passwd: improvements

- add shadow support.
- allow passwd without argument, prompt which user password is changed.
This commit is contained in:
Hiltjo Posthuma 2014-07-10 17:51:51 +00:00 committed by sin
parent a27035c281
commit f48d545c77
6 changed files with 160 additions and 69 deletions

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@ -18,6 +18,7 @@ LIB = \
util/agetcwd.o \
util/agetline.o \
util/apathmax.o \
util/concat.o \
util/ealloc.o \
util/eprintf.o \
util/estrtol.o \

2
TODO
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@ -31,4 +31,4 @@ Misc
====
* Decide what to do with 'bool vs int' debate.
* Beautify passwd(1) + shadow support.
* Beautify passwd(1).

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@ -2,12 +2,10 @@
.SH NAME
\fBpasswd\fR - Change a user's password
.SH SYNOPSIS
\fBpasswd\fR \fIusername\fR
\fBpasswd\fR [\fIusername\fR]
.SH DESCRIPTION
\fBpasswd\fR changes the user's password. The user is prompted
for their current password. If the current password is correctly typed,
a new password is requested. The new password must be entered twice to
avoid typing errors. The superuser is not required to provide a user's
current password.
.SH BUGS
Currently there's no shadow support.

181
passwd.c
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@ -11,51 +11,82 @@
#include <string.h>
#include <unistd.h>
#include <limits.h>
#include <shadow.h>
#include "config.h"
#include "passwd.h"
#include "util.h"
#include "text.h"
static void
usage(void)
{
eprintf("usage: %s username\n", argv0);
eprintf("usage: %s [username]\n", argv0);
}
static int
gettempfile(char *template)
{
int fd;
umask(077);
fd = mkostemp(template, O_RDWR);
if (fd < 0)
weprintf("mkstemp:");
return fd;
}
int
main(int argc, char *argv[])
{
char *pass;
char *cryptpass1 = NULL, *cryptpass2 = NULL, *cryptpass3 = NULL;
char *p;
char shadowfile[PATH_MAX], *inpass, *p, *pwd = NULL;
char template[] = "/tmp/pw.XXXXXX";
uid_t uid;
struct passwd *pw;
int ffd, tfd;
int r;
struct spwd *spw = NULL, *spwent;
uid_t uid;
FILE *fp = NULL, *tfp = NULL;
int ffd = -1, tfd = -1, r, status = EXIT_FAILURE;
ARGBEGIN {
default:
usage();
} ARGEND;
if (argc != 1)
usage();
pw_init();
errno = 0;
if (argc == 0)
pw = getpwuid(getuid());
else
pw = getpwnam(argv[0]);
if (!pw) {
if (errno)
eprintf("getpwnam: %s:", argv[0]);
else if (!pw)
else
eprintf("who are you?\n");
}
if (pw->pw_passwd[0] == 'x' && pw->pw_passwd[1] == '\0')
eprintf("no shadow support\n");
/* is using shadow entry ? */
if (pw->pw_passwd[0] == 'x') {
errno = 0;
spw = getspnam(pw->pw_name);
if (!spw) {
if (errno)
eprintf("getspnam: %s:", pw->pw_name);
else
eprintf("who are you?\n");
}
pwd = spw->sp_pwdp;
} else {
pwd = pw->pw_passwd;
}
uid = getuid();
if (uid == 0) {
if (pw->pw_passwd[0] == '!' ||
pw->pw_passwd[0] == 'x' ||
pw->pw_passwd[0] == '*' ||
pw->pw_passwd[0] == '\0')
pw->pw_passwd = PW_CIPHER;
@ -73,30 +104,29 @@ main(int argc, char *argv[])
/* Flush pending input */
ioctl(STDIN_FILENO, TCFLSH, (void *)0);
pass = getpass("Current password: ");
putchar('\n');
if (!pass)
printf("Changing password for %s\n", pw->pw_name);
inpass = getpass("Old password: ");
if (!inpass)
eprintf("getpass:");
if (pass[0] == '\0')
if (inpass[0] == '\0')
eprintf("no password supplied\n");
p = crypt(pass, pw->pw_passwd);
p = crypt(inpass, pwd);
if (!p)
eprintf("crypt:");
cryptpass1 = estrdup(p);
if (strcmp(cryptpass1, pw->pw_passwd) != 0)
if (strcmp(cryptpass1, pwd) != 0)
eprintf("incorrect password\n");
newpass:
/* Flush pending input */
ioctl(STDIN_FILENO, TCFLSH, (void *)0);
pass = getpass("Enter new password: ");
putchar('\n');
if (!pass)
inpass = getpass("Enter new password: ");
if (!inpass)
eprintf("getpass:");
if (pass[0] == '\0')
if (inpass[0] == '\0')
eprintf("no password supplied\n");
p = crypt(pass, pw->pw_passwd);
p = crypt(inpass, pwd);
if (!p)
eprintf("crypt:");
cryptpass2 = estrdup(p);
@ -106,58 +136,97 @@ newpass:
/* Flush pending input */
ioctl(STDIN_FILENO, TCFLSH, (void *)0);
pass = getpass("Retype new password: ");
putchar('\n');
if (!pass)
inpass = getpass("Retype new password: ");
if (!inpass)
eprintf("getpass:");
if (pass[0] == '\0')
if (inpass[0] == '\0')
eprintf("no password supplied\n");
p = crypt(pass, pw->pw_passwd);
p = crypt(inpass, pwd);
if (!p)
eprintf("crypt:");
cryptpass3 = estrdup(p);
if (strcmp(cryptpass2, cryptpass3) != 0)
eprintf("passwords don't match\n");
r = snprintf(shadowfile, sizeof(shadowfile), "/etc/tcb/%s/shadow", pw->pw_name);
if (r < 0 || (size_t)r >= sizeof(shadowfile))
eprintf("snprintf:");
fp = fopen(shadowfile, "r+");
if (!fp) {
strlcpy(shadowfile, "/etc/shadow", sizeof(shadowfile));
fp = fopen(shadowfile, "r+");
}
if (fp) {
if ((tfd = gettempfile(template)) == -1)
goto cleanup;
/* write to (tcb) shadow file. */
if (!(tfp = fdopen(tfd, "w+"))) {
weprintf("fdopen:");
goto cleanup;
}
while ((spwent = fgetspent(fp))) {
/* update entry on name match */
if (strcmp(spwent->sp_namp, spw->sp_namp) == 0)
spwent->sp_pwdp = cryptpass3;
errno = 0;
if (putspent(spwent, tfp) == -1) {
weprintf("putspent:");
goto cleanup;
}
}
fflush(tfp);
if (fseek(fp, 0, SEEK_SET) == -1 || fseek(tfp, 0, SEEK_SET) == -1) {
weprintf("rewind:");
goto cleanup;
}
/* old shadow file with temporary file data. */
concat(tfp, template, fp, shadowfile);
ftruncate(tfd, ftell(tfp));
} else {
/* write to /etc/passwd file. */
ffd = open("/etc/passwd", O_RDWR);
if (ffd < 0) {
weprintf("open %s:", "/etc/passwd");
goto cleanup;
}
pw->pw_passwd = cryptpass3;
ffd = open("/etc/passwd", O_RDWR);
if (ffd < 0)
eprintf("open %s:", "/etc/passwd");
tfd = mkostemp(template, O_RDWR);
if (tfd < 0)
eprintf("mkstemp:");
if ((tfd = gettempfile(template)) == -1)
goto cleanup;
r = pw_copy(ffd, tfd, pw);
if (r < 0) {
unlink(template);
exit(EXIT_FAILURE);
}
if (r < 0)
goto cleanup;
r = lseek(ffd, 0, SEEK_SET);
if (r < 0) {
unlink(template);
exit(EXIT_FAILURE);
}
if (r < 0)
goto cleanup;
r = lseek(tfd, 0, SEEK_SET);
if (r < 0) {
unlink(template);
exit(EXIT_FAILURE);
}
if (r < 0)
goto cleanup;
r = pw_copy(tfd, ffd, NULL);
if (r < 0) {
unlink(template);
exit(EXIT_FAILURE);
}
close(tfd);
if (r < 0)
goto cleanup;
close(ffd);
}
status = EXIT_SUCCESS;
cleanup:
if (fp)
fclose(fp);
if (tfp)
fclose(tfp);
if (tfd != -1) {
close(tfd);
unlink(template);
}
if (ffd != -1)
close(ffd);
free(cryptpass3);
free(cryptpass2);
free(cryptpass1);
return EXIT_SUCCESS;
return status;
}

2
text.h
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@ -9,3 +9,5 @@ struct linebuf {
void getlines(FILE *, struct linebuf *);
ssize_t agetline(char **, size_t *, FILE *);
void concat(FILE *, const char *, FILE *, const char *);

21
util/concat.c Normal file
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@ -0,0 +1,21 @@
/* See LICENSE file for copyright and license details. */
#include <stdio.h>
#include "../text.h"
#include "../util.h"
void
concat(FILE *fp1, const char *s1, FILE *fp2, const char *s2)
{
char buf[BUFSIZ];
size_t n;
while ((n = fread(buf, 1, sizeof buf, fp1)) > 0) {
if (fwrite(buf, 1, n, fp2) != n)
eprintf("%s: write error:", s2);
if (feof(fp1))
break;
}
if (ferror(fp1))
eprintf("%s: read error:", s1);
}