Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752662AbdFUOdx (ORCPT ); Wed, 21 Jun 2017 10:33:53 -0400 Received: from lhrrgout.huawei.com ([194.213.3.17]:29083 "EHLO lhrrgout.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751927AbdFUOci (ORCPT ); Wed, 21 Jun 2017 10:32:38 -0400 From: Roberto Sassu To: CC: , , , , Roberto Sassu Subject: [PATCH v3 1/6] tpm: use tpm_buf functions to perform a PCR read Date: Wed, 21 Jun 2017 16:29:36 +0200 Message-ID: <20170621142941.32674-2-roberto.sassu@huawei.com> X-Mailer: git-send-email 2.9.3 In-Reply-To: <20170621142941.32674-1-roberto.sassu@huawei.com> References: <20170621142941.32674-1-roberto.sassu@huawei.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.204.65.245] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020201.594A8383.032A,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2013-06-18 04:22:30, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: b6e705b68c1581613437862ee1f58501 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3628 Lines: 105 tpm2_pcr_read() now uses tpm_buf functions to build the TPM command to read a PCR. Those functions are preferred to passing a tpm2_cmd structure, as they provide protection against buffer overflow. Also, tpm2_pcr_read() code has been moved to tpm2_pcr_read_tpm_buf(). Callers have to pass a tpm_buf structure, an algorithm supported by the TPM and call tpm_buf_destroy(). The algorithm still cannot be passed to the TPM driver interface. This parameter has been introduced for determining the digest size of a given algorithm. Moving tpm2_pcr_read() code to tpm2_pcr_read_tpm_buf() is necessary because callers of the new function obtain different information from the output buffer: tpm2_pcr_read() gets the digest, tpm2_do_selftest() will get the command return code and tpm2_get_pcr_allocation() will get the digest size. Signed-off-by: Roberto Sassu --- drivers/char/tpm/tpm2-cmd.c | 54 +++++++++++++++++++++++++++------------------ 1 file changed, 32 insertions(+), 22 deletions(-) diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c index 3a99643..afd1b63 100644 --- a/drivers/char/tpm/tpm2-cmd.c +++ b/drivers/char/tpm/tpm2-cmd.c @@ -231,15 +231,37 @@ static const u8 tpm2_ordinal_duration[TPM2_CC_LAST - TPM2_CC_FIRST + 1] = { (sizeof(struct tpm_input_header) + \ sizeof(struct tpm2_pcr_read_in)) -#define TPM2_PCR_READ_RESP_BODY_SIZE \ - sizeof(struct tpm2_pcr_read_out) - static const struct tpm_input_header tpm2_pcrread_header = { .tag = cpu_to_be16(TPM2_ST_NO_SESSIONS), .length = cpu_to_be32(TPM2_PCR_READ_IN_SIZE), .ordinal = cpu_to_be32(TPM2_CC_PCR_READ) }; +static int tpm2_pcr_read_tpm_buf(struct tpm_chip *chip, int pcr_idx, + enum tpm2_algorithms algo, struct tpm_buf *buf, + char *msg) +{ + int rc; + u8 pcr_select[TPM2_PCR_SELECT_MIN] = {0}; + + if (pcr_idx >= TPM2_PLATFORM_PCR) + return -EINVAL; + + rc = tpm_buf_init(buf, TPM2_ST_NO_SESSIONS, TPM2_CC_PCR_READ); + if (rc) + return rc; + + pcr_select[pcr_idx >> 3] = 1 << (pcr_idx & 0x7); + + tpm_buf_append_u32(buf, 1); + tpm_buf_append_u16(buf, algo); + tpm_buf_append_u8(buf, TPM2_PCR_SELECT_MIN); + tpm_buf_append(buf, (const unsigned char *)pcr_select, + sizeof(pcr_select)); + + return tpm_transmit_cmd(chip, NULL, buf->data, PAGE_SIZE, 0, 0, msg); +} + /** * tpm2_pcr_read() - read a PCR value * @chip: TPM chip to use. @@ -251,29 +273,17 @@ static const struct tpm_input_header tpm2_pcrread_header = { int tpm2_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf) { int rc; - struct tpm2_cmd cmd; - u8 *buf; - - if (pcr_idx >= TPM2_PLATFORM_PCR) - return -EINVAL; - - cmd.header.in = tpm2_pcrread_header; - cmd.params.pcrread_in.pcr_selects_cnt = cpu_to_be32(1); - cmd.params.pcrread_in.hash_alg = cpu_to_be16(TPM2_ALG_SHA1); - cmd.params.pcrread_in.pcr_select_size = TPM2_PCR_SELECT_MIN; - - memset(cmd.params.pcrread_in.pcr_select, 0, - sizeof(cmd.params.pcrread_in.pcr_select)); - cmd.params.pcrread_in.pcr_select[pcr_idx >> 3] = 1 << (pcr_idx & 0x7); + struct tpm_buf buf; + struct tpm2_pcr_read_out *out; - rc = tpm_transmit_cmd(chip, NULL, &cmd, sizeof(cmd), - TPM2_PCR_READ_RESP_BODY_SIZE, - 0, "attempting to read a pcr value"); + rc = tpm2_pcr_read_tpm_buf(chip, pcr_idx, TPM2_ALG_SHA1, &buf, + "attempting to read a pcr value"); if (rc == 0) { - buf = cmd.params.pcrread_out.digest; - memcpy(res_buf, buf, TPM_DIGEST_SIZE); + out = (struct tpm2_pcr_read_out *)&buf.data[TPM_HEADER_SIZE]; + memcpy(res_buf, out->digest, TPM_DIGEST_SIZE); } + tpm_buf_destroy(&buf); return rc; } -- 2.9.3