From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pan Bian Subject: [PATCH] libceph: fix use after free Date: Tue, 27 Nov 2018 15:02:07 +0800 Message-ID: <1543302127-14435-1-git-send-email-bianpan2016@163.com> Cc: ceph-devel@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Pan Bian To: Ilya Dryomov , "Yan, Zheng" , Sage Weil , "David S. Miller" Return-path: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org The function ceph_monc_handle_map calls kfree(old) to free the old monitor map, old points to monc->monmap. However, after that, it reads monc->monmap->epoch and passes it to __ceph_monc_got_map. This result in a use-after-free bug. The patch moves the free operation after the call to __ceph_monc_got_map. Fixes: 82dcabad750("libceph: revamp subs code, switch to SUBSCRIBE2 protocol") Signed-off-by: Pan Bian --- net/ceph/mon_client.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/ceph/mon_client.c b/net/ceph/mon_client.c index 18deb3d..05ef5aa 100644 --- a/net/ceph/mon_client.c +++ b/net/ceph/mon_client.c @@ -478,9 +478,10 @@ static void ceph_monc_handle_map(struct ceph_mon_client *monc, } client->monc.monmap = monmap; - kfree(old); __ceph_monc_got_map(monc, CEPH_SUB_MONMAP, monc->monmap->epoch); + kfree(old); + client->have_fsid = true; out: -- 2.7.4