From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753029AbdJLA6r (ORCPT ); Wed, 11 Oct 2017 20:58:47 -0400 Received: from mx1.redhat.com ([209.132.183.28]:40610 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752921AbdJLA6n (ORCPT ); Wed, 11 Oct 2017 20:58:43 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com BF49E7F3F2 Authentication-Results: ext-mx01.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx01.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=rgb@redhat.com From: Richard Guy Briggs To: linux-security-module@vger.kernel.org, linux-audit@redhat.com, linux-kernel@vger.kernel.org Cc: Richard Guy Briggs , Kees Cook , Andy Lutomirski , "Serge E . Hallyn" , James Morris , Paul Moore , Steve Grubb , Eric Paris Subject: [PATCH GHAK16 V5 02/10] capabilities: intuitive names for cap gain status Date: Wed, 11 Oct 2017 20:57:06 -0400 Message-Id: In-Reply-To: References: In-Reply-To: References: X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Thu, 12 Oct 2017 00:58:42 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Introduce macros cap_gained, cap_grew, cap_full to make the use of the negation of is_subset() easier to read and analyse. Signed-off-by: Richard Guy Briggs Reviewed-by: Serge Hallyn Acked-by: James Morris Acked-by: Kees Cook Okay-ished-by: Paul Moore --- security/commoncap.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) diff --git a/security/commoncap.c b/security/commoncap.c index be9bca5..4c9af6e 100644 --- a/security/commoncap.c +++ b/security/commoncap.c @@ -741,6 +741,12 @@ static void handle_privileged_root(struct linux_binprm *bprm, bool has_cap, *effective = true; } +#define __cap_gained(field, target, source) \ + !cap_issubset(target->cap_##field, source->cap_##field) +#define __cap_grew(target, source, cred) \ + !cap_issubset(cred->cap_##target, cred->cap_##source) +#define __cap_full(field, cred) \ + cap_issubset(CAP_FULL_SET, cred->cap_##field) /** * cap_bprm_set_creds - Set up the proposed credentials for execve(). * @bprm: The execution parameters, including the proposed creds @@ -769,10 +775,9 @@ int cap_bprm_set_creds(struct linux_binprm *bprm) handle_privileged_root(bprm, has_cap, &effective, root_uid); /* if we have fs caps, clear dangerous personality flags */ - if (!cap_issubset(new->cap_permitted, old->cap_permitted)) + if (__cap_gained(permitted, new, old)) bprm->per_clear |= PER_CLEAR_ON_SETID; - /* Don't let someone trace a set[ug]id/setpcap binary with the revised * credentials unless they have the appropriate permit. * @@ -780,8 +785,7 @@ int cap_bprm_set_creds(struct linux_binprm *bprm) */ is_setid = !uid_eq(new->euid, old->uid) || !gid_eq(new->egid, old->gid); - if ((is_setid || - !cap_issubset(new->cap_permitted, old->cap_permitted)) && + if ((is_setid || __cap_gained(permitted, new, old)) && ((bprm->unsafe & ~LSM_UNSAFE_PTRACE) || !ptracer_capable(current, new->user_ns))) { /* downgrade; they get no more than they had, and maybe less */ @@ -831,8 +835,8 @@ int cap_bprm_set_creds(struct linux_binprm *bprm) * Number 1 above might fail if you don't have a full bset, but I think * that is interesting information to audit. */ - if (!cap_issubset(new->cap_effective, new->cap_ambient)) { - if (!cap_issubset(CAP_FULL_SET, new->cap_effective) || + if (__cap_grew(effective, ambient, new)) { + if (!__cap_full(effective, new) || !uid_eq(new->euid, root_uid) || !uid_eq(new->uid, root_uid) || issecure(SECURE_NOROOT)) { ret = audit_log_bprm_fcaps(bprm, new, old); @@ -852,7 +856,7 @@ int cap_bprm_set_creds(struct linux_binprm *bprm) bprm->cap_elevated = 1; } else if (!uid_eq(new->uid, root_uid)) { if (effective || - !cap_issubset(new->cap_permitted, new->cap_ambient)) + __cap_grew(permitted, ambient, new)) bprm->cap_elevated = 1; } -- 1.8.3.1