From patchwork Wed Sep 23 19:33:23 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lokesh Gidra X-Patchwork-Id: 11795587 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 D1E22112E for ; Wed, 23 Sep 2020 19:33:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9E1A0238D7 for ; Wed, 23 Sep 2020 19:33:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="TIdpodC0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726665AbgIWTdi (ORCPT ); Wed, 23 Sep 2020 15:33:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52268 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726532AbgIWTdg (ORCPT ); Wed, 23 Sep 2020 15:33:36 -0400 Received: from mail-qt1-x84a.google.com (mail-qt1-x84a.google.com [IPv6:2607:f8b0:4864:20::84a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 85488C0613D5 for ; Wed, 23 Sep 2020 12:33:35 -0700 (PDT) Received: by mail-qt1-x84a.google.com with SMTP id y53so776049qth.2 for ; Wed, 23 Sep 2020 12:33:35 -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=fQ+u0i/drpA23IAmEKGg6Wevn+USA3eu5o+lEdrjmF4=; b=TIdpodC0D5kyjhJ1OZ7/V6D71iGyyC+HLo84qVjmXf8+4UJyNWUBTtl0ecWQ3zK+dV guYsIXdfN5+aiBC9DDeEjR6X/qv2GIaj6lcLOwkEwduU90tc1JbE4KgYLZXUkEAPeyAG WjOkifXoEnYentlROfgUmP6q/1E+r9O8WbUxuQ8UcUY7rAhdYtTo1VtAqnN5RwuMEqDZ DT//vVhP6XQwsUEBqLjW37sy0wNnFalh/YTZG4MIx4+UIE/yvnOeS6Y8a6rKm1R4Jt0W Algpv/HVcMI2g5z0uon3qJviJNl8ygMJK4nWi7beRhpvadJu1jlPVw55BL2bICpo5/me D7Mw== 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=fQ+u0i/drpA23IAmEKGg6Wevn+USA3eu5o+lEdrjmF4=; b=tC2sSNPDOU5MOnkVIGM7buevbqepQ5IKyUkP4bKUdpaKlNgQWN6JmyqQMFsa+i2Uzc EFc5Lg6JWYbNTXsB0StnaUtDNIGt50KKhOc+eEJdzYwWfk4VVp82wo6ZPpieykF+xr8y blufVj9uo+N30c4bkHdtL/3gOltTkzDMbJFbh8knajPIj6GAhxsKZ/9L1068T99OLjaT Z0FeRKna8C/JoO3tXRw5gjF8PCayYjkJSMZRd+Bbnvf8TwYZWZC13E1T2z7ZoxbdA/kR 2DYBWU12NnHkunCYvXBbOKzIicSUXXfDQPi8BKNrTTHDPqDncGYQ3QqXlj71nS9uJ/uW AhPw== X-Gm-Message-State: AOAM533l9y5QFMwJz3h0sM3itWe24Kvxpy4ktUJW9q2T7RrlaZ/IaB/e 41rn8stGhF9TJgheLOv/YZ+e856oUUogP3isNQ== X-Google-Smtp-Source: ABdhPJydEopWkdCsDK1hYK982R+PVTqFSUL/UHH4+gAsJVgSbPdnY4co9Gqz5u+7y71ahPQ8g0DScxMsm1a7uyUVvw== Sender: "lokeshgidra via sendgmr" X-Received: from lg.mtv.corp.google.com ([2620:15c:211:202:f693:9fff:fef4:29dd]) (user=lokeshgidra job=sendgmr) by 2002:ad4:5387:: with SMTP id i7mr1603818qvv.43.1600889614631; Wed, 23 Sep 2020 12:33:34 -0700 (PDT) Date: Wed, 23 Sep 2020 12:33:23 -0700 In-Reply-To: <20200923193324.3090160-1-lokeshgidra@google.com> Message-Id: <20200923193324.3090160-3-lokeshgidra@google.com> Mime-Version: 1.0 References: <20200923193324.3090160-1-lokeshgidra@google.com> X-Mailer: git-send-email 2.28.0.681.g6f77f65b4e-goog Subject: [PATCH v9 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 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@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 Signed-off-by: Lokesh Gidra 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..7b22c3112583 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_initialized(&selinux_state))) + 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 } };