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authorDavid Ahern <dsahern@gmail.com>2018-04-23 11:32:07 -0700
committerDavid S. Miller <davem@davemloft.net>2018-04-23 16:12:55 -0400
commit8a14e46f140230ca889c2b0a4753ae8ea45fd770 (patch)
treea25f9508243656db0d31f15c1dde671845ba23e1 /net/ipv6/route.c
parentc3c14da0288de79ccef2c2380cf5737077fa64ed (diff)
net/ipv6: Fix missing rcu dereferences on from
kbuild test robot reported 2 uses of rt->from not properly accessed using rcu_dereference: 1. add rcu_dereference_protected to rt6_remove_exception_rt and make sure it is always called with rcu lock held. 2. change rt6_do_redirect to take a reference on 'from' when accessed the first time so it can be used the sceond time outside of the lock Fixes: a68886a69180 ("net/ipv6: Make from in rt6_info rcu protected") Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6/route.c')
-rw-r--r--net/ipv6/route.c15
1 files changed, 10 insertions, 5 deletions
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 354a5b8d016f..ac3e51631c65 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1541,11 +1541,13 @@ static struct rt6_info *rt6_find_cached_rt(struct fib6_info *rt,
static int rt6_remove_exception_rt(struct rt6_info *rt)
{
struct rt6_exception_bucket *bucket;
- struct fib6_info *from = rt->from;
struct in6_addr *src_key = NULL;
struct rt6_exception *rt6_ex;
+ struct fib6_info *from;
int err;
+ from = rcu_dereference_protected(rt->from,
+ lockdep_is_held(&rt6_exception_lock));
if (!from ||
!(rt->rt6i_flags & RTF_CACHE))
return -EINVAL;
@@ -2223,6 +2225,7 @@ static void ip6_link_failure(struct sk_buff *skb)
rt = (struct rt6_info *) skb_dst(skb);
if (rt) {
+ rcu_read_lock();
if (rt->rt6i_flags & RTF_CACHE) {
if (dst_hold_safe(&rt->dst))
rt6_remove_exception_rt(rt);
@@ -2230,15 +2233,14 @@ static void ip6_link_failure(struct sk_buff *skb)
struct fib6_info *from;
struct fib6_node *fn;
- rcu_read_lock();
from = rcu_dereference(rt->from);
if (from) {
fn = rcu_dereference(from->fib6_node);
if (fn && (rt->rt6i_flags & RTF_DEFAULT))
fn->fn_sernum = -1;
}
- rcu_read_unlock();
}
+ rcu_read_unlock();
}
}
@@ -3340,8 +3342,10 @@ static void rt6_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_bu
rcu_read_lock();
from = rcu_dereference(rt->from);
- nrt = ip6_rt_cache_alloc(from, &msg->dest, NULL);
+ fib6_info_hold(from);
rcu_read_unlock();
+
+ nrt = ip6_rt_cache_alloc(from, &msg->dest, NULL);
if (!nrt)
goto out;
@@ -3355,7 +3359,7 @@ static void rt6_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_bu
* a cached route because rt6_insert_exception() will
* takes care of it
*/
- if (rt6_insert_exception(nrt, rt->from)) {
+ if (rt6_insert_exception(nrt, from)) {
dst_release_immediate(&nrt->dst);
goto out;
}
@@ -3367,6 +3371,7 @@ static void rt6_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_bu
call_netevent_notifiers(NETEVENT_REDIRECT, &netevent);
out:
+ fib6_info_release(from);
neigh_release(neigh);
}