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authorCong Wang <xiyou.wangcong@gmail.com>2018-10-11 21:15:13 +0300
committerDavid S. Miller <davem@davemloft.net>2018-10-16 08:01:37 +0300
commit5a8e7aea953bdb6d4da13aff6f1e7f9c62023499 (patch)
treeeadd98d8a321daa8892ba298d62000ed3eb86fca /net/llc
parentd0f068e5720ac4eea13e184bb7526848f189f909 (diff)
downloadlinux-5a8e7aea953bdb6d4da13aff6f1e7f9c62023499.tar.xz
llc: set SOCK_RCU_FREE in llc_sap_add_socket()
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>
Diffstat (limited to 'net/llc')
-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 c0ac522b48a1..4ff89cb7c86f 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);