From patchwork Thu Aug 27 06:35:21 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lokesh Gidra X-Patchwork-Id: 11740009 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 565141731 for ; Thu, 27 Aug 2020 06:35:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 38588207BC for ; Thu, 27 Aug 2020 06:35:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=google.com header.i=@google.com header.b="wHwCCfOV" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727921AbgH0Gfn (ORCPT ); Thu, 27 Aug 2020 02:35:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40144 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727897AbgH0Gfd (ORCPT ); Thu, 27 Aug 2020 02:35:33 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6BFC1C061233 for ; Wed, 26 Aug 2020 23:35:33 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id p138so6093525yba.12 for ; Wed, 26 Aug 2020 23:35:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:in-reply-to:message-id:mime-version:references:subject :from:to:cc; bh=pLxaBib0LMkN4D4wR9hiVJIAOm60ZZrqLyNtSVQ6McE=; b=wHwCCfOVlKR+vTkeXOUL2ZliPAhdFBIlxDc+gQIk+nJ0ruhpVVIEiioyadTtOxwW/B NyuwpzBLYY3JGG7d+DpNz3uLscGKU6ea+m6fDZpubsy5qULyWo6c2LELhhZ8Z0TNUBOG PfNN8Ei1PEtGLZkBRw/S+v+P5zmDovIfN/LOcml/Fi4tlH1a3zFKu2wNbqxNg6hNQSvt ZSP9dzkUWMUOeMjxtihy6F0HFKpCTn+5DjFovfX1C6lXdKyS5hlMvI1r7fcOXVYJVFSt 0W23vbW7N7snvf4TnYXDLNbzRwzfitJxfDqKLLWpquCKn7MdxeL/31xHWswe6qLOwOv/ Cs5g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=pLxaBib0LMkN4D4wR9hiVJIAOm60ZZrqLyNtSVQ6McE=; b=Rjzb85y7dR267aEZOeV0vWZJ3AW9ZtsR/NVoikfrXwDMJLb3YY4rPFOXdX3CWa9T/q qz5+UyrDZENqVBI7EqEnsAp60L/Fl9J9Eu2Fzip90+mu4uNdO+mF6eQCTCAA4x7o2W1t viohppKeZdVij3lmdzx/tMHL7NGvj26LhPUz5P80ExC+quhDpsxvwAYoaCyTVG/G/rhm vun1MMLi05ipbLVGYTAxZMRsgD3Da30w+BikSshgUrn1bARjz/guOvNqbwTozwKX4iKx pdwEq88d5wePUA2iJtnIDAnflolk6sWl1zAC+Oh0tBR/AlnkIK5iryCR2cPcGSrsvPBr VHBQ== X-Gm-Message-State: AOAM531ig8H5qMFEeA2biiymVtUo8s6ncMIyaI83W0Esu1lA9WNuJ1xR 6qV6JLYH9NOl7AVnzamWSpEmoFclJzf2/S0Oug== X-Google-Smtp-Source: ABdhPJz66lEBcU2uHus1V086mNXk3LCt5yHkf8vbymGDl41kU7EQRALFBPJs7iT+92xVfsT0baMMKGLnl7YUkNR0tQ== X-Received: from lg.mtv.corp.google.com ([100.89.4.209]) (user=lokeshgidra job=sendgmr) by 2002:a25:ab0d:: with SMTP id u13mr28407715ybi.248.1598510132559; Wed, 26 Aug 2020 23:35:32 -0700 (PDT) Date: Wed, 26 Aug 2020 23:35:21 -0700 In-Reply-To: <20200827063522.2563293-1-lokeshgidra@google.com> Message-Id: <20200827063522.2563293-3-lokeshgidra@google.com> Mime-Version: 1.0 References: <20200827063522.2563293-1-lokeshgidra@google.com> X-Mailer: git-send-email 2.28.0.297.g1956fa8f8d-goog Subject: [PATCH v8 2/3] Teach SELinux about anonymous inodes From: Lokesh Gidra To: Alexander Viro , James Morris , Stephen Smalley , Casey Schaufler , Eric Biggers Cc: "Serge E. Hallyn" , Paul Moore , Eric Paris , Lokesh Gidra , Daniel Colascione , Kees Cook , "Eric W. Biederman" , KP Singh , David Howells , Thomas Cedeno , Anders Roxell , Sami Tolvanen , Matthew Garrett , Aaron Goidel , Randy Dunlap , "Joel Fernandes (Google)" , YueHaibing , Christian Brauner , Alexei Starovoitov , Alexey Budankov , Adrian Reber , Aleksa Sarai , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org, kaleshsingh@google.com, calin@google.com, surenb@google.com, nnk@google.com, jeffv@google.com, kernel-team@android.com, Daniel Colascione , Andrew Morton Sender: selinux-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: selinux@vger.kernel.org From: Daniel Colascione 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 anon_inode_getfd_secure() function. 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: Casey Schaufler Acked-by: Stephen Smalley Cc: Al Viro Cc: Andrew Morton --- 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 a340986aa92e..b83f56e5ef40 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -2926,6 +2926,58 @@ 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); @@ -6987,6 +7039,7 @@ 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 40cebde62856..ba2e01a6955c 100644 --- a/security/selinux/include/classmap.h +++ b/security/selinux/include/classmap.h @@ -249,6 +249,8 @@ struct security_class_mapping secclass_map[] = { {"open", "cpu", "kernel", "tracepoint", "read", "write"} }, { "lockdown", { "integrity", "confidentiality", NULL } }, + { "anon_inode", + { COMMON_FILE_PERMS, NULL } }, { NULL } };