From 91f7f3d773a469deeab3808d422363138295346e Mon Sep 17 00:00:00 2001 From: Roberto Sassu Date: Fri, 23 Jun 2017 15:41:56 +0200 Subject: [PATCH] tpm: use tpm_buf functions in tpm2_pcr_read() tpm2_pcr_read() now builds the PCR read command buffer with tpm_buf functions. This solution is preferred to using a tpm2_cmd structure, as tpm_buf functions provide protection against buffer overflow. Signed-off-by: Roberto Sassu Reviewed-by: Jarkko Sakkinen Tested-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen Signed-off-by: James Morris --- drivers/char/tpm/tpm2-cmd.c | 60 ++++++++++++++++++++++----------------------- 1 file changed, 30 insertions(+), 30 deletions(-) diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c index 1962c9b..76b0c87 100644 --- a/drivers/char/tpm/tpm2-cmd.c +++ b/drivers/char/tpm/tpm2-cmd.c @@ -42,17 +42,6 @@ struct tpm2_pcr_read_in { u8 pcr_select[TPM2_PCR_SELECT_MIN]; } __packed; -struct tpm2_pcr_read_out { - __be32 update_cnt; - __be32 pcr_selects_cnt; - __be16 hash_alg; - u8 pcr_select_size; - u8 pcr_select[TPM2_PCR_SELECT_MIN]; - __be32 digests_cnt; - __be16 digest_size; - u8 digest[TPM_DIGEST_SIZE]; -} __packed; - struct tpm2_get_tpm_pt_in { __be32 cap_id; __be32 property_id; @@ -80,7 +69,6 @@ union tpm2_cmd_params { struct tpm2_startup_in startup_in; struct tpm2_self_test_in selftest_in; struct tpm2_pcr_read_in pcrread_in; - struct tpm2_pcr_read_out pcrread_out; struct tpm2_get_tpm_pt_in get_tpm_pt_in; struct tpm2_get_tpm_pt_out get_tpm_pt_out; struct tpm2_get_random_in getrandom_in; @@ -231,15 +219,23 @@ 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) }; +struct tpm2_pcr_read_out { + __be32 update_cnt; + __be32 pcr_selects_cnt; + __be16 hash_alg; + u8 pcr_select_size; + u8 pcr_select[TPM2_PCR_SELECT_MIN]; + __be32 digests_cnt; + __be16 digest_size; + u8 digest[]; +} __packed; + /** * tpm2_pcr_read() - read a PCR value * @chip: TPM chip to use. @@ -251,29 +247,33 @@ 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; + struct tpm_buf buf; + struct tpm2_pcr_read_out *out; + u8 pcr_select[TPM2_PCR_SELECT_MIN] = {0}; 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; + rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_PCR_READ); + if (rc) + return rc; - 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); + pcr_select[pcr_idx >> 3] = 1 << (pcr_idx & 0x7); - rc = tpm_transmit_cmd(chip, NULL, &cmd, sizeof(cmd), - TPM2_PCR_READ_RESP_BODY_SIZE, - 0, "attempting to read a pcr value"); - if (rc == 0) { - buf = cmd.params.pcrread_out.digest; - memcpy(res_buf, buf, TPM_DIGEST_SIZE); + tpm_buf_append_u32(&buf, 1); + tpm_buf_append_u16(&buf, TPM2_ALG_SHA1); + tpm_buf_append_u8(&buf, TPM2_PCR_SELECT_MIN); + tpm_buf_append(&buf, (const unsigned char *)pcr_select, + sizeof(pcr_select)); + + rc = tpm_transmit_cmd(chip, NULL, buf.data, PAGE_SIZE, 0, 0, + res_buf ? "attempting to read a pcr value" : NULL); + if (rc == 0 && res_buf) { + out = (struct tpm2_pcr_read_out *)&buf.data[TPM_HEADER_SIZE]; + memcpy(res_buf, out->digest, SHA1_DIGEST_SIZE); } + tpm_buf_destroy(&buf); return rc; } -- 2.7.4