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 <roberto.sa...@huawei.com>
---
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 3a99643..fdce77d 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;
}
--
2.9.3
