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authorEric Dumazet <edumazet@google.com>2017-10-08 21:44:52 -0700
committerDavid S. Miller <davem@davemloft.net>2017-10-09 20:55:01 -0700
commitfbb1fb4ad415cb31ce944f65a5ca700aaf73a227 (patch)
treea7b1d3fddab2353229b73daaa103904ce539414d
parentnet: memcontrol: defer call to mem_cgroup_sk_alloc() (diff)
downloadlinux-dev-fbb1fb4ad415cb31ce944f65a5ca700aaf73a227.tar.xz
linux-dev-fbb1fb4ad415cb31ce944f65a5ca700aaf73a227.zip
net: defer call to cgroup_sk_alloc()
sk_clone_lock() might run while TCP/DCCP listener already vanished. In order to prevent use after free, it is better to defer cgroup_sk_alloc() to the point we know both parent and child exist, and from process context. Fixes: e994b2f0fb92 ("tcp: do not lock listener to process SYN packets") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--kernel/cgroup/cgroup.c11
-rw-r--r--net/core/sock.c3
-rw-r--r--net/ipv4/inet_connection_sock.c5
3 files changed, 6 insertions, 13 deletions
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 44857278eb8a..3380a3e49af5 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -5709,17 +5709,6 @@ void cgroup_sk_alloc(struct sock_cgroup_data *skcd)
if (cgroup_sk_alloc_disabled)
return;
- /* Socket clone path */
- if (skcd->val) {
- /*
- * We might be cloning a socket which is left in an empty
- * cgroup and the cgroup might have already been rmdir'd.
- * Don't use cgroup_get_live().
- */
- cgroup_get(sock_cgroup_ptr(skcd));
- return;
- }
-
rcu_read_lock();
while (true) {
diff --git a/net/core/sock.c b/net/core/sock.c
index 70c6ccbdf49f..4499e3153813 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1680,6 +1680,7 @@ struct sock *sk_clone_lock(const struct sock *sk, const gfp_t priority)
/* sk->sk_memcg will be populated at accept() time */
newsk->sk_memcg = NULL;
+ memset(&newsk->sk_cgrp_data, 0, sizeof(newsk->sk_cgrp_data));
atomic_set(&newsk->sk_drops, 0);
newsk->sk_send_head = NULL;
@@ -1718,8 +1719,6 @@ struct sock *sk_clone_lock(const struct sock *sk, const gfp_t priority)
newsk->sk_incoming_cpu = raw_smp_processor_id();
atomic64_set(&newsk->sk_cookie, 0);
- cgroup_sk_alloc(&newsk->sk_cgrp_data);
-
/*
* Before updating sk_refcnt, we must commit prior changes to memory
* (Documentation/RCU/rculist_nulls.txt for details)
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 67aec7a10686..d32c74507314 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -26,6 +26,8 @@
#include <net/tcp.h>
#include <net/sock_reuseport.h>
#include <net/addrconf.h>
+#include <net/cls_cgroup.h>
+#include <net/netprio_cgroup.h>
#ifdef INET_CSK_DEBUG
const char inet_csk_timer_bug_msg[] = "inet_csk BUG: unknown timer value\n";
@@ -476,6 +478,9 @@ struct sock *inet_csk_accept(struct sock *sk, int flags, int *err, bool kern)
spin_unlock_bh(&queue->fastopenq.lock);
}
mem_cgroup_sk_alloc(newsk);
+ cgroup_sk_alloc(&newsk->sk_cgrp_data);
+ sock_update_classid(&newsk->sk_cgrp_data);
+ sock_update_netprioidx(&newsk->sk_cgrp_data);
out:
release_sock(sk);
if (req)