tpm: seal/unseal for TPM 2.0
Added tpm_trusted_seal() and tpm_trusted_unseal() API for sealing
trusted keys.
This patch implements basic sealing and unsealing functionality for
TPM 2.0:
* Seal with a parent key using a 20 byte auth value.
* Unseal with a parent key using a 20 byte auth value.
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 011909a..bd7039f 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -1,5 +1,5 @@
/*
- * Copyright (C) 2014 Intel Corporation
+ * Copyright (C) 2014, 2015 Intel Corporation
*
* Authors:
* Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
@@ -16,6 +16,11 @@
*/
#include "tpm.h"
+#include <keys/trusted-type.h>
+
+enum tpm2_object_attributes {
+ TPM2_ATTR_USER_WITH_AUTH = BIT(6),
+};
struct tpm2_startup_in {
__be16 startup_type;
@@ -381,6 +386,249 @@
};
/**
+ * Append TPMS_AUTH_COMMAND to the buffer. The buffer must be allocated with
+ * tpm_buf_alloc().
+ *
+ * @param buf: an allocated tpm_buf instance
+ * @param nonce: the session nonce, may be NULL if not used
+ * @param nonce_len: the session nonce length, may be 0 if not used
+ * @param attributes: the session attributes
+ * @param hmac: the session HMAC or password, may be NULL if not used
+ * @param hmac_len: the session HMAC or password length, maybe 0 if not used
+ */
+static void tpm2_buf_append_auth(struct tpm_buf *buf, u32 session_handle,
+ const u8 *nonce, u16 nonce_len,
+ u8 attributes,
+ const u8 *hmac, u16 hmac_len)
+{
+ tpm_buf_append_u32(buf, 9 + nonce_len + hmac_len);
+ tpm_buf_append_u32(buf, session_handle);
+ tpm_buf_append_u16(buf, nonce_len);
+
+ if (nonce && nonce_len)
+ tpm_buf_append(buf, nonce, nonce_len);
+
+ tpm_buf_append_u8(buf, attributes);
+ tpm_buf_append_u16(buf, hmac_len);
+
+ if (hmac && hmac_len)
+ tpm_buf_append(buf, hmac, hmac_len);
+}
+
+/**
+ * tpm2_seal_trusted() - seal a trusted key
+ * @chip_num: A specific chip number for the request or TPM_ANY_NUM
+ * @options: authentication values and other options
+ * @payload: the key data in clear and encrypted form
+ *
+ * Returns < 0 on error and 0 on success.
+ */
+int tpm2_seal_trusted(struct tpm_chip *chip,
+ struct trusted_key_payload *payload,
+ struct trusted_key_options *options)
+{
+ unsigned int blob_len;
+ struct tpm_buf buf;
+ int rc;
+
+ rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_CREATE);
+ if (rc)
+ return rc;
+
+ tpm_buf_append_u32(&buf, options->keyhandle);
+ tpm2_buf_append_auth(&buf, TPM2_RS_PW,
+ NULL /* nonce */, 0,
+ 0 /* session_attributes */,
+ options->keyauth /* hmac */,
+ TPM_DIGEST_SIZE);
+
+ /* sensitive */
+ tpm_buf_append_u16(&buf, 4 + TPM_DIGEST_SIZE + payload->key_len);
+
+ tpm_buf_append_u16(&buf, TPM_DIGEST_SIZE);
+ tpm_buf_append(&buf, options->blobauth, TPM_DIGEST_SIZE);
+ tpm_buf_append_u16(&buf, payload->key_len);
+ tpm_buf_append(&buf, payload->key, payload->key_len);
+
+ /* public */
+ tpm_buf_append_u16(&buf, 14);
+
+ tpm_buf_append_u16(&buf, TPM2_ALG_KEYEDHASH);
+ tpm_buf_append_u16(&buf, TPM2_ALG_SHA256);
+ tpm_buf_append_u32(&buf, TPM2_ATTR_USER_WITH_AUTH);
+ tpm_buf_append_u16(&buf, 0); /* policy digest size */
+ tpm_buf_append_u16(&buf, TPM2_ALG_NULL);
+ tpm_buf_append_u16(&buf, 0);
+
+ /* outside info */
+ tpm_buf_append_u16(&buf, 0);
+
+ /* creation PCR */
+ tpm_buf_append_u32(&buf, 0);
+
+ if (buf.flags & TPM_BUF_OVERFLOW) {
+ rc = -E2BIG;
+ goto out;
+ }
+
+ rc = tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, "sealing data");
+ if (rc)
+ goto out;
+
+ blob_len = be32_to_cpup((__be32 *) &buf.data[TPM_HEADER_SIZE]);
+ if (blob_len > MAX_BLOB_SIZE) {
+ rc = -E2BIG;
+ goto out;
+ }
+
+ memcpy(payload->blob, &buf.data[TPM_HEADER_SIZE + 4], blob_len);
+ payload->blob_len = blob_len;
+
+out:
+ tpm_buf_destroy(&buf);
+
+ if (rc > 0)
+ rc = -EPERM;
+
+ return rc;
+}
+
+static int tpm2_load(struct tpm_chip *chip,
+ struct trusted_key_payload *payload,
+ struct trusted_key_options *options,
+ u32 *blob_handle)
+{
+ struct tpm_buf buf;
+ unsigned int private_len;
+ unsigned int public_len;
+ unsigned int blob_len;
+ int rc;
+
+ private_len = be16_to_cpup((__be16 *) &payload->blob[0]);
+ if (private_len > (payload->blob_len - 2))
+ return -E2BIG;
+
+ public_len = be16_to_cpup((__be16 *) &payload->blob[2 + private_len]);
+ blob_len = private_len + public_len + 4;
+ if (blob_len > payload->blob_len)
+ return -E2BIG;
+
+ rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_LOAD);
+ if (rc)
+ return rc;
+
+ tpm_buf_append_u32(&buf, options->keyhandle);
+ tpm2_buf_append_auth(&buf, TPM2_RS_PW,
+ NULL /* nonce */, 0,
+ 0 /* session_attributes */,
+ options->keyauth /* hmac */,
+ TPM_DIGEST_SIZE);
+
+ tpm_buf_append(&buf, payload->blob, blob_len);
+
+ if (buf.flags & TPM_BUF_OVERFLOW) {
+ rc = -E2BIG;
+ goto out;
+ }
+
+ rc = tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, "loading blob");
+ if (!rc)
+ *blob_handle = be32_to_cpup(
+ (__be32 *) &buf.data[TPM_HEADER_SIZE]);
+
+out:
+ tpm_buf_destroy(&buf);
+
+ if (rc > 0)
+ rc = -EPERM;
+
+ return rc;
+}
+
+static void tpm2_flush_context(struct tpm_chip *chip, u32 handle)
+{
+ struct tpm_buf buf;
+ int rc;
+
+ rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_FLUSH_CONTEXT);
+ if (rc) {
+ dev_warn(chip->pdev, "0x%08x was not flushed, out of memory\n",
+ handle);
+ return;
+ }
+
+ tpm_buf_append_u32(&buf, handle);
+
+ rc = tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, "flushing context");
+ if (rc)
+ dev_warn(chip->pdev, "0x%08x was not flushed, rc=%d\n", handle,
+ rc);
+
+ tpm_buf_destroy(&buf);
+}
+
+static int tpm2_unseal(struct tpm_chip *chip,
+ struct trusted_key_payload *payload,
+ struct trusted_key_options *options,
+ u32 blob_handle)
+{
+ struct tpm_buf buf;
+ int rc;
+
+ rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_UNSEAL);
+ if (rc)
+ return rc;
+
+ tpm_buf_append_u32(&buf, blob_handle);
+ tpm2_buf_append_auth(&buf, TPM2_RS_PW,
+ NULL /* nonce */, 0,
+ 0 /* session_attributes */,
+ options->blobauth /* hmac */,
+ TPM_DIGEST_SIZE);
+
+ rc = tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, "unsealing");
+ if (rc > 0)
+ rc = -EPERM;
+
+ if (!rc) {
+ payload->key_len = be16_to_cpup(
+ (__be16 *) &buf.data[TPM_HEADER_SIZE + 4]);
+
+ memcpy(payload->key, &buf.data[TPM_HEADER_SIZE + 6],
+ payload->key_len);
+ }
+
+ tpm_buf_destroy(&buf);
+ return rc;
+}
+
+/**
+ * tpm_unseal_trusted() - unseal a trusted key
+ * @chip_num: A specific chip number for the request or TPM_ANY_NUM
+ * @options: authentication values and other options
+ * @payload: the key data in clear and encrypted form
+ *
+ * Returns < 0 on error and 0 on success.
+ */
+int tpm2_unseal_trusted(struct tpm_chip *chip,
+ struct trusted_key_payload *payload,
+ struct trusted_key_options *options)
+{
+ u32 blob_handle;
+ int rc;
+
+ rc = tpm2_load(chip, payload, options, &blob_handle);
+ if (rc)
+ return rc;
+
+ rc = tpm2_unseal(chip, payload, options, blob_handle);
+
+ tpm2_flush_context(chip, blob_handle);
+
+ return rc;
+}
+
+/**
* tpm2_get_tpm_pt() - get value of a TPM_CAP_TPM_PROPERTIES type property
* @chip: TPM chip to use.
* @property_id: property ID.