From mboxrd@z Thu Jan 1 00:00:00 1970 From: rgb@redhat.com (Richard Guy Briggs) Date: Thu, 13 Apr 2017 04:50:56 -0400 Subject: [PATCH] capabilities: do not audit log BPRM_FCAPS on set*id In-Reply-To: <1833607.dNomLM3Ooh@x2> References: <515427654218b7ce22441f635115e93cf74d6302.1488491988.git.rgb@redhat.com> <20170412064321.GN18559@madcap2.tricolour.ca> <1833607.dNomLM3Ooh@x2> Message-ID: <20170413085056.GP1572@madcap2.tricolour.ca> To: linux-security-module@vger.kernel.org List-Id: linux-security-module.vger.kernel.org On 2017-04-12 14:49, Steve Grubb wrote: > On Wednesday, April 12, 2017 2:43:21 AM EDT Richard Guy Briggs wrote: > > On 2017-04-11 15:36, Paul Moore wrote: > > > On Wed, Mar 29, 2017 at 6:29 AM, Richard Guy Briggs > wrote: > > > > On 2017-03-09 09:34, Steve Grubb wrote: > > > >> On Tuesday, March 7, 2017 4:10:49 PM EST Richard Guy Briggs wrote: > > > >> > > > > > one possibly audit-worth case which (if I read correctly) > > > >> > > > > > this will > > > >> > > > > > skip is where a setuid-root binary has filecaps which *limit* > > > >> > > > > > its > > > >> > > > > > privs. > > > >> > > > > > Does that matter? > > > >> > > > > > > > >> > > > > I hadn't thought of that case, but I did consider in the setuid > > > >> > > > > case > > > >> > > > > comparing before and after without setuid forcing the drop of > > > >> > > > > all > > > >> > > > > capabilities via "ambient". Mind you, this bug has been around > > > >> > > > > before > > > >> > > > > Luto's patch that adds the ambient capabilities set. > > > >> > > > > > > >> > > > Can you suggest a scenario where that might happen? > > > >> > > > > > >> > > Sorry, do you mean the case I brought up, or the one you mentioned? > > > >> > > I > > > >> > > don't quite understnad the one you brought up. For mine it's > > > >> > > pretty > > > >> > > simple to reproduce, just > > > >> > > > > >> > I was talking about the case you brought up, but they could be the > > > >> > same > > > >> > case. > > > >> > > > > >> > I was thinking of a case where the caps actually change, but are > > > >> > overridden by the blanket full permissions of setuid. > > > >> If there actually is a change in capability bits besides the implied > > > >> change of capabilities based on the change of the uid alone, then it > > > >> should be logged.> > > > > > Are you speaking of a change in pP' only from pI, or also pI', pE' and > > > > pA'? > > > > > > > > Something like ( pP' xor pI ) not empty? This is what I'm trying to clarify. > > > > The previous patch I'd sent was reasonably easy to understand, but I'm > > > > having trouble adding this new twist to the logic expression in question > > > > due to the inverted combination of pre-existing items. I'm having > > > > trouble visualizing a 5 or more-dimensional Karnaugh map... > > > > > > > > While I am at it, I notice pA is missing from the audit record. The > > > > record contains fields "old_pp", "old_pi", "old_pe", "new_pp", "new_pi", > > > > "new_pe" so in keeping with the previous record normalizations, I'd like > > > > to change the "new_*" variants to simply drop the "new_" prefix. > > > > > > > > https://github.com/linux-audit/audit-kernel/issues/40 > > > > > > Yes, there is the separate ambient capabilities record patch, but > > > where do we stand with this patch? From what I gather there is still > > > some uncertainty here? > > > > Yes, I put this on my back burner thinking about how best to re-approach > > this, hoping others would offer some insight or advice how to attack > > this, otherwise I'm going to end up with a horrendous conditional > > expression, I fear. > > > > Steve, I was hoping to get a clarification from you about which > > capability bits had changed. > > I am not sure what you are asking of me. I'm trying to understand exactly which capability sets should be compared to determine if there was a material change, but perhaps that question is better asked of Serge. What does the certification care about in terms that helps me code this? > -Steve - RGB -- Richard Guy Briggs Sr. S/W Engineer, Kernel Security, Base Operating Systems Remote, Ottawa, Red Hat Canada IRC: rgb, SunRaycer Voice: +1.647.777.2635, Internal: (81) 32635 -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo at vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 From: Richard Guy Briggs Subject: Re: [PATCH] capabilities: do not audit log BPRM_FCAPS on set*id Date: Thu, 13 Apr 2017 04:50:56 -0400 Message-ID: <20170413085056.GP1572@madcap2.tricolour.ca> References: <515427654218b7ce22441f635115e93cf74d6302.1488491988.git.rgb@redhat.com> <20170412064321.GN18559@madcap2.tricolour.ca> <1833607.dNomLM3Ooh@x2> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1833607.dNomLM3Ooh@x2> Sender: owner-linux-security-module@vger.kernel.org To: Steve Grubb Cc: James Morris , "Serge E. Hallyn" , linux-security-module@vger.kernel.org, linux-audit@redhat.com, Andy Lutomirski , "Serge E. Hallyn" List-Id: linux-audit@redhat.com On 2017-04-12 14:49, Steve Grubb wrote: > On Wednesday, April 12, 2017 2:43:21 AM EDT Richard Guy Briggs wrote: > > On 2017-04-11 15:36, Paul Moore wrote: > > > On Wed, Mar 29, 2017 at 6:29 AM, Richard Guy Briggs > wrote: > > > > On 2017-03-09 09:34, Steve Grubb wrote: > > > >> On Tuesday, March 7, 2017 4:10:49 PM EST Richard Guy Briggs wrote: > > > >> > > > > > one possibly audit-worth case which (if I read correctly) > > > >> > > > > > this will > > > >> > > > > > skip is where a setuid-root binary has filecaps which *limit* > > > >> > > > > > its > > > >> > > > > > privs. > > > >> > > > > > Does that matter? > > > >> > > > > > > > >> > > > > I hadn't thought of that case, but I did consider in the setuid > > > >> > > > > case > > > >> > > > > comparing before and after without setuid forcing the drop of > > > >> > > > > all > > > >> > > > > capabilities via "ambient". Mind you, this bug has been around > > > >> > > > > before > > > >> > > > > Luto's patch that adds the ambient capabilities set. > > > >> > > > > > > >> > > > Can you suggest a scenario where that might happen? > > > >> > > > > > >> > > Sorry, do you mean the case I brought up, or the one you mentioned? > > > >> > > I > > > >> > > don't quite understnad the one you brought up. For mine it's > > > >> > > pretty > > > >> > > simple to reproduce, just > > > >> > > > > >> > I was talking about the case you brought up, but they could be the > > > >> > same > > > >> > case. > > > >> > > > > >> > I was thinking of a case where the caps actually change, but are > > > >> > overridden by the blanket full permissions of setuid. > > > >> If there actually is a change in capability bits besides the implied > > > >> change of capabilities based on the change of the uid alone, then it > > > >> should be logged.> > > > > > Are you speaking of a change in pP' only from pI, or also pI', pE' and > > > > pA'? > > > > > > > > Something like ( pP' xor pI ) not empty? This is what I'm trying to clarify. > > > > The previous patch I'd sent was reasonably easy to understand, but I'm > > > > having trouble adding this new twist to the logic expression in question > > > > due to the inverted combination of pre-existing items. I'm having > > > > trouble visualizing a 5 or more-dimensional Karnaugh map... > > > > > > > > While I am at it, I notice pA is missing from the audit record. The > > > > record contains fields "old_pp", "old_pi", "old_pe", "new_pp", "new_pi", > > > > "new_pe" so in keeping with the previous record normalizations, I'd like > > > > to change the "new_*" variants to simply drop the "new_" prefix. > > > > > > > > https://github.com/linux-audit/audit-kernel/issues/40 > > > > > > Yes, there is the separate ambient capabilities record patch, but > > > where do we stand with this patch? From what I gather there is still > > > some uncertainty here? > > > > Yes, I put this on my back burner thinking about how best to re-approach > > this, hoping others would offer some insight or advice how to attack > > this, otherwise I'm going to end up with a horrendous conditional > > expression, I fear. > > > > Steve, I was hoping to get a clarification from you about which > > capability bits had changed. > > I am not sure what you are asking of me. I'm trying to understand exactly which capability sets should be compared to determine if there was a material change, but perhaps that question is better asked of Serge. What does the certification care about in terms that helps me code this? > -Steve - RGB -- Richard Guy Briggs Sr. S/W Engineer, Kernel Security, Base Operating Systems Remote, Ottawa, Red Hat Canada IRC: rgb, SunRaycer Voice: +1.647.777.2635, Internal: (81) 32635