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| author | Xin Long <lucien.xin@gmail.com> | 2019-03-20 14:45:48 +0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-03-20 11:06:56 -0700 |
| commit | 1c87e79a002f6a159396138cd3f3ab554a2a8887 (patch) | |
| tree | d2b7ce3932787df5e48714428ac2e6ca614fda30 /net/ipv6 | |
| parent | 398f0132c14754fcd03c1c4f8e7176d001ce8ea1 (diff) | |
| download | linux-1c87e79a002f6a159396138cd3f3ab554a2a8887.tar.gz linux-1c87e79a002f6a159396138cd3f3ab554a2a8887.tar.bz2 linux-1c87e79a002f6a159396138cd3f3ab554a2a8887.zip | |
ipv6: make ip6_create_rt_rcu return ip6_null_entry instead of NULL
Jianlin reported a crash:
[ 381.484332] BUG: unable to handle kernel NULL pointer dereference at 0000000000000068
[ 381.619802] RIP: 0010:fib6_rule_lookup+0xa3/0x160
[ 382.009615] Call Trace:
[ 382.020762] <IRQ>
[ 382.030174] ip6_route_redirect.isra.52+0xc9/0xf0
[ 382.050984] ip6_redirect+0xb6/0xf0
[ 382.066731] icmpv6_notify+0xca/0x190
[ 382.083185] ndisc_redirect_rcv+0x10f/0x160
[ 382.102569] ndisc_rcv+0xfb/0x100
[ 382.117725] icmpv6_rcv+0x3f2/0x520
[ 382.133637] ip6_input_finish+0xbf/0x460
[ 382.151634] ip6_input+0x3b/0xb0
[ 382.166097] ipv6_rcv+0x378/0x4e0
It was caused by the lookup function __ip6_route_redirect() returns NULL in
fib6_rule_lookup() when ip6_create_rt_rcu() returns NULL.
So we fix it by simply making ip6_create_rt_rcu() return ip6_null_entry
instead of NULL.
v1->v2:
- move down 'fallback:' to make it more readable.
Fixes: e873e4b9cc7e ("ipv6: use fib6_info_hold_safe() when necessary")
Reported-by: Jianlin Shi <jishi@redhat.com>
Suggested-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Acked-by: Wei Wang <weiwan@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6')
| -rw-r--r-- | net/ipv6/route.c | 18 |
1 files changed, 10 insertions, 8 deletions
diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 4ef4bbdb49d4..0302e0eb07af 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -1040,14 +1040,20 @@ static struct rt6_info *ip6_create_rt_rcu(struct fib6_info *rt) struct rt6_info *nrt; if (!fib6_info_hold_safe(rt)) - return NULL; + goto fallback; nrt = ip6_dst_alloc(dev_net(dev), dev, flags); - if (nrt) - ip6_rt_copy_init(nrt, rt); - else + if (!nrt) { fib6_info_release(rt); + goto fallback; + } + ip6_rt_copy_init(nrt, rt); + return nrt; + +fallback: + nrt = dev_net(dev)->ipv6.ip6_null_entry; + dst_hold(&nrt->dst); return nrt; } @@ -1096,10 +1102,6 @@ restart: dst_hold(&rt->dst); } else { rt = ip6_create_rt_rcu(f6i); - if (!rt) { - rt = net->ipv6.ip6_null_entry; - dst_hold(&rt->dst); - } } rcu_read_unlock(); |