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-rw-r--r--lib/tpm.c351
1 files changed, 350 insertions, 1 deletions
diff --git a/lib/tpm.c b/lib/tpm.c
index 42c9bea..f0b4f59 100644
--- a/lib/tpm.c
+++ b/lib/tpm.c
@@ -1,5 +1,6 @@
/*
* Copyright (c) 2013 The Chromium OS Authors.
+ * Coypright (c) 2013 Guntermann & Drunck GmbH
*
* See file CREDITS for list of people who contributed to this
* project.
@@ -22,6 +23,7 @@
#include <common.h>
#include <stdarg.h>
+#include <sha1.h>
#include <tpm.h>
#include <asm/unaligned.h>
@@ -35,8 +37,31 @@ enum {
TPM_REQUEST_HEADER_LENGTH = 10,
TPM_RESPONSE_HEADER_LENGTH = 10,
PCR_DIGEST_LENGTH = 20,
+ DIGEST_LENGTH = 20,
+ TPM_REQUEST_AUTH_LENGTH = 45,
+ TPM_RESPONSE_AUTH_LENGTH = 41,
+ /* some max lengths, valid for RSA keys <= 2048 bits */
+ TPM_KEY12_MAX_LENGTH = 618,
+ TPM_PUBKEY_MAX_LENGTH = 288,
};
+#ifdef CONFIG_TPM_AUTH_SESSIONS
+
+#ifndef CONFIG_SHA1
+#error "TPM_AUTH_SESSIONS require SHA1 to be configured, too"
+#endif /* !CONFIG_SHA1 */
+
+struct session_data {
+ int valid;
+ uint32_t handle;
+ uint8_t nonce_even[DIGEST_LENGTH];
+ uint8_t nonce_odd[DIGEST_LENGTH];
+};
+
+static struct session_data oiap_session = {0, };
+
+#endif /* CONFIG_TPM_AUTH_SESSIONS */
+
/**
* Pack data into a byte string. The data types are specified in
* the format string: 'b' means unsigned byte, 'w' unsigned word,
@@ -235,7 +260,7 @@ static uint32_t tpm_sendrecv_command(const void *command,
response, &response_length);
if (err)
return TPM_LIB_ERROR;
- if (response)
+ if (size_ptr)
*size_ptr = response_length;
return tpm_return_code(response);
@@ -579,3 +604,327 @@ uint32_t tpm_get_capability(uint32_t cap_area, uint32_t sub_cap,
return 0;
}
+
+#ifdef CONFIG_TPM_AUTH_SESSIONS
+
+/**
+ * Fill an authentication block in a request.
+ * This func can create the first as well as the second auth block (for
+ * double authorized commands).
+ *
+ * @param request pointer to the request (w/ uninitialised auth data)
+ * @param request_len0 length of the request without auth data
+ * @param handles_len length of the handles area in request
+ * @param auth_session pointer to the (valid) auth session to be used
+ * @param request_auth pointer to the auth block of the request to be filled
+ * @param auth authentication data (HMAC key)
+ */
+static uint32_t create_request_auth(const void *request, size_t request_len0,
+ size_t handles_len,
+ struct session_data *auth_session,
+ void *request_auth, const void *auth)
+{
+ uint8_t hmac_data[DIGEST_LENGTH * 3 + 1];
+ sha1_context hash_ctx;
+ const size_t command_code_offset = 6;
+ const size_t auth_nonce_odd_offset = 4;
+ const size_t auth_continue_offset = 24;
+ const size_t auth_auth_offset = 25;
+
+ if (!auth_session || !auth_session->valid)
+ return TPM_LIB_ERROR;
+
+ sha1_starts(&hash_ctx);
+ sha1_update(&hash_ctx, request + command_code_offset, 4);
+ if (request_len0 > TPM_REQUEST_HEADER_LENGTH + handles_len)
+ sha1_update(&hash_ctx,
+ request + TPM_REQUEST_HEADER_LENGTH + handles_len,
+ request_len0 - TPM_REQUEST_HEADER_LENGTH
+ - handles_len);
+ sha1_finish(&hash_ctx, hmac_data);
+
+ sha1_starts(&hash_ctx);
+ sha1_update(&hash_ctx, auth_session->nonce_odd, DIGEST_LENGTH);
+ sha1_update(&hash_ctx, hmac_data, sizeof(hmac_data));
+ sha1_finish(&hash_ctx, auth_session->nonce_odd);
+
+ if (pack_byte_string(request_auth, TPM_REQUEST_AUTH_LENGTH, "dsb",
+ 0, auth_session->handle,
+ auth_nonce_odd_offset, auth_session->nonce_odd,
+ DIGEST_LENGTH,
+ auth_continue_offset, 1))
+ return TPM_LIB_ERROR;
+ if (pack_byte_string(hmac_data, sizeof(hmac_data), "ss",
+ DIGEST_LENGTH,
+ auth_session->nonce_even,
+ DIGEST_LENGTH,
+ 2 * DIGEST_LENGTH,
+ request_auth + auth_nonce_odd_offset,
+ DIGEST_LENGTH + 1))
+ return TPM_LIB_ERROR;
+ sha1_hmac(auth, DIGEST_LENGTH, hmac_data, sizeof(hmac_data),
+ request_auth + auth_auth_offset);
+
+ return TPM_SUCCESS;
+}
+
+/**
+ * Verify an authentication block in a response.
+ * Since this func updates the nonce_even in the session data it has to be
+ * called when receiving a succesfull AUTH response.
+ * This func can verify the first as well as the second auth block (for
+ * double authorized commands).
+ *
+ * @param command_code command code of the request
+ * @param response pointer to the request (w/ uninitialised auth data)
+ * @param handles_len length of the handles area in response
+ * @param auth_session pointer to the (valid) auth session to be used
+ * @param response_auth pointer to the auth block of the response to be verified
+ * @param auth authentication data (HMAC key)
+ */
+static uint32_t verify_response_auth(uint32_t command_code,
+ const void *response, size_t response_len0,
+ size_t handles_len,
+ struct session_data *auth_session,
+ const void *response_auth, const void *auth)
+{
+ uint8_t hmac_data[DIGEST_LENGTH * 3 + 1];
+ uint8_t computed_auth[DIGEST_LENGTH];
+ sha1_context hash_ctx;
+ const size_t return_code_offset = 6;
+ const size_t auth_continue_offset = 20;
+ const size_t auth_auth_offset = 21;
+ uint8_t auth_continue;
+
+ if (!auth_session || !auth_session->valid)
+ return TPM_AUTHFAIL;
+ if (pack_byte_string(hmac_data, sizeof(hmac_data), "d",
+ 0, command_code))
+ return TPM_LIB_ERROR;
+ if (response_len0 < TPM_RESPONSE_HEADER_LENGTH)
+ return TPM_LIB_ERROR;
+
+ sha1_starts(&hash_ctx);
+ sha1_update(&hash_ctx, response + return_code_offset, 4);
+ sha1_update(&hash_ctx, hmac_data, 4);
+ if (response_len0 > TPM_RESPONSE_HEADER_LENGTH + handles_len)
+ sha1_update(&hash_ctx,
+ response + TPM_RESPONSE_HEADER_LENGTH + handles_len,
+ response_len0 - TPM_RESPONSE_HEADER_LENGTH
+ - handles_len);
+ sha1_finish(&hash_ctx, hmac_data);
+
+ memcpy(auth_session->nonce_even, response_auth, DIGEST_LENGTH);
+ auth_continue = ((uint8_t *)response_auth)[auth_continue_offset];
+ if (pack_byte_string(hmac_data, sizeof(hmac_data), "ssb",
+ DIGEST_LENGTH,
+ response_auth,
+ DIGEST_LENGTH,
+ 2 * DIGEST_LENGTH,
+ auth_session->nonce_odd,
+ DIGEST_LENGTH,
+ 3 * DIGEST_LENGTH,
+ auth_continue))
+ return TPM_LIB_ERROR;
+
+ sha1_hmac(auth, DIGEST_LENGTH, hmac_data, sizeof(hmac_data),
+ computed_auth);
+
+ if (memcmp(computed_auth, response_auth + auth_auth_offset,
+ DIGEST_LENGTH))
+ return TPM_AUTHFAIL;
+
+ return TPM_SUCCESS;
+}
+
+
+uint32_t tpm_terminate_auth_session(uint32_t auth_handle)
+{
+ const uint8_t command[18] = {
+ 0x00, 0xc1, /* TPM_TAG */
+ 0x00, 0x00, 0x00, 0x00, /* parameter size */
+ 0x00, 0x00, 0x00, 0xba, /* TPM_COMMAND_CODE */
+ 0x00, 0x00, 0x00, 0x00, /* TPM_HANDLE */
+ 0x00, 0x00, 0x00, 0x02, /* TPM_RESSOURCE_TYPE */
+ };
+ const size_t req_handle_offset = TPM_REQUEST_HEADER_LENGTH;
+ uint8_t request[COMMAND_BUFFER_SIZE];
+
+ if (pack_byte_string(request, sizeof(request), "sd",
+ 0, command, sizeof(command),
+ req_handle_offset, auth_handle))
+ return TPM_LIB_ERROR;
+ if (oiap_session.valid && oiap_session.handle == auth_handle)
+ oiap_session.valid = 0;
+
+ return tpm_sendrecv_command(request, NULL, NULL);
+}
+
+uint32_t tpm_end_oiap(void)
+{
+ uint32_t err = TPM_SUCCESS;
+ if (oiap_session.valid)
+ err = tpm_terminate_auth_session(oiap_session.handle);
+ return err;
+}
+
+uint32_t tpm_oiap(uint32_t *auth_handle)
+{
+ const uint8_t command[10] = {
+ 0x00, 0xc1, /* TPM_TAG */
+ 0x00, 0x00, 0x00, 0x0a, /* parameter size */
+ 0x00, 0x00, 0x00, 0x0a, /* TPM_COMMAND_CODE */
+ };
+ const size_t res_auth_handle_offset = TPM_RESPONSE_HEADER_LENGTH;
+ const size_t res_nonce_even_offset = TPM_RESPONSE_HEADER_LENGTH + 4;
+ uint8_t response[COMMAND_BUFFER_SIZE];
+ size_t response_length = sizeof(response);
+ uint32_t err;
+
+ if (oiap_session.valid)
+ tpm_terminate_auth_session(oiap_session.handle);
+
+ err = tpm_sendrecv_command(command, response, &response_length);
+ if (err)
+ return err;
+ if (unpack_byte_string(response, response_length, "ds",
+ res_auth_handle_offset, &oiap_session.handle,
+ res_nonce_even_offset, &oiap_session.nonce_even,
+ (uint32_t)DIGEST_LENGTH))
+ return TPM_LIB_ERROR;
+ oiap_session.valid = 1;
+ if (auth_handle)
+ *auth_handle = oiap_session.handle;
+ return 0;
+}
+
+uint32_t tpm_load_key2_oiap(uint32_t parent_handle,
+ const void *key, size_t key_length,
+ const void *parent_key_usage_auth,
+ uint32_t *key_handle)
+{
+ const uint8_t command[14] = {
+ 0x00, 0xc2, /* TPM_TAG */
+ 0x00, 0x00, 0x00, 0x00, /* parameter size */
+ 0x00, 0x00, 0x00, 0x41, /* TPM_COMMAND_CODE */
+ 0x00, 0x00, 0x00, 0x00, /* parent handle */
+ };
+ const size_t req_size_offset = 2;
+ const size_t req_parent_handle_offset = TPM_REQUEST_HEADER_LENGTH;
+ const size_t req_key_offset = TPM_REQUEST_HEADER_LENGTH + 4;
+ const size_t res_handle_offset = TPM_RESPONSE_HEADER_LENGTH;
+ uint8_t request[sizeof(command) + TPM_KEY12_MAX_LENGTH
+ + TPM_REQUEST_AUTH_LENGTH];
+ uint8_t response[COMMAND_BUFFER_SIZE];
+ size_t response_length = sizeof(response);
+ uint32_t err;
+
+ if (!oiap_session.valid) {
+ err = tpm_oiap(NULL);
+ if (err)
+ return err;
+ }
+ if (pack_byte_string(request, sizeof(request), "sdds",
+ 0, command, sizeof(command),
+ req_size_offset,
+ sizeof(command) + key_length
+ + TPM_REQUEST_AUTH_LENGTH,
+ req_parent_handle_offset, parent_handle,
+ req_key_offset, key, key_length
+ ))
+ return TPM_LIB_ERROR;
+
+ err = create_request_auth(request, sizeof(command) + key_length, 4,
+ &oiap_session,
+ request + sizeof(command) + key_length,
+ parent_key_usage_auth);
+ if (err)
+ return err;
+ err = tpm_sendrecv_command(request, response, &response_length);
+ if (err) {
+ if (err == TPM_AUTHFAIL)
+ oiap_session.valid = 0;
+ return err;
+ }
+
+ err = verify_response_auth(0x00000041, response,
+ response_length - TPM_RESPONSE_AUTH_LENGTH,
+ 4, &oiap_session,
+ response + response_length - TPM_RESPONSE_AUTH_LENGTH,
+ parent_key_usage_auth);
+ if (err)
+ return err;
+
+ if (key_handle) {
+ if (unpack_byte_string(response, response_length, "d",
+ res_handle_offset, key_handle))
+ return TPM_LIB_ERROR;
+ }
+
+ return 0;
+}
+
+uint32_t tpm_get_pub_key_oiap(uint32_t key_handle, const void *usage_auth,
+ void *pubkey, size_t *pubkey_len)
+{
+ const uint8_t command[14] = {
+ 0x00, 0xc2, /* TPM_TAG */
+ 0x00, 0x00, 0x00, 0x00, /* parameter size */
+ 0x00, 0x00, 0x00, 0x21, /* TPM_COMMAND_CODE */
+ 0x00, 0x00, 0x00, 0x00, /* key handle */
+ };
+ const size_t req_size_offset = 2;
+ const size_t req_key_handle_offset = TPM_REQUEST_HEADER_LENGTH;
+ const size_t res_pubkey_offset = TPM_RESPONSE_HEADER_LENGTH;
+ uint8_t request[sizeof(command) + TPM_REQUEST_AUTH_LENGTH];
+ uint8_t response[TPM_RESPONSE_HEADER_LENGTH + TPM_PUBKEY_MAX_LENGTH
+ + TPM_RESPONSE_AUTH_LENGTH];
+ size_t response_length = sizeof(response);
+ uint32_t err;
+
+ if (!oiap_session.valid) {
+ err = tpm_oiap(NULL);
+ if (err)
+ return err;
+ }
+ if (pack_byte_string(request, sizeof(request), "sdd",
+ 0, command, sizeof(command),
+ req_size_offset,
+ (uint32_t)(sizeof(command)
+ + TPM_REQUEST_AUTH_LENGTH),
+ req_key_handle_offset, key_handle
+ ))
+ return TPM_LIB_ERROR;
+ err = create_request_auth(request, sizeof(command), 4, &oiap_session,
+ request + sizeof(command), usage_auth);
+ if (err)
+ return err;
+ err = tpm_sendrecv_command(request, response, &response_length);
+ if (err) {
+ if (err == TPM_AUTHFAIL)
+ oiap_session.valid = 0;
+ return err;
+ }
+ err = verify_response_auth(0x00000021, response,
+ response_length - TPM_RESPONSE_AUTH_LENGTH,
+ 0, &oiap_session,
+ response + response_length - TPM_RESPONSE_AUTH_LENGTH,
+ usage_auth);
+ if (err)
+ return err;
+
+ if (pubkey) {
+ if ((response_length - TPM_RESPONSE_HEADER_LENGTH
+ - TPM_RESPONSE_AUTH_LENGTH) > *pubkey_len)
+ return TPM_LIB_ERROR;
+ *pubkey_len = response_length - TPM_RESPONSE_HEADER_LENGTH
+ - TPM_RESPONSE_AUTH_LENGTH;
+ memcpy(pubkey, response + res_pubkey_offset,
+ response_length - TPM_RESPONSE_HEADER_LENGTH
+ - TPM_RESPONSE_AUTH_LENGTH);
+ }
+
+ return 0;
+}
+
+#endif /* CONFIG_TPM_AUTH_SESSIONS */