/* Unix SMB/CIFS implementation. Samba utility functions Copyright (C) Andrew Tridgell 1992-1998 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. */ /* fork a child process to exec passwd and write to its * tty to change a users password. This is running as the * user who is attempting to change the password. */ /* * This code was copied/borrowed and stolen from various sources. * The primary source was the poppasswd.c from the authors of POPMail. This software * was included as a client to change passwords using the 'passwd' program * on the remote machine. * * This routine is called by set_user_password() in password.c only if ALLOW_PASSWORD_CHANGE * is defined in the compiler directives located in the Makefile. * * This code has been hacked by Bob Nance (nance@niehs.nih.gov) and Evan Patterson * (patters2@niehs.nih.gov) at the National Institute of Environmental Health Sciences * and rights to modify, distribute or incorporate this change to the CAP suite or * using it for any other reason are granted, so long as this disclaimer is left intact. */ /* This code was hacked considerably for inclusion in Samba, primarily by Andrew.Tridgell@anu.edu.au. The biggest change was the addition of the "password chat" option, which allows the easy runtime specification of the expected sequence of events to change a password. */ #include "includes.h" extern struct passdb_ops pdb_ops; static BOOL check_oem_password(const char *user, uchar * lmdata, const uchar * lmhash, const uchar * ntdata, const uchar * nthash, SAM_ACCOUNT **hnd, char *new_passwd, int new_passwd_size); #if ALLOW_CHANGE_PASSWORD static int findpty(char **slave) { int master; static fstring line; DIR *dirp; char *dpname; #if defined(HAVE_GRANTPT) /* Try to open /dev/ptmx. If that fails, fall through to old method. */ if ((master = sys_open("/dev/ptmx", O_RDWR, 0)) >= 0) { grantpt(master); unlockpt(master); *slave = (char *)ptsname(master); if (*slave == NULL) { DEBUG(0, ("findpty: Unable to create master/slave pty pair.\n")); /* Stop fd leak on error. */ close(master); return -1; } else { DEBUG(10, ("findpty: Allocated slave pty %s\n", *slave)); return (master); } } #endif /* HAVE_GRANTPT */ fstrcpy(line, "/dev/ptyXX"); dirp = opendir("/dev"); if (!dirp) return (-1); while ((dpname = readdirname(dirp)) != NULL) { if (strncmp(dpname, "pty", 3) == 0 && strlen(dpname) == 5) { DEBUG(3, ("pty: try to open %s, line was %s\n", dpname, line)); line[8] = dpname[3]; line[9] = dpname[4]; if ((master = sys_open(line, O_RDWR, 0)) >= 0) { DEBUG(3, ("pty: opened %s\n", line)); line[5] = 't'; *slave = line; closedir(dirp); return (master); } } } closedir(dirp); return (-1); } static int dochild(int master, const char *slavedev, const struct passwd *pass, const char *passwordprogram, BOOL as_root) { int slave; struct termios stermios; gid_t gid; uid_t uid; if (pass == NULL) { DEBUG(0, ("dochild: user doesn't exist in the UNIX password database.\n")); return False; } gid = pass->pw_gid; uid = pass->pw_uid; gain_root_privilege(); /* Start new session - gets rid of controlling terminal. */ if (setsid() < 0) { DEBUG(3, ("Weirdness, couldn't let go of controlling terminal\n")); return (False); } /* Open slave pty and acquire as new controlling terminal. */ if ((slave = sys_open(slavedev, O_RDWR, 0)) < 0) { DEBUG(3, ("More weirdness, could not open %s\n", slavedev)); return (False); } #ifdef I_PUSH ioctl(slave, I_PUSH, "ptem"); ioctl(slave, I_PUSH, "ldterm"); #elif defined(TIOCSCTTY) if (ioctl(slave, TIOCSCTTY, 0) < 0) { DEBUG(3, ("Error in ioctl call for slave pty\n")); /* return(False); */ } #endif /* Close master. */ close(master); /* Make slave stdin/out/err of child. */ if (sys_dup2(slave, STDIN_FILENO) != STDIN_FILENO) { DEBUG(3, ("Could not re-direct stdin\n")); return (False); } if (sys_dup2(slave, STDOUT_FILENO) != STDOUT_FILENO) { DEBUG(3, ("Could not re-direct stdout\n")); return (False); } if (sys_dup2(slave, STDERR_FILENO) != STDERR_FILENO) { DEBUG(3, ("Could not re-direct stderr\n")); return (False); } if (slave > 2) close(slave); /* Set proper terminal attributes - no echo, canonical input processing, no map NL to CR/NL on output. */ if (tcgetattr(0, &stermios) < 0) { DEBUG(3, ("could not read default terminal attributes on pty\n")); return (False); } stermios.c_lflag &= ~(ECHO | ECHOE | ECHOK | ECHONL); stermios.c_lflag |= ICANON; stermios.c_oflag &= ~(ONLCR); if (tcsetattr(0, TCSANOW, &stermios) < 0) { DEBUG(3, ("could not set attributes of pty\n")); return (False); } /* make us completely into the right uid */ if (!as_root) { become_user_permanently(uid, gid); } DEBUG(10, ("Invoking '%s' as password change program.\n", passwordprogram)); /* execl() password-change application */ if (execl("/bin/sh", "sh", "-c", passwordprogram, NULL) < 0) { DEBUG(3, ("Bad status returned from %s\n", passwordprogram)); return (False); } return (True); } static int expect(int master, char *issue, char *expected) { pstring buffer; int attempts, timeout, nread, len; BOOL match = False; for (attempts = 0; attempts < 2; attempts++) { if (!strequal(issue, ".")) { if (lp_passwd_chat_debug()) DEBUG(100, ("expect: sending [%s]\n", issue)); if ((len = write(master, issue, strlen(issue))) != strlen(issue)) { DEBUG(2,("expect: (short) write returned %d\n", len )); return False; } } if (strequal(expected, ".")) return True; timeout = 2000; nread = 0; buffer[nread] = 0; while ((len = read_with_timeout(master, buffer + nread, 1, sizeof(buffer) - nread - 1, timeout)) > 0) { nread += len; buffer[nread] = 0; { /* Eat leading/trailing whitespace before match. */ pstring str; pstrcpy( str, buffer); trim_string( str, " ", " "); if ((match = (unix_wild_match(expected, str) == 0))) timeout = 200; } } if (lp_passwd_chat_debug()) DEBUG(100, ("expect: expected [%s] received [%s] match %s\n", expected, buffer, match ? "yes" : "no" )); if (match) break; if (len < 0) { DEBUG(2, ("expect: %s\n", strerror(errno))); return False; } } DEBUG(10,("expect: returning %s\n", match ? "True" : "False" )); return match; } static void pwd_sub(char *buf) { all_string_sub(buf, "\\n", "\n", 0); all_string_sub(buf, "\\r", "\r", 0); all_string_sub(buf, "\\s", " ", 0); all_string_sub(buf, "\\t", "\t", 0); } static int talktochild(int master, char *seq) { int count = 0; fstring issue, expected; fstrcpy(issue, "."); while (next_token(&seq, expected, NULL, sizeof(expected))) { pwd_sub(expected); count++; if (!expect(master, issue, expected)) { DEBUG(3, ("Response %d incorrect\n", count)); return False; } if (!next_token(&seq, issue, NULL, sizeof(issue))) fstrcpy(issue, "."); pwd_sub(issue); } if (!strequal(issue, ".")) { /* we have one final issue to send */ fstrcpy(expected, "."); if (!expect(master, issue, expected)) return False; } return (count > 0); } static BOOL chat_with_program(char *passwordprogram, struct passwd *pass, char *chatsequence, BOOL as_root) { char *slavedev; int master; pid_t pid, wpid; int wstat; BOOL chstat = False; if (pass == NULL) { DEBUG(0, ("chat_with_program: user doesn't exist in the UNIX password database.\n")); return False; } /* allocate a pseudo-terminal device */ if ((master = findpty(&slavedev)) < 0) { DEBUG(3, ("Cannot Allocate pty for password change: %s\n", pass->pw_name)); return (False); } /* * We need to temporarily stop CatchChild from eating * SIGCLD signals as it also eats the exit status code. JRA. */ CatchChildLeaveStatus(); if ((pid = sys_fork()) < 0) { DEBUG(3, ("Cannot fork() child for password change: %s\n", pass->pw_name)); close(master); CatchChild(); return (False); } /* we now have a pty */ if (pid > 0) { /* This is the parent process */ if ((chstat = talktochild(master, chatsequence)) == False) { DEBUG(3, ("Child failed to change password: %s\n", pass->pw_name)); kill(pid, SIGKILL); /* be sure to end this process */ } while ((wpid = sys_waitpid(pid, &wstat, 0)) < 0) { if (errno == EINTR) { errno = 0; continue; } break; } if (wpid < 0) { DEBUG(3, ("The process is no longer waiting!\n\n")); close(master); CatchChild(); return (False); } /* * Go back to ignoring children. */ CatchChild(); close(master); if (pid != wpid) { DEBUG(3, ("We were waiting for the wrong process ID\n")); return (False); } if (WIFEXITED(wstat) == 0) { DEBUG(3, ("The process exited while we were waiting\n")); return (False); } if (WEXITSTATUS(wstat) != 0) { DEBUG(3, ("The status of the process exiting was %d\n", wstat)); return (False); } } else { /* CHILD */ /* * Lose any oplock capabilities. */ oplock_set_capability(False, False); /* make sure it doesn't freeze */ alarm(20); if (as_root) become_root(); DEBUG(3, ("Dochild for user %s (uid=%d,gid=%d)\n", pass->pw_name, (int)getuid(), (int)getgid())); chstat = dochild(master, slavedev, pass, passwordprogram, as_root); if (as_root) unbecome_root(); /* * The child should never return from dochild() .... */ DEBUG(0, ("chat_with_program: Error: dochild() returned %d\n", chstat)); exit(1); } if (chstat) DEBUG(3, ("Password change %ssuccessful for user %s\n", (chstat ? "" : "un"), pass->pw_name)); return (chstat); } BOOL chgpasswd(const char *name, const char *oldpass, const char *newpass, BOOL as_root) { pstring passwordprogram; pstring chatsequence; size_t i; size_t len; struct passwd *pass; if (!name) { DEBUG(1, ("NULL username specfied to chgpasswd()!\n")); } DEBUG(3, ("Password change for user: %s\n", name)); #if DEBUG_PASSWORD DEBUG(100, ("Passwords: old=%s new=%s\n", oldpass, newpass)); #endif /* Take the passed information and test it for minimum criteria */ /* Minimum password length */ if (strlen(newpass) < lp_min_passwd_length()) { /* too short, must be at least MINPASSWDLENGTH */ DEBUG(0, ("Password Change: user %s, New password is shorter than minimum password length = %d\n", name, lp_min_passwd_length())); return (False); /* inform the user */ } /* Password is same as old password */ if (strcmp(oldpass, newpass) == 0) { /* don't allow same password */ DEBUG(2, ("Password Change: %s, New password is same as old\n", name)); /* log the attempt */ return (False); /* inform the user */ } /* * Check the old and new passwords don't contain any control * characters. */ len = strlen(oldpass); for (i = 0; i < len; i++) { if (iscntrl((int)oldpass[i])) { DEBUG(0, ("chat_with_program: oldpass contains control characters (disallowed).\n")); return False; } } len = strlen(newpass); for (i = 0; i < len; i++) { if (iscntrl((int)newpass[i])) { DEBUG(0, ("chat_with_program: newpass contains control characters (disallowed).\n")); return False; } } pass = Get_Pwnam(name); #ifdef WITH_PAM if (lp_pam_password_change()) { BOOL ret; if (as_root) become_root(); if (pass) { ret = smb_pam_passchange(pass->pw_name, oldpass, newpass); } else { ret = smb_pam_passchange(name, oldpass, newpass); } if (as_root) unbecome_root(); return ret; } #endif /* A non-PAM password change just doen't make sense without a valid local user */ if (pass == NULL) { DEBUG(0, ("chgpasswd: user %s doesn't exist in the UNIX password database.\n", name)); return False; } pstrcpy(passwordprogram, lp_passwd_program()); pstrcpy(chatsequence, lp_passwd_chat()); if (!*chatsequence) { DEBUG(2, ("chgpasswd: Null chat sequence - no password changing\n")); return (False); } if (!*passwordprogram) { DEBUG(2, ("chgpasswd: Null password program - no password changing\n")); return (False); } if (as_root) { /* The password program *must* contain the user name to work. Fail if not. */ if (strstr(passwordprogram, "%u") == NULL) { DEBUG(0,("chgpasswd: Running as root the 'passwd program' parameter *MUST* contain \ the string %%u, and the given string %s does not.\n", passwordprogram )); return False; } } pstring_sub(passwordprogram, "%u", name); /* note that we do NOT substitute the %o and %n in the password program as this would open up a security hole where the user could use a new password containing shell escape characters */ pstring_sub(chatsequence, "%u", name); all_string_sub(chatsequence, "%o", oldpass, sizeof(pstring)); all_string_sub(chatsequence, "%n", newpass, sizeof(pstring)); return (chat_with_program (passwordprogram, pass, chatsequence, as_root)); } #else /* ALLOW_CHANGE_PASSWORD */ BOOL chgpasswd(const char *name, const char *oldpass, const char *newpass, BOOL as_root) { DEBUG(0, ("Password changing not compiled in (user=%s)\n", name)); return (False); } #endif /* ALLOW_CHANGE_PASSWORD */ /*********************************************************** Code to check the lanman hashed password. ************************************************************/ BOOL check_lanman_password(char *user, uchar * pass1, uchar * pass2, SAM_ACCOUNT **hnd) { uchar unenc_new_pw[16]; uchar unenc_old_pw[16]; SAM_ACCOUNT *sampass = NULL; uint16 acct_ctrl; const uint8 *lanman_pw; BOOL ret; become_root(); ret = pdb_getsampwnam(sampass, user); unbecome_root(); if (ret == False) { DEBUG(0,("check_lanman_password: getsampwnam returned NULL\n")); pdb_free_sam(&sampass); return False; } acct_ctrl = pdb_get_acct_ctrl (sampass); lanman_pw = pdb_get_lanman_passwd (sampass); if (acct_ctrl & ACB_DISABLED) { DEBUG(0,("check_lanman_password: account %s disabled.\n", user)); pdb_free_sam(&sampass); return False; } if (lanman_pw == NULL) { if (acct_ctrl & ACB_PWNOTREQ) { /* this saves the pointer for the caller */ *hnd = sampass; return True; } else { DEBUG(0, ("check_lanman_password: no lanman password !\n")); pdb_free_sam(&sampass); return False; } } /* Get the new lanman hash. */ D_P16(lanman_pw, pass2, unenc_new_pw); /* Use this to get the old lanman hash. */ D_P16(unenc_new_pw, pass1, unenc_old_pw); /* Check that the two old passwords match. */ if (memcmp(lanman_pw, unenc_old_pw, 16)) { DEBUG(0,("check_lanman_password: old password doesn't match.\n")); pdb_free_sam(&sampass); return False; } /* this saves the pointer for the caller */ *hnd = sampass; return True; } /*********************************************************** Code to change the lanman hashed password. It nulls out the NT hashed password as it will no longer be valid. ************************************************************/ BOOL change_lanman_password(SAM_ACCOUNT *sampass, uchar * pass1, uchar * pass2) { static uchar null_pw[16]; uchar unenc_new_pw[16]; BOOL ret; uint16 acct_ctrl; const uint8 *pwd; if (sampass == NULL) { DEBUG(0,("change_lanman_password: no smb password entry.\n")); return False; } acct_ctrl = pdb_get_acct_ctrl(sampass); pwd = pdb_get_lanman_passwd(sampass); if (acct_ctrl & ACB_DISABLED) { DEBUG(0,("change_lanman_password: account %s disabled.\n", pdb_get_username(sampass))); return False; } if (pwd == NULL) { if (acct_ctrl & ACB_PWNOTREQ) { uchar no_pw[14]; memset(no_pw, '\0', 14); E_P16(no_pw, null_pw); /* Get the new lanman hash. */ D_P16(null_pw, pass2, unenc_new_pw); } else { DEBUG(0,("change_lanman_password: no lanman password !\n")); return False; } } else { /* Get the new lanman hash. */ D_P16(pwd, pass2, unenc_new_pw); } if (!pdb_set_lanman_passwd(sampass, unenc_new_pw)) { return False; } if (!pdb_set_nt_passwd (sampass, NULL)) { return False; /* We lose the NT hash. Sorry. */ } if (!pdb_set_pass_changed_now (sampass)) { pdb_free_sam(&sampass); /* Not quite sure what this one qualifies as, but this will do */ return False; } /* Now flush the sam_passwd struct to persistent storage */ become_root(); ret = pdb_update_sam_account (sampass); unbecome_root(); return ret; } /*********************************************************** Code to check and change the OEM hashed password. ************************************************************/ BOOL pass_oem_change(char *user, uchar * lmdata, uchar * lmhash, uchar * ntdata, uchar * nthash) { fstring new_passwd; const char *unix_user; SAM_ACCOUNT *sampass = NULL; BOOL ret = check_oem_password(user, lmdata, lmhash, ntdata, nthash, &sampass, new_passwd, sizeof(new_passwd)); /* * At this point we have the new case-sensitive plaintext * password in the fstring new_passwd. If we wanted to synchronise * with UNIX passwords we would call a UNIX password changing * function here. However it would have to be done as root * as the plaintext of the old users password is not * available. JRA. */ unix_user = pdb_get_username(sampass); if ((ret) && (unix_user) && (*unix_user) && lp_unix_password_sync()) ret = chgpasswd(unix_user, "", new_passwd, True); if (ret) ret = change_oem_password(sampass, new_passwd); memset(new_passwd, 0, sizeof(new_passwd)); pdb_free_sam(&sampass); return ret; } /*********************************************************** Code to check the OEM hashed password. this function ignores the 516 byte nt OEM hashed password but does use the lm OEM password to check the nt hashed-hash. ************************************************************/ static BOOL check_oem_password(const char *user, uchar * lmdata, const uchar * lmhash, const uchar * ntdata, const uchar * nthash, SAM_ACCOUNT **hnd, char *new_passwd, int new_passwd_size) { static uchar null_pw[16]; static uchar null_ntpw[16]; SAM_ACCOUNT *sampass = NULL; const uint8 *lanman_pw, *nt_pw; uint16 acct_ctrl; int new_pw_len; uchar new_ntp16[16]; uchar unenc_old_ntpw[16]; uchar new_p16[16]; uchar unenc_old_pw[16]; char no_pw[2]; BOOL ret; BOOL nt_pass_set = (ntdata != NULL && nthash != NULL); pdb_init_sam(&sampass); become_root(); ret = pdb_getsampwnam(sampass, user); unbecome_root(); if (ret == False) { DEBUG(0, ("check_oem_password: getsmbpwnam returned NULL\n")); return False; } *hnd = sampass; acct_ctrl = pdb_get_acct_ctrl(sampass); if (acct_ctrl & ACB_DISABLED) { DEBUG(0,("check_lanman_password: account %s disabled.\n", user)); return False; } /* construct a null password (in case one is needed */ no_pw[0] = 0; no_pw[1] = 0; nt_lm_owf_gen(no_pw, null_ntpw, null_pw); /* save pointers to passwords so we don't have to keep looking them up */ lanman_pw = pdb_get_lanman_passwd(sampass); nt_pw = pdb_get_nt_passwd (sampass); /* check for null passwords */ if (lanman_pw == NULL) { if (!(acct_ctrl & ACB_PWNOTREQ)) { DEBUG(0,("check_oem_password: no lanman password !\n")); return False; } } if (pdb_get_nt_passwd(sampass) == NULL && nt_pass_set) { if (!(acct_ctrl & ACB_PWNOTREQ)) { DEBUG(0,("check_oem_password: no ntlm password !\n")); return False; } } /* * Call the hash function to get the new password. */ SamOEMhash( lmdata, lanman_pw, 516); /* * The length of the new password is in the last 4 bytes of * the data buffer. */ new_pw_len = IVAL(lmdata, 512); if (new_pw_len < 0 || new_pw_len > new_passwd_size - 1) { DEBUG(0,("check_oem_password: incorrect password length (%d).\n", new_pw_len)); return False; } if (nt_pass_set) { /* * nt passwords are in unicode */ pull_ucs2(NULL, new_passwd, (const smb_ucs2_t *)&lmdata[512 - new_pw_len], new_passwd_size, new_pw_len, 0); } else { memcpy(new_passwd, &lmdata[512 - new_pw_len], new_pw_len); new_passwd[new_pw_len] = 0; } /* * To ensure we got the correct new password, hash it and * use it as a key to test the passed old password. */ nt_lm_owf_gen(new_passwd, new_ntp16, new_p16); if (!nt_pass_set) { /* * Now use new_p16 as the key to see if the old * password matches. */ D_P16(new_p16, lmhash, unenc_old_pw); if (memcmp(lanman_pw, unenc_old_pw, 16)) { DEBUG(0,("check_oem_password: old lm password doesn't match.\n")); return False; } #ifdef DEBUG_PASSWORD DEBUG(100, ("check_oem_password: password %s ok\n", new_passwd)); #endif return True; } /* * Now use new_p16 as the key to see if the old * password matches. */ D_P16(new_ntp16, lmhash, unenc_old_pw); D_P16(new_ntp16, nthash, unenc_old_ntpw); if (memcmp(lanman_pw, unenc_old_pw, 16)) { DEBUG(0,("check_oem_password: old lm password doesn't match.\n")); return False; } if (memcmp(nt_pw, unenc_old_ntpw, 16)) { DEBUG(0,("check_oem_password: old nt password doesn't match.\n")); return False; } #ifdef DEBUG_PASSWORD DEBUG(100, ("check_oem_password: password %s ok\n", new_passwd)); #endif return True; } /*********************************************************** Code to change the oem password. Changes both the lanman and NT hashes. ************************************************************/ BOOL change_oem_password(SAM_ACCOUNT *hnd, char *new_passwd) { BOOL ret; if (!pdb_set_plaintext_passwd (hnd, new_passwd)) { return False; } /* Now write it into the file. */ become_root(); ret = pdb_update_sam_account (hnd); unbecome_root(); return ret; }