linux-kernel - Re: [PATCH v2 RESEND] powerpc/audit: Convert powerpc to AUDIT_ARCH_COMPAT

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Message-ID: <CAHC9VhSG8tPAkAAz5Z77HDMKXLAiaEOanxR+oY5c1E_Xoiso9Q@mail.gmail.com>
Date:   Tue, 24 Aug 2021 19:01:48 -0400
From:   Paul Moore <paul@...l-moore.com>
To:     Christophe Leroy <christophe.leroy@...roup.eu>
Cc:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        Eric Paris <eparis@...hat.com>, linux-audit@...hat.com
Subject: Re: [PATCH v2 RESEND] powerpc/audit: Convert powerpc to AUDIT_ARCH_COMPAT_GENERIC

On Tue, Aug 24, 2021 at 1:11 PM Christophe Leroy
<christophe.leroy@...roup.eu> wrote:
> Le 24/08/2021 à 16:47, Paul Moore a écrit :
> > On Tue, Aug 24, 2021 at 9:36 AM Christophe Leroy
> > <christophe.leroy@...roup.eu> wrote:
> >>
> >> Commit e65e1fc2d24b ("[PATCH] syscall class hookup for all normal
> >> targets") added generic support for AUDIT but that didn't include
> >> support for bi-arch like powerpc.
> >>
> >> Commit 4b58841149dc ("audit: Add generic compat syscall support")
> >> added generic support for bi-arch.
> >>
> >> Convert powerpc to that bi-arch generic audit support.
> >>
> >> Cc: Paul Moore <paul@...l-moore.com>
> >> Cc: Eric Paris <eparis@...hat.com>
> >> Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
> >> ---
> >> Resending v2 with Audit people in Cc
> >>
> >> v2:
> >> - Missing 'git add' for arch/powerpc/include/asm/unistd32.h
> >> - Finalised commit description
> >> ---
> >>   arch/powerpc/Kconfig                |  5 +-
> >>   arch/powerpc/include/asm/unistd32.h |  7 +++
> >>   arch/powerpc/kernel/Makefile        |  3 --
> >>   arch/powerpc/kernel/audit.c         | 84 -----------------------------
> >>   arch/powerpc/kernel/compat_audit.c  | 44 ---------------
> >>   5 files changed, 8 insertions(+), 135 deletions(-)
> >>   create mode 100644 arch/powerpc/include/asm/unistd32.h
> >>   delete mode 100644 arch/powerpc/kernel/audit.c
> >>   delete mode 100644 arch/powerpc/kernel/compat_audit.c
> >
> > Can you explain, in detail please, the testing you have done to verify
> > this patch?
> >
>
> I built ppc64_defconfig and checked that the generated code is functionnaly equivalent.
>
> ppc32_classify_syscall() is exactly the same as audit_classify_compat_syscall() except that the
> later takes the syscall as second argument (ie in r4) whereas the former takes it as first argument
> (ie in r3).
>
> audit_classify_arch() and powerpc audit_classify_syscall() are slightly different between the
> powerpc version and the generic version because the powerpc version checks whether it is
> AUDIT_ARCH_PPC or not (ie value 20), while the generic one checks whether it has bit
> __AUDIT_ARCH_64BIT set or not (__AUDIT_ARCH_64BIT is the sign bit of a word), but taking into
> account that the abi is either AUDIT_ARCH_PPC, AUDIT_ARCH_PPC64 or AUDIT_ARCH_PPC64LE, the result is
> the same.
>
> If you are asking I guess you saw something wrong ?

I was asking because I didn't see any mention of testing, and when you
are enabling something significant like this it is nice to see that it
has been verified to work :)

While binary dumps and comparisons are nice, it is always good to see
verification from a test suite.  I don't have access to the necessary
hardware to test this, but could you verify that the audit-testsuite
passes on your test system with your patches applied?

 * https://github.com/linux-audit/audit-testsuite

-- 
paul moore
www.paul-moore.com