From: sgrubb@redhat.com (Steve Grubb) To: linux-security-module@vger.kernel.org Subject: [PATCH] capabilities: do not audit log BPRM_FCAPS on set*id Date: Wed, 12 Apr 2017 14:49:02 -0400 [thread overview] Message-ID: <1833607.dNomLM3Ooh@x2> (raw) In-Reply-To: <20170412064321.GN18559@madcap2.tricolour.ca> 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 <rgb@redhat.com> 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? > > > > > > 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. -Steve -- 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
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From: Steve Grubb <sgrubb@redhat.com> To: Richard Guy Briggs <rgb@redhat.com> Cc: Paul Moore <paul@paul-moore.com>, "Serge E. Hallyn" <serge@hallyn.com>, linux-security-module@vger.kernel.org, linux-audit@redhat.com, Andy Lutomirski <luto@kernel.org>, "Serge E. Hallyn" <serge.hallyn@ubuntu.com>, Kees Cook <keescook@chromium.org>, James Morris <james.l.morris@oracle.com>, Eric Paris <eparis@redhat.com>, Paul Moore <pmoore@redhat.com> Subject: Re: [PATCH] capabilities: do not audit log BPRM_FCAPS on set*id Date: Wed, 12 Apr 2017 14:49:02 -0400 [thread overview] Message-ID: <1833607.dNomLM3Ooh@x2> (raw) In-Reply-To: <20170412064321.GN18559@madcap2.tricolour.ca> 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 <rgb@redhat.com> 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? > > > > > > 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. -Steve
next prev parent reply other threads:[~2017-04-12 18:49 UTC|newest] Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-03-03 1:10 [PATCH] capabilities: do not audit log BPRM_FCAPS on set*id Richard Guy Briggs 2017-03-03 2:07 ` Serge E. Hallyn 2017-03-03 2:50 ` Richard Guy Briggs 2017-03-07 17:22 ` Richard Guy Briggs 2017-03-07 18:10 ` Serge E. Hallyn 2017-03-07 21:10 ` Richard Guy Briggs 2017-03-07 21:25 ` Serge E. Hallyn 2017-03-09 14:34 ` Steve Grubb 2017-03-09 14:34 ` Steve Grubb 2017-03-29 10:29 ` Richard Guy Briggs 2017-03-29 10:29 ` Richard Guy Briggs 2017-04-11 19:36 ` Paul Moore 2017-04-11 19:36 ` Paul Moore 2017-04-12 6:43 ` Richard Guy Briggs 2017-04-12 6:43 ` Richard Guy Briggs 2017-04-12 14:51 ` Serge E. Hallyn 2017-04-12 14:51 ` Serge E. Hallyn 2017-04-12 18:49 ` Steve Grubb [this message] 2017-04-12 18:49 ` Steve Grubb 2017-04-13 8:50 ` Richard Guy Briggs 2017-04-13 8:50 ` Richard Guy Briggs 2017-04-13 19:36 ` Steve Grubb 2017-04-13 19:36 ` Steve Grubb
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