[blfs-support] Su and Sudo--Getting Both to Work

William Harrington kb0iic at berzerkula.org
Mon Dec 2 20:04:13 PST 2013

On Dec 2, 2013, at 4:44 PM, Dan McGhee wrote:

> I reset root's password and then realized I, when I tried to run su,  
> may
> have been misleading in this post. The actual return I get is:
> Crypt: Invalid argument

It's always helpful to run strace to get a better idea of what is  
going on.

Also, it helps to have the exact message. I see crypt: Invalid  
argument, I have also seen Crypt: Invalid Argument, and lots of upper  
and lower case differences between other people and their posts.

Give the exact message.

Crypt(3) is this:

char *crypt(const char *key, const char *salt);

When you have something not correct with your configuration you will  
get a problem.

Usually it is from an invalid seed. Especially when using an invalid  
salt format. When the password is set a second time, after login.defs  
is set and you setup sudo (especially when using cracklib and setting  
up sudo for login and passwd),  you may need to reset the root passwd  
for a valid salt. Not too sure about that, but that is what I'm  


William Harrington

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