Add support for returning a device to factory defaults

This change adds a `factory` tool, and login shell, that schedules a
reset of all writable (overlay) filesystems.  The tool is set up with
the suid gid flag to allow all members of the wheel group to perform
the reset.

The login method only allows reset from /dev/console, to prevent any
malicious reset over SSH.  This should be further constrained later
when PAM is introduced.

To initiate factory reset from the login prompt, use login/pass:

    factory/reset

To initiate factory reset from the shell, call

    factory

Both methods are interactive by default, but two command line options
can be used to modify the behavior:

  -r  Skip reboot, and "reboot now?" question
  -y  Assume yes to all questions, for non-interactive use

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>
This commit is contained in:
Joachim Wiberg
2023-01-04 15:24:36 +01:00
parent ec177085d9
commit bc21f93ec2
10 changed files with 224 additions and 0 deletions
+1
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@@ -0,0 +1 @@
factory -1 wheel -1 =reset - /sbin/factory - Reset to factory defaults
+3
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@@ -0,0 +1,3 @@
# Allow users in wheel group to reboot and perform a factory reset
/sbin/initctl f 4750 root wheel - - - - -
/sbin/factory f 4750 root wheel - - - - -
+3
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@@ -11,10 +11,12 @@ BR2_GLOBAL_PATCH_DIR="$(BR2_EXTERNAL_INFIX_PATH)/patches"
BR2_TARGET_GENERIC_HOSTNAME="infix"
BR2_TARGET_GENERIC_ISSUE="Infix by KernelKit"
BR2_INIT_FINIT=y
BR2_ROOTFS_DEVICE_TABLE="system/device_table.txt $(BR2_EXTERNAL_INFIX_PATH)/board/common/xattrs"
BR2_SYSTEM_BIN_SH_BASH=y
BR2_ENABLE_LOCALE_WHITELIST="C en_US en_CA"
BR2_GENERATE_LOCALE="en_US en_CA"
BR2_TARGET_TZ_INFO=y
BR2_ROOTFS_USERS_TABLES="$(BR2_EXTERNAL_INFIX_PATH)/board/common/users"
BR2_ROOTFS_OVERLAY="$(BR2_EXTERNAL_INFIX_PATH)/board/common/rootfs"
BR2_ROOTFS_POST_BUILD_SCRIPT="$(BR2_EXTERNAL_INFIX_PATH)/board/common/post-build.sh"
BR2_ROOTFS_POST_IMAGE_SCRIPT="$(TOPDIR)/support/scripts/genimage.sh $(BR2_EXTERNAL_INFIX_PATH)/board/common/post-image.sh"
@@ -63,6 +65,7 @@ BR2_TARGET_ROOTFS_SQUASHFS=y
BR2_PACKAGE_HOST_ENVIRONMENT_SETUP=y
BR2_PACKAGE_HOST_GENEXT2FS=y
BR2_PACKAGE_HOST_GENIMAGE=y
BR2_PACKAGE_FACTORY=y
BR2_PACKAGE_FINIT_SULOGIN=y
BR2_PACKAGE_FINIT_PLUGIN_HOTPLUG=y
BR2_PACKAGE_FINIT_PLUGIN_HOOK_SCRIPTS=y
+3
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@@ -10,11 +10,13 @@ BR2_GLOBAL_PATCH_DIR="$(BR2_EXTERNAL_INFIX_PATH)/patches"
BR2_TARGET_GENERIC_HOSTNAME="infix"
BR2_TARGET_GENERIC_ISSUE="Infix by KernelKit"
BR2_INIT_FINIT=y
BR2_ROOTFS_DEVICE_TABLE="system/device_table.txt $(BR2_EXTERNAL_INFIX_PATH)/board/common/xattrs"
BR2_SYSTEM_BIN_SH_BASH=y
BR2_SYSTEM_DHCP="eth0"
BR2_ENABLE_LOCALE_WHITELIST="C en_US en_CA"
BR2_GENERATE_LOCALE="en_US en_CA"
BR2_TARGET_TZ_INFO=y
BR2_ROOTFS_USERS_TABLES="$(BR2_EXTERNAL_INFIX_PATH)/board/common/users"
BR2_ROOTFS_OVERLAY="$(BR2_EXTERNAL_INFIX_PATH)/board/common/rootfs"
BR2_ROOTFS_POST_BUILD_SCRIPT="board/qemu/x86_64/post-build.sh $(BR2_EXTERNAL_INFIX_PATH)/board/common/post-build.sh"
BR2_ROOTFS_POST_IMAGE_SCRIPT="board/qemu/post-image.sh $(BR2_EXTERNAL_INFIX_PATH)/board/common/post-image.sh"
@@ -56,6 +58,7 @@ BR2_TARGET_ROOTFS_EXT2=y
BR2_TARGET_ROOTFS_EXT2_SIZE="128M"
# BR2_TARGET_ROOTFS_TAR is not set
BR2_PACKAGE_HOST_ENVIRONMENT_SETUP=y
BR2_PACKAGE_FACTORY=y
BR2_PACKAGE_FINIT_SULOGIN=y
BR2_PACKAGE_FINIT_PLUGIN_HOTPLUG=y
BR2_PACKAGE_FINIT_PLUGIN_HOOK_SCRIPTS=y
+1
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@@ -1,3 +1,4 @@
source "$BR2_EXTERNAL_INFIX_PATH/package/factory/Config.in"
source "$BR2_EXTERNAL_INFIX_PATH/package/finit/Config.in"
source "$BR2_EXTERNAL_INFIX_PATH/package/ifupdown2/Config.in"
source "$BR2_EXTERNAL_INFIX_PATH/package/mdnsd/Config.in"
+10
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@@ -0,0 +1,10 @@
config BR2_PACKAGE_FACTORY
bool "factory-reset"
help
Simple factory reset program/login-shell for instructing the
system to factory reset itself, and reboot.
The program is made to run as SUID root to be able to tell the
system to reboot. Sufficient care has been taken to make the
factory program as secure as possible. With the worst possible
eftect to only be abused to reboot the system.
+21
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@@ -0,0 +1,21 @@
################################################################################
#
# factory
#
################################################################################
FACTORY_VERSION = 1.0
FACTORY_LICENSE = MIT
FACTORY_SITE_METHOD = local
FACTORY_SITE = $(BR2_EXTERNAL_INFIX_PATH)/src/factory
define FACTORY_BUILD_CMDS
$(TARGET_MAKE_ENV) $(TARGET_CONFIGURE_OPTS) $(MAKE) -C $(@D) \
LDLIBS="$(TARGET_LDFLAGS)"
endef
define FACTORY_INSTALL_TARGET_CMDS
$(TARGET_MAKE_ENV) $(TARGET_CONFIGURE_OPTS) $(MAKE) -C $(@D) \
DESTDIR="$(TARGET_DIR)" install
endef
$(eval $(generic-package))
+22
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@@ -0,0 +1,22 @@
MIT License
Copyright (c) 2021 Westermo Network Technologies
Copyright (c) 2023 Joachim Wiberg
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
+12
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@@ -0,0 +1,12 @@
CFLAGS += -Wall -Wextra -Werror
all: factory
clean:
-rm factory
distclean: clean
-rm *~
install:
install -D factory $(DESTDIR)/sbin/
+148
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@@ -0,0 +1,148 @@
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <getopt.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/types.h>
#define RESETME "/rw/infix/.reset"
#define touch(f) mknod((f), S_IFREG|0644, 0)
char rawgetch(void)
{
struct termios saved, c;
char key;
if (tcgetattr(fileno(stdin), &saved) < 0)
return -1;
c = saved;
c.c_lflag &= ~ICANON;
c.c_lflag &= ~ECHO;
c.c_cc[VMIN] = 1;
c.c_cc[VTIME] = 0;
if (tcsetattr(fileno(stdin), TCSANOW, &c) < 0) {
tcsetattr(fileno(stdin), TCSANOW, &saved);
return -1;
}
key = getchar();
tcsetattr(fileno(stdin), TCSANOW, &saved);
return key;
}
int yorn(const char *prompt)
{
char yorn;
fputs(prompt, stderr);
yorn = rawgetch();
fprintf(stderr, "%c\n", yorn);
if (yorn != 'y' && yorn != 'Y')
return 0;
return 1;
}
static int usage(int rc)
{
printf("usage: factory [opts]\n"
"\n"
"Options:\n"
" -h, --help This help text\n"
" -r, --no-reboot Don't reboot. Reboot manually to activate.\n"
" -y, --assume-yes Automatic yes to prompts; assume \"yes\" as answer to all\n"
" prompts and run non-interactively\n"
"\n"
"Note: this program initiates a factory reset by raising a flag and rebooting\n"
" the system. When it comes back up it safely removes all the OverlayFS\n"
" worker/upper directories for /etc, /home, and /var\n");
return rc;
}
static int run(const char *cmd)
{
int status = system(cmd);
int rc;
rc = WEXITSTATUS(status);
if (WIFEXITED(status))
return rc;
if (WIFSIGNALED(status)) {
if (rc == 0)
rc = 1; /* adjust, we were aborted */
}
return rc;
}
int main(int argc, char *argv[])
{
struct option long_opts[] = {
{ "help", 0, NULL, 'h' },
{ "no-reboot", 0, NULL, 'r' },
{ "assume-yes", 0, NULL, 'y' },
{ NULL, 0, NULL, 0 }
};
int reboot = 1;
int yes = 0;
char *tty;
int c;
while ((c = getopt_long(argc, argv, "h?ry", long_opts, NULL)) != EOF) {
switch (c) {
case 'h':
case '?':
return usage(0);
case 'r':
reboot = 0;
break;
case 'y':
yes = 1;
break;
default:
return usage(1);
}
}
tty = ttyname(STDIN_FILENO);
if (!tty && errno == ENOTTY)
yes = 1;
if (argv[0][0] == '-' && tty && strcmp(tty, "/dev/console"))
errx(1, "factory reset only allowed from console login!");
if (yes || yorn("Factory reset device (y/N)? ")) {
if (touch(RESETME) && errno != EEXIST)
err(1, "failed");
warnx("scheduled factory reset on next boot.");
if (reboot && (yes || yorn("Reboot now to perform reset, (y/N)? ")))
return run("/sbin/reboot");
warnx("remember to reboot the system to perform the factory reset.");
}
return 0;
}
/**
* Local Variables:
* indent-tabs-mode: t
* c-file-style: "linux"
* End:
*/