Getpwnam no such file or directory

[James889]

Hi,

I'm trying to write a simple authentication plugin which authenticates a user against /etc/master.passwd.
The problem is the call to getpwnam() which fails with 'no such file or directory'

Relevant code below

char username[10];
memset(username,0,sizeof(username));

/* Read the username */
        printf("Username:");
        fgets(username,sizeof(username),stdin);        /* Read the password */
        crypt_set_format("sha512");
        char *pass;
        pass = getpass("password:");
        char *p = (char *)calloc(strlen(pass),sizeof(char));         strlcpy(p,crypt(pass,salt),sizeof(p));
         struct passwd *local_pass = getpwnam(username);
                if( local_pass == NULL){
                printf("%s",strerror(errno));
                exit(1);
        }

Replacing the reference to the username buffer with "<actual username>" works.
Any ideas?

 

[jim mcnamara]

Your username string has a trailing '\n' remove it and your call will work.

 

[James889]

Duh, silly newbie mistake :)

 

[jim mcnamara]

Well, it looks like you are trying to duplicate what the getlogin modules already do. That is not an easy to duplicate: FreeBSD pam modules are going to be different from box to box, so this will have zero portability. Any-hoo, get and read the FreeBSD source before attempting something like this, just so you no longer think this is a slam dunk if nothing else. It is okay to pilfer and use what hundreds of programmers have already worked on for years, and tried to perfect. That is the whole idea of opensource.

 

[James889]

There seems to be a similar situation with the hashed password found in master.password and the hash generated by crypt(),
they are different, despite hashing being done on the same clear text password. In this case there are no trailing newlines.