From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.10]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F24E724B3A for ; Tue, 16 Jan 2024 22:28:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.10 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705444124; cv=none; b=t3UEoYa2pFIW5hNtTJ9Ev3IXr6i4y7Y9koaooMfNjc7ZZPzISKD1zyPPvVkbQZWLdoMAvK7Xqs5hYDdJuAMyeAXBKggMJmi/c8ouLkBei98O6S9bXjLR2aFOpBtP7o3tmkml77b4sE9e/agDahb+8MJ0wwjaorBRlSiIFXFzwPE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705444124; c=relaxed/simple; bh=9Ezf4ND7hXOBpmbgOSwM5A6lJTvji0aEFSttJmVgKdA=; h=DKIM-Signature:X-IronPort-AV:X-IronPort-AV:Received:X-ExtLoop1: X-IronPort-AV:Received:Message-ID:Date:MIME-Version:User-Agent: Subject:Content-Language:To:Cc:References:From:In-Reply-To: Content-Type:Content-Transfer-Encoding; b=D/l+M0wZtsmhh1yDGQWtON7dudjU8tW02th9eG5w9AQzu/i6MpTJ8iuozR4OynzEShlKhIre97V9SxF9rOUTn5DCPWnS7XRMWKe4ohx+qK3DQ3bY/M5MdoMbdHEevpdvD36UKZl5z3vXnB9/87tUADcKMfTscVB9H2VTeCmWzGI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=LL5Ahp0k; arc=none smtp.client-ip=198.175.65.10 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="LL5Ahp0k" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1705444123; x=1736980123; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=9Ezf4ND7hXOBpmbgOSwM5A6lJTvji0aEFSttJmVgKdA=; b=LL5Ahp0kAmKvgqjTHnLQGJvYGkR0zAMWocmd5VgVc/q/DjrYt3DDimU7 YXIlTgcQhEVYLBYqkRdwpPnqxizX64XgrE3g4AATXgRsSEfgHbhmukJhY wpADWJsXsS7jdW4r/gURsk+XxTTK7H6BUImFLdwBKZNDMHwKxSapQZD7G dD9c8vUe5yQGBSimxkBWcEyX6qfNLYBCxYJRkqvlzbai7dpN1RWiJD1Zn wwsVTyAvBbIx0DDa+/m/GmL8ylSqTJlf+2lOogInO7lns8UOfjlDCDufO dnoXBwQxGW1o2R+sHP1Cbe9rexb/uldToDfv0T2bZSiwWeT6IWppvECPo w==; X-IronPort-AV: E=McAfee;i="6600,9927,10955"; a="13360022" X-IronPort-AV: E=Sophos;i="6.05,200,1701158400"; d="scan'208";a="13360022" Received: from fmviesa002.fm.intel.com ([10.60.135.142]) by orvoesa102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Jan 2024 14:28:42 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.05,200,1701158400"; d="scan'208";a="18612293" Received: from rjcolson-mobl2.amr.corp.intel.com (HELO [10.209.69.176]) ([10.209.69.176]) by fmviesa002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Jan 2024 14:28:41 -0800 Message-ID: <1bbf8d3e-aa94-48c7-a1e4-76f9eefc4af7@linux.intel.com> Date: Tue, 16 Jan 2024 14:28:29 -0800 Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH v1 3/4] tsm: Allow for mapping RTMRs to TCG TPM PCRs Content-Language: en-US To: Samuel Ortiz , Dan Williams Cc: linux-coco@lists.linux.dev, linux-kernel@vger.kernel.org References: <20240114223532.290550-1-sameo@rivosinc.com> <20240114223532.290550-4-sameo@rivosinc.com> From: Kuppuswamy Sathyanarayanan In-Reply-To: <20240114223532.290550-4-sameo@rivosinc.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 1/14/24 2:35 PM, Samuel Ortiz wrote: > Many user space and internal kernel subsystems (e.g. the Linux IMA) > expect a Root of Trust for Storage (RTS) that allows for extending > and reading measurement registers that are compatible with the TCG TPM > PCRs layout, e.g. a TPM. In order to allow those components to > alternatively use a platform TSM as their RTS, a TVM could map the > available RTMRs to one or more TCG TPM PCRs. Once configured, those PCR > to RTMR mappings give the kernel TSM layer all the necessary information > to be a RTS for e.g. the Linux IMA or any other components that expects > a TCG compliant TPM PCRs layout. > > TPM PCR mappings are configured through configfs: > > // Create and configure 2 RTMRs > mkdir /sys/kernel/config/tsm/rtmrs/rtmr0 > mkdir /sys/kernel/config/tsm/rtmrs/rtmr1 > echo 0 > /sys/kernel/config/tsm/rtmrs/rtmr0/index > echo 1 > /sys/kernel/config/tsm/rtmrs/rtmr1/index > > // Map RTMR 0 to PCRs 4, 5, 6, 7 and 8 > echo 4-8 > /sys/kernel/config/tsm/rtmrs/rtmr0/tcg_map > > // Map RTMR 1 to PCRs 16, 17 and 18 > echo 16-18 > /sys/kernel/config/tsm/rtmrs/rtmr1/tcg_map Any information on how this mapping will be used by TPM or IMA ? RTMR to PCR mapping is fixed by design, right? If yes, why allow user to configure it. We can let vendor drivers to configure it, right? > > Signed-off-by: Samuel Ortiz > --- > drivers/virt/coco/tsm.c | 60 +++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 60 insertions(+) > > diff --git a/drivers/virt/coco/tsm.c b/drivers/virt/coco/tsm.c > index 15b67d99fd54..f35f91cb7bd3 100644 > --- a/drivers/virt/coco/tsm.c > +++ b/drivers/virt/coco/tsm.c > @@ -472,8 +472,68 @@ static ssize_t tsm_rtmr_index_show(struct config_item *cfg, > } > CONFIGFS_ATTR(tsm_rtmr_, index); > > +static ssize_t tsm_rtmr_tcg_map_store(struct config_item *cfg, > + const char *buf, size_t len) > +{ > + struct tsm_rtmr_state *rtmr_state = to_tsm_rtmr_state(cfg); > + int i, pcrs[TPM2_PLATFORM_PCR + 1]; > + > + get_options(buf, ARRAY_SIZE(pcrs), pcrs); > + > + if (pcrs[0] > TPM2_PLATFORM_PCR - 1) > + return -EINVAL; > + > + guard(rwsem_write)(&tsm_rwsem); > + /* Check that the PCR list is valid */ > + for (i = 0; i < pcrs[0]; i++) { > + /* It must be a valid TPM2 PCR number */ > + if (pcrs[i] > TPM2_PLATFORM_PCR - 1) > + return -EINVAL; > + > + /* If another RTMR maps to this PCR, the list is discarded */ > + if (tsm_rtmrs->tcg_map[pcrs[i + 1]] && > + tsm_rtmrs->tcg_map[pcrs[i + 1]] != rtmr_state) > + return -EBUSY; > + } > + > + for (i = 0; i < pcrs[0]; i++) > + tsm_rtmrs->tcg_map[pcrs[i + 1]] = rtmr_state; > + > + return len; > +} > + > +static ssize_t tsm_rtmr_tcg_map_show(struct config_item *cfg, > + char *buf) > +{ > + struct tsm_rtmr_state *rtmr_state = to_tsm_rtmr_state(cfg); > + unsigned int nr_pcrs = ARRAY_SIZE(tsm_rtmrs->tcg_map), i; > + unsigned long *pcr_mask; > + ssize_t len; > + > + /* Build a bitmap mask of all PCRs that this RTMR covers */ > + pcr_mask = bitmap_zalloc(nr_pcrs, GFP_KERNEL); > + if (!pcr_mask) > + return -ENOMEM; > + > + guard(rwsem_read)(&tsm_rwsem); > + for (i = 0; i < nr_pcrs; i++) { > + if (tsm_rtmrs->tcg_map[i] != rtmr_state) > + continue; > + > + __set_bit(i, pcr_mask); > + } > + > + len = bitmap_print_list_to_buf(buf, pcr_mask, nr_pcrs, 0, > + nr_pcrs * 3 /* 2 ASCII digits and one comma */); > + bitmap_free(pcr_mask); > + > + return len; > +} > +CONFIGFS_ATTR(tsm_rtmr_, tcg_map); > + > static struct configfs_attribute *tsm_rtmr_attrs[] = { > &tsm_rtmr_attr_index, > + &tsm_rtmr_attr_tcg_map, > NULL, > }; > -- Sathyanarayanan Kuppuswamy Linux Kernel Developer