From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55509) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eBsEa-0005NY-1q for qemu-devel@nongnu.org; Mon, 06 Nov 2017 19:59:23 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eBsEW-0003pZ-RP for qemu-devel@nongnu.org; Mon, 06 Nov 2017 19:59:20 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:42918 helo=mx0a-001b2d01.pphosted.com) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eBsEW-0003pD-M4 for qemu-devel@nongnu.org; Mon, 06 Nov 2017 19:59:16 -0500 Received: from pps.filterd (m0098421.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id vA70sDDd019429 for ; Mon, 6 Nov 2017 19:59:10 -0500 Received: from e13.ny.us.ibm.com (e13.ny.us.ibm.com [129.33.205.203]) by mx0a-001b2d01.pphosted.com with ESMTP id 2e306j6pch-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Mon, 06 Nov 2017 19:59:10 -0500 Received: from localhost by e13.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 6 Nov 2017 19:59:09 -0500 From: Stefan Berger Date: Mon, 6 Nov 2017 19:58:56 -0500 In-Reply-To: <1510016336-4086-1-git-send-email-stefanb@linux.vnet.ibm.com> References: <1510016336-4086-1-git-send-email-stefanb@linux.vnet.ibm.com> Message-Id: <1510016336-4086-6-git-send-email-stefanb@linux.vnet.ibm.com> Subject: [Qemu-devel] [PATCH 5/5] tpm: tpm_passthrough: Fail startup if FE buffer size < BE buffer size List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, marcandre.lureau@redhat.com Cc: amarnath.valluri@intel.com, Stefan Berger If the requested buffer size of the frontend is smaller than the fixed buffer size of the host's TPM, fail the startup_tpm() interface function, which will make the device unusable. We fail it because the backend TPM could produce larger packets than what the frontend could pass to the OS. The current combination of TIS frontend and either passthrough or emulator backend will not lead to this case since the TIS can support any size of buffer. Signed-off-by: Stefan Berger --- hw/tpm/tpm_passthrough.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/hw/tpm/tpm_passthrough.c b/hw/tpm/tpm_passthrough.c index ec755fe..66d5098 100644 --- a/hw/tpm/tpm_passthrough.c +++ b/hw/tpm/tpm_passthrough.c @@ -304,6 +304,20 @@ static TPMBackend *tpm_passthrough_create(QemuOpts *opts) return TPM_BACKEND(obj); } +static int tpm_passthrough_startup_tpm(TPMBackend *tb, uint32_t buffersize) +{ + TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb); + + if (buffersize && buffersize < tpm_pt->tpm_buffersize) { + error_report("Requested buffer size of %u is smaller than host TPM's " + "fixed buffer size of %u", + buffersize, tpm_pt->tpm_buffersize); + return -1; + } + + return 0; +} + static TpmTypeOptions *tpm_passthrough_get_tpm_options(TPMBackend *tb) { TpmTypeOptions *options = g_new0(TpmTypeOptions, 1); @@ -362,6 +376,7 @@ static void tpm_passthrough_class_init(ObjectClass *klass, void *data) tbc->opts = tpm_passthrough_cmdline_opts; tbc->desc = "Passthrough TPM backend driver"; tbc->create = tpm_passthrough_create; + tbc->startup_tpm = tpm_passthrough_startup_tpm; tbc->reset = tpm_passthrough_reset; tbc->cancel_cmd = tpm_passthrough_cancel_cmd; tbc->get_tpm_established_flag = tpm_passthrough_get_tpm_established_flag; -- 2.5.5