From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Johansen Subject: Re: [PATCH security-next v4 23/32] selinux: Remove boot parameter Date: Tue, 2 Oct 2018 11:57:41 -0700 Message-ID: References: <20181002005505.6112-1-keescook@chromium.org> <20181002005505.6112-24-keescook@chromium.org> <785ef6a9-ae46-3533-0348-74bcf6f10928@tycho.nsa.gov> <809f1cfd-077b-ee58-51ba-b22daf46d12b@tycho.nsa.gov> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Language: en-GB Sender: linux-kernel-owner@vger.kernel.org To: Kees Cook , Jordan Glover Cc: Stephen Smalley , Paul Moore , James Morris , Casey Schaufler , Tetsuo Handa , "Schaufler, Casey" , linux-security-module , Jonathan Corbet , "open list:DOCUMENTATION" , linux-arch , LKML List-Id: linux-arch.vger.kernel.org On 10/02/2018 09:54 AM, Kees Cook wrote: > On Tue, Oct 2, 2018 at 9:33 AM, Jordan Glover > wrote: >> It's always documented as: "selinux=1 security=selinux" so security= should >> still do the job and selinux=1 become no-op, no? > > The v3 patch set worked this way, yes. (The per-LSM enable defaults > were set by the LSM. Only in the case of "lsm.disable=selinux" would > the above stop working.) > > John did not like the separation of having two CONFIG and two still don't > bootparams mixing the controls. The v3 resolution rules were: > > SECURITY_SELINUX_BOOTPARAM_VALUE overrides CONFIG_LSM_ENABLE. > SECURITY_APPARMOR_BOOTPARAM_VALUE overrides CONFIG_LSM_ENABLE. > selinux= overrides SECURITY_SELINUX_BOOTPARAM_VALUE. > apparmor.enabled= overrides SECURITY_APPARMOR_BOOTPARAM_VALUE. > apparmor= overrides apparmor.enabled=. > lsm.enable= overrides selinux=. > lsm.enable= overrides apparmor=. > lsm.disable= overrides lsm.enable=. > major LSM _omission_ from security= (if present) overrides lsm.enable. > Yeah I would really like to remove the potential confusion for the user. The user now has 4 kernel options to play with, and get confused by LSM= (I'll count apparmor.enabled= here as well) security= lsm.enabled= lsm.disabled= I really don't like this, it will be very confusing for users. I also think an authoritative list of what is enabled is easier for users than mixing a list of whats enabled with kernel config default settings. Under the current scheme lsm.enabled=selinux could actually mean selinux,yama,loadpin,something_else are enabled. If we extend this behavior to when full stacking lands lsm.enabled=selinux,yama might mean selinux,yama,apparmor,loadpin,something_else and what that list is will vary from kernel to kernel, which I think is harder for the user than the lsm.enabled list being what is actually enabled at boot If we have to have multiple kernel parameter, I prefer a behvior where if you hav conflicting kernel parameters specified apparmor=0 lsm.enabled=apparmor that the conflict is logged and the lsm is left disabled, as I think it is easier for users to understand than the overrides scheme of v3, and sans logging of the conflict is effectively what we had in the past apparmor=0 security=apparmor or apparmor=1 security=selinux would result in apparmor being disabed That being said I get we have a mess currently, and there really doesn't seem to be a good way to fix it. I think getting this right for the user is important enough that I am willing to break current apparmor userspace api. While apparmor=0 is documented we have also documented security=X for years and apparmor=0 isn't used too often so I think we can drop it to help clean this mess up abit. I am not going to Nak, or block on v3 behavior if that is considered the best path forward after this discussion/rant. > v4 removed the per-LSM boot params and CONFIGs at John's request, but > Paul and Stephen don't want this for SELinux. > > The pieces for reducing conflict with CONFIG_LSM_ENABLE and > lsm.{enable,disable}= were: > > 1- Remove SECURITY_APPARMOR_BOOTPARAM_VALUE. > 2- Remove apparmor= and apparmor.enabled=. > 3- Remove SECURITY_SELINUX_BOOTPARAM_VALUE. > 4- Remove selinux=. > > v4 used all of 1-4 above. SELinux says "4" cannot happen as it's too > commonly used. Would 3 be okay for SELinux? > > John, with 4 not happening, do you prefer to not have 2 happen? > > With CONFIGs removed, then the boot time defaults are controlled by > CONFIG_LSM_ENABLE, but the boot params continue to work as before. > Only the use of the new lsm.enable= and lsm.disable= would override > the per-LSM boot params. This would clean up the build-time CONFIG > weirdness, and leave the existing boot params as before (putting us > functionally in between the v3 and v4 series). > I'm ambivalent. I really want to clean this up but atm it doesn't really look like 2 is going to provide much of a benefit. If you think it helps clean this up, do it. Regardless 1 is going to happen, and I will start updating documentation and try to get users moving away from using the apparmor= kernel parameter. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from youngberry.canonical.com ([91.189.89.112]:44487 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726508AbeJCBmj (ORCPT ); Tue, 2 Oct 2018 21:42:39 -0400 Subject: Re: [PATCH security-next v4 23/32] selinux: Remove boot parameter References: <20181002005505.6112-1-keescook@chromium.org> <20181002005505.6112-24-keescook@chromium.org> <785ef6a9-ae46-3533-0348-74bcf6f10928@tycho.nsa.gov> <809f1cfd-077b-ee58-51ba-b22daf46d12b@tycho.nsa.gov> From: John Johansen Message-ID: Date: Tue, 2 Oct 2018 11:57:41 -0700 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-arch-owner@vger.kernel.org List-ID: To: Kees Cook , Jordan Glover Cc: Stephen Smalley , Paul Moore , James Morris , Casey Schaufler , Tetsuo Handa , "Schaufler, Casey" , linux-security-module , Jonathan Corbet , "open list:DOCUMENTATION" , linux-arch , LKML Message-ID: <20181002185741.HQW6RATe4A-oYs6bDQrv8h5WnfJNISIaX5yGVCy76tc@z> On 10/02/2018 09:54 AM, Kees Cook wrote: > On Tue, Oct 2, 2018 at 9:33 AM, Jordan Glover > wrote: >> It's always documented as: "selinux=1 security=selinux" so security= should >> still do the job and selinux=1 become no-op, no? > > The v3 patch set worked this way, yes. (The per-LSM enable defaults > were set by the LSM. Only in the case of "lsm.disable=selinux" would > the above stop working.) > > John did not like the separation of having two CONFIG and two still don't > bootparams mixing the controls. The v3 resolution rules were: > > SECURITY_SELINUX_BOOTPARAM_VALUE overrides CONFIG_LSM_ENABLE. > SECURITY_APPARMOR_BOOTPARAM_VALUE overrides CONFIG_LSM_ENABLE. > selinux= overrides SECURITY_SELINUX_BOOTPARAM_VALUE. > apparmor.enabled= overrides SECURITY_APPARMOR_BOOTPARAM_VALUE. > apparmor= overrides apparmor.enabled=. > lsm.enable= overrides selinux=. > lsm.enable= overrides apparmor=. > lsm.disable= overrides lsm.enable=. > major LSM _omission_ from security= (if present) overrides lsm.enable. > Yeah I would really like to remove the potential confusion for the user. The user now has 4 kernel options to play with, and get confused by LSM= (I'll count apparmor.enabled= here as well) security= lsm.enabled= lsm.disabled= I really don't like this, it will be very confusing for users. I also think an authoritative list of what is enabled is easier for users than mixing a list of whats enabled with kernel config default settings. Under the current scheme lsm.enabled=selinux could actually mean selinux,yama,loadpin,something_else are enabled. If we extend this behavior to when full stacking lands lsm.enabled=selinux,yama might mean selinux,yama,apparmor,loadpin,something_else and what that list is will vary from kernel to kernel, which I think is harder for the user than the lsm.enabled list being what is actually enabled at boot If we have to have multiple kernel parameter, I prefer a behvior where if you hav conflicting kernel parameters specified apparmor=0 lsm.enabled=apparmor that the conflict is logged and the lsm is left disabled, as I think it is easier for users to understand than the overrides scheme of v3, and sans logging of the conflict is effectively what we had in the past apparmor=0 security=apparmor or apparmor=1 security=selinux would result in apparmor being disabed That being said I get we have a mess currently, and there really doesn't seem to be a good way to fix it. I think getting this right for the user is important enough that I am willing to break current apparmor userspace api. While apparmor=0 is documented we have also documented security=X for years and apparmor=0 isn't used too often so I think we can drop it to help clean this mess up abit. I am not going to Nak, or block on v3 behavior if that is considered the best path forward after this discussion/rant. > v4 removed the per-LSM boot params and CONFIGs at John's request, but > Paul and Stephen don't want this for SELinux. > > The pieces for reducing conflict with CONFIG_LSM_ENABLE and > lsm.{enable,disable}= were: > > 1- Remove SECURITY_APPARMOR_BOOTPARAM_VALUE. > 2- Remove apparmor= and apparmor.enabled=. > 3- Remove SECURITY_SELINUX_BOOTPARAM_VALUE. > 4- Remove selinux=. > > v4 used all of 1-4 above. SELinux says "4" cannot happen as it's too > commonly used. Would 3 be okay for SELinux? > > John, with 4 not happening, do you prefer to not have 2 happen? > > With CONFIGs removed, then the boot time defaults are controlled by > CONFIG_LSM_ENABLE, but the boot params continue to work as before. > Only the use of the new lsm.enable= and lsm.disable= would override > the per-LSM boot params. This would clean up the build-time CONFIG > weirdness, and leave the existing boot params as before (putting us > functionally in between the v3 and v4 series). > I'm ambivalent. I really want to clean this up but atm it doesn't really look like 2 is going to provide much of a benefit. If you think it helps clean this up, do it. Regardless 1 is going to happen, and I will start updating documentation and try to get users moving away from using the apparmor= kernel parameter.