check Linux password from /etc/shadow and C language

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

Using the encrypted password of the shadow file

i have an application that uses the encrypted password that's in the /etc/shadow file. i copied the line for the particular username i was interested it in from shadow file and i pasted it into the password file of the application. the application is nagios. this application allowed that...

2. Shell Programming and Scripting

Users who have never changed their password from /etc/shadow.

Hello, I have to do a script which returns users who have never changed their password from /etc/shadow. Here is what have I done and I'm not sure if it's ok. I tried to return just users who doesn;t have password set or are locked. Can be there other kind of user who never changed the...

3. Red Hat

Shadow file password policy

Today i was going through some of security guides written on linux . Under shadow file security following points were mentioned. 1)The encrypted password stored under /etc/shadow file should have more than 14-25 characters. 2)Usernames in shadow file must satisfy to all the same rules as...

4. UNIX for Advanced & Expert Users

/etc/shadow encrypted password

Hi I wonder whether is possible to generate enrypted passwd for some user and paste it into /etc/shadow file ? What kind of encryption is used in /etc/shadow file ? ths for help.

5. Solaris

Password Recovery From /etc/shadow file

Is it possible to reset a normal user password , by editing password field in /etc/shadow file? Thanks

6. Solaris

hash password in shadow show 'x' ???

Hello, I want to know the reason behing the scene why some systems have hashed password in /etc/shadow file as "x" not the alienoid language like A1Dksxi3kaA.. (13 characters) As far as I understand, etc/password will show password as "x" and move all hashed password to etc/shadow....

7. Linux

Interpreting the encrypted shadow password?

We are currently using a script to copy the same encrypted password between our HP-UX and Solaris servers editing the trusted and shadow files directly. The encrypted password is only 13 characters long on both servers and decrypts the same way. Is there a way to copy this same string to Linux...

8. UNIX for Dummies Questions & Answers

shadow file after a password reset

hi, I had to reset a lost root password by editing the /etc/passwd and /etc/shadow files ( this is a xen vm file, so i mounted and chrooted the file ) after the reboot with an empty password on root , i have set a new password with passwd but it only changed the /etc/passwd file....

9. Shell Programming and Scripting

I want to append password in /etc/shadow file

Hi, I want to append password into /etc/shadow file using a shell script. My below script does add the users to both /etc/passwd and /etc/shadow but how can I add the hordcoded passwords to /etc/shadow file can some one help me ? # To add the groups into /etc/group file for a_user...

10. UNIX for Dummies Questions & Answers

remove shadow password

Does anyone know how to remove a stanza in the shadow password file if the user account has already been removed on an AIX box? I know it can be done by editing the file itself but I would prefer not to do it that way. cheers gizaa

LEARN ABOUT MINIX

pwdauth

PWDAUTH()																 PWDAUTH()

NAME

       pwdauth - password authentication program

SYNOPSIS

       /usr/lib/pwdauth

DESCRIPTION

       Pwdauth is a program that is used by the crypt(3) function to do the hard work.	It is a setuid root utility so that it is able to read the
       shadow password file.

       Pwdauth expects on standard input two null terminated strings, the password typed by the user, and the salt.  That is, the two arguments of
       the  crypt  function.   The input read in a single read call must be 1024 characters or less including the nulls.  Pwdauth takes one of two
       actions depending on the salt.

       If the salt has the form "##user" then the user is used to index the shadow password file to obtain  the  encrypted  password.	The  input
       password  is encrypted with the one-way encryption function contained within pwdauth and compared to the encrypted password from the shadow
       password file.  If equal then pwdauth returns the string "##user" with exit code 0, otherwise exit code 2 to signal  failure.   The  string
       "##user" is also returned if both the shadow password and the input password are null strings to allow a password-less login.

       If  the salt is not of the form "##user" then the password is encrypted and the result of the encryption is returned.  If salt and password
       are null strings then a null string is returned.

       The return value is written to standard output as a null terminated string of 1024 characters or less including the null.

       The exit code is 1 on any error.

SEE ALSO

       crypt(3), passwd(5).

NOTES

       A password must be checked like in this example:

	      pw_ok = (strcmp(crypt(key, pw->pw_passwd), pw->pw_passwd) == 0);

       The second argument of crypt must be the entire encrypted password and not just the two character salt.

AUTHOR

       Kees J. Bot (kjb@cs.vu.nl)

																	 PWDAUTH()

Programming