Pam-list Digest, Vol 42, Issue 3

[Dan Yefimov]

On Sun, 5 Aug 2007, Chu Qiu wrote:

> I get some new results , but i don't unterstand what's going on?
>  
> 1. I login the system as root , and complied my code , then run it ,
> everything is ok
> 2. I login the system as no-root , run the program complied by root , get
> this code "PAM_AUTHINFO_UNAVAIL"

pam_unix.so, as it was said previously, requires access to /etc/shadow, which
is of course denied to processes not running as root.

> 3. I login the system as no-root , complied my code ,then run the program ,
> get this code "PAM_AUTHINFO_UNAVAIL"

The same notice as above is applicable here.

> 4. I login the system as no-root ,then run "sudo chmod u+s check_user" on
> the program i just complied,  run it ,
>  I get the code "PAM_AUTHINFO_UNAVAIL"
> 

'chmod u+s check_user' makes your program setuid to the owner of the file 
'check_user', which is, af far as I got you, non-root.
-- 

    Sincerely Your, Dan.