264 lines
7.1 KiB
C
264 lines
7.1 KiB
C
/*
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* Copyright (c) 1993-1996,1998-2005, 2007-2014
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* 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/time.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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# include <string.h>
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#endif /* HAVE_STRING_H */
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#ifdef HAVE_STRINGS_H
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# include <strings.h>
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#endif /* HAVE_STRINGS_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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#ifdef TIME_WITH_SYS_TIME
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# include <time.h>
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#endif
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#include <errno.h>
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#include <fcntl.h>
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#include <pwd.h>
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#include <grp.h>
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#include "sudoers.h"
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#include "check.h"
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static bool display_lecture(int);
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static struct passwd *get_authpw(int);
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/*
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* Returns true if the user successfully authenticates, false if not
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* or -1 on error.
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*/
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static int
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check_user_interactive(int validated, int mode, struct passwd *auth_pw)
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{
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int status, rval = true;
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debug_decl(check_user_interactive, SUDOERS_DEBUG_AUTH, sudoers_debug_instance)
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/* Always need a password when -k was specified with the command. */
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if (ISSET(mode, MODE_IGNORE_TICKET))
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SET(validated, FLAG_CHECK_USER);
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if (build_timestamp(auth_pw) == -1) {
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rval = -1;
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goto done;
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}
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status = timestamp_status(auth_pw);
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if (status != TS_CURRENT || ISSET(validated, FLAG_CHECK_USER)) {
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char *prompt;
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bool lectured;
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/* Bail out if we are non-interactive and a password is required */
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if (ISSET(mode, MODE_NONINTERACTIVE)) {
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validated |= FLAG_NON_INTERACTIVE;
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log_auth_failure(validated, 0);
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rval = -1;
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goto done;
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}
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/* XXX - should not lecture if askpass helper is being used. */
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lectured = display_lecture(status);
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/* Expand any escapes in the prompt. */
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prompt = expand_prompt(user_prompt ? user_prompt : def_passprompt,
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auth_pw->pw_name);
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if (prompt == NULL) {
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rval = -1;
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goto done;
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}
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rval = verify_user(auth_pw, prompt, validated);
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if (rval == true && lectured)
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set_lectured();
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sudo_efree(prompt);
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}
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/* Only update timestamp if user was validated. */
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if (rval == true && ISSET(validated, VALIDATE_OK) &&
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!ISSET(mode, MODE_IGNORE_TICKET) && status != TS_ERROR)
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update_timestamp(auth_pw);
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done:
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debug_return_bool(rval);
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}
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/*
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* Returns true if the user successfully authenticates, false if not
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* or -1 on error.
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*/
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int
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check_user(int validated, int mode)
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{
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struct passwd *auth_pw;
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int rval = -1;
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debug_decl(check_user, SUDOERS_DEBUG_AUTH, sudoers_debug_instance)
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/*
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* Init authentication system regardless of whether we need a password.
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* Required for proper PAM session support.
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*/
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if ((auth_pw = get_authpw(mode)) == NULL)
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goto done;
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if (sudo_auth_init(auth_pw) == -1)
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goto done;
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/*
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* Don't prompt for the root passwd or if the user is exempt.
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* If the user is not changing uid/gid, no need for a password.
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*/
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if (!def_authenticate || user_is_exempt()) {
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rval = true;
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goto done;
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}
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if (user_uid == 0 || (user_uid == runas_pw->pw_uid &&
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(!runas_gr || user_in_group(sudo_user.pw, runas_gr->gr_name)))) {
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#ifdef HAVE_SELINUX
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if (user_role == NULL && user_type == NULL)
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#endif
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#ifdef HAVE_PRIV_SET
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if (runas_privs == NULL && runas_limitprivs == NULL)
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#endif
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{
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rval = true;
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goto done;
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}
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}
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rval = check_user_interactive(validated, mode, auth_pw);
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done:
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sudo_auth_cleanup(auth_pw);
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sudo_pw_delref(auth_pw);
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debug_return_bool(rval);
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}
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/*
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* Display sudo lecture (standard or custom).
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* Returns true if the user was lectured, else false.
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*/
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static bool
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display_lecture(int status)
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{
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FILE *fp;
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char buf[BUFSIZ];
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ssize_t nread;
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struct sudo_conv_message msg;
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struct sudo_conv_reply repl;
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debug_decl(lecture, SUDOERS_DEBUG_AUTH, sudoers_debug_instance)
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if (def_lecture == never ||
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(def_lecture == once && already_lectured(status)))
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debug_return_bool(false);
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memset(&msg, 0, sizeof(msg));
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memset(&repl, 0, sizeof(repl));
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if (def_lecture_file && (fp = fopen(def_lecture_file, "r")) != NULL) {
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while ((nread = fread(buf, sizeof(char), sizeof(buf) - 1, fp)) != 0) {
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buf[nread] = '\0';
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msg.msg_type = SUDO_CONV_ERROR_MSG;
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msg.msg = buf;
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sudo_conv(1, &msg, &repl);
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}
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fclose(fp);
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} else {
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msg.msg_type = SUDO_CONV_ERROR_MSG;
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msg.msg = _("\n"
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"We trust you have received the usual lecture from the local System\n"
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"Administrator. It usually boils down to these three things:\n\n"
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" #1) Respect the privacy of others.\n"
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" #2) Think before you type.\n"
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" #3) With great power comes great responsibility.\n\n");
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sudo_conv(1, &msg, &repl);
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}
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debug_return_bool(true);
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}
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/*
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* Checks if the user is exempt from supplying a password.
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*/
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bool
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user_is_exempt(void)
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{
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bool rval = false;
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debug_decl(user_is_exempt, SUDOERS_DEBUG_AUTH, sudoers_debug_instance)
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if (def_exempt_group)
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rval = user_in_group(sudo_user.pw, def_exempt_group);
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debug_return_bool(rval);
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}
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/*
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* Get passwd entry for the user we are going to authenticate as.
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* By default, this is the user invoking sudo. In the most common
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* case, this matches sudo_user.pw or runas_pw.
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*/
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static struct passwd *
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get_authpw(int mode)
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{
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struct passwd *pw = NULL;
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debug_decl(get_authpw, SUDOERS_DEBUG_AUTH, sudoers_debug_instance)
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if (ISSET(mode, (MODE_CHECK|MODE_LIST))) {
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/* In list mode we always prompt for the user's password. */
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sudo_pw_addref(sudo_user.pw);
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pw = sudo_user.pw;
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} else {
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if (def_rootpw) {
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if ((pw = sudo_getpwuid(ROOT_UID)) == NULL) {
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log_warningx(SLOG_SEND_MAIL, N_("unknown uid: %u"), ROOT_UID);
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}
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} else if (def_runaspw) {
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if ((pw = sudo_getpwnam(def_runas_default)) == NULL) {
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log_warningx(SLOG_SEND_MAIL,
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N_("unknown user: %s"), def_runas_default);
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}
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} else if (def_targetpw) {
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if (runas_pw->pw_name == NULL) {
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/* This should never be NULL as we fake up the passwd struct */
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log_warningx(SLOG_RAW_MSG, N_("unknown uid: %u"),
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(unsigned int) runas_pw->pw_uid);
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} else {
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sudo_pw_addref(runas_pw);
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pw = runas_pw;
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}
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} else {
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sudo_pw_addref(sudo_user.pw);
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pw = sudo_user.pw;
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}
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}
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debug_return_ptr(pw);
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}
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