From: Borislav Petkov <bp@suse.de>
To: Peter Gonda <pgonda@google.com>
Cc: thomas.lendacky@amd.com, Dionna Glaze <dionnaglaze@google.com>,
Michael Roth <michael.roth@amd.com>,
Haowen Bai <baihaowen@meizu.com>,
Yang Yingliang <yangyingliang@huawei.com>,
Marc Orr <marcorr@google.com>,
David Rientjes <rientjes@google.com>,
Ashish Kalra <Ashish.Kalra@amd.com>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Subject: Re: [PATCH V4] virt: sev: Prevent IV reuse in SNP guest driver
Date: Wed, 16 Nov 2022 13:20:00 +0100 [thread overview]
Message-ID: <Y3TVcJnQ/Ym6dGz2@zn.tnic> (raw)
In-Reply-To: <CAMkAt6o-jcG7u1=zw4jJp5evrO4sFJR-iG_ApF7LhT+7c55_Wg@mail.gmail.com>
On Tue, Nov 15, 2022 at 02:47:31PM -0700, Peter Gonda wrote:
> > > + * certificate data buffer retry the same guest request without the
> > > + * extended data request.
> > > + */
> > > + if (exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST &&
> > > + err == SNP_GUEST_REQ_INVALID_LEN) {
> > > + const unsigned int certs_npages = snp_dev->input.data_npages;
> > > +
> > > + exit_code = SVM_VMGEXIT_GUEST_REQUEST;
> > > + rc = snp_issue_guest_request(exit_code, &snp_dev->input, &err);
> > > +
> > > + err = SNP_GUEST_REQ_INVALID_LEN;
> >
> > Huh, why are we overwriting err here?
>
> I have added a comment for the next revision.
>
> We are overwriting err here so that userspace is alerted that they
> supplied a buffer too small.
Sure but you're not checking rc either. What if that reissue fails for
whatever other reason? -EIO for example...
--
Regards/Gruss,
Boris.
SUSE Software Solutions Germany GmbH
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Martje Boudien Moerman
(HRB 36809, AG Nürnberg)
next prev parent reply other threads:[~2022-11-16 12:24 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-03 15:23 [PATCH V4] virt: sev: Prevent IV reuse in SNP guest driver Peter Gonda
2022-11-04 17:39 ` Tom Lendacky
2022-11-11 16:46 ` Borislav Petkov
2022-11-14 21:11 ` Peter Gonda
2022-11-15 21:36 ` Borislav Petkov
2022-11-15 21:48 ` Peter Gonda
2022-11-15 21:47 ` Peter Gonda
2022-11-16 12:20 ` Borislav Petkov [this message]
2022-11-16 16:23 ` Peter Gonda
2022-11-16 16:58 ` Tom Lendacky
2022-11-16 17:10 ` Peter Gonda
2022-11-16 17:28 ` Borislav Petkov
2022-11-16 17:57 ` Peter Gonda
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