From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Bottomley Subject: Re: [tpmdd-devel] [PATCH RFC v3 5/5] tpm2: expose resource manager via a device link /dev/tpms Date: Sat, 21 Jan 2017 11:28:55 -0800 Message-ID: <1485026935.26703.12.camel@HansenPartnership.com> References: <20170116131215.28930-1-jarkko.sakkinen@linux.intel.com> <20170116131215.28930-6-jarkko.sakkinen@linux.intel.com> <1484751663.2717.10.camel@HansenPartnership.com> <20170119104922.vhgz4rxw6yzdrxqt@intel.com> <1484828380.3140.11.camel@HansenPartnership.com> <20170120133914.2wk43nteh2hh7n3c@intel.com> <20170120210522.glx4y4oui36oimld@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20170120210522.glx4y4oui36oimld@intel.com> Sender: linux-kernel-owner@vger.kernel.org To: Jarkko Sakkinen Cc: linux-security-module@vger.kernel.org, tpmdd-devel@lists.sourceforge.net, open list List-Id: tpmdd-devel@lists.sourceforge.net On Fri, 2017-01-20 at 23:05 +0200, Jarkko Sakkinen wrote: > On Fri, Jan 20, 2017 at 03:39:14PM +0200, Jarkko Sakkinen wrote: > > On Thu, Jan 19, 2017 at 07:19:40AM -0500, James Bottomley wrote: > > > On Thu, 2017-01-19 at 12:49 +0200, Jarkko Sakkinen wrote: > > > > On Wed, Jan 18, 2017 at 10:01:03AM -0500, James Bottomley > > > > wrote: > > > > > On Mon, 2017-01-16 at 15:12 +0200, Jarkko Sakkinen wrote: > > > > > > From: James Bottomley < > > > > > > James.Bottomley@HansenPartnership.com> > > > > > > > > > > > > Currently the Resource Manager (RM) is not exposed to > > > > > > userspace. > > > > > > Make this exposure via a separate device, which can now be > > > > > > opened multiple times because each read/write transaction > > > > > > goes > > > > > > separately via the RM. > > > > > > > > > > > > Concurrency is protected by the chip->tpm_mutex for each > > > > > > read/write transaction separately. The TPM is cleared of > > > > > > all > > > > > > transient objects by the time the mutex is dropped, so > > > > > > there > > > > > > should be no interference between the kernel and userspace. > > > > > > > > > > There's actually a missing kfree of context_buf on the > > > > > tpms_release > > > > > path as well. This patch fixes it up. > > > > > > > > Can you send me a fresh version of the whole patch so that I > > > > can > > > > include to v4 that includes also changes that I requested in my > > > > recent comments + all the fixes? > > > > > > Sure, I think the attached is basically it > > > > > > James > > > > Thank you! > > 'tabrm4' branch has been now rebased. It's now on top of master > branch > that contains Stefan's latest patch (min body length check) that I've > reviewed and tested. It also contains your updated /dev/tpms patch. > > I guess the 5 commits that are there now are such that we have fairly > good consensus, don't we? If so, can I add your reviewed-by and > tested-by to my commits and vice versa? Did you actually test it? It doesn't work for me. The bisected fault commit is this one (newly introduced into the tabrm4 branch) commit 9b7f4252655228c8d0b86e1492cc7fb3feaa5686 Author: Stefan Berger Date: Thu Jan 19 07:19:12 2017 -0500 tpm: Check size of response before accessing data The specific problem is that our min_rsp_length in tpm_{load,save}_context includes a header size and the check this introduces does the check is against the body size, meaning the load fails because tpm_transmit_cmd thinks the response is too short. The patch to fix this is below. James --- commit 480f2bb484f5a7e6100c6b0d1c79f72a05a0ca88 Author: James Bottomley Date: Sat Jan 21 11:26:24 2017 -0800 fix tpm_transmit_cmd min response size problem diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c index 4b5c714..3237d7c 100644 --- a/drivers/char/tpm/tpm2-space.c +++ b/drivers/char/tpm/tpm2-space.c @@ -53,7 +53,7 @@ static int tpm2_load_context(struct tpm_chip *chip, u8 *buf, tpm_buf_append(&tbuf, &buf[*offset], body_size); rc = tpm_transmit_cmd(chip, NULL, tbuf.data, PAGE_SIZE, - TPM_HEADER_SIZE + 4, TPM_TRANSMIT_UNLOCKED, "load context"); + 4, TPM_TRANSMIT_UNLOCKED, "load context"); if ((rc & TPM2_RC_HANDLE) == TPM2_RC_HANDLE) { rc = -ENOENT; tpm_buf_destroy(&tbuf); @@ -89,7 +89,7 @@ static int tpm2_save_context(struct tpm_chip *chip, u32 handle, u8 *buf, tpm_buf_append_u32(&tbuf, handle); - rc = tpm_transmit_cmd(chip, NULL, tbuf.data, PAGE_SIZE, TPM_HEADER_SIZE, + rc = tpm_transmit_cmd(chip, NULL, tbuf.data, PAGE_SIZE, 0, TPM_TRANSMIT_UNLOCKED, NULL); if (rc < 0) { dev_warn(&chip->dev, "%s: saving failed with a system error %d\n",