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 <roberto.sassu@huawei.com> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
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@ -42,17 +42,6 @@ struct tpm2_pcr_read_in {
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u8 pcr_select[TPM2_PCR_SELECT_MIN];
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} __packed;
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struct tpm2_pcr_read_out {
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__be32 update_cnt;
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__be32 pcr_selects_cnt;
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__be16 hash_alg;
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u8 pcr_select_size;
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u8 pcr_select[TPM2_PCR_SELECT_MIN];
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__be32 digests_cnt;
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__be16 digest_size;
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u8 digest[TPM_DIGEST_SIZE];
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} __packed;
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struct tpm2_get_tpm_pt_in {
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__be32 cap_id;
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__be32 property_id;
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@ -80,7 +69,6 @@ union tpm2_cmd_params {
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struct tpm2_startup_in startup_in;
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struct tpm2_self_test_in selftest_in;
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struct tpm2_pcr_read_in pcrread_in;
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struct tpm2_pcr_read_out pcrread_out;
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struct tpm2_get_tpm_pt_in get_tpm_pt_in;
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struct tpm2_get_tpm_pt_out get_tpm_pt_out;
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struct tpm2_get_random_in getrandom_in;
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@ -231,15 +219,23 @@ static const u8 tpm2_ordinal_duration[TPM2_CC_LAST - TPM2_CC_FIRST + 1] = {
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(sizeof(struct tpm_input_header) + \
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sizeof(struct tpm2_pcr_read_in))
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#define TPM2_PCR_READ_RESP_BODY_SIZE \
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sizeof(struct tpm2_pcr_read_out)
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static const struct tpm_input_header tpm2_pcrread_header = {
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.tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
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.length = cpu_to_be32(TPM2_PCR_READ_IN_SIZE),
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.ordinal = cpu_to_be32(TPM2_CC_PCR_READ)
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};
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struct tpm2_pcr_read_out {
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__be32 update_cnt;
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__be32 pcr_selects_cnt;
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__be16 hash_alg;
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u8 pcr_select_size;
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u8 pcr_select[TPM2_PCR_SELECT_MIN];
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__be32 digests_cnt;
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__be16 digest_size;
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u8 digest[];
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} __packed;
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/**
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* tpm2_pcr_read() - read a PCR value
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* @chip: TPM chip to use.
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@ -251,29 +247,33 @@ static const struct tpm_input_header tpm2_pcrread_header = {
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int tpm2_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
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{
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int rc;
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struct tpm2_cmd cmd;
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u8 *buf;
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struct tpm_buf buf;
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struct tpm2_pcr_read_out *out;
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u8 pcr_select[TPM2_PCR_SELECT_MIN] = {0};
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if (pcr_idx >= TPM2_PLATFORM_PCR)
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return -EINVAL;
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cmd.header.in = tpm2_pcrread_header;
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cmd.params.pcrread_in.pcr_selects_cnt = cpu_to_be32(1);
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cmd.params.pcrread_in.hash_alg = cpu_to_be16(TPM2_ALG_SHA1);
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cmd.params.pcrread_in.pcr_select_size = TPM2_PCR_SELECT_MIN;
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rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_PCR_READ);
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if (rc)
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return rc;
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memset(cmd.params.pcrread_in.pcr_select, 0,
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sizeof(cmd.params.pcrread_in.pcr_select));
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cmd.params.pcrread_in.pcr_select[pcr_idx >> 3] = 1 << (pcr_idx & 0x7);
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pcr_select[pcr_idx >> 3] = 1 << (pcr_idx & 0x7);
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rc = tpm_transmit_cmd(chip, NULL, &cmd, sizeof(cmd),
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TPM2_PCR_READ_RESP_BODY_SIZE,
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0, "attempting to read a pcr value");
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if (rc == 0) {
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buf = cmd.params.pcrread_out.digest;
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memcpy(res_buf, buf, TPM_DIGEST_SIZE);
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tpm_buf_append_u32(&buf, 1);
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tpm_buf_append_u16(&buf, TPM2_ALG_SHA1);
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tpm_buf_append_u8(&buf, TPM2_PCR_SELECT_MIN);
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tpm_buf_append(&buf, (const unsigned char *)pcr_select,
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sizeof(pcr_select));
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rc = tpm_transmit_cmd(chip, NULL, buf.data, PAGE_SIZE, 0, 0,
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res_buf ? "attempting to read a pcr value" : NULL);
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if (rc == 0 && res_buf) {
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out = (struct tpm2_pcr_read_out *)&buf.data[TPM_HEADER_SIZE];
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memcpy(res_buf, out->digest, SHA1_DIGEST_SIZE);
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}
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tpm_buf_destroy(&buf);
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return rc;
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}
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