From bc21f93ec27efd628384eccb52fbec223933f779 Mon Sep 17 00:00:00 2001 From: Joachim Wiberg Date: Wed, 4 Jan 2023 15:16:32 +0100 Subject: [PATCH] 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 --- board/common/users | 1 + board/common/xattrs | 3 + configs/aarch64_defconfig | 3 + configs/amd64_defconfig | 3 + package/Config.in | 1 + package/factory/Config.in | 10 +++ package/factory/factory.mk | 21 ++++++ src/factory/LICENSE | 22 ++++++ src/factory/Makefile | 12 +++ src/factory/factory.c | 148 +++++++++++++++++++++++++++++++++++++ 10 files changed, 224 insertions(+) create mode 100644 board/common/users create mode 100644 board/common/xattrs create mode 100644 package/factory/Config.in create mode 100644 package/factory/factory.mk create mode 100644 src/factory/LICENSE create mode 100644 src/factory/Makefile create mode 100644 src/factory/factory.c diff --git a/board/common/users b/board/common/users new file mode 100644 index 00000000..a4f05e6e --- /dev/null +++ b/board/common/users @@ -0,0 +1 @@ +factory -1 wheel -1 =reset - /sbin/factory - Reset to factory defaults diff --git a/board/common/xattrs b/board/common/xattrs new file mode 100644 index 00000000..b38f8f61 --- /dev/null +++ b/board/common/xattrs @@ -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 - - - - - diff --git a/configs/aarch64_defconfig b/configs/aarch64_defconfig index 7f4b089c..00bc42d7 100644 --- a/configs/aarch64_defconfig +++ b/configs/aarch64_defconfig @@ -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 $(BR2_EXTERNAL_INFIX_PATH)/board/common/post-image.sh" @@ -63,6 +65,7 @@ BR2_TARGET_ROOTFS_SQUASHFS=y BR2_PACKAGE_HOST_ENVIRONMENT_SETUP=y BR2_PACKAGE_HOST_GENEXT2FS=y BR2_PACKAGE_HOST_GENIMAGE=y +BR2_PACKAGE_FACTORY=y BR2_PACKAGE_FINIT_SULOGIN=y BR2_PACKAGE_FINIT_PLUGIN_HOTPLUG=y BR2_PACKAGE_FINIT_PLUGIN_HOOK_SCRIPTS=y diff --git a/configs/amd64_defconfig b/configs/amd64_defconfig index 07ef3e42..568ab7bf 100644 --- a/configs/amd64_defconfig +++ b/configs/amd64_defconfig @@ -10,11 +10,13 @@ BR2_GLOBAL_PATCH_DIR="$(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 $(BR2_EXTERNAL_INFIX_PATH)/board/common/post-image.sh" @@ -56,6 +58,7 @@ BR2_TARGET_ROOTFS_EXT2=y BR2_TARGET_ROOTFS_EXT2_SIZE="128M" # BR2_TARGET_ROOTFS_TAR is not set BR2_PACKAGE_HOST_ENVIRONMENT_SETUP=y +BR2_PACKAGE_FACTORY=y BR2_PACKAGE_FINIT_SULOGIN=y BR2_PACKAGE_FINIT_PLUGIN_HOTPLUG=y BR2_PACKAGE_FINIT_PLUGIN_HOOK_SCRIPTS=y diff --git a/package/Config.in b/package/Config.in index 889af08e..723ca11a 100644 --- a/package/Config.in +++ b/package/Config.in @@ -1,3 +1,4 @@ +source "$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" diff --git a/package/factory/Config.in b/package/factory/Config.in new file mode 100644 index 00000000..1361fa15 --- /dev/null +++ b/package/factory/Config.in @@ -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. diff --git a/package/factory/factory.mk b/package/factory/factory.mk new file mode 100644 index 00000000..7c0928b8 --- /dev/null +++ b/package/factory/factory.mk @@ -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)) diff --git a/src/factory/LICENSE b/src/factory/LICENSE new file mode 100644 index 00000000..06121c99 --- /dev/null +++ b/src/factory/LICENSE @@ -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. diff --git a/src/factory/Makefile b/src/factory/Makefile new file mode 100644 index 00000000..a144debb --- /dev/null +++ b/src/factory/Makefile @@ -0,0 +1,12 @@ +CFLAGS += -Wall -Wextra -Werror + +all: factory + +clean: + -rm factory + +distclean: clean + -rm *~ + +install: + install -D factory $(DESTDIR)/sbin/ diff --git a/src/factory/factory.c b/src/factory/factory.c new file mode 100644 index 00000000..c70ec12b --- /dev/null +++ b/src/factory/factory.c @@ -0,0 +1,148 @@ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#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: + */