From patchwork Wed Jan 30 11:41:46 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ondrej Mosnacek X-Patchwork-Id: 10788365 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C4DC46C2 for ; Wed, 30 Jan 2019 11:43:16 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B314F2E732 for ; Wed, 30 Jan 2019 11:43:16 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A75AB2E739; Wed, 30 Jan 2019 11:43:16 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 208C62E732 for ; Wed, 30 Jan 2019 11:43:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728205AbfA3LnP (ORCPT ); Wed, 30 Jan 2019 06:43:15 -0500 Received: from mail-wm1-f66.google.com ([209.85.128.66]:37568 "EHLO mail-wm1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727838AbfA3LnP (ORCPT ); Wed, 30 Jan 2019 06:43:15 -0500 Received: by mail-wm1-f66.google.com with SMTP id g67so21226886wmd.2 for ; Wed, 30 Jan 2019 03:43:13 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=qWCOjIpCOk81UALDGpP07aau3ZMFw3eCyGnAaDjo63o=; b=bo6YumdQneAldGdk7bUA1/QCLGvrbIeQWIZJCEgQZILKBcFIozn8HNoScq1tvaLItd 8p2HO2xZjcZaR7uLb/vVhrWDjE1HK/SzOSK4Pb8+vSdCXsf/6lAugwFstARZDDxn+cVQ rTL+vp2b1OAjl3tB/sCWcs8PrPvSEBG0ONq/SAnSj/hCFJD2oVu4ynVEeJ3mDxUP927o eZr0c5mfF+wksLff3FWwcP4ghnRV6qtj9Xkc1okgXjRh2+d2MhAqGuqDhO6BgKRMFP6d KAFA2xpLC958IgdVMx0adq0JYwIxo4nmv7WyTjJgZiN+u/+gJEhKdZxJtFUHqeRwW0T9 OsDw== X-Gm-Message-State: AJcUukfZAomiLGlt82VT2ZwEIr7ZpApL3WCSUD8Hk4+0LYV6bLeXdONg hg3t6KV+t0dmgW2tnQOnCSBz5YzZQPM= X-Google-Smtp-Source: ALg8bN5t4b+/Gm3kYlGxNJVYZSxn2uP4Ep0vNW2epEJkRvCqvsCQKVc35UR4cmvaCTO9HMSq6WBDwA== X-Received: by 2002:a1c:c10f:: with SMTP id r15mr24911424wmf.27.1548848592279; Wed, 30 Jan 2019 03:43:12 -0800 (PST) Received: from localhost.localdomain.com (nat-pool-brq-t.redhat.com. [213.175.37.10]) by smtp.gmail.com with ESMTPSA id n124sm2417691wmd.15.2019.01.30.03.43.10 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 30 Jan 2019 03:43:11 -0800 (PST) From: Ondrej Mosnacek To: selinux@vger.kernel.org, Paul Moore Cc: Stephen Smalley , linux-security-module@vger.kernel.org, Casey Schaufler , Greg Kroah-Hartman , Tejun Heo , linux-fsdevel@vger.kernel.org, cgroups@vger.kernel.org, Ondrej Mosnacek Subject: [PATCH v3 1/5] selinux: try security xattr after genfs for kernfs filesystems Date: Wed, 30 Jan 2019 12:41:46 +0100 Message-Id: <20190130114150.27807-2-omosnace@redhat.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190130114150.27807-1-omosnace@redhat.com> References: <20190130114150.27807-1-omosnace@redhat.com> MIME-Version: 1.0 Sender: selinux-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: selinux@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Since kernfs supports the security xattr handlers, we can simply use these to determine the inode's context, dropping the need to update it from kernfs explicitly using a security_inode_notifysecctx() call. We achieve this by setting a new sbsec flag SE_SBGENFS_XATTR to all mounts that are known to use kernfs under the hood and then fetching the xattrs after determining the fallback genfs sid in inode_doinit_with_dentry() when this flag is set. This will allow implementing full security xattr support in kernfs and removing the ...notifysecctx() call in a subsequent patch. Signed-off-by: Ondrej Mosnacek --- security/selinux/hooks.c | 159 +++++++++++++++------------- security/selinux/include/security.h | 1 + 2 files changed, 88 insertions(+), 72 deletions(-) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 81e012c66d95..758a99d1086e 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -793,11 +793,13 @@ static int selinux_set_mnt_opts(struct super_block *sb, if (!strcmp(sb->s_type->name, "debugfs") || !strcmp(sb->s_type->name, "tracefs") || - !strcmp(sb->s_type->name, "sysfs") || - !strcmp(sb->s_type->name, "pstore") || + !strcmp(sb->s_type->name, "pstore")) + sbsec->flags |= SE_SBGENFS; + + if (!strcmp(sb->s_type->name, "sysfs") || !strcmp(sb->s_type->name, "cgroup") || !strcmp(sb->s_type->name, "cgroup2")) - sbsec->flags |= SE_SBGENFS; + sbsec->flags |= SE_SBGENFS | SE_SBGENFS_XATTR; if (!sbsec->behavior) { /* @@ -1392,6 +1394,71 @@ static int selinux_genfs_get_sid(struct dentry *dentry, return rc; } +static int inode_doinit_use_xattr(struct inode *inode, struct dentry *dentry, + u32 def_sid, u32 *sid) +{ +#define INITCONTEXTLEN 255 + char *context = NULL; + unsigned int len = 0; + int rc; + + *sid = def_sid; + + if (!(inode->i_opflags & IOP_XATTR)) + return 0; + + len = INITCONTEXTLEN; + context = kmalloc(len + 1, GFP_NOFS); + if (!context) + return -ENOMEM; + + context[len] = '\0'; + rc = __vfs_getxattr(dentry, inode, XATTR_NAME_SELINUX, context, len); + if (rc == -ERANGE) { + kfree(context); + + /* Need a larger buffer. Query for the right size. */ + rc = __vfs_getxattr(dentry, inode, XATTR_NAME_SELINUX, NULL, 0); + if (rc < 0) + return rc; + + len = rc; + context = kmalloc(len + 1, GFP_NOFS); + if (!context) + return -ENOMEM; + + context[len] = '\0'; + rc = __vfs_getxattr(dentry, inode, XATTR_NAME_SELINUX, + context, len); + } + if (rc < 0) { + kfree(context); + if (rc != -ENODATA) { + pr_warn("SELinux: %s: getxattr returned %d for dev=%s ino=%ld\n", + __func__, -rc, inode->i_sb->s_id, inode->i_ino); + return rc; + } + return 0; + } + + rc = security_context_to_sid_default(&selinux_state, context, rc, sid, + def_sid, GFP_NOFS); + if (rc) { + char *dev = inode->i_sb->s_id; + unsigned long ino = inode->i_ino; + + if (rc == -EINVAL) { + pr_notice_ratelimited("SELinux: inode=%lu on dev=%s was found to have an invalid context=%s. This indicates you may need to relabel the inode or the filesystem in question.\n", + ino, dev, context); + } else { + pr_warn("SELinux: %s: context_to_sid(%s) returned %d for dev=%s ino=%ld\n", + __func__, context, -rc, dev, ino); + } + } + kfree(context); + return 0; +} + /* The inode's security attributes must be initialized before first use. */ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dentry) { @@ -1401,8 +1468,6 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent u16 sclass; struct dentry *dentry; #define INITCONTEXTLEN 255 - char *context = NULL; - unsigned len = 0; int rc = 0; if (isec->initialized == LABEL_INITIALIZED) @@ -1470,72 +1535,11 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent goto out; } - len = INITCONTEXTLEN; - context = kmalloc(len+1, GFP_NOFS); - if (!context) { - rc = -ENOMEM; - dput(dentry); - goto out; - } - context[len] = '\0'; - rc = __vfs_getxattr(dentry, inode, XATTR_NAME_SELINUX, context, len); - if (rc == -ERANGE) { - kfree(context); - - /* Need a larger buffer. Query for the right size. */ - rc = __vfs_getxattr(dentry, inode, XATTR_NAME_SELINUX, NULL, 0); - if (rc < 0) { - dput(dentry); - goto out; - } - len = rc; - context = kmalloc(len+1, GFP_NOFS); - if (!context) { - rc = -ENOMEM; - dput(dentry); - goto out; - } - context[len] = '\0'; - rc = __vfs_getxattr(dentry, inode, XATTR_NAME_SELINUX, context, len); - } + rc = inode_doinit_use_xattr(inode, dentry, sbsec->def_sid, + &sid); dput(dentry); - if (rc < 0) { - if (rc != -ENODATA) { - pr_warn("SELinux: %s: getxattr returned " - "%d for dev=%s ino=%ld\n", __func__, - -rc, inode->i_sb->s_id, inode->i_ino); - kfree(context); - goto out; - } - /* Map ENODATA to the default file SID */ - sid = sbsec->def_sid; - rc = 0; - } else { - rc = security_context_to_sid_default(&selinux_state, - context, rc, &sid, - sbsec->def_sid, - GFP_NOFS); - if (rc) { - char *dev = inode->i_sb->s_id; - unsigned long ino = inode->i_ino; - - if (rc == -EINVAL) { - if (printk_ratelimit()) - pr_notice("SELinux: inode=%lu on dev=%s was found to have an invalid " - "context=%s. This indicates you may need to relabel the inode or the " - "filesystem in question.\n", ino, dev, context); - } else { - pr_warn("SELinux: %s: context_to_sid(%s) " - "returned %d for dev=%s ino=%ld\n", - __func__, context, -rc, dev, ino); - } - kfree(context); - /* Leave with the unlabeled SID */ - rc = 0; - break; - } - } - kfree(context); + if (rc) + goto out; break; case SECURITY_FS_USE_TASK: sid = task_sid; @@ -1586,9 +1590,20 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent goto out; rc = selinux_genfs_get_sid(dentry, sclass, sbsec->flags, &sid); - dput(dentry); - if (rc) + if (rc) { + dput(dentry); goto out; + } + + if (sbsec->flags & SE_SBGENFS_XATTR) { + rc = inode_doinit_use_xattr(inode, dentry, + sid, &sid); + if (rc) { + dput(dentry); + goto out; + } + } + dput(dentry); } break; } diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h index f68fb25b5702..6e5928f951da 100644 --- a/security/selinux/include/security.h +++ b/security/selinux/include/security.h @@ -58,6 +58,7 @@ #define SE_SBINITIALIZED 0x0100 #define SE_SBPROC 0x0200 #define SE_SBGENFS 0x0400 +#define SE_SBGENFS_XATTR 0x0800 #define CONTEXT_STR "context=" #define FSCONTEXT_STR "fscontext="