From mboxrd@z Thu Jan 1 00:00:00 1970 From: Casey Schaufler Subject: Re: [kernel-hardening] [RFC PATCH 1/2] security, capabilities: create CAP_TRUSTED Date: Sat, 21 Oct 2017 10:25:21 -0700 Message-ID: References: <20171021134558.21195-1-nicolas@belouin.fr> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s2048; t=1508606729; bh=Vkco9I3waDobUi1N9H+rQ+JooCsYnXjQ9IPj8Vbai2k=; h=Subject:To:References:From:Date:In-Reply-To:From:Subject; b=DV+ifqgR1RLRJ7KM2K8Bz35z6OtmuzZSmu/xEeMZkBRnvTgj8QepVuhK8rcCM3/G8ZMmjvubV6GZiY+nqUS6za5lwAxHMbe7614iO0zVl114fSk/hAuIZ3EegVgx/06hwqUqZN2PIkDG/jV+WqJ+ZmR3ZEf+5VpZy5UmHpHU9qe/0hrQ2kWjV2wiE9bg1Ok16iGjtMGPcWVqmeC/NkJKCDQ4YQedFhWUEWfOHaw8GyaIYJWbZIb7rInMdqAIxdLB4OYG8ZzwsqK8i5BQ0I5wmMmiKZsGrxLaFIi/vsX5cQzCa34BYw7EDWPv9TT/nAq6x9A+Xh9RHTc6/tMRmb/KXQ== In-Reply-To: <20171021134558.21195-1-nicolas@belouin.fr> Content-Language: en-US Sender: reiserfs-devel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Nicolas Belouin , Jan Kara , Theodore Ts'o , Andreas Dilger , Jaegeuk Kim , Chao Yu , David Woodhouse , Dave Kleikamp , Mark Fasheh , Joel Becker , Miklos Szeredi , Phillip Lougher , Richard Weinberger , Artem Bityutskiy , Adrian Hunter , Alexander Viro , Serge Hallyn , Paul Moore , Stephen Smalley , Eric Paris , James Morris On 10/21/2017 6:45 AM, Nicolas Belouin wrote: > with CAP_SYS_ADMIN being bloated, the usefulness of using it to > flag a process to be entrusted for e.g reading and writing trusted > xattr is near zero. > CAP_TRUSTED aims to provide userland with a way to mark a process as > entrusted to do specific (not specially admin-centered) actions. It > would for example allow a process to red/write the trusted xattrs. Please explain how this is different from CAP_MAC_ADMIN in any existing use case. If it is significantly different, how would the two interact? > Signed-off-by: Nicolas Belouin > --- > include/uapi/linux/capability.h | 6 +++++- > security/selinux/include/classmap.h | 5 +++-- > 2 files changed, 8 insertions(+), 3 deletions(-) > > diff --git a/include/uapi/linux/capability.h b/include/uapi/linux/capability.h > index ce230aa6d928..27e457b93c84 100644 > --- a/include/uapi/linux/capability.h > +++ b/include/uapi/linux/capability.h > @@ -369,7 +369,11 @@ struct vfs_ns_cap_data { > > #define CAP_SYS_MOUNT 38 > > -#define CAP_LAST_CAP CAP_SYS_MOUNT > +/* Allow read/write trusted xattr */ > + > +#define CAP_TRUSTED 39 > + > +#define CAP_LAST_CAP CAP_TRUSTED > > #define cap_valid(x) ((x) >= 0 && (x) <= CAP_LAST_CAP) > > diff --git a/security/selinux/include/classmap.h b/security/selinux/include/classmap.h > index a873dce97fd5..f5dc8e109f5a 100644 > --- a/security/selinux/include/classmap.h > +++ b/security/selinux/include/classmap.h > @@ -24,9 +24,10 @@ > "audit_control", "setfcap" > > #define COMMON_CAP2_PERMS "mac_override", "mac_admin", "syslog", \ > - "wake_alarm", "block_suspend", "audit_read", "sys_mount" > + "wake_alarm", "block_suspend", "audit_read", "sys_mount", \ > + "trusted" > > -#if CAP_LAST_CAP > CAP_SYS_MOUNT > +#if CAP_LAST_CAP > CAP_TRUSTED > #error New capability defined, please update COMMON_CAP2_PERMS. > #endif >