From patchwork Thu Apr 7 12:09:31 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Yang Xu (Fujitsu)" X-Patchwork-Id: 12805059 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 42DD2C433EF for ; Thu, 7 Apr 2022 11:09:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244662AbiDGLLk (ORCPT ); Thu, 7 Apr 2022 07:11:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57830 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244657AbiDGLLh (ORCPT ); Thu, 7 Apr 2022 07:11:37 -0400 Received: from mail1.bemta34.messagelabs.com (mail1.bemta34.messagelabs.com [195.245.231.3]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1C5B84C79C; Thu, 7 Apr 2022 04:09:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fujitsu.com; s=170520fj; t=1649329773; i=@fujitsu.com; bh=NzauDbBxvAOczt/DDOj64ajj68yNYs5AxACWnWWKhio=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=BkPkQOLgriYZyOVQlc6u+Mn64XJY2OCshqMJ/goJp6N3ADgTiHbVdbUiZkrFssxta tCw6iiatQyNrZIP8wizjQZfe3G8P48iANSVeoKBmiemOGQuJTEC9ladu3MJIIUe7PK TADC7AsB5Wc04Z6yYRHTHn4X/kb1cUsDdMQH3om00lURmEnJBfrPrYYW/CBDGeqkty BTNoECGPTCXvXPixFZUq4fINLMfSN8v+onqLuOC1raMj4r1MqHieOx8IAkRF1oxISE RtuOcHGs20CTNtjOepeBqhUxTDRpxoRcnCKGBkWBaQ2JcibeWyMljP4h6KHNlN7B0w XC7QuilnLkN5Q== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFvrMIsWRWlGSWpSXmKPExsViZ8MxSTfnmF+ Swf3T2havD39itNhy7B6jxeUnfBanW/ayW+zZe5LFgdXj1CIJj02rOtk8Pm+SC2COYs3MS8qv SGDNWN7Qx1iwO7jixLUV7A2Mk1y7GLk4hAS2MEq8nd/HAuEsYJJY+38WK4Szm1Fi+5sDTF2Mn BxsApoSzzoXMIPYIgIuEt/2/2UDsZkFUiQazjcxgtjCAr4S3d0H2EFsFgEViW9bF4P18gp4SB xYdZEFxJYQUJCY8vA92BxOAU+Ju4+/g80RAqppvjGDEaJeUOLkzCcsEPMlJA6+eMEM0asocan jGyOEXSExa1YbE4StJnH13CbmCYyCs5C0z0LSvoCRaRWjdVJRZnpGSW5iZo6uoYGBrqGhqa6x BZAy1Eus0k3USy3VLU8tLtE10kssL9ZLLS7WK67MTc5J0ctLLdnECAz/lGK1/B2Mf1f+1DvEK MnBpCTK27DTL0mILyk/pTIjsTgjvqg0J7X4EKMMB4eSBG/iEaCcYFFqempFWmYOMBZh0hIcPE oivEcPA6V5iwsSc4sz0yFSpxh1Of5++ruXWYglLz8vVUqcN+8oUJEASFFGaR7cCFhauMQoKyX My8jAwCDEU5BalJtZgir/ilGcg1FJmFcDZApPZl4J3KZXQEcwAR1Rd9AX5IiSRISUVAPTVr6T jfeeCMkvrLtYXj+1VmJaeuvqSwGTd/pMnLtCeA+7V+xWxx/fHXkM4jcwHs89mHmabXvzyuAzL etVfn68tXbHpybhWX5cGptYPPuXvP0RuEJKipFlzx2TOue0kx+2seczTw1tKXt9cRuj2gnDKT znf0pH13LGHK//eKZq74wFMq++VJmEfysMecLevN7cw5j34Y/Gxxd/57yTaBP9pcxuL6tewbf W/6mhp9cUj77tqqt1Yg7klHNFfizbe2Tj5EN7/t1fNef9FwV5U/ZSK4cHdeENut2MM5v+Vxdd WibV9cF0ovj2H7uXTz70x9zM6bTTm4jDOu+jVdYEbvvGwbn8+6t9mQKXE5Jdvrt9UmIpzkg01 GIuKk4EAErmeOqGAwAA X-Env-Sender: xuyang2018.jy@fujitsu.com X-Msg-Ref: server-21.tower-571.messagelabs.com!1649329772!30939!1 X-Originating-IP: [62.60.8.146] X-SYMC-ESS-Client-Auth: outbound-route-from=pass X-StarScan-Received: X-StarScan-Version: 9.85.5; banners=-,-,- X-VirusChecked: Checked Received: (qmail 14754 invoked from network); 7 Apr 2022 11:09:32 -0000 Received: from unknown (HELO n03ukasimr02.n03.fujitsu.local) (62.60.8.146) by server-21.tower-571.messagelabs.com with ECDHE-RSA-AES256-GCM-SHA384 encrypted SMTP; 7 Apr 2022 11:09:32 -0000 Received: from n03ukasimr02.n03.fujitsu.local (localhost [127.0.0.1]) by n03ukasimr02.n03.fujitsu.local (Postfix) with ESMTP id 4EDF910046B; Thu, 7 Apr 2022 12:09:32 +0100 (BST) Received: from R01UKEXCASM126.r01.fujitsu.local (unknown [10.183.43.178]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by n03ukasimr02.n03.fujitsu.local (Postfix) with ESMTPS id 419D2100451; Thu, 7 Apr 2022 12:09:32 +0100 (BST) Received: from localhost.localdomain (10.167.220.84) by R01UKEXCASM126.r01.fujitsu.local (10.183.43.178) with Microsoft SMTP Server (TLS) id 15.0.1497.32; Thu, 7 Apr 2022 12:09:15 +0100 From: Yang Xu To: , , CC: , , Yang Xu Subject: [PATCH v2 2/6] idmapped-mounts: Add mknodat operation in setgid test Date: Thu, 7 Apr 2022 20:09:31 +0800 Message-ID: <1649333375-2599-2-git-send-email-xuyang2018.jy@fujitsu.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1649333375-2599-1-git-send-email-xuyang2018.jy@fujitsu.com> References: <1649333375-2599-1-git-send-email-xuyang2018.jy@fujitsu.com> MIME-Version: 1.0 X-Originating-IP: [10.167.220.84] X-ClientProxiedBy: G08CNEXCHPEKD07.g08.fujitsu.local (10.167.33.80) To R01UKEXCASM126.r01.fujitsu.local (10.183.43.178) X-Virus-Scanned: ClamAV using ClamSMTP Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Since mknodat can create file, we should also check whether strip S_ISGID. Also add new helper caps_down_fsetid to drop CAP_FSETID because strip S_ISGID depond on this cap and keep other cap(ie CAP_MKNOD) because create character device needs it when using mknod. Only test mknodat with character device in setgid_create function because the another two functions test mknodat with whiteout device. Since kernel commit a3c751a50 ("vfs: allow unprivileged whiteout creation") in v5.8-rc1, we can create whiteout device in userns test. Since kernel 5.12, mount_setattr and MOUNT_ATTR_IDMAP was supported, we don't need to detect kernel whether allow unprivileged whiteout creation. Using fs_allow_idmap as a proxy is safe. Tested-by: Christian Brauner (Microsoft) Reviewed-by: Christian Brauner (Microsoft) Signed-off-by: Yang Xu --- src/idmapped-mounts/idmapped-mounts.c | 190 +++++++++++++++++++++++++- 1 file changed, 183 insertions(+), 7 deletions(-) diff --git a/src/idmapped-mounts/idmapped-mounts.c b/src/idmapped-mounts/idmapped-mounts.c index dff6820f..e8a856de 100644 --- a/src/idmapped-mounts/idmapped-mounts.c +++ b/src/idmapped-mounts/idmapped-mounts.c @@ -241,6 +241,34 @@ static inline bool caps_supported(void) return ret; } +static int caps_down_fsetid(void) +{ + bool fret = false; +#ifdef HAVE_SYS_CAPABILITY_H + cap_t caps = NULL; + cap_value_t cap = CAP_FSETID; + int ret = -1; + + caps = cap_get_proc(); + if (!caps) + goto out; + + ret = cap_set_flag(caps, CAP_EFFECTIVE, 1, &cap, 0); + if (ret) + goto out; + + ret = cap_set_proc(caps); + if (ret) + goto out; + + fret = true; + +out: + cap_free(caps); +#endif + return fret; +} + /* caps_down - lower all effective caps */ static int caps_down(void) { @@ -7805,8 +7833,8 @@ out_unmap: #endif /* HAVE_LIBURING_H */ /* The following tests are concerned with setgid inheritance. These can be - * filesystem type specific. For xfs, if a new file or directory is created - * within a setgid directory and irix_sgid_inhiert is set then inherit the + * filesystem type specific. For xfs, if a new file or directory or node is + * created within a setgid directory and irix_sgid_inhiert is set then inherit the * setgid bit if the caller is in the group of the directory. */ static int setgid_create(void) @@ -7863,15 +7891,41 @@ static int setgid_create(void) if (!is_setgid(t_dir1_fd, DIR1, 0)) die("failure: is_setgid"); + /* create a special file via mknodat() vfs_create */ + if (mknodat(t_dir1_fd, DIR1 "/" FILE1, S_IFREG | S_ISGID | 0755, 0)) + die("failure: mknodat"); + + if (!is_setgid(t_dir1_fd, DIR1 "/" FILE1, 0)) + die("failure: is_setgid"); + + /* create a character device via mknodat() vfs_mknod */ + if (mknodat(t_dir1_fd, CHRDEV1, S_IFCHR | S_ISGID | 0755, makedev(5, 1))) + die("failure: mknodat"); + + if (!is_setgid(t_dir1_fd, CHRDEV1, 0)) + die("failure: is_setgid"); + if (!expected_uid_gid(t_dir1_fd, FILE1, 0, 0, 0)) die("failure: check ownership"); + if (!expected_uid_gid(t_dir1_fd, DIR1 "/" FILE1, 0, 0, 0)) + die("failure: check ownership"); + + if (!expected_uid_gid(t_dir1_fd, CHRDEV1, 0, 0, 0)) + die("failure: check ownership"); + if (!expected_uid_gid(t_dir1_fd, DIR1, 0, 0, 0)) die("failure: check ownership"); if (unlinkat(t_dir1_fd, FILE1, 0)) die("failure: delete"); + if (unlinkat(t_dir1_fd, DIR1 "/" FILE1, 0)) + die("failure: delete"); + + if (unlinkat(t_dir1_fd, CHRDEV1, 0)) + die("failure: delete"); + if (unlinkat(t_dir1_fd, DIR1, AT_REMOVEDIR)) die("failure: delete"); @@ -7889,8 +7943,8 @@ static int setgid_create(void) if (!switch_ids(0, 10000)) die("failure: switch_ids"); - if (!caps_down()) - die("failure: caps_down"); + if (!caps_down_fsetid()) + die("failure: caps_down_fsetid"); /* create regular file via open() */ file1_fd = openat(t_dir1_fd, FILE1, O_CREAT | O_EXCL | O_CLOEXEC, S_IXGRP | S_ISGID); @@ -7917,6 +7971,19 @@ static int setgid_create(void) die("failure: is_setgid"); } + /* create a special file via mknodat() vfs_create */ + if (mknodat(t_dir1_fd, DIR1 "/" FILE1, S_IFREG | S_ISGID | 0755, 0)) + die("failure: mknodat"); + + if (is_setgid(t_dir1_fd, DIR1 "/" FILE1, 0)) + die("failure: is_setgid"); + + /* create a character device via mknodat() vfs_mknod */ + if (mknodat(t_dir1_fd, CHRDEV1, S_IFCHR | S_ISGID | 0755, makedev(5, 1))) + die("failure: mknodat"); + + if (is_setgid(t_dir1_fd, CHRDEV1, 0)) + die("failure: is_setgid"); /* * In setgid directories newly created files always inherit the * gid from the parent directory. Verify that the file is owned @@ -7933,6 +8000,24 @@ static int setgid_create(void) if (!expected_uid_gid(t_dir1_fd, DIR1, 0, 0, 0)) die("failure: check ownership"); + if (!expected_uid_gid(t_dir1_fd, DIR1 "/" FILE1, 0, 0, 0)) + die("failure: check ownership"); + + if (!expected_uid_gid(t_dir1_fd, CHRDEV1, 0, 0, 0)) + die("failure: check ownership"); + + if (unlinkat(t_dir1_fd, FILE1, 0)) + die("failure: delete"); + + if (unlinkat(t_dir1_fd, DIR1 "/" FILE1, 0)) + die("failure: delete"); + + if (unlinkat(t_dir1_fd, CHRDEV1, 0)) + die("failure: delete"); + + if (unlinkat(t_dir1_fd, DIR1, AT_REMOVEDIR)) + die("failure: delete"); + exit(EXIT_SUCCESS); } if (wait_for_pid(pid)) @@ -8051,6 +8136,12 @@ static int setgid_create_idmapped(void) if (!expected_uid_gid(open_tree_fd, DIR1, 0, 10000, 10000)) die("failure: check ownership"); + if (unlinkat(open_tree_fd, FILE1, 0)) + die("failure: delete"); + + if (unlinkat(open_tree_fd, DIR1, AT_REMOVEDIR)) + die("failure: delete"); + exit(EXIT_SUCCESS); } if (wait_for_pid(pid)) @@ -8149,15 +8240,37 @@ static int setgid_create_idmapped_in_userns(void) if (!is_setgid(open_tree_fd, DIR1, 0)) die("failure: is_setgid"); + /* create a special file via mknodat() vfs_create */ + if (mknodat(open_tree_fd, DIR1 "/" FILE1, S_IFREG | S_ISGID | 755, 0)) + die("failure: mknodat"); + + if (!is_setgid(open_tree_fd, DIR1 "/" FILE1, 0)) + die("failure: is_setgid"); + + if (mknodat(open_tree_fd, CHRDEV1, S_IFCHR | S_ISGID | 0755, 0)) + die("failure: mknodat"); + + if (!is_setgid(open_tree_fd, CHRDEV1, 0)) + die("failure: is_setgid"); + if (!expected_uid_gid(open_tree_fd, FILE1, 0, 0, 0)) die("failure: check ownership"); if (!expected_uid_gid(open_tree_fd, DIR1, 0, 0, 0)) die("failure: check ownership"); + if (!expected_uid_gid(open_tree_fd, DIR1 "/" FILE1, 0, 0, 0)) + die("failure: check ownership"); + + if (!expected_uid_gid(open_tree_fd, CHRDEV1, 0, 0, 0)) + die("failure: check ownership"); + if (unlinkat(open_tree_fd, FILE1, 0)) die("failure: delete"); - + if (unlinkat(open_tree_fd, DIR1 "/" FILE1, 0)) + die("failure: delete"); + if (unlinkat(open_tree_fd, CHRDEV1, 0)) + die("failure: delete"); if (unlinkat(open_tree_fd, DIR1, AT_REMOVEDIR)) die("failure: delete"); @@ -8190,9 +8303,12 @@ static int setgid_create_idmapped_in_userns(void) exit(EXIT_SUCCESS); } - if (!switch_userns(attr.userns_fd, 0, 0, true)) + if (!switch_userns(attr.userns_fd, 0, 0, false)) die("failure: switch_userns"); + if (!caps_down_fsetid()) + die("failure: caps_down_fsetid"); + /* create regular file via open() */ file1_fd = openat(open_tree_fd, FILE1, O_CREAT | O_EXCL | O_CLOEXEC, S_IXGRP | S_ISGID); if (file1_fd < 0) @@ -8218,6 +8334,20 @@ static int setgid_create_idmapped_in_userns(void) die("failure: is_setgid"); } + /* create a special file via mknodat() vfs_create */ + if (mknodat(open_tree_fd, DIR1 "/" FILE1, S_IFREG | S_ISGID | 0755, 0)) + die("failure: mknodat"); + + if (is_setgid(open_tree_fd, DIR1 "/" FILE1, 0)) + die("failure: is_setgid"); + + /* create a special file via mknodat() vfs_create */ + if (mknodat(open_tree_fd, CHRDEV1, S_IFCHR | S_ISGID | 0755, 0)) + die("failure: mknodat"); + + if (is_setgid(open_tree_fd, CHRDEV1, 0)) + die("failure: is_setgid"); + /* * In setgid directories newly created files always inherit the * gid from the parent directory. Verify that the file is owned @@ -8234,9 +8364,21 @@ static int setgid_create_idmapped_in_userns(void) if (!expected_uid_gid(open_tree_fd, DIR1, 0, 0, 1000)) die("failure: check ownership"); + if (!expected_uid_gid(open_tree_fd, DIR1 "/" FILE1, 0, 0, 1000)) + die("failure: check ownership"); + + if (!expected_uid_gid(open_tree_fd, CHRDEV1, 0, 0, 1000)) + die("failure: check ownership"); + if (unlinkat(open_tree_fd, FILE1, 0)) die("failure: delete"); + if (unlinkat(open_tree_fd, DIR1 "/" FILE1, 0)) + die("failure: delete"); + + if (unlinkat(open_tree_fd, CHRDEV1, 0)) + die("failure: delete"); + if (unlinkat(open_tree_fd, DIR1, AT_REMOVEDIR)) die("failure: delete"); @@ -8266,9 +8408,12 @@ static int setgid_create_idmapped_in_userns(void) exit(EXIT_SUCCESS); } - if (!switch_userns(attr.userns_fd, 0, 1000, true)) + if (!switch_userns(attr.userns_fd, 0, 1000, false)) die("failure: switch_userns"); + if (!caps_down_fsetid()) + die("failure: caps_down_fsetid"); + /* create regular file via open() */ file1_fd = openat(open_tree_fd, FILE1, O_CREAT | O_EXCL | O_CLOEXEC, S_IXGRP | S_ISGID); if (file1_fd < 0) @@ -8295,12 +8440,43 @@ static int setgid_create_idmapped_in_userns(void) die("failure: is_setgid"); } + /* create a special file via mknodat() vfs_create */ + if (mknodat(open_tree_fd, DIR1 "/" FILE1, S_IFREG | S_ISGID | 0755, 0)) + die("failure: mknodat"); + + if (is_setgid(open_tree_fd, DIR1 "/" FILE1, 0)) + die("failure: is_setgid"); + + if (mknodat(open_tree_fd, CHRDEV1, S_IFCHR | S_ISGID | 0755, 0)) + die("failure: mknodat"); + + if (is_setgid(open_tree_fd, CHRDEV1, 0)) + die("failure: is_setgid"); + if (!expected_uid_gid(open_tree_fd, FILE1, 0, 0, 0)) die("failure: check ownership"); if (!expected_uid_gid(open_tree_fd, DIR1, 0, 0, 0)) die("failure: check ownership"); + if (!expected_uid_gid(open_tree_fd, DIR1 "/" FILE1, 0, 0, 0)) + die("failure: check ownership"); + + if (!expected_uid_gid(open_tree_fd, CHRDEV1, 0, 0, 0)) + die("failure: check ownership"); + + if (unlinkat(open_tree_fd, FILE1, 0)) + die("failure: delete"); + + if (unlinkat(open_tree_fd, DIR1 "/" FILE1, 0)) + die("failure: delete"); + + if (unlinkat(open_tree_fd, CHRDEV1, 0)) + die("failure: delete"); + + if (unlinkat(open_tree_fd, DIR1, AT_REMOVEDIR)) + die("failure: delete"); + exit(EXIT_SUCCESS); } if (wait_for_pid(pid))