busybox/loginutils/passwd.c
2006-07-16 08:06:34 +00:00

398 lines
8.8 KiB
C

/* vi: set sw=4 ts=4: */
/*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <signal.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <utime.h>
#include <syslog.h>
#include <time.h>
#include <sys/resource.h>
#include <errno.h>
#include "busybox.h"
static char crypt_passwd[128];
static int create_backup(const char *backup, FILE * fp);
static int new_password(const struct passwd *pw, int amroot, int algo);
static void set_filesize_limit(int blocks);
static int get_algo(char *a)
{
int x = 1; /* standard: MD5 */
if (strcasecmp(a, "des") == 0)
x = 0;
return x;
}
static int update_passwd(const struct passwd *pw, const char *crypt_pw)
{
char filename[1024];
char buf[1025];
char buffer[80];
char username[32];
char *pw_rest;
int mask;
int continued;
FILE *fp;
FILE *out_fp;
struct stat sb;
struct flock lock;
#if ENABLE_FEATURE_SHADOWPASSWDS
if (access(bb_path_shadow_file, F_OK) == 0) {
snprintf(filename, sizeof filename, "%s", bb_path_shadow_file);
} else
#endif
{
snprintf(filename, sizeof filename, "%s", bb_path_passwd_file);
}
if (((fp = fopen(filename, "r+")) == 0) || (fstat(fileno(fp), &sb))) {
/* return 0; */
return 1;
}
/* Lock the password file before updating */
lock.l_type = F_WRLCK;
lock.l_whence = SEEK_SET;
lock.l_start = 0;
lock.l_len = 0;
if (fcntl(fileno(fp), F_SETLK, &lock) < 0) {
fprintf(stderr, "%s: %s\n", filename, strerror(errno));
return 1;
}
lock.l_type = F_UNLCK;
snprintf(buf, sizeof buf, "%s-", filename);
if (create_backup(buf, fp)) {
fcntl(fileno(fp), F_SETLK, &lock);
fclose(fp);
return 1;
}
snprintf(buf, sizeof buf, "%s+", filename);
mask = umask(0777);
out_fp = fopen(buf, "w");
umask(mask);
if ((!out_fp) || (fchmod(fileno(out_fp), sb.st_mode & 0777))
|| (fchown(fileno(out_fp), sb.st_uid, sb.st_gid))) {
fcntl(fileno(fp), F_SETLK, &lock);
fclose(fp);
fclose(out_fp);
return 1;
}
continued = 0;
snprintf(username, sizeof username, "%s:", pw->pw_name);
rewind(fp);
while (!feof(fp)) {
fgets(buffer, sizeof buffer, fp);
if (!continued) { /* Check to see if we're updating this line. */
if (strncmp(username, buffer, strlen(username)) == 0) {
/* we have a match. */
pw_rest = strchr(buffer, ':');
*pw_rest++ = '\0';
pw_rest = strchr(pw_rest, ':');
fprintf(out_fp, "%s:%s%s", buffer, crypt_pw, pw_rest);
} else {
fputs(buffer, out_fp);
}
} else {
fputs(buffer, out_fp);
}
if (buffer[strlen(buffer) - 1] == '\n') {
continued = 0;
} else {
continued = 1;
}
memset(buffer, 0, sizeof buffer);
}
if (fflush(out_fp) || fsync(fileno(out_fp)) || fclose(out_fp)) {
unlink(buf);
fcntl(fileno(fp), F_SETLK, &lock);
fclose(fp);
return 1;
}
if (rename(buf, filename) < 0) {
fcntl(fileno(fp), F_SETLK, &lock);
fclose(fp);
return 1;
} else {
fcntl(fileno(fp), F_SETLK, &lock);
fclose(fp);
return 0;
}
}
int passwd_main(int argc, char **argv)
{
int amroot;
char *cp;
char *np;
char *name;
char *myname;
int flag;
int algo = 1; /* -a - password algorithm */
int lflg = 0; /* -l - lock account */
int uflg = 0; /* -u - unlock account */
int dflg = 0; /* -d - delete password */
const struct passwd *pw;
amroot = (getuid() == 0);
openlog("passwd", LOG_PID | LOG_CONS | LOG_NOWAIT, LOG_AUTH);
while ((flag = getopt(argc, argv, "a:dlu")) != EOF) {
switch (flag) {
case 'a':
algo = get_algo(optarg);
break;
case 'd':
dflg++;
break;
case 'l':
lflg++;
break;
case 'u':
uflg++;
break;
default:
bb_show_usage();
}
}
myname = (char *) bb_xstrdup(bb_getpwuid(NULL, getuid(), -1));
/* exits on error */
if (optind < argc) {
name = argv[optind];
} else {
name = myname;
}
if ((lflg || uflg || dflg) && (optind >= argc || !amroot)) {
bb_show_usage();
}
pw = getpwnam(name);
if (!pw) {
bb_error_msg_and_die("Unknown user %s\n", name);
}
if (!amroot && pw->pw_uid != getuid()) {
syslog(LOG_WARNING, "can't change pwd for `%s'", name);
bb_error_msg_and_die("Permission denied.\n");
}
if (ENABLE_FEATURE_SHADOWPASSWDS) {
struct spwd *sp = getspnam(name);
if (!sp) bb_error_msg_and_die("Unknown user %s", name);
cp = sp->sp_pwdp;
} else cp = pw->pw_passwd;
np = name;
safe_strncpy(crypt_passwd, cp, sizeof(crypt_passwd));
if (!(dflg || lflg || uflg)) {
if (!amroot) {
if (cp[0] == '!') {
syslog(LOG_WARNING, "password locked for `%s'", np);
bb_error_msg_and_die( "The password for `%s' cannot be changed.\n", np);
}
}
printf("Changing password for %s\n", name);
if (new_password(pw, amroot, algo)) {
bb_error_msg_and_die( "The password for %s is unchanged.\n", name);
}
} else if (lflg) {
if (crypt_passwd[0] != '!') {
memmove(&crypt_passwd[1], crypt_passwd,
sizeof crypt_passwd - 1);
crypt_passwd[sizeof crypt_passwd - 1] = '\0';
crypt_passwd[0] = '!';
}
} else if (uflg) {
if (crypt_passwd[0] == '!') {
memmove(crypt_passwd, &crypt_passwd[1],
sizeof crypt_passwd - 1);
}
} else if (dflg) {
crypt_passwd[0] = '\0';
}
set_filesize_limit(30000);
signal(SIGHUP, SIG_IGN);
signal(SIGINT, SIG_IGN);
signal(SIGQUIT, SIG_IGN);
umask(077);
xsetuid(0);
if (!update_passwd(pw, crypt_passwd)) {
syslog(LOG_INFO, "password for `%s' changed by user `%s'", name,
myname);
printf("Password changed.\n");
} else {
syslog(LOG_WARNING, "an error occurred updating the password file");
bb_error_msg_and_die("An error occurred updating the password file.\n");
}
if (ENABLE_FEATURE_CLEAN_UP) free(myname);
return (0);
}
static int create_backup(const char *backup, FILE * fp)
{
struct stat sb;
struct utimbuf ub;
FILE *bkfp;
int c, mask;
if (fstat(fileno(fp), &sb))
/* return -1; */
return 1;
mask = umask(077);
bkfp = fopen(backup, "w");
umask(mask);
if (!bkfp)
/* return -1; */
return 1;
/* TODO: faster copy, not one-char-at-a-time. --marekm */
rewind(fp);
while ((c = getc(fp)) != EOF) {
if (putc(c, bkfp) == EOF)
break;
}
if (c != EOF || fflush(bkfp)) {
fclose(bkfp);
/* return -1; */
return 1;
}
if (fclose(bkfp))
/* return -1; */
return 1;
ub.actime = sb.st_atime;
ub.modtime = sb.st_mtime;
utime(backup, &ub);
return 0;
}
static int i64c(int i)
{
if (i <= 0)
return ('.');
if (i == 1)
return ('/');
if (i >= 2 && i < 12)
return ('0' - 2 + i);
if (i >= 12 && i < 38)
return ('A' - 12 + i);
if (i >= 38 && i < 63)
return ('a' - 38 + i);
return ('z');
}
static char *crypt_make_salt(void)
{
time_t now;
static unsigned long x;
static char result[3];
time(&now);
x += now + getpid() + clock();
result[0] = i64c(((x >> 18) ^ (x >> 6)) & 077);
result[1] = i64c(((x >> 12) ^ x) & 077);
result[2] = '\0';
return result;
}
static int new_password(const struct passwd *pw, int amroot, int algo)
{
char *clear;
char *cipher;
char *cp;
char salt[12]; /* "$N$XXXXXXXX" or "XX" */
char orig[200];
char pass[200];
if (!amroot && crypt_passwd[0]) {
if (!(clear = bb_askpass(0, "Old password:"))) {
/* return -1; */
return 1;
}
cipher = pw_encrypt(clear, crypt_passwd);
if (strcmp(cipher, crypt_passwd) != 0) {
syslog(LOG_WARNING, "incorrect password for `%s'",
pw->pw_name);
bb_do_delay(FAIL_DELAY);
fprintf(stderr, "Incorrect password.\n");
/* return -1; */
return 1;
}
safe_strncpy(orig, clear, sizeof(orig));
memset(clear, 0, strlen(clear));
memset(cipher, 0, strlen(cipher));
} else {
orig[0] = '\0';
}
if (! (cp=bb_askpass(0, "Enter the new password (minimum of 5, maximum of 8 characters)\n"
"Please use a combination of upper and lower case letters and numbers.\n"
"Enter new password: ")))
{
memset(orig, 0, sizeof orig);
/* return -1; */
return 1;
}
safe_strncpy(pass, cp, sizeof(pass));
memset(cp, 0, strlen(cp));
/* if (!obscure(orig, pass, pw)) { */
if (obscure(orig, pass, pw)) {
if (amroot) {
printf("\nWarning: weak password (continuing).\n");
} else {
/* return -1; */
return 1;
}
}
if (!(cp = bb_askpass(0, "Re-enter new password: "))) {
memset(orig, 0, sizeof orig);
/* return -1; */
return 1;
}
if (strcmp(cp, pass)) {
fprintf(stderr, "Passwords do not match.\n");
/* return -1; */
return 1;
}
memset(cp, 0, strlen(cp));
memset(orig, 0, sizeof(orig));
memset(salt, 0, sizeof(salt));
if (algo == 1) {
strcpy(salt, "$1$");
strcat(salt, crypt_make_salt());
strcat(salt, crypt_make_salt());
strcat(salt, crypt_make_salt());
}
strcat(salt, crypt_make_salt());
cp = pw_encrypt(pass, salt);
memset(pass, 0, sizeof pass);
safe_strncpy(crypt_passwd, cp, sizeof(crypt_passwd));
return 0;
}
static void set_filesize_limit(int blocks)
{
struct rlimit rlimit_fsize;
rlimit_fsize.rlim_cur = rlimit_fsize.rlim_max = 512L * blocks;
setrlimit(RLIMIT_FSIZE, &rlimit_fsize);
}