From patchwork Thu Jul 4 19:01:37 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= X-Patchwork-Id: 13724201 X-Patchwork-Delegate: paul@paul-moore.com Received: from smtp-bc0e.mail.infomaniak.ch (smtp-bc0e.mail.infomaniak.ch [45.157.188.14]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4B8F213D2BC for ; Thu, 4 Jul 2024 19:02:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.157.188.14 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720119737; cv=none; b=BlO8nhKtGJ0jwsLgIMeTy7nCqgWQKGkizyI6s7e82Qzikw1YXUl0XwLZWq/evPYLgPEprQ/arqKWhTlrpFd9duvv5as0dmjF0L/827hYNYWkaoA5F7A02UovhyiIMDm3aNwEJcaTxsIU8UySrDG2non7RkJJrkDMwDp4uSho5n0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720119737; c=relaxed/simple; bh=oF6rZ0nuBxG6YDixlM9cat48r0Oum2JdP1zOs4FQ5/c=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=HeIMYiIO4uT1JeSem3bn42Wzxj29RyujAyDjHgcwMiKwzOVqkVmTH0N7hgLoIaPNqn4Zm0IuxtCTfTHj46edM1EVpPNW9tfbwjTXtGVlcc585oaV1S/GWKFltf2bUBT40PBXwsbBDVC/xsHtQ5t+i54/fvXyo663J0vgy7LV4FY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=digikod.net; spf=pass smtp.mailfrom=digikod.net; dkim=pass (1024-bit key) header.d=digikod.net header.i=@digikod.net header.b=sz775JKN; arc=none smtp.client-ip=45.157.188.14 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=digikod.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=digikod.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=digikod.net header.i=@digikod.net header.b="sz775JKN" Received: from smtp-4-0001.mail.infomaniak.ch (smtp-4-0001.mail.infomaniak.ch [10.7.10.108]) by smtp-3-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4WFQxd4WXSz114p; Thu, 4 Jul 2024 21:02:13 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=digikod.net; s=20191114; t=1720119733; bh=v0fxaXOdLtc/Ju12bV32vY14OcdVSThIgNKjl9+i++A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sz775JKNODOr34yQ+Cv6KYcDvi+5ptHtkytGJ4G92ILUZoxk4zmBBIN1RY/1M1tms ZO3bjuRTATAsvIlizxMEmtFYYYIpG6mKsV5ckhQqA6RKyNXIXh9DUoYxtxxVrb/Yc1 MGjtdlShlQavT56SM7tKhkep7CajraMh20U4V77E= Received: from unknown by smtp-4-0001.mail.infomaniak.ch (Postfix) with ESMTPA id 4WFQxc5zxzzTK7; Thu, 4 Jul 2024 21:02:12 +0200 (CEST) From: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= To: Al Viro , Christian Brauner , Kees Cook , Linus Torvalds , Paul Moore , Theodore Ts'o Cc: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Alejandro Colomar , Aleksa Sarai , Andrew Morton , Andy Lutomirski , Arnd Bergmann , Casey Schaufler , Christian Heimes , Dmitry Vyukov , Eric Biggers , Eric Chiang , Fan Wu , Florian Weimer , Geert Uytterhoeven , James Morris , Jan Kara , Jann Horn , Jeff Xu , Jonathan Corbet , Jordan R Abrahams , Lakshmi Ramasubramanian , Luca Boccassi , Luis Chamberlain , "Madhavan T . Venkataraman" , Matt Bobrowski , Matthew Garrett , Matthew Wilcox , Miklos Szeredi , Mimi Zohar , Nicolas Bouchinet , Scott Shell , Shuah Khan , Stephen Rothwell , Steve Dower , Steve Grubb , Thibaut Sautereau , Vincent Strubel , Xiaoming Ni , Yin Fengwei , kernel-hardening@lists.openwall.com, linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org Subject: [RFC PATCH v19 5/5] samples/should-exec: Add set-should-exec Date: Thu, 4 Jul 2024 21:01:37 +0200 Message-ID: <20240704190137.696169-6-mic@digikod.net> In-Reply-To: <20240704190137.696169-1-mic@digikod.net> References: <20240704190137.696169-1-mic@digikod.net> Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Infomaniak-Routing: alpha Add a simple tool to set SECBIT_SHOULD_EXEC_CHECK, SECBIT_SHOULD_EXEC_RESTRICT, and their lock counterparts before executing a command. This should be useful to easily test against script interpreters. Cc: Al Viro Cc: Christian Brauner Cc: Kees Cook Cc: Paul Moore Signed-off-by: Mickaël Salaün Link: https://lore.kernel.org/r/20240704190137.696169-6-mic@digikod.net --- samples/Kconfig | 7 +++ samples/Makefile | 1 + samples/should-exec/.gitignore | 1 + samples/should-exec/Makefile | 13 ++++ samples/should-exec/set-should-exec.c | 88 +++++++++++++++++++++++++++ 5 files changed, 110 insertions(+) create mode 100644 samples/should-exec/.gitignore create mode 100644 samples/should-exec/Makefile create mode 100644 samples/should-exec/set-should-exec.c diff --git a/samples/Kconfig b/samples/Kconfig index b288d9991d27..d8f2639bc830 100644 --- a/samples/Kconfig +++ b/samples/Kconfig @@ -180,6 +180,13 @@ config SAMPLE_SECCOMP Build samples of seccomp filters using various methods of BPF filter construction. +config SAMPLE_SHOULD_EXEC + bool "Should-exec secure bits examples" + depends on CC_CAN_LINK && HEADERS_INSTALL + help + Build a tool to easily configure SECBIT_SHOULD_EXEC_CHECK, + SECBIT_SHOULD_EXEC_RESTRICT and their lock counterparts. + config SAMPLE_TIMER bool "Timer sample" depends on CC_CAN_LINK && HEADERS_INSTALL diff --git a/samples/Makefile b/samples/Makefile index b85fa64390c5..0e7a97fb222d 100644 --- a/samples/Makefile +++ b/samples/Makefile @@ -19,6 +19,7 @@ subdir-$(CONFIG_SAMPLE_PIDFD) += pidfd obj-$(CONFIG_SAMPLE_QMI_CLIENT) += qmi/ obj-$(CONFIG_SAMPLE_RPMSG_CLIENT) += rpmsg/ subdir-$(CONFIG_SAMPLE_SECCOMP) += seccomp +subdir-$(CONFIG_SAMPLE_SHOULD_EXEC) += should-exec subdir-$(CONFIG_SAMPLE_TIMER) += timers obj-$(CONFIG_SAMPLE_TRACE_EVENTS) += trace_events/ obj-$(CONFIG_SAMPLE_TRACE_CUSTOM_EVENTS) += trace_events/ diff --git a/samples/should-exec/.gitignore b/samples/should-exec/.gitignore new file mode 100644 index 000000000000..ac46c614ec80 --- /dev/null +++ b/samples/should-exec/.gitignore @@ -0,0 +1 @@ +/set-should-exec diff --git a/samples/should-exec/Makefile b/samples/should-exec/Makefile new file mode 100644 index 000000000000..c4294278dd07 --- /dev/null +++ b/samples/should-exec/Makefile @@ -0,0 +1,13 @@ +# SPDX-License-Identifier: BSD-3-Clause + +userprogs-always-y := set-should-exec + +userccflags += -I usr/include + +.PHONY: all clean + +all: + $(MAKE) -C ../.. samples/should-exec/ + +clean: + $(MAKE) -C ../.. M=samples/should-exec/ clean diff --git a/samples/should-exec/set-should-exec.c b/samples/should-exec/set-should-exec.c new file mode 100644 index 000000000000..b3c31106d916 --- /dev/null +++ b/samples/should-exec/set-should-exec.c @@ -0,0 +1,88 @@ +// SPDX-License-Identifier: BSD-3-Clause +/* + * Simple tool to set SECBIT_SHOULD_EXEC_CHECK, SECBIT_SHOULD_EXEC_RESTRICT, + * and their lock counterparts before executing a command. + * + * Copyright © 2024 Microsoft Corporation + */ + +#define _GNU_SOURCE +#define __SANE_USERSPACE_TYPES__ +#include +#include +#include +#include +#include +#include +#include +#include +#include + +static void print_usage(const char *argv0) +{ + fprintf(stderr, "usage: %s -c|-r [-l] -- [args]...\n\n", argv0); + fprintf(stderr, "Execute a command with\n"); + fprintf(stderr, "- SECBIT_SHOULD_EXEC_CHECK set: -c\n"); + fprintf(stderr, "- SECBIT_SHOULD_EXEC_RESTRICT set: -r\n"); + fprintf(stderr, "- SECBIT_SHOULD_EXEC_*_LOCKED set: -l\n"); +} + +int main(const int argc, char *const argv[], char *const *const envp) +{ + const char *cmd_path; + char *const *cmd_argv; + int opt, secbits, err; + bool has_policy = false; + + secbits = prctl(PR_GET_SECUREBITS); + + while ((opt = getopt(argc, argv, "crl")) != -1) { + switch (opt) { + case 'c': + secbits |= SECBIT_SHOULD_EXEC_CHECK; + has_policy = true; + break; + case 'r': + secbits |= SECBIT_SHOULD_EXEC_RESTRICT; + has_policy = true; + break; + case 'l': + secbits |= SECBIT_SHOULD_EXEC_CHECK_LOCKED; + secbits |= SECBIT_SHOULD_EXEC_RESTRICT_LOCKED; + break; + default: + print_usage(argv[0]); + return 1; + } + } + + if (!argv[optind] || !has_policy) { + print_usage(argv[0]); + return 1; + } + + err = prctl(PR_SET_SECUREBITS, secbits); + if (err) { + perror("Failed to set secure bit(s)."); + fprintf(stderr, + "Hint: The running kernel may not support this feature.\n"); + return 1; + } + + fprintf(stderr, "SECBIT_SHOULD_EXEC_CHECK: %d\n", + !!(secbits & SECBIT_SHOULD_EXEC_CHECK)); + fprintf(stderr, "SECBIT_SHOULD_EXEC_CHECK_LOCKED: %d\n", + !!(secbits & SECBIT_SHOULD_EXEC_CHECK_LOCKED)); + fprintf(stderr, "SECBIT_SHOULD_EXEC_RESTRICT: %d\n", + !!(secbits & SECBIT_SHOULD_EXEC_RESTRICT)); + fprintf(stderr, "SECBIT_SHOULD_EXEC_RESTRICT_LOCKED: %d\n", + !!(secbits & SECBIT_SHOULD_EXEC_RESTRICT_LOCKED)); + + cmd_path = argv[optind]; + cmd_argv = argv + optind; + fprintf(stderr, "Executing command...\n"); + execvpe(cmd_path, cmd_argv, envp); + fprintf(stderr, "Failed to execute \"%s\": %s\n", cmd_path, + strerror(errno)); + return 1; +}