[CIFS] When mandatory encryption on share, fail mount

    When mandatory encryption is configured in samba server on a
    share (smb.conf parameter "smb encrypt = mandatory") the
    server will hang up the tcp session when we try to send
    the first frame after the tree connect if it is not a
    QueryFSUnixInfo, this causes cifs mount to hang (it must
    be killed with ctl-c).  Move the QueryFSUnixInfo call
    earlier in the mount sequence, and check whether the SetFSUnixInfo
    fails due to mandatory encryption so we can return a sensible
    error (EACCES) on mount.

    In a future patch (for 2.6.40) we will support mandatory
    encryption.

CC: Stable <stable@kernel.org>
Reviewed-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <sfrench@us.ibm.com>

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 2e7a79cd2b93b0bef9b8672b039d4ca1a090dafd..581654fb174dfefea0bd171b57490b0f2397f30f 100644 (file)
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -2530,7 +2530,7 @@ void reset_cifs_unix_caps(int xid, struct cifsTconInfo *tcon,
 
        if (!CIFSSMBQFSUnixInfo(xid, tcon)) {
                __u64 cap = le64_to_cpu(tcon->fsUnixInfo.Capability);
-
+               cFYI(1, "unix caps which server supports %lld", cap);
                /* check for reconnect case in which we do not
                   want to change the mount behavior if we can avoid it */
                if (vol_info == NULL) {
@@ -2548,6 +2548,9 @@ void reset_cifs_unix_caps(int xid, struct cifsTconInfo *tcon,
                        }
                }
 
+               if (cap & CIFS_UNIX_TRANSPORT_ENCRYPTION_MANDATORY_CAP)
+                       cERROR(1, "per-share encryption not supported yet");
+
                cap &= CIFS_UNIX_CAP_MASK;
                if (vol_info && vol_info->no_psx_acl)
                        cap &= ~CIFS_UNIX_POSIX_ACL_CAP;
@@ -2596,6 +2599,10 @@ void reset_cifs_unix_caps(int xid, struct cifsTconInfo *tcon,
                        cFYI(1, "very large read cap");
                if (cap & CIFS_UNIX_LARGE_WRITE_CAP)
                        cFYI(1, "very large write cap");
+               if (cap & CIFS_UNIX_TRANSPORT_ENCRYPTION_CAP)
+                       cFYI(1, "transport encryption cap");
+               if (cap & CIFS_UNIX_TRANSPORT_ENCRYPTION_MANDATORY_CAP)
+                       cFYI(1, "mandatory transport encryption cap");
 #endif /* CIFS_DEBUG2 */
                if (CIFSSMBSetFSUnixInfo(xid, tcon, cap)) {
                        if (vol_info == NULL) {
@@ -3022,20 +3029,26 @@ try_mount_again:
                goto remote_path_check;
        }
 
-       /* do not care if following two calls succeed - informational */
-       if (!tcon->ipc) {
-               CIFSSMBQFSDeviceInfo(xid, tcon);
-               CIFSSMBQFSAttributeInfo(xid, tcon);
-       }
-
        /* tell server which Unix caps we support */
-       if (tcon->ses->capabilities & CAP_UNIX)
+       if (tcon->ses->capabilities & CAP_UNIX) {
                /* reset of caps checks mount to see if unix extensions
                   disabled for just this mount */
                reset_cifs_unix_caps(xid, tcon, sb, volume_info);
-       else
+               if ((tcon->ses->server->tcpStatus == CifsNeedReconnect) &&
+                   (le64_to_cpu(tcon->fsUnixInfo.Capability) &
+                    CIFS_UNIX_TRANSPORT_ENCRYPTION_MANDATORY_CAP)) {
+                       rc = -EACCES;
+                       goto mount_fail_check;
+               }
+       } else
                tcon->unix_ext = 0; /* server does not support them */
 
+       /* do not care if following two calls succeed - informational */
+       if (!tcon->ipc) {
+               CIFSSMBQFSDeviceInfo(xid, tcon);
+               CIFSSMBQFSAttributeInfo(xid, tcon);
+       }
+
        /* convert forward to back slashes in prepath here if needed */
        if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS) == 0)
                convert_delimiter(cifs_sb->prepath, CIFS_DIR_SEP(cifs_sb));