09db3d2bc4
database, for use by unprivileged users to verify their own password (in particular for screen savers) thanks to many people for comments
60 lines
1.3 KiB
C
60 lines
1.3 KiB
C
/* $NetBSD: pwauth_suid_helper.c,v 1.1.1.1 2007/01/08 18:39:44 drochner Exp $ */
|
|
|
|
#include <pwd.h>
|
|
#include <string.h>
|
|
#include <errno.h>
|
|
#include <unistd.h>
|
|
|
|
static char pwbuf[_PASSWORD_LEN + 1];
|
|
|
|
int
|
|
main(int argc, char **argv)
|
|
{
|
|
const struct passwd *pwent;
|
|
ssize_t res;
|
|
char *bufptr;
|
|
const char *pwhash;
|
|
size_t buflen;
|
|
|
|
if (argc != 2)
|
|
return (EINVAL);
|
|
|
|
/*
|
|
* mlock(2) pwbuf[]? NetBSD's getpass(3) doesn't,
|
|
* so don't bother for now.
|
|
*/
|
|
|
|
bufptr = pwbuf;
|
|
buflen = sizeof(pwbuf);
|
|
do {
|
|
res = read(STDIN_FILENO, bufptr, buflen);
|
|
if (res < 0)
|
|
return (errno);
|
|
bufptr += res;
|
|
buflen -= res;
|
|
} while (res > 0 && buflen > 0);
|
|
if (buflen == 0)
|
|
return (ENOMEM);
|
|
/* pwbuf is \0-terminated here b/c pwbuf is in bss */
|
|
|
|
/*
|
|
* Use username as key rather than uid so that it will not
|
|
* fail completely if multiple pw entries share a uid.
|
|
* Return same result in "not me" and "doesn't exist" cases
|
|
* to avoid leak of account information.
|
|
*/
|
|
pwent = getpwnam(argv[1]);
|
|
if (!pwent || (pwent->pw_uid != getuid()))
|
|
return (EPERM);
|
|
|
|
/*
|
|
* Forcibly eat up some wall time to prevent use of this program
|
|
* to brute-force? For now assume that process startup time etc.
|
|
* make it already ineffective.
|
|
*/
|
|
pwhash = crypt(pwbuf, pwent->pw_passwd);
|
|
if (pwhash && strcmp(pwhash, pwent->pw_passwd) == 0)
|
|
return (0);
|
|
|
|
return (EAUTH);
|
|
}
|