hush/loginutils/passwd.c
2006-11-27 16:49:55 +00:00

377 lines
8.3 KiB
C

/* vi: set sw=4 ts=4: */
/*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/
#include "busybox.h"
#include <syslog.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);
}
fp = fopen(filename, "r+");
if (fp == 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) {
bb_perror_msg("%s", filename);
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)
{
enum {
OPT_algo = 0x1, /* -a - password algorithm */
OPT_lock = 0x2, /* -l - lock account */
OPT_unlock = 0x4, /* -u - unlock account */
OPT_delete = 0x8, /* -d - delete password */
OPT_lud = 0xe,
};
unsigned opt;
char *opt_a;
int amroot;
char *cp;
char *np;
char *name;
char *myname;
int algo = 1;
const struct passwd *pw;
amroot = (getuid() == 0);
openlog("passwd", LOG_PID | LOG_CONS | LOG_NOWAIT, LOG_AUTH);
opt = getopt32(argc, argv, "a:lud", &opt_a);
argc -= optind;
argv += optind;
if (opt & OPT_algo) algo = get_algo(opt_a); // -a
if ((opt & OPT_lud) && (!argc || !amroot))
bb_show_usage();
myname = xstrdup(bb_getpwuid(NULL, getuid(), -1));
name = myname;
if (argc) name = argv[0];
pw = getpwnam(name);
if (!pw) {
bb_error_msg_and_die("unknown user %s", name);
}
if (!amroot && pw->pw_uid != getuid()) {
syslog(LOG_WARNING, "can't change pwd for '%s'", name);
bb_error_msg_and_die("permission denied");
}
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 (!(opt & OPT_lud)) {
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", 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", name);
}
} else if (opt & OPT_lock) {
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 (opt & OPT_unlock) {
if (crypt_passwd[0] == '!') {
memmove(crypt_passwd, &crypt_passwd[1],
sizeof crypt_passwd - 1);
}
} else if (opt & OPT_delete) {
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);
puts("Password changed");
} else {
syslog(LOG_WARNING, "cannot update password file");
bb_error_msg_and_die("cannot update password file");
}
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]) {
clear = bb_askpass(0, "Old password:");
if (!clear) {
/* 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);
puts("Incorrect password");
/* return -1; */
return 1;
}
safe_strncpy(orig, clear, sizeof(orig));
memset(clear, 0, strlen(clear));
memset(cipher, 0, strlen(cipher));
} else {
orig[0] = '\0';
}
cp = bb_askpass(0, "Enter the new password (minimum of 5 characters).\n"
"Please use a combination of upper and lower case letters and numbers.\n"
"Enter new password: ");
if (!cp ) {
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) {
puts("\nWarning: weak password (continuing)");
} else {
/* return -1; */
return 1;
}
}
cp = bb_askpass(0, "Re-enter new password: ");
if (!cp) {
memset(orig, 0, sizeof orig);
/* return -1; */
return 1;
}
if (strcmp(cp, pass)) {
puts("Passwords do not match");
/* 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);
}