From patchwork Wed Aug 23 10:12:56 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Richard Guy Briggs X-Patchwork-Id: 9917041 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id DB05D60327 for ; Wed, 23 Aug 2017 10:13:55 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id CB7F8288B6 for ; Wed, 23 Aug 2017 10:13:55 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id BD1D12893D; Wed, 23 Aug 2017 10:13:55 +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=-6.9 required=2.0 tests=BAYES_00,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 5ADCF288B6 for ; Wed, 23 Aug 2017 10:13:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753853AbdHWKNy (ORCPT ); Wed, 23 Aug 2017 06:13:54 -0400 Received: from mx1.redhat.com ([209.132.183.28]:47480 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753606AbdHWKNy (ORCPT ); Wed, 23 Aug 2017 06:13:54 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id BB329C05680C; Wed, 23 Aug 2017 10:13:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com BB329C05680C Authentication-Results: ext-mx08.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx08.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=rgb@redhat.com Received: from madcap2.tricolour.ca (ovpn-112-7.rdu2.redhat.com [10.10.112.7]) by smtp.corp.redhat.com (Postfix) with ESMTP id DCF6463767; Wed, 23 Aug 2017 10:13:47 +0000 (UTC) From: Richard Guy Briggs To: linux-security-module@vger.kernel.org, linux-audit@redhat.com Cc: Richard Guy Briggs , Andy Lutomirski , "Serge E. Hallyn" , Kees Cook , James Morris , Eric Paris , Paul Moore , Steve Grubb Subject: [PATCH V3 05/10] capabilities: use intuitive names for id changes Date: Wed, 23 Aug 2017 06:12:56 -0400 Message-Id: <1360ed3437f87ac0b9e076ff5ea05c67ee8a7ed8.1503459890.git.rgb@redhat.com> In-Reply-To: References: In-Reply-To: References: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Wed, 23 Aug 2017 10:13:53 +0000 (UTC) Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP Introduce a number of inlines to make the use of the negation of uid_eq() easier to read and analyse. Signed-off-by: Richard Guy Briggs Reviewed-by: Serge Hallyn Acked-by: James Morris --- security/commoncap.c | 26 +++++++++++++++++++++----- 1 files changed, 21 insertions(+), 5 deletions(-) diff --git a/security/commoncap.c b/security/commoncap.c index 36c38a1..1af7dec 100644 --- a/security/commoncap.c +++ b/security/commoncap.c @@ -483,6 +483,15 @@ static int get_file_caps(struct linux_binprm *bprm, bool *effective, bool *has_f static inline bool root_privileged(void) { return !issecure(SECURE_NOROOT); } +static inline bool is_real(kuid_t uid, struct cred *cred) +{ return uid_eq(cred->uid, uid); } + +static inline bool is_eff(kuid_t uid, struct cred *cred) +{ return uid_eq(cred->euid, uid); } + +static inline bool is_suid(kuid_t uid, struct cred *cred) +{ return !is_real(uid, cred) && is_eff(uid, cred); } + void handle_privileged_root(struct linux_binprm *bprm, bool has_fcap, bool *effective, kuid_t root_uid) { const struct cred *old = current_cred(); @@ -493,7 +502,7 @@ void handle_privileged_root(struct linux_binprm *bprm, bool has_fcap, bool *effe * for a setuid root binary run by a non-root user. Do set it * for a root user just to cause least surprise to an admin. */ - if (has_fcap && !uid_eq(new->uid, root_uid) && uid_eq(new->euid, root_uid)) { + if (has_fcap && is_suid(root_uid, new)) { warn_setuid_and_fcaps_mixed(bprm->filename); return; } @@ -504,12 +513,12 @@ void handle_privileged_root(struct linux_binprm *bprm, bool has_fcap, bool *effe * * If only the real uid is 0, we do not set the effective bit. */ - if (uid_eq(new->euid, root_uid) || uid_eq(new->uid, root_uid)) { + if (is_eff(root_uid, new) || is_real(root_uid, new)) { /* pP' = (cap_bset & ~0) | (pI & ~0) */ new->cap_permitted = cap_combine(old->cap_bset, old->cap_inheritable); } - if (uid_eq(new->euid, root_uid)) + if (is_eff(root_uid, new)) *effective = true; } @@ -519,6 +528,13 @@ void handle_privileged_root(struct linux_binprm *bprm, bool has_fcap, bool *effe !cap_issubset(cred->cap_##target, cred->cap_##source) #define cap_full(field, cred) \ cap_issubset(CAP_FULL_SET, cred->cap_##field) + +static inline bool is_setuid(struct cred *new, const struct cred *old) +{ return !uid_eq(new->euid, old->uid); } + +static inline bool is_setgid(struct cred *new, const struct cred *old) +{ return !gid_eq(new->egid, old->gid); } + /** * cap_bprm_set_creds - Set up the proposed credentials for execve(). * @bprm: The execution parameters, including the proposed creds @@ -556,7 +572,7 @@ int cap_bprm_set_creds(struct linux_binprm *bprm) * * In addition, if NO_NEW_PRIVS, then ensure we get no new privs. */ - is_setid = !uid_eq(new->euid, old->uid) || !gid_eq(new->egid, old->gid); + is_setid = is_setuid(new, old) || is_setgid(new, old); if ((is_setid || cap_gained(permitted, new, old)) && ((bprm->unsafe & ~LSM_UNSAFE_PTRACE) || @@ -612,7 +628,7 @@ int cap_bprm_set_creds(struct linux_binprm *bprm) */ if (cap_grew(effective, ambient, new)) { if (!cap_full(effective, new) || - !uid_eq(new->euid, root_uid) || !uid_eq(new->uid, root_uid) || + !is_eff(root_uid, new) || !is_real(root_uid, new) || !root_privileged()) { ret = audit_log_bprm_fcaps(bprm, new, old); if (ret < 0)