91 lines
2.5 KiB
C
91 lines
2.5 KiB
C
/*
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* SPDX-License-Identifier: ISC
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*
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* Copyright (c) 2023 Todd C. Miller <Todd.Miller@sudo.ws>
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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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/*
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* This is an open source non-commercial project. Dear PVS-Studio, please check it.
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* PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
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*/
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#include <config.h>
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#include <stdio.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include "sudoers.h"
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#define OLD_ROOT 0
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#define OLD_CWD 1
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/*
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* Pivot to a new root directory, storing the old root and old cwd
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* in fds[2]. Changes current working directory to the new root.
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* Returns true on success, else false.
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*/
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bool
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pivot_root(const char *new_root, int fds[2])
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{
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debug_decl(pivot_root, SUDOERS_DEBUG_UTIL);
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fds[OLD_ROOT] = open("/", O_RDONLY);
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fds[OLD_CWD] = open(".", O_RDONLY);
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if (fds[OLD_ROOT] == -1 || fds[OLD_CWD] == -1 || chroot(new_root) == -1) {
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if (fds[OLD_ROOT] != -1) {
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close(fds[OLD_ROOT]);
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fds[OLD_ROOT] = -1;
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}
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if (fds[OLD_CWD] != -1) {
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close(fds[OLD_CWD]);
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fds[OLD_CWD] = -1;
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}
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debug_return_bool(false);
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}
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debug_return_bool(chdir("/") == 0);
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}
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/*
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* Pivot back to the stored root directory and restore the old cwd.
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* Returns true on success, else false.
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*/
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bool
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unpivot_root(int fds[2])
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{
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bool ret = true;
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debug_decl(unpivot_root, SUDOERS_DEBUG_UTIL);
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/* Order is important: restore old root, *then* change cwd. */
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if (fds[OLD_ROOT] != -1) {
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if (fchdir(fds[OLD_ROOT]) == -1 || chroot(".") == -1) {
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sudo_warn("%s", U_("unable to restore root directory"));
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ret = false;
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}
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close(fds[OLD_ROOT]);
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fds[OLD_ROOT] = -1;
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}
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if (fds[OLD_CWD] != -1) {
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if (fchdir(fds[OLD_CWD]) == -1) {
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sudo_warn("%s", U_("unable to restore current working directory"));
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ret = false;
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}
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close(fds[OLD_CWD]);
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fds[OLD_CWD] = -1;
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}
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debug_return_bool(ret);
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}
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