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authorXin Long <lucien.xin@gmail.com>2019-03-20 14:45:48 +0800
committerDavid S. Miller <davem@davemloft.net>2019-03-20 11:06:56 -0700
commit1c87e79a002f6a159396138cd3f3ab554a2a8887 (patch)
treed2b7ce3932787df5e48714428ac2e6ca614fda30 /net
parent398f0132c14754fcd03c1c4f8e7176d001ce8ea1 (diff)
downloadlinux-1c87e79a002f6a159396138cd3f3ab554a2a8887.tar.bz2
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')
-rw-r--r--net/ipv6/route.c18
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();