From patchwork Thu Mar 26 20:06:33 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Colascione X-Patchwork-Id: 11460995 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 2C1B06CA for ; Thu, 26 Mar 2020 20:07:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0F0362076A for ; Thu, 26 Mar 2020 20:07:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Ffjr9V6L" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728756AbgCZUGv (ORCPT ); Thu, 26 Mar 2020 16:06:51 -0400 Received: from mail-qk1-f201.google.com ([209.85.222.201]:43302 "EHLO mail-qk1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728750AbgCZUGu (ORCPT ); Thu, 26 Mar 2020 16:06:50 -0400 Received: by mail-qk1-f201.google.com with SMTP id w195so5969156qkb.10 for ; Thu, 26 Mar 2020 13:06:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=jxOc9o6NdvdCnjWFdn8kUz8yJ8bzL6ZGVJ74OA5uXfY=; b=Ffjr9V6LlkXfWH5QWPvkkOxpxxaPg2dBmP9aODBfh2MLONLCpKoT5k6cl3xcUKMvoK RQzzut1js/XvxLH1WYNzXDMxzX/EUHXmEsJjRsd0rxdpdtySLJicp7wXKmiALgbYim3E 6+WdDcZIplOzHSme1fEbEIyao/XjxmX4fDidOvBTabMGEHqP9x9xqJls0Ih4lpPheMUE SThJQS41nDzmr15P9GPI0LlcZCAHx3mEzRVxzGHnuqrdlfKC9JYb69H4B7ke/lcJyHhW 74YCrn8uaVita3ZLizNU2C8Qiv8rvRuFk4BSMQKezoD4iCwQC6QACAFgpb0AjRumR3ud DgeA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=jxOc9o6NdvdCnjWFdn8kUz8yJ8bzL6ZGVJ74OA5uXfY=; b=EMSfwEHqF305WTa1zGoQOmuVF91V7rPpWwmC6j2tnPd0ZVAowDAXuBkiHIkKrnZgDe 65U8TEfSNSP+3vGH7+ohS/4Gr1mwMmhY+WaVqVpaQAkc6zLIsE6fAixV3BvPc4dscZye j3L84Z6+A9nDer2y3I9XU8QhzEHOKLl8ZbtntA1keLYAKSZrvGumxpbmKahTtvl10o4Q rpsKdFU/MmK+kPY5opEKt0qe0avX22A3rGOhyneAjLcWEeaq63j0TVmWCwOoeFQvLAHc 0p0GNCRaybA2pyJQwnuVCQKjndn27D2YUi9GGbLWKAXn8uhsx89v7vHRyCSULB3D1YEO Naaw== X-Gm-Message-State: ANhLgQ18rPYK4g7pcNFgI7dAqkcfHnug06woOzQP98BGGLWXrChpGEOF x1XOW9nHM9ZMjBqdBGbc8CGxTg2kSVM= X-Google-Smtp-Source: ADFU+vvaexDqyLY8GoD+ICFTM/vR7zLUOM6FxoFEd6oCKQxs/tDvOvNnpUYgLbAaeb0sHk5Q7eX0naECVtc= X-Received: by 2002:ac8:1c17:: with SMTP id a23mr10721235qtk.239.1585253209979; Thu, 26 Mar 2020 13:06:49 -0700 (PDT) Date: Thu, 26 Mar 2020 13:06:33 -0700 In-Reply-To: <20200326200634.222009-1-dancol@google.com> Message-Id: <20200326200634.222009-3-dancol@google.com> Mime-Version: 1.0 References: <20200326181456.132742-1-dancol@google.com> <20200326200634.222009-1-dancol@google.com> X-Mailer: git-send-email 2.25.1.696.g5e7596f4ac-goog Subject: [PATCH v4 2/3] Teach SELinux about anonymous inodes From: Daniel Colascione To: timmurray@google.com, selinux@vger.kernel.org, linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, viro@zeniv.linux.org.uk, paul@paul-moore.com, nnk@google.com, sds@tycho.nsa.gov, lokeshgidra@google.com, jmorris@namei.org Cc: Daniel Colascione Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org This change uses the anon_inodes and LSM infrastructure introduced in the previous patch to give SELinux the ability to control anonymous-inode files that are created using the new _secure() anon_inodes functions. A SELinux policy author detects and controls these anonymous inodes by adding a name-based type_transition rule that assigns a new security type to anonymous-inode files created in some domain. The name used for the name-based transition is the name associated with the anonymous inode for file listings --- e.g., "[userfaultfd]" or "[perf_event]". Example: type uffd_t; type_transition sysadm_t sysadm_t : anon_inode uffd_t "[userfaultfd]"; allow sysadm_t uffd_t:anon_inode { create }; (The next patch in this series is necessary for making userfaultfd support this new interface. The example above is just for exposition.) Signed-off-by: Daniel Colascione Acked-by: Stephen Smalley --- security/selinux/hooks.c | 53 +++++++++++++++++++++++++++++ security/selinux/include/classmap.h | 2 ++ 2 files changed, 55 insertions(+) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 1659b59fb5d7..6f7222d2e404 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -2915,6 +2915,58 @@ static int selinux_inode_init_security(struct inode *inode, struct inode *dir, return 0; } +static int selinux_inode_init_security_anon(struct inode *inode, + const struct qstr *name, + const struct inode *context_inode) +{ + const struct task_security_struct *tsec = selinux_cred(current_cred()); + struct common_audit_data ad; + struct inode_security_struct *isec; + int rc; + + if (unlikely(!selinux_state.initialized)) + return 0; + + isec = selinux_inode(inode); + + /* + * We only get here once per ephemeral inode. The inode has + * been initialized via inode_alloc_security but is otherwise + * untouched. + */ + + if (context_inode) { + struct inode_security_struct *context_isec = + selinux_inode(context_inode); + isec->sclass = context_isec->sclass; + isec->sid = context_isec->sid; + } else { + isec->sclass = SECCLASS_ANON_INODE; + rc = security_transition_sid( + &selinux_state, tsec->sid, tsec->sid, + isec->sclass, name, &isec->sid); + if (rc) + return rc; + } + + isec->initialized = LABEL_INITIALIZED; + + /* + * Now that we've initialized security, check whether we're + * allowed to actually create this type of anonymous inode. + */ + + ad.type = LSM_AUDIT_DATA_INODE; + ad.u.inode = inode; + + return avc_has_perm(&selinux_state, + tsec->sid, + isec->sid, + isec->sclass, + FILE__CREATE, + &ad); +} + static int selinux_inode_create(struct inode *dir, struct dentry *dentry, umode_t mode) { return may_create(dir, dentry, SECCLASS_FILE); @@ -6923,6 +6975,7 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = { LSM_HOOK_INIT(inode_free_security, selinux_inode_free_security), LSM_HOOK_INIT(inode_init_security, selinux_inode_init_security), + LSM_HOOK_INIT(inode_init_security_anon, selinux_inode_init_security_anon), LSM_HOOK_INIT(inode_create, selinux_inode_create), LSM_HOOK_INIT(inode_link, selinux_inode_link), LSM_HOOK_INIT(inode_unlink, selinux_inode_unlink), diff --git a/security/selinux/include/classmap.h b/security/selinux/include/classmap.h index 986f3ac14282..263750b6aaac 100644 --- a/security/selinux/include/classmap.h +++ b/security/selinux/include/classmap.h @@ -248,6 +248,8 @@ struct security_class_mapping secclass_map[] = { {"open", "cpu", "kernel", "tracepoint", "read", "write"} }, { "lockdown", { "integrity", "confidentiality", NULL } }, + { "anon_inode", + { COMMON_FILE_PERMS, NULL } }, { NULL } };