From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933883AbdABStN (ORCPT ); Mon, 2 Jan 2017 13:49:13 -0500 Received: from mx1.redhat.com ([209.132.183.28]:39570 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933206AbdABStL (ORCPT ); Mon, 2 Jan 2017 13:49:11 -0500 From: Steve Grubb To: Tyler Hicks Cc: linux-audit@redhat.com, Paul Moore , Eric Paris , Kees Cook , Andy Lutomirski , Will Drewry , linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] seccomp: Audit SECCOMP_RET_ERRNO actions with errno values Date: Mon, 02 Jan 2017 13:49:11 -0500 Message-ID: <1540151.sullFKCz8n@x2> Organization: Red Hat User-Agent: KMail/5.3.3 (Linux/4.8.15-200.fc24.x86_64; KDE/5.27.0; x86_64; ; ) In-Reply-To: <20170102174246.GA17677@sec> References: <1483375990-14948-1-git-send-email-tyhicks@canonical.com> <5284369.V7krsaxZyN@x2> <20170102174246.GA17677@sec> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Mon, 02 Jan 2017 18:49:11 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Monday, January 2, 2017 5:42:47 PM EST Tyler Hicks wrote: > On 2017-01-02 12:20:53, Steve Grubb wrote: > > On Monday, January 2, 2017 4:53:10 PM EST Tyler Hicks wrote: > > > Generate audit records for SECCOMP_RET_ERRNO actions, which were > > > previously not audited. > > > > > > Additionally, include the errno value that will be set in the audit > > > message. > > > > > > Signed-off-by: Tyler Hicks > > > --- > > > > > > include/linux/audit.h | 19 ++++++++++++++++++- > > > kernel/auditsc.c | 3 +++ > > > kernel/seccomp.c | 4 +++- > > > 3 files changed, 24 insertions(+), 2 deletions(-) > > > > > > diff --git a/include/linux/audit.h b/include/linux/audit.h > > > index 8c588c3..6815812 100644 > > > --- a/include/linux/audit.h > > > +++ b/include/linux/audit.h > > > @@ -87,7 +87,10 @@ struct audit_field { > > > > > > struct audit_seccomp_info { > > > > > > int code; > > > > > > - long signr; > > > + union { > > > + int errno; > > > + long signr; > > > + }; > > > > > > }; > > > > > > extern int is_audit_feature_set(int which); > > > > > > @@ -319,6 +322,20 @@ static inline void audit_inode_child(struct inode > > > *parent, } > > > > > > void audit_core_dumps(long signr); > > > > > > +static inline void audit_seccomp_errno(unsigned long syscall, int > > > errno, > > > + int code) > > > +{ > > > + if (!audit_enabled) > > > + return; > > > + > > > + if (errno || unlikely(!audit_dummy_context())) { > > > + struct audit_seccomp_info info = { .code = code, > > > + .errno = errno }; > > > + > > > + __audit_seccomp(syscall, &info); > > > + } > > > +} > > > + > > > > > > static inline void audit_seccomp_signal(unsigned long syscall, long > > > signr, > > > > > > int code) > > > > > > { > > > > > > diff --git a/kernel/auditsc.c b/kernel/auditsc.c > > > index b3472f2..db5fc9d 100644 > > > --- a/kernel/auditsc.c > > > +++ b/kernel/auditsc.c > > > @@ -2426,6 +2426,9 @@ void __audit_seccomp(unsigned long syscall, struct > > > audit_seccomp_info *info) audit_log_task(ab); > > > > > > switch (info->code) { > > > > > > + case SECCOMP_RET_ERRNO: > > > + audit_log_format(ab, " errno=%d", info->errno); > > > + break; > > > > "exit" is the field name that syscalls use to return errno to user space. > > I'd rather not see another field created that maps to the same thing. You > > can check > > the translation with the auformat utility: > Thanks for having a look at the field name I was using. Although I > prefer "errno" over "exit" in terms of clarity, I agree that it makes > sense to be consistent with the field names across record types. "exit" > works for me. > > > http://people.redhat.com/sgrubb/files/auformat.tar.gz > > > > $ ausearch --start today --just-one -m syscall -sv no --raw | ./auformat > > "%EXIT\n" > > > > Also, I am working to normalize all the records. That mean every event > > record of the same type has the same fields, in the same order, with the > > same representation. I would think "exit" could be added to the current > > record after syscall so that its ordered similarly to a syscall record. > > This patch goes against your normalization efforts in more ways than > just the placement of the "exit" field. If the action is > SECCOMP_RET_KILL, a "sig" field is present but if the action is > SECCOMP_RET_ERRNO, the "sig" field will not be present but the "errno" > field will be present. This happens all within the AUDIT_SECCOMP record > type. How would you suggest normalizing AUDIT_SECCOMP records for > different seccomp return actions? Typically when the layout has to change, we just give it a new record type. -Steve > > > case SECCOMP_RET_KILL: > > > audit_log_format(ab, " sig=%ld", info->signr); > > > break; > > > > > > diff --git a/kernel/seccomp.c b/kernel/seccomp.c > > > index 54c01b6..e99c566 100644 > > > --- a/kernel/seccomp.c > > > +++ b/kernel/seccomp.c > > > @@ -576,9 +576,11 @@ static int __seccomp_filter(int this_syscall, const > > > struct seccomp_data *sd, /* Set low-order bits as an errno, capped at > > > MAX_ERRNO. */ > > > > > > if (data > MAX_ERRNO) > > > > > > data = MAX_ERRNO; > > > > > > + > > > + audit_seccomp_errno(this_syscall, data, action); > > > > > > syscall_set_return_value(current, task_pt_regs(current), > > > > > > -data, 0); > > > > > > - goto skip; > > > + return -1; > > > > > > case SECCOMP_RET_TRAP: > > > /* Show the handler the original registers. */