Rework source layout in preparation for modular sudo.
This commit is contained in:
Todd C. Miller
336
plugins/sudoers/auth/pam.c
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336
plugins/sudoers/auth/pam.c
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/*
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* Copyright (c) 1999-2005, 2007-2009 Todd C. Miller <Todd.Miller@courtesan.com>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* Sponsored in part by the Defense Advanced Research Projects
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* Agency (DARPA) and Air Force Research Laboratory, Air Force
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* Materiel Command, USAF, under agreement number F39502-99-1-0512.
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*/
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#include <config.h>
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#include <sys/types.h>
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#include <sys/param.h>
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#include <stdio.h>
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#ifdef STDC_HEADERS
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# include <stdlib.h>
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# include <stddef.h>
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#else
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# ifdef HAVE_STDLIB_H
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# include <stdlib.h>
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# endif
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#endif /* STDC_HEADERS */
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#ifdef HAVE_STRING_H
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# if defined(HAVE_MEMORY_H) && !defined(STDC_HEADERS)
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# include <memory.h>
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# endif
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# include <string.h>
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#else
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# ifdef HAVE_STRINGS_H
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# include <strings.h>
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# endif
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#endif /* HAVE_STRING_H */
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#ifdef HAVE_UNISTD_H
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# include <unistd.h>
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#endif /* HAVE_UNISTD_H */
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#include <pwd.h>
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#include <errno.h>
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#ifdef HAVE_PAM_PAM_APPL_H
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# include <pam/pam_appl.h>
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#else
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# include <security/pam_appl.h>
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#endif
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#ifdef HAVE_DGETTEXT
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# include <libintl.h>
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# if defined(__LINUX_PAM__)
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# define PAM_TEXT_DOMAIN "Linux-PAM"
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# elif defined(__sun__)
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# define PAM_TEXT_DOMAIN "SUNW_OST_SYSOSPAM"
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# endif
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#endif
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#include "sudo.h"
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#include "sudo_auth.h"
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/* Only OpenPAM and Linux PAM use const qualifiers. */
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#if defined(_OPENPAM) || defined(__LIBPAM_VERSION) || defined(__LINUX_PAM__)
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# define PAM_CONST const
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#else
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# define PAM_CONST
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#endif
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static int sudo_conv __P((int, PAM_CONST struct pam_message **,
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struct pam_response **, void *));
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static char *def_prompt = "Password:";
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static int gotintr;
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#ifndef PAM_DATA_SILENT
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#define PAM_DATA_SILENT 0
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#endif
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static pam_handle_t *pamh; /* global due to pam_prep_user() */
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int
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pam_init(pw, promptp, auth)
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struct passwd *pw;
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char **promptp;
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sudo_auth *auth;
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{
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static struct pam_conv pam_conv;
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static int pam_status;
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/* Initial PAM setup */
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if (auth != NULL)
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auth->data = (void *) &pam_status;
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pam_conv.conv = sudo_conv;
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pam_status = pam_start("sudo", pw->pw_name, &pam_conv, &pamh);
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if (pam_status != PAM_SUCCESS) {
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log_error(USE_ERRNO|NO_EXIT|NO_MAIL, "unable to initialize PAM");
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return(AUTH_FATAL);
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}
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/*
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* Set PAM_RUSER to the invoking user (the "from" user).
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* We set PAM_RHOST to avoid a bug in Solaris 7 and below.
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*/
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(void) pam_set_item(pamh, PAM_RUSER, user_name);
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(void) pam_set_item(pamh, PAM_RHOST, user_host);
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/*
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* Some versions of pam_lastlog have a bug that
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* will cause a crash if PAM_TTY is not set so if
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* there is no tty, set PAM_TTY to the empty string.
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*/
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if (user_ttypath == NULL)
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(void) pam_set_item(pamh, PAM_TTY, "");
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else
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(void) pam_set_item(pamh, PAM_TTY, user_ttypath);
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return(AUTH_SUCCESS);
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}
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int
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pam_verify(pw, prompt, auth)
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struct passwd *pw;
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char *prompt;
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sudo_auth *auth;
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{
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const char *s;
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int *pam_status = (int *) auth->data;
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def_prompt = prompt; /* for sudo_conv */
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/* PAM_SILENT prevents the authentication service from generating output. */
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*pam_status = pam_authenticate(pamh, PAM_SILENT);
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switch (*pam_status) {
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case PAM_SUCCESS:
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*pam_status = pam_acct_mgmt(pamh, PAM_SILENT);
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switch (*pam_status) {
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case PAM_SUCCESS:
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return(AUTH_SUCCESS);
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case PAM_AUTH_ERR:
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log_error(NO_EXIT|NO_MAIL, "pam_acct_mgmt: %d",
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*pam_status);
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return(AUTH_FAILURE);
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case PAM_NEW_AUTHTOK_REQD:
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log_error(NO_EXIT|NO_MAIL, "%s, %s",
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"Account or password is expired",
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"reset your password and try again");
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*pam_status = pam_chauthtok(pamh,
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PAM_CHANGE_EXPIRED_AUTHTOK);
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if (*pam_status == PAM_SUCCESS)
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return(AUTH_SUCCESS);
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if ((s = pam_strerror(pamh, *pam_status)))
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log_error(NO_EXIT|NO_MAIL, "pam_chauthtok: %s", s);
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return(AUTH_FAILURE);
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case PAM_AUTHTOK_EXPIRED:
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log_error(NO_EXIT|NO_MAIL,
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"Password expired, contact your system administrator");
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return(AUTH_FATAL);
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case PAM_ACCT_EXPIRED:
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log_error(NO_EXIT|NO_MAIL, "%s %s",
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"Account expired or PAM config lacks an \"account\"",
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"section for sudo, contact your system administrator");
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return(AUTH_FATAL);
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}
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/* FALLTHROUGH */
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case PAM_AUTH_ERR:
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if (gotintr) {
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/* error or ^C from tgetpass() */
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return(AUTH_INTR);
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}
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case PAM_MAXTRIES:
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case PAM_PERM_DENIED:
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return(AUTH_FAILURE);
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default:
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if ((s = pam_strerror(pamh, *pam_status)))
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log_error(NO_EXIT|NO_MAIL, "pam_authenticate: %s", s);
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return(AUTH_FATAL);
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}
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}
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int
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pam_cleanup(pw, auth)
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struct passwd *pw;
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sudo_auth *auth;
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{
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int *pam_status = (int *) auth->data;
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/* If successful, we can't close the session until pam_prep_user() */
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if (auth->status == AUTH_SUCCESS)
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return(AUTH_SUCCESS);
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*pam_status = pam_end(pamh, *pam_status | PAM_DATA_SILENT);
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return(*pam_status == PAM_SUCCESS ? AUTH_SUCCESS : AUTH_FAILURE);
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}
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int
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pam_prep_user(pw)
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struct passwd *pw;
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{
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int eval;
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if (pamh == NULL)
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pam_init(pw, NULL, NULL);
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/*
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* Update PAM_USER to reference the user we are running the command
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* as, as opposed to the user we authenticated as.
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*/
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(void) pam_set_item(pamh, PAM_USER, pw->pw_name);
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/*
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* Set credentials (may include resource limits, device ownership, etc).
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* We don't check the return value here because in Linux-PAM 0.75
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* it returns the last saved return code, not the return code
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* for the setcred module. Because we haven't called pam_authenticate(),
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* this is not set and so pam_setcred() returns PAM_PERM_DENIED.
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* We can't call pam_acct_mgmt() with Linux-PAM for a similar reason.
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*/
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(void) pam_setcred(pamh, PAM_ESTABLISH_CRED);
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#ifndef NO_PAM_SESSION
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/*
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* To fully utilize PAM sessions we would need to keep a
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* sudo process around until the command exits. However, we
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* can at least cause pam_limits to be run by opening and then
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* immediately closing the session.
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*/
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if ((eval = pam_open_session(pamh, 0)) != PAM_SUCCESS) {
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(void) pam_end(pamh, eval | PAM_DATA_SILENT);
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return(AUTH_FAILURE);
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}
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(void) pam_close_session(pamh, 0);
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#endif
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if (pam_end(pamh, PAM_SUCCESS | PAM_DATA_SILENT) == PAM_SUCCESS)
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return(AUTH_SUCCESS);
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else
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return(AUTH_FAILURE);
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}
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/*
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* ``Conversation function'' for PAM.
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* XXX - does not handle PAM_BINARY_PROMPT
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*/
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static int
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sudo_conv(num_msg, msg, response, appdata_ptr)
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int num_msg;
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PAM_CONST struct pam_message **msg;
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struct pam_response **response;
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void *appdata_ptr;
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{
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struct pam_response *pr;
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PAM_CONST struct pam_message *pm;
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const char *prompt;
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char *pass;
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int n, flags, std_prompt;
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if ((*response = malloc(num_msg * sizeof(struct pam_response))) == NULL)
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return(PAM_SYSTEM_ERR);
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zero_bytes(*response, num_msg * sizeof(struct pam_response));
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for (pr = *response, pm = *msg, n = num_msg; n--; pr++, pm++) {
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flags = tgetpass_flags;
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switch (pm->msg_style) {
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case PAM_PROMPT_ECHO_ON:
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SET(flags, TGP_ECHO);
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case PAM_PROMPT_ECHO_OFF:
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prompt = def_prompt;
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/* Is the sudo prompt standard? (If so, we'l just use PAM's) */
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std_prompt = strncmp(def_prompt, "Password:", 9) == 0 &&
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(def_prompt[9] == '\0' ||
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(def_prompt[9] == ' ' && def_prompt[10] == '\0'));
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/* Only override PAM prompt if it matches /^Password: ?/ */
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#if defined(PAM_TEXT_DOMAIN) && defined(HAVE_DGETTEXT)
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if (!def_passprompt_override && (std_prompt ||
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(strcmp(pm->msg, dgettext(PAM_TEXT_DOMAIN, "Password: ")) &&
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strcmp(pm->msg, dgettext(PAM_TEXT_DOMAIN, "Password:")))))
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prompt = pm->msg;
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#else
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if (!def_passprompt_override && (std_prompt ||
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strncmp(pm->msg, "Password:", 9) || (pm->msg[9] != '\0'
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&& (pm->msg[9] != ' ' || pm->msg[10] != '\0'))))
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prompt = pm->msg;
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#endif
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/* Read the password unless interrupted. */
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pass = tgetpass(prompt, def_passwd_timeout * 60, flags);
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if (pass == NULL) {
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/* We got ^C instead of a password; abort quickly. */
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if (errno == EINTR)
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gotintr = 1;
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#if defined(__darwin__) || defined(__APPLE__)
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pass = "";
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#else
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goto err;
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#endif
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}
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pr->resp = estrdup(pass);
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zero_bytes(pass, strlen(pass));
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break;
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case PAM_TEXT_INFO:
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if (pm->msg)
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(void) puts(pm->msg);
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break;
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case PAM_ERROR_MSG:
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if (pm->msg) {
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(void) fputs(pm->msg, stderr);
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(void) fputc('\n', stderr);
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}
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break;
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default:
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goto err;
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}
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}
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return(PAM_SUCCESS);
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err:
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/* Zero and free allocated memory and return an error. */
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for (pr = *response, n = num_msg; n--; pr++) {
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if (pr->resp != NULL) {
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zero_bytes(pr->resp, strlen(pr->resp));
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free(pr->resp);
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pr->resp = NULL;
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}
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}
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zero_bytes(*response, num_msg * sizeof(struct pam_response));
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free(*response);
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*response = NULL;
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return(gotintr ? PAM_AUTH_ERR : PAM_CONV_ERR);
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}
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