[082/146] [CIFS] When mandatory encryption on share, fail mount

Greg KH
2011-06-01T09:16:51Z

From: Steve French <sfrench@us.ibm.com>

commit 6848b7334b24b47aa3d0e70342ff839ffa95d5fa upstream.

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.

Reviewed-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
fs/cifs/connect.c | 31 ++++++++++++++++++++++---------
1 file changed, 22 insertions(+), 9 deletions(-)

--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -2431,7 +2431,7 @@ void reset_cifs_unix_caps(int xid, struc

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) {
@@ -2449,6 +2449,9 @@ void reset_cifs_unix_caps(int xid, struc
}
}

+ 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;
@@ -2497,6 +2500,10 @@ void reset_cifs_unix_caps(int xid, struc
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) {
@@ -2815,20 +2822,26 @@ 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));