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authorCong Wang <xiyou.wangcong@gmail.com>2018-09-10 18:27:26 -0700
committerDavid S. Miller <davem@davemloft.net>2018-09-12 00:09:19 -0700
commitcc4dfb7f70a344f24c1c71e298deea0771dadcb2 (patch)
treedd8d719e691092423031333cf0b834623f432086 /net/rds
parent6ad569019999300afd8e614d296fdc356550b77f (diff)
downloadlinux-stericsson-cc4dfb7f70a344f24c1c71e298deea0771dadcb2.tar.gz
rds: fix two RCU related problems
When a rds sock is bound, it is inserted into the bind_hash_table which is protected by RCU. But when releasing rds sock, after it is removed from this hash table, it is freed immediately without respecting RCU grace period. This could cause some use-after-free as reported by syzbot. Mark the rds sock with SOCK_RCU_FREE before inserting it into the bind_hash_table, so that it would be always freed after a RCU grace period. The other problem is in rds_find_bound(), the rds sock could be freed in between rhashtable_lookup_fast() and rds_sock_addref(), so we need to extend RCU read lock protection in rds_find_bound() to close this race condition. Reported-and-tested-by: syzbot+8967084bcac563795dc6@syzkaller.appspotmail.com Reported-by: syzbot+93a5839deb355537440f@syzkaller.appspotmail.com Cc: Sowmini Varadhan <sowmini.varadhan@oracle.com> Cc: Santosh Shilimkar <santosh.shilimkar@oracle.com> Cc: rds-devel@oss.oracle.com Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Acked-by: Santosh Shilimkar <santosh.shilimkar@oarcle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/rds')
-rw-r--r--net/rds/bind.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/net/rds/bind.c b/net/rds/bind.c
index 3ab55784b637..762d2c6788a3 100644
--- a/net/rds/bind.c
+++ b/net/rds/bind.c
@@ -76,11 +76,13 @@ struct rds_sock *rds_find_bound(const struct in6_addr *addr, __be16 port,
struct rds_sock *rs;
__rds_create_bind_key(key, addr, port, scope_id);
- rs = rhashtable_lookup_fast(&bind_hash_table, key, ht_parms);
+ rcu_read_lock();
+ rs = rhashtable_lookup(&bind_hash_table, key, ht_parms);
if (rs && !sock_flag(rds_rs_to_sk(rs), SOCK_DEAD))
rds_sock_addref(rs);
else
rs = NULL;
+ rcu_read_unlock();
rdsdebug("returning rs %p for %pI6c:%u\n", rs, addr,
ntohs(port));
@@ -235,6 +237,7 @@ int rds_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
goto out;
}
+ sock_set_flag(sk, SOCK_RCU_FREE);
ret = rds_add_bound(rs, binding_addr, &port, scope_id);
if (ret)
goto out;