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From: Simon McVittie <smcv@collabora.com>
To: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Casey Schaufler <casey@schaufler-ca.com>,
	casey.schaufler@intel.com, jmorris@namei.org,
	linux-security-module@vger.kernel.org, selinux@vger.kernel.org,
	keescook@chromium.org, john.johansen@canonical.com,
	penguin-kernel@i-love.sakura.ne.jp, paul@paul-moore.com
Subject: Re: [PATCH v14 22/23] LSM: Add /proc attr entry for full LSM context
Date: Mon, 10 Feb 2020 11:56:11 +0000	[thread overview]
Message-ID: <20200210115611.GA13930@horizon> (raw)
In-Reply-To: <09d96236-715a-344a-38bc-c05208698125@tycho.nsa.gov>

On Mon, 03 Feb 2020 at 13:54:45 -0500, Stephen Smalley wrote:
> The printable ASCII bit is based on what the dbus maintainer requested in
> previous discussions.

I thought in previous discussions, we had come to the conclusion that
I can't assume it's 7-bit ASCII. (If I *can* assume that for this new
API, that's even better.)

To be clear, when I say ASCII I mean a sequence of bytes != '\0' with
their high bit unset (x & 0x7f == x) and the obvious mapping to/from
Unicode (bytes '\1' to '\x7f' represent codepoints U+0001 to U+007F). Is
that the same thing you mean?

I thought the conclusion we had come to in previous conversations was
that the LSM context is what GLib calls a "bytestring", the same as
filenames and environment variables - an opaque sequence of bytes != '\0',
with no further guarantees, and no specified encoding or mapping to/from
Unicode (most likely some superset of ASCII like UTF-8 or Latin-1,
but nobody knows which one, and they could equally well be some binary
encoding with no Unicode meaning, as long as it avoids '\0').

If I can safely assume that a new kernel <-> user-space API is constrained
to UTF-8 or a UTF-8 subset like ASCII, then I can provide more friendly
APIs for user-space features built over it. If that isn't possible, the
next best thing is a "bytestring" like filenames, environment variables,
and most kernel <-> user-space strings in general.

    smcv

  parent reply	other threads:[~2020-02-10 11:56 UTC|newest]

Thread overview: 61+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20200124002306.3552-1-casey.ref@schaufler-ca.com>
2020-01-24  0:22 ` [PATCH v14 00/23] LSM: Module stacking for AppArmor Casey Schaufler
2020-01-24  0:22   ` [PATCH v14 01/23] LSM: Infrastructure management of the sock security Casey Schaufler
2020-01-24  0:22   ` [PATCH v14 02/23] LSM: Create and manage the lsmblob data structure Casey Schaufler
2020-01-24 14:21     ` Stephen Smalley
2020-01-24  0:22   ` [PATCH v14 03/23] LSM: Use lsmblob in security_audit_rule_match Casey Schaufler
2020-01-24  0:22   ` [PATCH v14 04/23] LSM: Use lsmblob in security_kernel_act_as Casey Schaufler
2020-01-24  0:22   ` [PATCH v14 05/23] net: Prepare UDS for security module stacking Casey Schaufler
2020-01-24  0:22   ` [PATCH v14 06/23] Use lsmblob in security_secctx_to_secid Casey Schaufler
2020-01-24 14:29     ` Stephen Smalley
2020-01-24  0:22   ` [PATCH v14 07/23] LSM: Use lsmblob in security_secid_to_secctx Casey Schaufler
2020-01-24  0:22   ` [PATCH v14 08/23] LSM: Use lsmblob in security_ipc_getsecid Casey Schaufler
2020-01-24  0:22   ` [PATCH v14 09/23] LSM: Use lsmblob in security_task_getsecid Casey Schaufler
2020-01-24  0:22   ` [PATCH v14 10/23] LSM: Use lsmblob in security_inode_getsecid Casey Schaufler
2020-01-24  0:22   ` [PATCH v14 11/23] LSM: Use lsmblob in security_cred_getsecid Casey Schaufler
2020-01-24  0:22   ` [PATCH v14 12/23] IMA: Change internal interfaces to use lsmblobs Casey Schaufler
2020-01-24  0:22   ` [PATCH v14 13/23] LSM: Specify which LSM to display Casey Schaufler
2020-01-24  0:22   ` [PATCH v14 14/23] LSM: Ensure the correct LSM context releaser Casey Schaufler
2020-01-24  0:22   ` [PATCH v14 15/23] LSM: Use lsmcontext in security_secid_to_secctx Casey Schaufler
2020-01-24  0:22   ` [PATCH v14 16/23] LSM: Use lsmcontext in security_inode_getsecctx Casey Schaufler
2020-01-24  0:23   ` [PATCH v14 17/23] LSM: security_secid_to_secctx in netlink netfilter Casey Schaufler
2020-01-24  0:23   ` [PATCH v14 18/23] NET: Store LSM netlabel data in a lsmblob Casey Schaufler
2020-01-24 14:36     ` Stephen Smalley
2020-01-24  0:23   ` [PATCH v14 19/23] LSM: Verify LSM display sanity in binder Casey Schaufler
2020-01-24  0:23   ` [PATCH v14 20/23] Audit: Add subj_LSM fields when necessary Casey Schaufler
2020-01-24  0:23   ` [PATCH v14 21/23] Audit: Include object data for all security modules Casey Schaufler
2020-01-24  0:23   ` [PATCH v14 22/23] LSM: Add /proc attr entry for full LSM context Casey Schaufler
2020-01-24 14:42     ` Stephen Smalley
2020-01-24 16:20       ` Stephen Smalley
2020-01-24 19:28         ` Casey Schaufler
2020-01-24 20:16           ` Stephen Smalley
2020-01-27 20:05             ` Simon McVittie
2020-02-03 20:54               ` John Johansen
2020-01-27 22:49             ` Casey Schaufler
2020-01-31 22:10             ` Casey Schaufler
2020-02-03 18:54               ` Stephen Smalley
2020-02-03 19:37                 ` Stephen Smalley
2020-02-03 21:39                   ` Casey Schaufler
2020-02-04 13:37                     ` Stephen Smalley
2020-02-04 17:14                       ` Casey Schaufler
2020-02-10 11:56                 ` Simon McVittie [this message]
2020-02-10 13:25                   ` Stephen Smalley
2020-02-10 14:55                     ` Stephen Smalley
2020-02-10 18:32                       ` Casey Schaufler
2020-02-10 19:00                         ` John Johansen
2020-02-11 15:59                           ` Stephen Smalley
2020-02-11 17:58                             ` John Johansen
2020-02-11 18:35                               ` Casey Schaufler
2020-02-11 19:11                                 ` John Johansen
2020-02-10 18:56                       ` John Johansen
2020-02-03 21:02             ` John Johansen
2020-02-03 21:43               ` Casey Schaufler
2020-02-03 22:49                 ` John Johansen
2020-02-03 20:59           ` John Johansen
2020-01-24  0:23   ` [PATCH v14 23/23] AppArmor: Remove the exclusive flag Casey Schaufler
2020-01-24 15:05   ` [PATCH v14 00/23] LSM: Module stacking for AppArmor Stephen Smalley
2020-01-24 21:04   ` Stephen Smalley
2020-01-24 21:49     ` Casey Schaufler
2020-01-27 16:14       ` Stephen Smalley
2020-01-27 16:56         ` KASAN slab-out-of-bounds in tun_chr_open/sock_init_data (Was: Re: [PATCH v14 00/23] LSM: Module stacking for AppArmor) Stephen Smalley
2020-01-27 17:34           ` Casey Schaufler
2020-01-27 17:16         ` [PATCH v14 00/23] LSM: Module stacking for AppArmor Casey Schaufler

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