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

[Stefan Berger]

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;
+}