From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Cc: tpmdd-devel@lists.sourceforge.net,
linux-security-module@vger.kernel.org,
Peter Huewe <peterhuewe@gmx.de>,
Marcel Selhorst <tpmdd@selhorst.net>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH RFC] tpm: migrate pubek_show to struct tpm_buf
Date: Tue, 30 May 2017 07:52:08 +0300 [thread overview]
Message-ID: <20170530045208.vqnik6t3zulp4mxe@intel.com> (raw)
In-Reply-To: <20170525224050.GA15715@obsidianresearch.com>
On Thu, May 25, 2017 at 04:40:50PM -0600, Jason Gunthorpe wrote:
> On Thu, May 25, 2017 at 03:28:01PM -0700, Jarkko Sakkinen wrote:
> > On Thu, May 25, 2017 at 03:16:13PM -0600, Jason Gunthorpe wrote:
> > > On Thu, May 25, 2017 at 02:11:04PM -0700, Jarkko Sakkinen wrote:
> > > > struct tpm_chip *chip = to_tpm_chip(dev);
> > > > + char anti_replay[20];
> > > >
> > > > - tpm_cmd.header.in = tpm_readpubek_header;
> > > > - err = tpm_transmit_cmd(chip, NULL, &tpm_cmd, READ_PUBEK_RESULT_SIZE,
> > > > + rc = tpm_buf_init(&tpm_buf, TPM_TAG_RQU_COMMAND, TPM_ORD_READPUBEK);
> > > > + if (rc)
> > > > + return rc;
> > > > +
> > > > + /* The checksum is ignored so it doesn't matter what the contents are.
> > > > + */
> > > > + tpm_buf_append(&tpm_buf, anti_replay, sizeof(anti_replay));
> > >
> > > It does matter, we do not want to leak random kernel memory incase it
> > > has something sensitive. Zero anti_replay.
> >
> > If there was a leak it has existed before this change as tpm_cmd was
> > also allocated from stack. And there is not leak because the checksum is
> > not printed.
>
> It leaks stack memory to the TPM which is not OK.
Right, of course, vtpm_tpm_proxy.
/Jarkko
prev parent reply other threads:[~2017-05-30 4:52 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-25 21:11 [PATCH RFC] tpm: migrate pubek_show to struct tpm_buf Jarkko Sakkinen
2017-05-25 21:16 ` Jason Gunthorpe
2017-05-25 22:28 ` Jarkko Sakkinen
[not found] ` <20170525222801.mayost6gxcggurjo-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
2017-05-25 22:40 ` Jason Gunthorpe
2017-05-30 4:52 ` Jarkko Sakkinen [this message]
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