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 09:15:24 +0100 |
| commit | 605387c7c69972a5b9b53571e01a4825e2affe08 (patch) | |
| tree | 8c1baddd4486a28ab662f94e3816f1227e2aaeff /fs/cifs | |
| parent | 088f75885bb41dd587af216f0b4b070f239dc0bf (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 f7a9adab0b84..6f5d78b172ba 100644 --- a/fs/cifs/smb1ops.c +++ b/fs/cifs/smb1ops.c @@ -180,6 +180,9 @@ 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. |