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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D8112C4708A for ; Tue, 5 Apr 2022 08:01:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236410AbiDEICM (ORCPT ); Tue, 5 Apr 2022 04:02:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57060 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233088AbiDEHwH (ORCPT ); Tue, 5 Apr 2022 03:52:07 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0C9D69A9A8; Tue, 5 Apr 2022 00:48:22 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 91264B81B18; Tue, 5 Apr 2022 07:48:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E85A9C340EE; Tue, 5 Apr 2022 07:48:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649144899; bh=NCtORz99CQECjvkHop6fKoctS6oPu/LXqkX7lYb0PiI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RP+ysa6EL9n2+aFpmc0XD9kOf+oT1Qq4DcZk0XzhGhtghsZqqHHh//C6W2cAXqqJq gL5JAD1rmtzom3vidAUyhC917WUEDPnF3LOgpnKUE3KqrM2nMdJwufaLnichkr5Vwh upPPjDLyVdsX3MaIXRNUEh5W76WlgO4CGk3yz1Bs= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Scott Mayhew , Paul Moore , Sasha Levin Subject: [PATCH 5.17 0210/1126] selinux: Fix selinux_sb_mnt_opts_compat() Date: Tue, 5 Apr 2022 09:15:57 +0200 Message-Id: <20220405070413.773434329@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220405070407.513532867@linuxfoundation.org> References: <20220405070407.513532867@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Scott Mayhew [ Upstream commit b8b87fd954b4b1bdd2d739c8f50bf685351a1a94 ] selinux_sb_mnt_opts_compat() is called under the sb_lock spinlock and shouldn't be performing any memory allocations. Fix this by parsing the sids at the same time we're chopping up the security mount options string and then using the pre-parsed sids when doing the comparison. Fixes: cc274ae7763d ("selinux: fix sleeping function called from invalid context") Fixes: 69c4a42d72eb ("lsm,selinux: add new hook to compare new mount to an existing mount") Signed-off-by: Scott Mayhew Signed-off-by: Paul Moore Signed-off-by: Sasha Levin --- security/selinux/hooks.c | 75 ++++++++++++++++++++++------------------ 1 file changed, 41 insertions(+), 34 deletions(-) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index a0243bae8423..a7306208649a 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -342,6 +342,10 @@ static void inode_free_security(struct inode *inode) struct selinux_mnt_opts { const char *fscontext, *context, *rootcontext, *defcontext; + u32 fscontext_sid; + u32 context_sid; + u32 rootcontext_sid; + u32 defcontext_sid; }; static void selinux_free_mnt_opts(void *mnt_opts) @@ -598,15 +602,14 @@ static int bad_option(struct superblock_security_struct *sbsec, char flag, return 0; } -static int parse_sid(struct super_block *sb, const char *s, u32 *sid, - gfp_t gfp) +static int parse_sid(struct super_block *sb, const char *s, u32 *sid) { int rc = security_context_str_to_sid(&selinux_state, s, - sid, gfp); + sid, GFP_KERNEL); if (rc) pr_warn("SELinux: security_context_str_to_sid" "(%s) failed for (dev %s, type %s) errno=%d\n", - s, sb->s_id, sb->s_type->name, rc); + s, sb ? sb->s_id : "?", sb ? sb->s_type->name : "?", rc); return rc; } @@ -673,8 +676,7 @@ static int selinux_set_mnt_opts(struct super_block *sb, */ if (opts) { if (opts->fscontext) { - rc = parse_sid(sb, opts->fscontext, &fscontext_sid, - GFP_KERNEL); + rc = parse_sid(sb, opts->fscontext, &fscontext_sid); if (rc) goto out; if (bad_option(sbsec, FSCONTEXT_MNT, sbsec->sid, @@ -683,8 +685,7 @@ static int selinux_set_mnt_opts(struct super_block *sb, sbsec->flags |= FSCONTEXT_MNT; } if (opts->context) { - rc = parse_sid(sb, opts->context, &context_sid, - GFP_KERNEL); + rc = parse_sid(sb, opts->context, &context_sid); if (rc) goto out; if (bad_option(sbsec, CONTEXT_MNT, sbsec->mntpoint_sid, @@ -693,8 +694,7 @@ static int selinux_set_mnt_opts(struct super_block *sb, sbsec->flags |= CONTEXT_MNT; } if (opts->rootcontext) { - rc = parse_sid(sb, opts->rootcontext, &rootcontext_sid, - GFP_KERNEL); + rc = parse_sid(sb, opts->rootcontext, &rootcontext_sid); if (rc) goto out; if (bad_option(sbsec, ROOTCONTEXT_MNT, root_isec->sid, @@ -703,8 +703,7 @@ static int selinux_set_mnt_opts(struct super_block *sb, sbsec->flags |= ROOTCONTEXT_MNT; } if (opts->defcontext) { - rc = parse_sid(sb, opts->defcontext, &defcontext_sid, - GFP_KERNEL); + rc = parse_sid(sb, opts->defcontext, &defcontext_sid); if (rc) goto out; if (bad_option(sbsec, DEFCONTEXT_MNT, sbsec->def_sid, @@ -996,21 +995,29 @@ static int selinux_add_opt(int token, const char *s, void **mnt_opts) if (opts->context || opts->defcontext) goto err; opts->context = s; + if (selinux_initialized(&selinux_state)) + parse_sid(NULL, s, &opts->context_sid); break; case Opt_fscontext: if (opts->fscontext) goto err; opts->fscontext = s; + if (selinux_initialized(&selinux_state)) + parse_sid(NULL, s, &opts->fscontext_sid); break; case Opt_rootcontext: if (opts->rootcontext) goto err; opts->rootcontext = s; + if (selinux_initialized(&selinux_state)) + parse_sid(NULL, s, &opts->rootcontext_sid); break; case Opt_defcontext: if (opts->context || opts->defcontext) goto err; opts->defcontext = s; + if (selinux_initialized(&selinux_state)) + parse_sid(NULL, s, &opts->defcontext_sid); break; } @@ -2648,8 +2655,6 @@ static int selinux_sb_mnt_opts_compat(struct super_block *sb, void *mnt_opts) { struct selinux_mnt_opts *opts = mnt_opts; struct superblock_security_struct *sbsec = selinux_superblock(sb); - u32 sid; - int rc; /* * Superblock not initialized (i.e. no options) - reject if any @@ -2666,34 +2671,36 @@ static int selinux_sb_mnt_opts_compat(struct super_block *sb, void *mnt_opts) return (sbsec->flags & SE_MNTMASK) ? 1 : 0; if (opts->fscontext) { - rc = parse_sid(sb, opts->fscontext, &sid, GFP_NOWAIT); - if (rc) + if (opts->fscontext_sid == SECSID_NULL) return 1; - if (bad_option(sbsec, FSCONTEXT_MNT, sbsec->sid, sid)) + else if (bad_option(sbsec, FSCONTEXT_MNT, sbsec->sid, + opts->fscontext_sid)) return 1; } if (opts->context) { - rc = parse_sid(sb, opts->context, &sid, GFP_NOWAIT); - if (rc) + if (opts->context_sid == SECSID_NULL) return 1; - if (bad_option(sbsec, CONTEXT_MNT, sbsec->mntpoint_sid, sid)) + else if (bad_option(sbsec, CONTEXT_MNT, sbsec->mntpoint_sid, + opts->context_sid)) return 1; } if (opts->rootcontext) { - struct inode_security_struct *root_isec; - - root_isec = backing_inode_security(sb->s_root); - rc = parse_sid(sb, opts->rootcontext, &sid, GFP_NOWAIT); - if (rc) - return 1; - if (bad_option(sbsec, ROOTCONTEXT_MNT, root_isec->sid, sid)) + if (opts->rootcontext_sid == SECSID_NULL) return 1; + else { + struct inode_security_struct *root_isec; + + root_isec = backing_inode_security(sb->s_root); + if (bad_option(sbsec, ROOTCONTEXT_MNT, root_isec->sid, + opts->rootcontext_sid)) + return 1; + } } if (opts->defcontext) { - rc = parse_sid(sb, opts->defcontext, &sid, GFP_NOWAIT); - if (rc) + if (opts->defcontext_sid == SECSID_NULL) return 1; - if (bad_option(sbsec, DEFCONTEXT_MNT, sbsec->def_sid, sid)) + else if (bad_option(sbsec, DEFCONTEXT_MNT, sbsec->def_sid, + opts->defcontext_sid)) return 1; } return 0; @@ -2713,14 +2720,14 @@ static int selinux_sb_remount(struct super_block *sb, void *mnt_opts) return 0; if (opts->fscontext) { - rc = parse_sid(sb, opts->fscontext, &sid, GFP_KERNEL); + rc = parse_sid(sb, opts->fscontext, &sid); if (rc) return rc; if (bad_option(sbsec, FSCONTEXT_MNT, sbsec->sid, sid)) goto out_bad_option; } if (opts->context) { - rc = parse_sid(sb, opts->context, &sid, GFP_KERNEL); + rc = parse_sid(sb, opts->context, &sid); if (rc) return rc; if (bad_option(sbsec, CONTEXT_MNT, sbsec->mntpoint_sid, sid)) @@ -2729,14 +2736,14 @@ static int selinux_sb_remount(struct super_block *sb, void *mnt_opts) if (opts->rootcontext) { struct inode_security_struct *root_isec; root_isec = backing_inode_security(sb->s_root); - rc = parse_sid(sb, opts->rootcontext, &sid, GFP_KERNEL); + rc = parse_sid(sb, opts->rootcontext, &sid); if (rc) return rc; if (bad_option(sbsec, ROOTCONTEXT_MNT, root_isec->sid, sid)) goto out_bad_option; } if (opts->defcontext) { - rc = parse_sid(sb, opts->defcontext, &sid, GFP_KERNEL); + rc = parse_sid(sb, opts->defcontext, &sid); if (rc) return rc; if (bad_option(sbsec, DEFCONTEXT_MNT, sbsec->def_sid, sid)) -- 2.34.1