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authorEric Dumazet <edumazet@google.com>2015-12-02 21:53:57 -0800
committerDavid S. Miller <davem@davemloft.net>2015-12-03 11:32:06 -0500
commit6bd4f355df2eae80b8a5c7b097371cd1e05f20d5 (patch)
treee903f55cdcc87ed834790e4f257d407f886a9d23 /net
parentipv6: sctp: add rcu protection around np->opt (diff)
downloadlinux-dev-6bd4f355df2eae80b8a5c7b097371cd1e05f20d5.tar.xz
linux-dev-6bd4f355df2eae80b8a5c7b097371cd1e05f20d5.zip
ipv6: kill sk_dst_lock
While testing the np->opt RCU conversion, I found that UDP/IPv6 was using a mixture of xchg() and sk_dst_lock to protect concurrent changes to sk->sk_dst_cache, leading to possible corruptions and crashes. ip6_sk_dst_lookup_flow() uses sk_dst_check() anyway, so the simplest way to fix the mess is to remove sk_dst_lock completely, as we did for IPv4. __ip6_dst_store() and ip6_dst_store() share same implementation. sk_setup_caps() being called with socket lock being held or not, we have to use sk_dst_set() instead of __sk_dst_set() Note that I had to move the "np->dst_cookie = rt6_get_cookie(rt);" in ip6_dst_store() before the sk_setup_caps(sk, dst) call. This is because ip6_dst_store() can be called from process context, without any lock held. As soon as the dst is installed in sk->sk_dst_cache, dst can be freed from another cpu doing a concurrent ip6_dst_store() Doing the dst dereference before doing the install is needed to make sure no use after free would trigger. Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/core/sock.c4
-rw-r--r--net/dccp/ipv6.c4
-rw-r--r--net/ipv6/af_inet6.c2
-rw-r--r--net/ipv6/icmp.c14
-rw-r--r--net/ipv6/inet6_connection_sock.c10
-rw-r--r--net/ipv6/tcp_ipv6.c4
6 files changed, 7 insertions, 31 deletions
diff --git a/net/core/sock.c b/net/core/sock.c
index 9d79569935a3..e31dfcee1729 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1530,7 +1530,6 @@ struct sock *sk_clone_lock(const struct sock *sk, const gfp_t priority)
skb_queue_head_init(&newsk->sk_receive_queue);
skb_queue_head_init(&newsk->sk_write_queue);
- spin_lock_init(&newsk->sk_dst_lock);
rwlock_init(&newsk->sk_callback_lock);
lockdep_set_class_and_name(&newsk->sk_callback_lock,
af_callback_keys + newsk->sk_family,
@@ -1607,7 +1606,7 @@ void sk_setup_caps(struct sock *sk, struct dst_entry *dst)
{
u32 max_segs = 1;
- __sk_dst_set(sk, dst);
+ sk_dst_set(sk, dst);
sk->sk_route_caps = dst->dev->features;
if (sk->sk_route_caps & NETIF_F_GSO)
sk->sk_route_caps |= NETIF_F_GSO_SOFTWARE;
@@ -2388,7 +2387,6 @@ void sock_init_data(struct socket *sock, struct sock *sk)
} else
sk->sk_wq = NULL;
- spin_lock_init(&sk->sk_dst_lock);
rwlock_init(&sk->sk_callback_lock);
lockdep_set_class_and_name(&sk->sk_callback_lock,
af_callback_keys + sk->sk_family,
diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c
index e7e0b9bc2a43..9c6d0508e63a 100644
--- a/net/dccp/ipv6.c
+++ b/net/dccp/ipv6.c
@@ -459,7 +459,7 @@ static struct sock *dccp_v6_request_recv_sock(const struct sock *sk,
* comment in that function for the gory details. -acme
*/
- __ip6_dst_store(newsk, dst, NULL, NULL);
+ ip6_dst_store(newsk, dst, NULL, NULL);
newsk->sk_route_caps = dst->dev->features & ~(NETIF_F_IP_CSUM |
NETIF_F_TSO);
newdp6 = (struct dccp6_sock *)newsk;
@@ -883,7 +883,7 @@ static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
np->saddr = *saddr;
inet->inet_rcv_saddr = LOOPBACK4_IPV6;
- __ip6_dst_store(sk, dst, NULL, NULL);
+ ip6_dst_store(sk, dst, NULL, NULL);
icsk->icsk_ext_hdr_len = 0;
if (opt)
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index 38d66ddfb937..8ec0df75f1c4 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -673,7 +673,7 @@ int inet6_sk_rebuild_header(struct sock *sk)
return PTR_ERR(dst);
}
- __ip6_dst_store(sk, dst, NULL, NULL);
+ ip6_dst_store(sk, dst, NULL, NULL);
}
return 0;
diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index 36c5a98b0472..0a37ddc7af51 100644
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c
@@ -834,11 +834,6 @@ void icmpv6_flow_init(struct sock *sk, struct flowi6 *fl6,
security_sk_classify_flow(sk, flowi6_to_flowi(fl6));
}
-/*
- * Special lock-class for __icmpv6_sk:
- */
-static struct lock_class_key icmpv6_socket_sk_dst_lock_key;
-
static int __net_init icmpv6_sk_init(struct net *net)
{
struct sock *sk;
@@ -860,15 +855,6 @@ static int __net_init icmpv6_sk_init(struct net *net)
net->ipv6.icmp_sk[i] = sk;
- /*
- * Split off their lock-class, because sk->sk_dst_lock
- * gets used from softirqs, which is safe for
- * __icmpv6_sk (because those never get directly used
- * via userspace syscalls), but unsafe for normal sockets.
- */
- lockdep_set_class(&sk->sk_dst_lock,
- &icmpv6_socket_sk_dst_lock_key);
-
/* Enough space for 2 64K ICMP packets, including
* sk_buff struct overhead.
*/
diff --git a/net/ipv6/inet6_connection_sock.c b/net/ipv6/inet6_connection_sock.c
index 3ff5208772bb..a7ca2cde2ecb 100644
--- a/net/ipv6/inet6_connection_sock.c
+++ b/net/ipv6/inet6_connection_sock.c
@@ -111,14 +111,6 @@ void inet6_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr)
EXPORT_SYMBOL_GPL(inet6_csk_addr2sockaddr);
static inline
-void __inet6_csk_dst_store(struct sock *sk, struct dst_entry *dst,
- const struct in6_addr *daddr,
- const struct in6_addr *saddr)
-{
- __ip6_dst_store(sk, dst, daddr, saddr);
-}
-
-static inline
struct dst_entry *__inet6_csk_dst_check(struct sock *sk, u32 cookie)
{
return __sk_dst_check(sk, cookie);
@@ -153,7 +145,7 @@ static struct dst_entry *inet6_csk_route_socket(struct sock *sk,
dst = ip6_dst_lookup_flow(sk, fl6, final_p);
if (!IS_ERR(dst))
- __inet6_csk_dst_store(sk, dst, NULL, NULL);
+ ip6_dst_store(sk, dst, NULL, NULL);
}
return dst;
}
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 6a50bb4a0dae..e7aab561b7b4 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -257,7 +257,7 @@ static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
inet->inet_rcv_saddr = LOOPBACK4_IPV6;
sk->sk_gso_type = SKB_GSO_TCPV6;
- __ip6_dst_store(sk, dst, NULL, NULL);
+ ip6_dst_store(sk, dst, NULL, NULL);
if (tcp_death_row.sysctl_tw_recycle &&
!tp->rx_opt.ts_recent_stamp &&
@@ -1060,7 +1060,7 @@ static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *
*/
newsk->sk_gso_type = SKB_GSO_TCPV6;
- __ip6_dst_store(newsk, dst, NULL, NULL);
+ ip6_dst_store(newsk, dst, NULL, NULL);
inet6_sk_rx_dst_set(newsk, skb);
newtcp6sk = (struct tcp6_sock *)newsk;