Ubuntu SecurityFlags at boot

It would be possible to build cifs.ko to enable plain text passwords permanently, but may be simpler to just set this in one of the init scripts. Generally we want to discourage anyone from using authentication types other than ntlmv2 and kerberos for obvious security reasons.

Quoted 3 lines · On Sun, Aug 5, 2012 at 6:31 AM, <blueduck@...> wrote:

Hi,

Looking at fs/cifs/README, I managed to mount shares with plaintext > passwords (using Kubuntu 12.04)

with "echo 0x30030 > /proc/fs/cifs/SecurityFlags". But it as to be done after each boot.

Quoted 2 lines

Is there any configuration file to modify to make the change permanent?

I hope it's not too late to reply to this thread from August 2012, and that someone can please find time to explain to me how to set security flags for CIFS.

In a nutshell I'm trying to connect a freshly installed ubuntu 12.04 desktop as a client to get files from an old samba server that demands passwords as plaintext. No printing, nothing fancy, just file service.

Is there still a feature in Ubuntu 12.04 to allow this, possibly by manipulating these security flags?

I'm basically doing just this:

sudo mount -t cifs //myoldtiredserver/lott /mnt

And watching /var/log/kern.log I see this:

Oct  1 18:14:57 cltp kernel: [ 3397.554888] CIFS VFS: Server requests 
plain text password but client support disabled
Oct  1 18:14:57 cltp kernel: [ 3397.616357] CIFS VFS: cifs_mount failed 

w/return code = -13

All attempts to echo a value to a magic file in /proc/fs/cifs such as the one shown below are met with permission denied, even with sudo:

$ sudo echo 0x30030 > /proc/fs/cifs/SecurityFlags
bash: /proc/fs/cifs/SecurityFlags: Permission denied

Please let me know if I'm not asking sensible questions. :/ Thanks in advance for any help!

The sudo in the above command just covers the echo command. The shell redirection (and hence the write to SecurityFlags) is done as the original user, which is why you're getting EACCES. You probably want to do something like this to ensure that the shell redirection is done as root as well:

     $ sudo sh -c "echo 0x30030 > /proc/fs/cifs/SecurityFlags"

Thank you so much for explaining what should have been utterly obvious.
It worked perfectly when I did this:

% sudo -i

# echo 0x30030 > /proc/fs/cifs/SecurityFlags
# mount -t cifs //myoldtiredserver/lott /mnt

I'm still getting used to using echo for communicating with a kernel module but that's just gonna take time :)

Quoted 8 lines · Jeff Layton

The sudo in the above command just covers the echo command. The shell redirection (and hence the write to SecurityFlags) is done as the original user, which is why you're getting EACCES. You probably want to do something like this to ensure that the shell redirection is done as root as well:

     $ sudo sh -c "echo 0x30030 > /proc/fs/cifs/SecurityFlags"