From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from picard.linux.it (picard.linux.it [213.254.12.146]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 99DB4C5DF82 for ; Thu, 20 Aug 2026 07:47:52 +0000 (UTC) Received: from picard.linux.it (localhost [IPv6:::1]) by picard.linux.it (Postfix) with ESMTP id 24C983C1E1C for ; Thu, 20 Aug 2026 09:47:51 +0200 (CEST) Received: from in-5.smtp.seeweb.it (in-5.smtp.seeweb.it [217.194.8.5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (secp384r1)) (No client certificate requested) by picard.linux.it (Postfix) with ESMTPS id 17FF03CE782 for ; Thu, 20 Aug 2026 09:45:03 +0200 (CEST) Received: from smtp-out2.suse.de (smtp-out2.suse.de [IPv6:2a07:de40:b251:101:10:150:64:2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by in-5.smtp.seeweb.it (Postfix) with ESMTPS id 85756600157 for ; Thu, 20 Aug 2026 09:45:02 +0200 (CEST) Received: from imap1.dmz-prg2.suse.org (unknown [10.150.64.97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 443D43EF3; Thu, 20 Aug 2026 07:44:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1787211897; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=6XsK/M68ki2c9QfX3Ku6Lv80iJFfWxHof8WouLPuITY=; b=tqTmbDAlF5QmkHGye9dpAlsgHdyVe+3FZDq4rHLwN5oR8rLFc5en3A1dlF5nM4cCslF4DZ dqjQmmCGlszoR747xtOPIMB0EscezT4F3S9vVH6tTVMu7Q/Cnn5sBE3QadAmwQfcui9cS5 O4SP+gULJXiJxP4AIq7Fzu5A2RkMaEU= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1787211897; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=6XsK/M68ki2c9QfX3Ku6Lv80iJFfWxHof8WouLPuITY=; b=YU4e77HeoJomfWAH49oNA/iCzLCeypuAx3OF/7JaXJNsYa8w3/1eZLyGU8hCGlo+HEg1Kt rFxPzgPguGSL1bBw== Authentication-Results: smtp-out2.suse.de; none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1787211893; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=6XsK/M68ki2c9QfX3Ku6Lv80iJFfWxHof8WouLPuITY=; b=Y1WEMotH7WtyPS7wNbhXJD4AQZlEhvA/rTPtuvBovS08C81CnGfPKcGrEguNxQq2nlHK8a 5FI9WF7AmgUQiHq8tWSY6cK1Br+yeHXzVs4y+rFfj9Fvd2QemWS1ubTJ7cV96q1jkEafGH NuOmybNmcei4IKxZsJtAwQB/e2inzaY= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1787211893; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=6XsK/M68ki2c9QfX3Ku6Lv80iJFfWxHof8WouLPuITY=; b=yzEkWqrJSMaH6i1FakfbNbs4L/oXxzrjURNI15iQ5j8FyiAQq0dbhp+Gv1uESc9NChrjHY GV+W260S8asUdeCw== Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id 659EB3687; Thu, 20 Aug 2026 07:44:47 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id aEu5FW+whmr3YgAAD6G6ig (envelope-from ); Thu, 20 Aug 2026 07:44:47 +0000 From: Andrea Cervesato Date: Thu, 20 Aug 2026 09:44:54 +0200 MIME-Version: 1.0 Message-Id: <20260820-fchroot-v2-14-062ed20957a0@suse.com> References: <20260820-fchroot-v2-0-062ed20957a0@suse.com> In-Reply-To: <20260820-fchroot-v2-0-062ed20957a0@suse.com> To: Linux Test Project X-Mailer: b4 0.16.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1787211883; l=3299; i=andrea.cervesato@suse.com; s=20251210; h=from:subject:message-id; bh=Gtd8m+OIBggB5iBKvdxycMw0u9ZFPBiXjmOemxhZC6c=; b=NYL6wCqcQ68gJfI8z8h53sG+UyIOS3TAVnuy7TiutCi9xf3fiaJuxXOHPnNBj65sI33Cf0eoz RlNZwBtJFG4BzCic494hBAPE/x+TpxiYt5xM+ZiOgdLWBFgEBtq28kI X-Developer-Key: i=andrea.cervesato@suse.com; a=ed25519; pk=zKY+6GCauOiuHNZ//d8PQ/UL4jFCTKbXrzXAOQSLevI= X-Spamd-Result: default: False [-4.30 / 50.00]; BAYES_HAM(-3.00)[100.00%]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.20)[-0.998]; MIME_GOOD(-0.10)[text/plain]; RCPT_COUNT_TWO(0.00)[2]; RCVD_TLS_ALL(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; ARC_NA(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; TO_DN_ALL(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; FROM_HAS_DN(0.00)[]; MIME_TRACE(0.00)[0:+]; FROM_EQ_ENVFROM(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.com:mid, suse.com:email, imap1.dmz-prg2.suse.org:helo] X-Virus-Scanned: clamav-milter 1.0.9 at in-5.smtp.seeweb.it X-Virus-Status: Clean Subject: [LTP] [PATCH STAGING v2 14/16] fchroot11: test failfs entry with no_new_privs X-BeenThere: ltp@lists.linux.it X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux Test Project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ltp-bounces+ltp=archiver.kernel.org@lists.linux.it Sender: "ltp" From: Andrea Cervesato Verify that an unprivileged process may enter failfs when it committed to no_new_privs, since setuid binaries then pose no confused deputy risk anymore. The test also verifies that a process which entered failfs counts as chrooted: it can no longer create a user namespace with unshare() to regain CAP_SYS_CHROOT. Signed-off-by: Andrea Cervesato --- runtest/staging | 1 + testcases/kernel/syscalls/fchroot/.gitignore | 1 + testcases/kernel/syscalls/fchroot/fchroot11.c | 70 +++++++++++++++++++++++++++ 3 files changed, 72 insertions(+) diff --git a/runtest/staging b/runtest/staging index 9ec2a7897..137e3f99a 100644 --- a/runtest/staging +++ b/runtest/staging @@ -10,3 +10,4 @@ fchroot07 fchroot07 fchroot08 fchroot08 fchroot09 fchroot09 fchroot10 fchroot10 +fchroot11 fchroot11 diff --git a/testcases/kernel/syscalls/fchroot/.gitignore b/testcases/kernel/syscalls/fchroot/.gitignore index 570da2b98..0eca20548 100644 --- a/testcases/kernel/syscalls/fchroot/.gitignore +++ b/testcases/kernel/syscalls/fchroot/.gitignore @@ -8,3 +8,4 @@ fchroot07 fchroot08 fchroot09 fchroot10 +fchroot11 diff --git a/testcases/kernel/syscalls/fchroot/fchroot11.c b/testcases/kernel/syscalls/fchroot/fchroot11.c new file mode 100644 index 000000000..85401e5fe --- /dev/null +++ b/testcases/kernel/syscalls/fchroot/fchroot11.c @@ -0,0 +1,70 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2026 SUSE LLC Andrea Cervesato + */ + +/*\ + * Test unprivileged :manpage:`fchroot(2)` into failfs with no_new_privs + * set. + * + * An unprivileged process may enter failfs when it committed to + * no_new_privs, since setuid binaries then pose no confused deputy risk + * anymore. The test also verifies that a process which entered failfs + * counts as chrooted: it can no longer create a user namespace with + * :manpage:`unshare(2)` to regain ``CAP_SYS_CHROOT``. + * + * The user namespace check requires ``CONFIG_USER_NS``, which is enforced + * with ``.needs_kconfigs``. + * + * Root is required to drop to an unprivileged user in the forked child. + */ + +#define _GNU_SOURCE +#include +#include +#include +#include "tst_test.h" +#include "lapi/fcntl.h" +#include "lapi/prctl.h" +#include "lapi/sched.h" +#include "lapi/syscalls.h" + +static struct passwd *ltpuser; + +static void run(void) +{ + if (SAFE_FORK()) + return; + + SAFE_SETRESUID(ltpuser->pw_uid, ltpuser->pw_uid, + ltpuser->pw_uid); + + SAFE_PRCTL(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); + + TST_EXP_PASS(tst_syscall(__NR_fchroot, FD_FAILFS_ROOT, 0), + "unprivileged fchroot() with no_new_privs"); + + TST_EXP_FAIL2(open("/etc/passwd", O_RDONLY), EOPNOTSUPP, + "absolute lookup after entering failfs"); + + TST_EXP_FAIL(unshare(CLONE_NEWUSER), EPERM, + "user namespace creation blocked by the failfs root"); + + exit(0); +} + +static void setup(void) +{ + ltpuser = SAFE_GETPWNAM("nobody"); +} + +static struct tst_test test = { + .setup = setup, + .test_all = run, + .needs_root = 1, + .forks_child = 1, + .needs_kconfigs = (const char *[]) { + "CONFIG_USER_NS=y", + NULL, + } +}; -- 2.51.0 -- Mailing list info: https://lists.linux.it/listinfo/ltp