_node)) /* The route was removed from the tree, do not send |