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/*
* SPDX-License-Identifier: ISC
*
* Copyright (c) 2023 Todd C. Miller <Todd.Miller@sudo.ws>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/*
* This is an open source non-commercial project. Dear PVS-Studio, please check it.
* PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
*/
#include <config.h>
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <sudoers.h>
/*
* Pivot to a new root directory, storing the old root and old cwd
* in state. Changes current working directory to the new root.
* Returns true on success, else false.
*/
bool
pivot_root(const char *new_root, struct sudoers_pivot *state)
{
debug_decl(pivot_root, SUDOERS_DEBUG_UTIL);
state->saved_root = open("/", O_RDONLY);
state->saved_cwd = open(".", O_RDONLY);
if (state->saved_root == -1 || state->saved_cwd == -1 || chroot(new_root) == -1) {
if (state->saved_root != -1) {
close(state->saved_root);
state->saved_root = -1;
}
if (state->saved_cwd != -1) {
close(state->saved_cwd);
state->saved_cwd = -1;
}
debug_return_bool(false);
}
debug_return_bool(chdir("/") == 0);
}
/*
* Pivot back to the stored root directory and restore the old cwd.
* Returns true on success, else false.
*/
bool
unpivot_root(struct sudoers_pivot *state)
{
bool ret = true;
debug_decl(unpivot_root, SUDOERS_DEBUG_UTIL);
/* Order is important: restore old root, *then* change cwd. */
if (state->saved_root != -1) {
if (fchdir(state->saved_root) == -1 || chroot(".") == -1) {
sudo_warn("%s", U_("unable to restore root directory"));
ret = false;
}
close(state->saved_root);
state->saved_root = -1;
}
if (state->saved_cwd != -1) {
if (fchdir(state->saved_cwd) == -1) {
sudo_warn("%s", U_("unable to restore current working directory"));
ret = false;
}
close(state->saved_cwd);
state->saved_cwd = -1;
}
debug_return_bool(ret);
}
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