Re: [tpmdd-devel] [PATCH RFC v4 1/5] tpm: validate TPM 2.0 commands

Stefan Berger
2017-01-23T02:02:30Z

On 01/22/2017 06:44 PM, Jarkko Sakkinen wrote:
> @@ -1025,8 +1029,60 @@ int tpm2_auto_startup(struct tpm_chip *chip)
> }
> }
>
> + rc = tpm2_get_tpm_pt(chip, TPM_PT_TOTAL_COMMANDS, &nr_commands, NULL);
> + if (rc)
> + goto out;
> +
> + /* sanity check */
> + if (nr_commands > INT_MAX) {
> + rc = -E2BIG;
> + goto out;
> + }
> +
> + chip->cc_attrs_tbl = devm_kzalloc(&chip->dev, 4 * nr_commands,
> + GFP_KERNEL);
> +
> + rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_GET_CAPABILITY);
> + if (rc)
> + goto out;
> +
> + tpm_buf_append_u32(&buf, TPM2_CAP_COMMANDS);
> + tpm_buf_append_u32(&buf, TPM2_CC_FIRST);
> + tpm_buf_append_u32(&buf, nr_commands);
> +
> + rc = tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, 0, 0, NULL);

You should probably pass the min_rsp_body_size as 5 + 4 + nr_commands * 4

> + if (rc < 0) {
> + tpm_buf_destroy(&buf);
> + goto out;
> + }
> +
> + if (nr_commands !=
> + be32_to_cpup((__be32 *)&buf.data[TPM_HEADER_SIZE + 5])) {
> + tpm_buf_destroy(&buf);
> + goto out;
> + }
> +
> + chip->nr_commands = nr_commands;
> +
> + attrs = (u32 *)&buf.data[TPM_HEADER_SIZE + 9];
> + for (i = 0; i < nr_commands; i++, attrs++)
> + chip->cc_attrs_tbl[i] = be32_to_cpup(attrs);
> +
> + tpm_buf_destroy(&buf);
> +
> out:
> if (rc > 0)
> rc = -ENODEV;
> return rc;
> }
> +
> +int tpm2_find_cc(struct tpm_chip *chip, u32 cc)
> +{
> + int i;
> +
> + for (i = 0; i < chip->nr_commands; i++)
> + if (cc == (chip->cc_attrs_tbl[i] & GENMASK(15, 0)))
> + return i;
> +
> + return -1;
> +}