path: root/source3/utils/smbpasswd.c

/*
 * Unix SMB/Netbios implementation. Version 1.9. smbpasswd module. Copyright
 * (C) Jeremy Allison 1995-1998
 * 
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 * 
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 * 
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 675
 * Mass Ave, Cambridge, MA 02139, USA.
 */

#include "includes.h"

/* Static buffers we will return. */
static struct smb_passwd pw_buf;
static pstring  user_name;
static unsigned char smbpwd[16];
static unsigned char smbntpwd[16];

static int gethexpwd(char *p, char *pwd)
{
	int i;
	unsigned char   lonybble, hinybble;
	char           *hexchars = "0123456789ABCDEF";
	char           *p1, *p2;
	for (i = 0; i < 32; i += 2) {
		hinybble = toupper(p[i]);
		lonybble = toupper(p[i + 1]);

		p1 = strchr(hexchars, hinybble);
		p2 = strchr(hexchars, lonybble);
		if (!p1 || !p2)
			return (False);

		hinybble = PTR_DIFF(p1, hexchars);
		lonybble = PTR_DIFF(p2, hexchars);

		pwd[i / 2] = (hinybble << 4) | lonybble;
	}
	return (True);
}

static struct smb_passwd *
_my_get_smbpwnam(FILE * fp, char *name, BOOL * valid_old_pwd, 
		BOOL *got_valid_nt_entry, long *pwd_seekpos)
{
	char            linebuf[256];
	unsigned char   c;
	unsigned char  *p;
	long            uidval;
	long            linebuf_len;

	/*
	 * Scan the file, a line at a time and check if the name matches.
	 */
	while (!feof(fp)) {
		linebuf[0] = '\0';
		*pwd_seekpos = ftell(fp);

		fgets(linebuf, 256, fp);
		if (ferror(fp))
			return NULL;

		/*
		 * Check if the string is terminated with a newline - if not
		 * then we must keep reading and discard until we get one.
		 */
		linebuf_len = strlen(linebuf);
		if (linebuf[linebuf_len - 1] != '\n') {
			c = '\0';
			while (!ferror(fp) && !feof(fp)) {
				c = fgetc(fp);
				if (c == '\n')
					break;
			}
		} else
			linebuf[linebuf_len - 1] = '\0';

		if ((linebuf[0] == 0) && feof(fp))
			break;
		/*
		 * The line we have should be of the form :-
		 * 
		 * username:uid:[32hex bytes]:....other flags presently
		 * ignored....
		 * 
		 * or,
		 * 
		 * username:uid:[32hex bytes]:[32hex bytes]:....ignored....
		 * 
		 * if Windows NT compatible passwords are also present.
		 */

		if (linebuf[0] == '#' || linebuf[0] == '\0')
			continue;
		p = (unsigned char *) strchr(linebuf, ':');
		if (p == NULL)
			continue;
		/*
		 * As 256 is shorter than a pstring we don't need to check
		 * length here - if this ever changes....
		 */
		strncpy(user_name, linebuf, PTR_DIFF(p, linebuf));
		user_name[PTR_DIFF(p, linebuf)] = '\0';
		if (!strequal(user_name, name))
			continue;

		/* User name matches - get uid and password */
		p++;		/* Go past ':' */
		if (!isdigit(*p))
			return (False);

		uidval = atoi((char *) p);
		while (*p && isdigit(*p))
			p++;

		if (*p != ':')
			return (False);

		/*
		 * Now get the password value - this should be 32 hex digits
		 * which are the ascii representations of a 16 byte string.
		 * Get two at a time and put them into the password.
		 */
		p++;
		*pwd_seekpos += PTR_DIFF(p, linebuf);	/* Save exact position
							 * of passwd in file -
							 * this is used by
							 * smbpasswd.c */
		if (*p == '*' || *p == 'X') {
			/* Password deliberately invalid - end here. */
			*valid_old_pwd = False;
			*got_valid_nt_entry = False;
			pw_buf.smb_nt_passwd = NULL;	/* No NT password (yet)*/

			/* Now check if the NT compatible password is
			   available. */
			p += 33; /* Move to the first character of the line after 
						the lanman password. */
			if ((linebuf_len >= (PTR_DIFF(p, linebuf) + 33)) && (p[32] == ':')) {
				/* NT Entry was valid - even if 'X' or '*', can be overwritten */
				*got_valid_nt_entry = True;
				if (*p != '*' && *p != 'X') {
				  if (gethexpwd((char *)p,(char *)smbntpwd))
				    pw_buf.smb_nt_passwd = smbntpwd;
				}
			}
			pw_buf.smb_name = user_name;
			pw_buf.smb_userid = uidval;
			pw_buf.smb_passwd = NULL;	/* No password */
			return (&pw_buf);
		}
		if (linebuf_len < (PTR_DIFF(p, linebuf) + 33))
			return (False);

		if (p[32] != ':')
			return (False);

		if (!strncasecmp((char *)p, "NO PASSWORD", 11)) {
		  pw_buf.smb_passwd = NULL;	/* No password */
		} else {
		  if(!gethexpwd((char *)p,(char *)smbpwd))
		    return False;
		  pw_buf.smb_passwd = smbpwd;
		}

		pw_buf.smb_name = user_name;
		pw_buf.smb_userid = uidval;
		pw_buf.smb_nt_passwd = NULL;
		*got_valid_nt_entry = False;
		*valid_old_pwd = True;

		/* Now check if the NT compatible password is
		   available. */
		p += 33; /* Move to the first character of the line after 
					the lanman password. */
		if ((linebuf_len >= (PTR_DIFF(p, linebuf) + 33)) && (p[32] == ':')) {
			/* NT Entry was valid - even if 'X' or '*', can be overwritten */
			*got_valid_nt_entry = True;
			if (*p != '*' && *p != 'X') {
			  if (gethexpwd((char *)p,(char *)smbntpwd))
			    pw_buf.smb_nt_passwd = smbntpwd;
			}
		}
		return &pw_buf;
	}
	return NULL;
}

/*
 * Print command usage on stderr and die.
 */
static void usage(char *name)
{
	fprintf(stderr, "Usage is : %s [-add] [username] [password]\n", name);
	exit(1);
}

 int main(int argc, char **argv)
{
  int             real_uid;
  struct passwd  *pwd;
  fstring         old_passwd;
  uchar           old_p16[16];
  uchar           old_nt_p16[16];
  fstring         new_passwd;
  uchar           new_p16[16];
  uchar           new_nt_p16[16];
  char           *p;
  struct smb_passwd *smb_pwent;
  FILE           *fp;
  BOOL            valid_old_pwd = False;
  BOOL 			got_valid_nt_entry = False;
  BOOL            add_user = False;
  int             add_pass = 0;
  long            seekpos;
  int             pwfd;
  char            ascii_p16[66];
  char            c;
  int             ret, i, err, writelen;
  int             lockfd = -1;
  char           *pfile = SMB_PASSWD_FILE;
  char            readbuf[16 * 1024];
  
  TimeInit();

  setup_logging(argv[0],True);
  
  charset_initialise();
  
#ifndef DEBUG_PASSWORD
  /* Check the effective uid */
  if (geteuid() != 0) {
    fprintf(stderr, "%s: Must be setuid root.\n", argv[0]);
    exit(1);
  }
#endif
  
  /* Get the real uid */
  real_uid = getuid();
  
  /* Deal with usage problems */
  if (real_uid == 0)
  {
    /* As root we can change anothers password and add a user. */
    if (argc > 4 )
      usage(argv[0]);
  }
  else if (argc == 2 || argc > 3)
  {
    fprintf(stderr, "%s: Only root can set anothers password.\n", argv[0]);
    usage(argv[0]);
  }
  
  if (real_uid == 0 && (argc > 1))
  {
    /* We are root - check if we should add the user */
    if ((argv[1][0] == '-') && (argv[1][1] == 'a'))
      add_user = True;

    if(add_user && (argc <= 2 || argc > 4))
      usage(argv[0]);

    /* root can specify password on command-line */
    if (argc == (add_user ? 4 : 3))
    {
      /* -a argument (add_user): new password is 3rd argument. */
      /* no -a argument (add_user): new password is 2nd argument */

      add_pass = add_user ? 3 : 2;
    }

    /* If we are root we can change another's password. */
    strncpy(user_name, add_user ? argv[2] : argv[1], sizeof(user_name) - 1);
    user_name[sizeof(user_name) - 1] = '\0';

    pwd = getpwnam(user_name);
  }
  else
  {
    /* non-root can specify old pass / new pass on command-line */
    if (argc == 3)
    {
       /* non-root specifies new password as 2nd argument */
       add_pass = 2;
    }

    pwd = getpwuid(real_uid);
  }
  
  if (pwd == 0) {
    fprintf(stderr, "%s: Unable to get UNIX password entry for user.\n", argv[0]);
    exit(1);
  }

  /* If we are root we don't ask for the old password. */
  old_passwd[0] = '\0';
  if (real_uid != 0)
  {
    if (add_pass)
    {
      /* old password, as non-root, is 1st argument */
      strncpy(old_passwd, argv[1], sizeof(fstring));
    }
    else
    {
      p = getpass("Old SMB password:");
      strncpy(old_passwd, p, sizeof(fstring));
    }
    old_passwd[sizeof(fstring)-1] = '\0';
  }

  if (add_pass)
  {
    /* new password is specified on the command line */
    strncpy(new_passwd, argv[add_user ? 3 : 2], sizeof(new_passwd) - 1);
    new_passwd[sizeof(new_passwd) - 1] = '\0';
  }
  else
  {
    new_passwd[0] = '\0';

    p = getpass("New SMB password:");

    strncpy(new_passwd, p, sizeof(fstring));
    new_passwd[sizeof(fstring)-1] = '\0';

    p = getpass("Retype new SMB password:");

    if (strncmp(p, new_passwd, sizeof(fstring)-1))
    {
      fprintf(stderr, "%s: Mismatch - password unchanged.\n", argv[0]);
      exit(1);
    }
  }
  
  if (new_passwd[0] == '\0')
  {
    printf("Password not set\n");
    exit(0);
  }
  
  /* Calculate the MD4 hash (NT compatible) of the old and new passwords */
  memset(old_nt_p16, '\0', 16);
  E_md4hash((uchar *)old_passwd, old_nt_p16);
  
  memset(new_nt_p16, '\0', 16);
  E_md4hash((uchar *) new_passwd, new_nt_p16);
  
  /* Mangle the passwords into Lanman format */
  old_passwd[14] = '\0';
  strupper(old_passwd);
  new_passwd[14] = '\0';
  strupper(new_passwd);
  
  /*
   * Calculate the SMB (lanman) hash functions of both old and new passwords.
   */
  
  memset(old_p16, '\0', 16);
  E_P16((uchar *) old_passwd, old_p16);
  
  memset(new_p16, '\0', 16);
  E_P16((uchar *) new_passwd, new_p16);
  
  /*
   * Open the smbpaswd file XXXX - we need to parse smb.conf to get the
   * filename
   */
  fp = fopen(pfile, "r+");
  if (!fp && errno == ENOENT) {
	  fp = fopen(pfile, "w");
	  if (fp) {
		  fprintf(fp, "# Samba SMB password file\n");
		  fclose(fp);
		  fp = fopen(pfile, "r+");
	  }
  }
  if (!fp) {
	  err = errno;
	  fprintf(stderr, "%s: Failed to open password file %s.\n",
		  argv[0], pfile);
	  errno = err;
	  perror(argv[0]);
	  exit(err);
  }
  
  /* Set read buffer to 16k for effiecient reads */
  setvbuf(fp, readbuf, _IOFBF, sizeof(readbuf));
  
  /* make sure it is only rw by the owner */
  chmod(pfile, 0600);

  /* Lock the smbpasswd file for write. */
  if ((lockfd = pw_file_lock(pfile, F_WRLCK, 5)) < 0) {
    err = errno;
    fprintf(stderr, "%s: Failed to lock password file %s.\n",
	    argv[0], pfile);
    fclose(fp);
    errno = err;
    perror(argv[0]);
    exit(err);
  }
  /* Get the smb passwd entry for this user */
  smb_pwent = _my_get_smbpwnam(fp, pwd->pw_name, &valid_old_pwd, 
			       &got_valid_nt_entry, &seekpos);
  if (smb_pwent == NULL) {
    if(add_user == False) {
      fprintf(stderr, "%s: Failed to find entry for user %s in file %s.\n",
  	      argv[0], pwd->pw_name, pfile);
      fclose(fp);
      pw_file_unlock(lockfd);
      exit(1);
    }

    /* Create a new smb passwd entry and set it to the given password. */
    {
      int fd;
      int new_entry_length;
      char *new_entry;
      long offpos;

      /* The add user write needs to be atomic - so get the fd from 
         the fp and do a raw write() call.
       */
      fd = fileno(fp);

      if((offpos = lseek(fd, 0, SEEK_END)) == -1) {
        fprintf(stderr, "%s: Failed to add entry for user %s to file %s. \
Error was %s\n", argv[0], pwd->pw_name, pfile, strerror(errno));
        fclose(fp);
        pw_file_unlock(lockfd);
        exit(1);
      }

      new_entry_length = strlen(pwd->pw_name) + 1 + 15 + 1 + 
                         32 + 1 + 32 + 1 + strlen(pwd->pw_gecos) + 
                         1 + strlen(pwd->pw_dir) + 1 + 
                         strlen(pwd->pw_shell) + 1;
      if((new_entry = (char *)malloc( new_entry_length )) == 0) {
        fprintf(stderr, "%s: Failed to add entry for user %s to file %s. \
Error was %s\n", argv[0], pwd->pw_name, pfile, strerror(errno));
        fclose(fp);
        pw_file_unlock(lockfd);
        exit(1);
      }

      sprintf(new_entry, "%s:%u:", pwd->pw_name, (unsigned)pwd->pw_uid);
      p = &new_entry[strlen(new_entry)];
      for( i = 0; i < 16; i++)
        sprintf(&p[i*2], "%02X", new_p16[i]);
      p += 32;
      *p++ = ':';
      for( i = 0; i < 16; i++)
        sprintf(&p[i*2], "%02X", new_nt_p16[i]);
      p += 32;
      *p++ = ':';
      sprintf(p, "%s:%s:%s\n", pwd->pw_gecos, 
              pwd->pw_dir, pwd->pw_shell);
      if(write(fd, new_entry, strlen(new_entry)) != strlen(new_entry)) {
        fprintf(stderr, "%s: Failed to add entry for user %s to file %s. \
Error was %s\n", argv[0], pwd->pw_name, pfile, strerror(errno));
        /* Remove the entry we just wrote. */
        if(ftruncate(fd, offpos) == -1) {
          fprintf(stderr, "%s: ERROR failed to ftruncate file %s. \
Error was %s. Password file may be corrupt ! Please examine by hand !\n", 
                   argv[0], pwd->pw_name, strerror(errno));
        }
        fclose(fp);
        pw_file_unlock(lockfd);
        exit(1);
      }
      
      fclose(fp);  
      pw_file_unlock(lockfd);  
      exit(0);
    }
  } else {
	  /* the entry already existed */
	  add_user = False;
  }

  /* If we are root or the password is 'NO PASSWORD' then
     we don't need to check the old password. */
  if (real_uid != 0) {
    if (valid_old_pwd == False) {
      fprintf(stderr, "%s: User %s has no old SMB password.\n", argv[0], pwd->pw_name);
    }
    /* Check the old Lanman password - NULL means 'NO PASSWORD' */
    if (smb_pwent->smb_passwd != NULL) {
      if (memcmp(old_p16, smb_pwent->smb_passwd, 16)) {
        fprintf(stderr, "%s: Couldn't change password.\n", argv[0]);
        fclose(fp);
        pw_file_unlock(lockfd);
        exit(1);
      }
    }
    /* Check the NT password if it exists */
    if (smb_pwent->smb_nt_passwd != NULL) {
      if (memcmp(old_nt_p16, smb_pwent->smb_nt_passwd, 16)) {
	fprintf(stderr, "%s: Couldn't change password.\n", argv[0]);
	fclose(fp);
	pw_file_unlock(lockfd);
	exit(1);
      }
    }
  }
  /*
   * If we get here either we were root or the old password checked out
   * ok.
   */
  /* Create the 32 byte representation of the new p16 */
  for (i = 0; i < 16; i++) {
    sprintf(&ascii_p16[i * 2], "%02X", (uchar) new_p16[i]);
  }
  if(got_valid_nt_entry) {
    /* Add on the NT md4 hash */
    ascii_p16[32] = ':';
    for (i = 0; i < 16; i++) {
      sprintf(&ascii_p16[(i * 2)+33], "%02X", (uchar) new_nt_p16[i]);
    }
  }
  /*
   * Do an atomic write into the file at the position defined by
   * seekpos.
   */
  pwfd = fileno(fp);
  ret = lseek(pwfd, seekpos - 1, SEEK_SET);
  if (ret != seekpos - 1) {
    err = errno;
    fprintf(stderr, "%s: seek fail on file %s.\n",
	    argv[0], pfile);
    fclose(fp);
    errno = err;
    perror(argv[0]);
    pw_file_unlock(lockfd);
    exit(1);
  }
  /* Sanity check - ensure the character is a ':' */
  if (read(pwfd, &c, 1) != 1) {
    err = errno;
    fprintf(stderr, "%s: read fail on file %s.\n",
	    argv[0], pfile);
    fclose(fp);
    errno = err;
    perror(argv[0]);
    pw_file_unlock(lockfd);
    exit(1);
  }
  if (c != ':') {
    fprintf(stderr, "%s: sanity check on passwd file %s failed.\n",
	    argv[0], pfile);
    fclose(fp);
    pw_file_unlock(lockfd);
    exit(1);
  }
  writelen = (got_valid_nt_entry) ? 65 : 32;
  if (write(pwfd, ascii_p16, writelen) != writelen) {
    err = errno;
    fprintf(stderr, "%s: write fail in file %s.\n",
	    argv[0], pfile);
    fclose(fp);
    errno = err;
    perror(argv[0]);
    pw_file_unlock(lockfd);
    exit(err);
  }
  fclose(fp);
  pw_file_unlock(lockfd);
  printf("Password changed\n");
  return 0;
}