linux-kernel - [PATCH AUTOSEL 5.4 22/26] cifs: fix missing spinlock around update to ses->status

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]

Date:   Mon,  5 Jul 2021 11:30:35 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Steve French <stfrench@...rosoft.com>,
        Sasha Levin <sashal@...nel.org>, linux-cifs@...r.kernel.org,
        samba-technical@...ts.samba.org
Subject: [PATCH AUTOSEL 5.4 22/26] cifs: fix missing spinlock around update to ses->status

From: Steve French <stfrench@...rosoft.com>

[ Upstream commit 0060a4f28a9ef45ae8163c0805e944a2b1546762 ]

In the other places where we update ses->status we protect the
updates via GlobalMid_Lock. So to be consistent add the same
locking around it in cifs_put_smb_ses where it was missing.

Addresses-Coverity: 1268904 ("Data race condition")
Signed-off-by: Steve French <stfrench@...rosoft.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 fs/cifs/cifsglob.h | 3 ++-
 fs/cifs/connect.c  | 5 ++++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index b16c994414ab..9c0e348cb00f 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -964,7 +964,7 @@ struct cifs_ses {
 	struct mutex session_mutex;
 	struct TCP_Server_Info *server;	/* pointer to server info */
 	int ses_count;		/* reference counter */
-	enum statusEnum status;
+	enum statusEnum status;  /* updates protected by GlobalMid_Lock */
 	unsigned overrideSecFlg;  /* if non-zero override global sec flags */
 	char *serverOS;		/* name of operating system underlying server */
 	char *serverNOS;	/* name of network operating system of server */
@@ -1814,6 +1814,7 @@ require use of the stronger protocol */
  *	list operations on pending_mid_q and oplockQ
  *      updates to XID counters, multiplex id  and SMB sequence numbers
  *      list operations on global DnotifyReqList
+ *      updates to ses->status
  *  tcp_ses_lock protects:
  *	list operations on tcp and SMB session lists
  *  tcon->open_file_lock protects the list of open files hanging off the tcon
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index ab9eeb5ff8e5..da0720f41ebc 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -3049,9 +3049,12 @@ void cifs_put_smb_ses(struct cifs_ses *ses)
 		spin_unlock(&cifs_tcp_ses_lock);
 		return;
 	}
+	spin_unlock(&cifs_tcp_ses_lock);
+
+	spin_lock(&GlobalMid_Lock);
 	if (ses->status == CifsGood)
 		ses->status = CifsExiting;
-	spin_unlock(&cifs_tcp_ses_lock);
+	spin_unlock(&GlobalMid_Lock);
 
 	cifs_free_ipc(ses);
 
-- 
2.30.2