diff options
| author | Roberto Bergantinos Corpas <rbergant@redhat.com> | 2019-10-14 10:59:23 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-10-29 09:20:01 +0100 |
| commit | 71cf88165ff0ac8c9dc570536542e409bea41281 (patch) | |
| tree | 362cc73a98be47ffa21fa2ae4d09008726416fc4 /fs/cifs | |
| parent | 4292745536d22a2320fe262fa181cb88ec9ba94a (diff) | |
CIFS: avoid using MID 0xFFFF
commit 03d9a9fe3f3aec508e485dd3dcfa1e99933b4bdb upstream.
According to MS-CIFS specification MID 0xFFFF should not be used by the
CIFS client, but we actually do. Besides, this has proven to cause races
leading to oops between SendReceive2/cifs_demultiplex_thread. On SMB1,
MID is a 2 byte value easy to reach in CurrentMid which may conflict with
an oplock break notification request coming from server
Signed-off-by: Roberto Bergantinos Corpas <rbergant@redhat.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/cifs')
| -rw-r--r-- | fs/cifs/smb1ops.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/cifs/smb1ops.c b/fs/cifs/smb1ops.c index 47db8eb6cbcf..c7f0c8566442 100644 --- a/fs/cifs/smb1ops.c +++ b/fs/cifs/smb1ops.c @@ -183,6 +183,9 @@ cifs_get_next_mid(struct TCP_Server_Info *server) /* we do not want to loop forever */ last_mid = cur_mid; cur_mid++; + /* avoid 0xFFFF MID */ + if (cur_mid == 0xffff) + cur_mid++; /* * This nested loop looks more expensive than it is. |