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authorCong Wang <xiyou.wangcong@gmail.com>2018-10-11 11:15:13 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-11-10 07:42:57 -0800
commitaa23c2207d2911d04df76001cd98d212cedfe69b (patch)
tree207c7cf6fe3d89786a6b545b2426a4948e6c2364 /net
parent510e6c3bd51ac59c0ff2296c2ce84529ac7cfbfc (diff)
llc: set SOCK_RCU_FREE in llc_sap_add_socket()
[ Upstream commit 5a8e7aea953bdb6d4da13aff6f1e7f9c62023499 ] WHen an llc sock is added into the sk_laddr_hash of an llc_sap, it is not marked with SOCK_RCU_FREE. This causes that the sock could be freed while it is still being read by __llc_lookup_established() with RCU read lock. sock is refcounted, but with RCU read lock, nothing prevents the readers getting a zero refcnt. Fix it by setting SOCK_RCU_FREE in llc_sap_add_socket(). Reported-by: syzbot+11e05f04c15e03be5254@syzkaller.appspotmail.com Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
-rw-r--r--net/llc/llc_conn.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/net/llc/llc_conn.c b/net/llc/llc_conn.c
index 79c346fd859b..b9290a183a2f 100644
--- a/net/llc/llc_conn.c
+++ b/net/llc/llc_conn.c
@@ -734,6 +734,7 @@ void llc_sap_add_socket(struct llc_sap *sap, struct sock *sk)
llc_sk(sk)->sap = sap;
spin_lock_bh(&sap->sk_lock);
+ sock_set_flag(sk, SOCK_RCU_FREE);
sap->sk_count++;
sk_nulls_add_node_rcu(sk, laddr_hb);
hlist_add_head(&llc->dev_hash_node, dev_hb);