From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753186AbbE0Xsg (ORCPT ); Wed, 27 May 2015 19:48:36 -0400 Received: from mail.kernel.org ([198.145.29.136]:52115 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752201AbbE0XsY (ORCPT ); Wed, 27 May 2015 19:48:24 -0400 From: Andy Lutomirski To: Serge Hallyn , Andrew Morton , James Morris Cc: Jarkko Sakkinen , Andrew Lutomirski , "Ted Ts'o" , "Andrew G. Morgan" , Linux API , Mimi Zohar , Michael Kerrisk , Austin S Hemmelgarn , linux-security-module , Aaron Jones , Serge Hallyn , LKML , Markku Savela , Kees Cook , Jonathan Corbet , Christoph Lameter , Andy Lutomirski Subject: [PATCH v3 2/2] capabilities: Add a securebit to disable PR_CAP_AMBIENT_RAISE Date: Wed, 27 May 2015 16:47:59 -0700 Message-Id: <8b3a8b2fa031e043483f2f444f0b51aed0681e85.1432770087.git.luto@kernel.org> X-Mailer: git-send-email 2.1.0 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Per Andrew Morgan's request, add a securebit to allow admins to disable PR_CAP_AMBIENT_RAISE. This securebit will prevent processes from adding capabilities to their ambient set. For simplicity, this disables PR_CAP_AMBIENT_RAISE entirely rather than just disabling setting previously cleared bits. Acked-By: Andrew G. Morgan Cc: Kees Cook Cc: Christoph Lameter Cc: Serge Hallyn Cc: Andy Lutomirski Cc: Jonathan Corbet Cc: Aaron Jones CC: Ted Ts'o Cc: linux-security-module@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-api@vger.kernel.org Cc: akpm@linuxfoundation.org Cc: Andrew G. Morgan Cc: Mimi Zohar Cc: Austin S Hemmelgarn Cc: Markku Savela Cc: Jarkko Sakkinen Cc: Michael Kerrisk Signed-off-by: Andy Lutomirski --- include/uapi/linux/securebits.h | 11 ++++++++++- security/commoncap.c | 3 ++- 2 files changed, 12 insertions(+), 2 deletions(-) diff --git a/include/uapi/linux/securebits.h b/include/uapi/linux/securebits.h index 985aac9e6bf8..35ac35cef217 100644 --- a/include/uapi/linux/securebits.h +++ b/include/uapi/linux/securebits.h @@ -43,9 +43,18 @@ #define SECBIT_KEEP_CAPS (issecure_mask(SECURE_KEEP_CAPS)) #define SECBIT_KEEP_CAPS_LOCKED (issecure_mask(SECURE_KEEP_CAPS_LOCKED)) +/* When set, a process cannot add new capabilities to its ambient set. */ +#define SECURE_NO_CAP_AMBIENT_RAISE 6 +#define SECURE_NO_CAP_AMBIENT_RAISE_LOCKED 7 /* make bit-6 immutable */ + +#define SECBIT_NO_CAP_AMBIENT_RAISE (issecure_mask(SECURE_NO_CAP_AMBIENT_RAISE)) +#define SECBIT_NO_CAP_AMBIENT_RAISE_LOCKED \ + (issecure_mask(SECURE_NO_CAP_AMBIENT_RAISE_LOCKED)) + #define SECURE_ALL_BITS (issecure_mask(SECURE_NOROOT) | \ issecure_mask(SECURE_NO_SETUID_FIXUP) | \ - issecure_mask(SECURE_KEEP_CAPS)) + issecure_mask(SECURE_KEEP_CAPS) | \ + issecure_mask(SECURE_NO_CAP_AMBIENT_RAISE)) #define SECURE_ALL_LOCKS (SECURE_ALL_BITS << 1) #endif /* _UAPI_LINUX_SECUREBITS_H */ diff --git a/security/commoncap.c b/security/commoncap.c index 835a7584f7ea..22b7b91c5eae 100644 --- a/security/commoncap.c +++ b/security/commoncap.c @@ -987,7 +987,8 @@ int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3, if (arg2 == PR_CAP_AMBIENT_RAISE && (!cap_raised(current_cred()->cap_permitted, arg3) || !cap_raised(current_cred()->cap_inheritable, - arg3))) + arg3) || + issecure(SECURE_NO_CAP_AMBIENT_RAISE))) return -EPERM; new = prepare_creds(); -- 2.1.0