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-rw-r--r--common/u2f.c77
1 files changed, 52 insertions, 25 deletions
diff --git a/common/u2f.c b/common/u2f.c
index eaeb38b08c..91cb4ab121 100644
--- a/common/u2f.c
+++ b/common/u2f.c
@@ -10,6 +10,7 @@
#include "cryptoc/sha256.h"
#include "dcrypto.h"
#include "extension.h"
+#include "fips_rand.h"
#include "system.h"
#include "u2f_impl.h"
#include "u2f.h"
@@ -127,8 +128,10 @@ static enum vendor_cmd_rc u2f_generate(enum vendor_cmd_cc code, void *buf,
struct u2f_key_handle kh;
struct u2f_versioned_key_handle vkh;
} kh_buf;
- size_t kh_size = (kh_version == 0) ? sizeof(kh_buf.kh) :
- sizeof(kh_buf.vkh);
+ size_t keypair_input_size =
+ (kh_version == 0) ?
+ sizeof(kh_buf.kh) :
+ sizeof(struct u2f_versioned_key_handle_header);
/* Whether key handle generation succeeded */
int generate_kh_rc;
@@ -168,13 +171,14 @@ static enum vendor_cmd_rc u2f_generate(enum vendor_cmd_cc code, void *buf,
else
generate_kh_rc = u2f_origin_user_versioned_keyhandle(
req->appId, req->userSecret, od_seed,
- kh_version, &kh_buf.vkh);
+ kh_version, &kh_buf.vkh.header);
if (generate_kh_rc != EC_SUCCESS)
return VENDOR_RC_INTERNAL_ERROR;
generate_keypair_rc = u2f_origin_user_keypair(
- (uint8_t *)&kh_buf, kh_size, &od, &opk_x, &opk_y);
+ (uint8_t *)&kh_buf, keypair_input_size, &od, &opk_x,
+ &opk_y);
} while (generate_keypair_rc == EC_ERROR_TRY_AGAIN);
if (generate_keypair_rc != EC_SUCCESS)
@@ -188,6 +192,17 @@ static enum vendor_cmd_rc u2f_generate(enum vendor_cmd_cc code, void *buf,
copy_kh_pubkey_out(&opk_x, &opk_y, &kh_buf.kh, buf);
*response_size = sizeof(struct u2f_generate_resp);
} else {
+ if (!fips_rand_bytes(kh_buf.vkh.authorization_salt,
+ U2F_AUTHORIZATION_SALT_SIZE))
+ return VENDOR_RC_INTERNAL_ERROR;
+
+ if (u2f_authorization_hmac(kh_buf.vkh.authorization_salt,
+ &kh_buf.vkh.header,
+ req->authTimeSecretHash,
+ kh_buf.vkh.authorization_hmac) !=
+ EC_SUCCESS)
+ return VENDOR_RC_INTERNAL_ERROR;
+
copy_versioned_kh_pubkey_out(&opk_x, &opk_y, &kh_buf.vkh, buf);
*response_size = sizeof(struct u2f_generate_versioned_resp);
}
@@ -242,14 +257,14 @@ static int verify_kh_owned(const uint8_t *user_secret, const uint8_t *app_id,
return rc;
}
-static int
-verify_versioned_kh_owned(const uint8_t *user_secret, const uint8_t *app_id,
- const struct u2f_versioned_key_handle *key_handle,
- int *owned)
+static int verify_versioned_kh_owned(
+ const uint8_t *user_secret, const uint8_t *app_id,
+ const struct u2f_versioned_key_handle_header *key_handle_header,
+ int *owned)
{
int rc;
/* Re-created key handle. */
- struct u2f_versioned_key_handle recreated_kh;
+ struct u2f_versioned_key_handle_header recreated_kh_header;
/*
* Re-create the key handle and compare against that which
@@ -258,13 +273,13 @@ verify_versioned_kh_owned(const uint8_t *user_secret, const uint8_t *app_id,
*/
rc = u2f_origin_user_versioned_keyhandle(app_id, user_secret,
- key_handle->origin_seed,
- key_handle->version,
- &recreated_kh);
+ key_handle_header->origin_seed,
+ key_handle_header->version,
+ &recreated_kh_header);
if (rc == EC_SUCCESS)
- *owned = safe_memcmp(&recreated_kh, key_handle,
- sizeof(recreated_kh)) == 0;
+ *owned = safe_memcmp(&recreated_kh_header, key_handle_header,
+ sizeof(recreated_kh_header)) == 0;
return rc;
}
@@ -321,8 +336,8 @@ static enum vendor_cmd_rc u2f_sign(enum vendor_cmd_cc code, void *buf,
/* Version of KH; 0 if KH is not versioned. */
uint8_t version;
- /* Size of KH in bytes. */
- size_t kh_size;
+ /* Size of the part of KH used to derive keypair, in bytes. */
+ size_t keypair_input_size;
int verify_owned_rc;
@@ -334,18 +349,19 @@ static enum vendor_cmd_rc u2f_sign(enum vendor_cmd_cc code, void *buf,
key_handle = (uint8_t *)&req->keyHandle;
hash = req->hash;
flags = req->flags;
- kh_size = sizeof(struct u2f_key_handle);
+ keypair_input_size = sizeof(struct u2f_key_handle);
verify_owned_rc = verify_kh_owned(req->userSecret, req->appId,
&req->keyHandle, &kh_owned);
} else if (input_size == sizeof(struct u2f_sign_versioned_req)) {
- version = req_versioned->keyHandle.version;
+ version = req_versioned->keyHandle.header.version;
key_handle = (uint8_t *)&req_versioned->keyHandle;
hash = req_versioned->hash;
flags = req_versioned->flags;
- kh_size = sizeof(struct u2f_versioned_key_handle);
+ keypair_input_size =
+ sizeof(struct u2f_versioned_key_handle_header);
verify_owned_rc = verify_versioned_kh_owned(
req_versioned->userSecret, req_versioned->appId,
- &req_versioned->keyHandle, &kh_owned);
+ &req_versioned->keyHandle.header, &kh_owned);
} else {
return VENDOR_RC_BOGUS_ARGS;
}
@@ -378,17 +394,28 @@ static enum vendor_cmd_rc u2f_sign(enum vendor_cmd_cc code, void *buf,
if ((flags & U2F_AUTH_CHECK_ONLY) == U2F_AUTH_CHECK_ONLY)
return VENDOR_RC_SUCCESS;
- /* Always enforce user presence, with optional consume. */
- if (pop_check_presence(flags & G2F_CONSUME) != POP_TOUCH_YES)
- return VENDOR_RC_NOT_ALLOWED;
+ /*
+ * Enforce user presence for version 0 KHs, with optional consume.
+ */
+ if (pop_check_presence(flags & G2F_CONSUME) != POP_TOUCH_YES) {
+ if (version != U2F_KH_VERSION_1)
+ return VENDOR_RC_NOT_ALLOWED;
+ if ((flags & U2F_AUTH_FLAG_TUP) != 0)
+ return VENDOR_RC_NOT_ALLOWED;
+ /*
+ * TODO(yichengli): When auth-time secrets is ready, enforce
+ * authorization hmac when no power button press.
+ */
+ }
/* Re-create origin-specific key. */
if (legacy_kh) {
if (u2f_origin_key(legacy_origin_seed, &origin_d) != EC_SUCCESS)
return VENDOR_RC_INTERNAL_ERROR;
} else {
- if (u2f_origin_user_keypair(key_handle, kh_size, &origin_d,
- NULL, NULL) != EC_SUCCESS)
+ if (u2f_origin_user_keypair(key_handle, keypair_input_size,
+ &origin_d, NULL,
+ NULL) != EC_SUCCESS)
return VENDOR_RC_INTERNAL_ERROR;
}