lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20190215021121.177674-34-sashal@kernel.org>
Date:   Thu, 14 Feb 2019 21:10:50 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Ilya Dryomov <idryomov@...il.com>, Sasha Levin <sashal@...nel.org>,
        ceph-devel@...r.kernel.org, netdev@...r.kernel.org
Subject: [PATCH AUTOSEL 4.19 34/65] libceph: avoid KEEPALIVE_PENDING races in ceph_con_keepalive()

From: Ilya Dryomov <idryomov@...il.com>

[ Upstream commit 4aac9228d16458cedcfd90c7fb37211cf3653ac3 ]

con_fault() can transition the connection into STANDBY right after
ceph_con_keepalive() clears STANDBY in clear_standby():

    libceph user thread               ceph-msgr worker

ceph_con_keepalive()
  mutex_lock(&con->mutex)
  clear_standby(con)
  mutex_unlock(&con->mutex)
                                mutex_lock(&con->mutex)
                                con_fault()
                                  ...
                                  if KEEPALIVE_PENDING isn't set
                                    set state to STANDBY
                                  ...
                                mutex_unlock(&con->mutex)
  set KEEPALIVE_PENDING
  set WRITE_PENDING

This triggers warnings in clear_standby() when either ceph_con_send()
or ceph_con_keepalive() get to clearing STANDBY next time.

I don't see a reason to condition queue_con() call on the previous
value of KEEPALIVE_PENDING, so move the setting of KEEPALIVE_PENDING
into the critical section -- unlike WRITE_PENDING, KEEPALIVE_PENDING
could have been a non-atomic flag.

Reported-by: syzbot+acdeb633f6211ccdf886@...kaller.appspotmail.com
Signed-off-by: Ilya Dryomov <idryomov@...il.com>
Tested-by: Myungho Jung <mhjungk@...il.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 net/ceph/messenger.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 9a1c27c61de8..a127d1442116 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -3240,9 +3240,10 @@ void ceph_con_keepalive(struct ceph_connection *con)
 	dout("con_keepalive %p\n", con);
 	mutex_lock(&con->mutex);
 	clear_standby(con);
+	con_flag_set(con, CON_FLAG_KEEPALIVE_PENDING);
 	mutex_unlock(&con->mutex);
-	if (con_flag_test_and_set(con, CON_FLAG_KEEPALIVE_PENDING) == 0 &&
-	    con_flag_test_and_set(con, CON_FLAG_WRITE_PENDING) == 0)
+
+	if (con_flag_test_and_set(con, CON_FLAG_WRITE_PENDING) == 0)
 		queue_con(con);
 }
 EXPORT_SYMBOL(ceph_con_keepalive);
-- 
2.19.1

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ