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: <20191211150247.522356509@linuxfoundation.org>
Date:   Wed, 11 Dec 2019 16:05:54 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Pavel Shilovsky <pshilov@...rosoft.com>,
        Steve French <stfrench@...rosoft.com>
Subject: [PATCH 5.3 065/105] CIFS: Fix SMB2 oplock break processing

From: Pavel Shilovsky <pshilov@...rosoft.com>

commit fa9c2362497fbd64788063288dc4e74daf977ebb upstream.

Even when mounting modern protocol version the server may be
configured without supporting SMB2.1 leases and the client
uses SMB2 oplock to optimize IO performance through local caching.

However there is a problem in oplock break handling that leads
to missing a break notification on the client who has a file
opened. It latter causes big latencies to other clients that
are trying to open the same file.

The problem reproduces when there are multiple shares from the
same server mounted on the client. The processing code tries to
match persistent and volatile file ids from the break notification
with an open file but it skips all share besides the first one.
Fix this by looking up in all shares belonging to the server that
issued the oplock break.

Cc: Stable <stable@...r.kernel.org>
Signed-off-by: Pavel Shilovsky <pshilov@...rosoft.com>
Signed-off-by: Steve French <stfrench@...rosoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 fs/cifs/smb2misc.c |    7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

--- a/fs/cifs/smb2misc.c
+++ b/fs/cifs/smb2misc.c
@@ -673,10 +673,10 @@ smb2_is_valid_oplock_break(char *buffer,
 	spin_lock(&cifs_tcp_ses_lock);
 	list_for_each(tmp, &server->smb_ses_list) {
 		ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
+
 		list_for_each(tmp1, &ses->tcon_list) {
 			tcon = list_entry(tmp1, struct cifs_tcon, tcon_list);
 
-			cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
 			spin_lock(&tcon->open_file_lock);
 			list_for_each(tmp2, &tcon->openFileList) {
 				cfile = list_entry(tmp2, struct cifsFileInfo,
@@ -688,6 +688,8 @@ smb2_is_valid_oplock_break(char *buffer,
 					continue;
 
 				cifs_dbg(FYI, "file id match, oplock break\n");
+				cifs_stats_inc(
+				    &tcon->stats.cifs_stats.num_oplock_brks);
 				cinode = CIFS_I(d_inode(cfile->dentry));
 				spin_lock(&cfile->file_info_lock);
 				if (!CIFS_CACHE_WRITE(cinode) &&
@@ -720,9 +722,6 @@ smb2_is_valid_oplock_break(char *buffer,
 				return true;
 			}
 			spin_unlock(&tcon->open_file_lock);
-			spin_unlock(&cifs_tcp_ses_lock);
-			cifs_dbg(FYI, "No matching file for oplock break\n");
-			return true;
 		}
 	}
 	spin_unlock(&cifs_tcp_ses_lock);


Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ