diff options
author | Kuniyuki Iwashima <kuniyu@amazon.com> | 2022-07-13 13:51:53 -0700 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2022-07-15 11:49:55 +0100 |
commit | 60c158dc7b1f0558f6cadd5b50d0386da0000d50 (patch) | |
tree | 7f70607a57abd8881ac567ffdeb7f67c0960d47e | |
parent | 0968d2a441bf6afb551fd99e60fa65ed67068963 (diff) |
ip: Fix data-races around sysctl_ip_fwd_use_pmtu.
While reading sysctl_ip_fwd_use_pmtu, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its readers.
Fixes: f87c10a8aa1e ("ipv4: introduce ip_dst_mtu_maybe_forward and protect forwarding path against pmtu spoofing")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r-- | include/net/ip.h | 2 | ||||
-rw-r--r-- | net/ipv4/route.c | 2 |
2 files changed, 2 insertions, 2 deletions
diff --git a/include/net/ip.h b/include/net/ip.h index 26fffda78cca..05fe313f72fa 100644 --- a/include/net/ip.h +++ b/include/net/ip.h @@ -446,7 +446,7 @@ static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst, struct net *net = dev_net(dst->dev); unsigned int mtu; - if (net->ipv4.sysctl_ip_fwd_use_pmtu || + if (READ_ONCE(net->ipv4.sysctl_ip_fwd_use_pmtu) || ip_mtu_locked(dst) || !forwarding) { mtu = rt->rt_pmtu; diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 356f535f3443..91c4f60de75a 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -1398,7 +1398,7 @@ u32 ip_mtu_from_fib_result(struct fib_result *res, __be32 daddr) struct fib_info *fi = res->fi; u32 mtu = 0; - if (dev_net(dev)->ipv4.sysctl_ip_fwd_use_pmtu || + if (READ_ONCE(dev_net(dev)->ipv4.sysctl_ip_fwd_use_pmtu) || fi->fib_metrics->metrics[RTAX_LOCK - 1] & (1 << RTAX_MTU)) mtu = fi->fib_mtu; |