diff options
Diffstat (limited to 'include/u2f.h')
| -rw-r--r-- | include/u2f.h | 76 |
1 files changed, 67 insertions, 9 deletions
diff --git a/include/u2f.h b/include/u2f.h index 6680ef5300..f24eac84a4 100644 --- a/include/u2f.h +++ b/include/u2f.h @@ -5,6 +5,14 @@ #ifndef __U2F_H_INCLUDED__ #define __U2F_H_INCLUDED__ +/** + * Note: This header file should be self-sufficient as it is shared + * with other boards and with userland daemons (u2fd). + * + * chromeos-ec-headers package installs it in ChromeOS development environment. + * + */ + #ifdef _MSC_VER /* Windows */ typedef unsigned char uint8_t; typedef unsigned short uint16_t; @@ -20,7 +28,7 @@ extern "C" { /* General constants */ -#define U2F_EC_KEY_SIZE 32 /* EC key size in bytes */ +#define U2F_EC_KEY_SIZE 32 /* EC key size in bytes, NIST P-256 Curve */ #define U2F_EC_POINT_SIZE ((U2F_EC_KEY_SIZE * 2) + 1) /* Size of EC point */ #define U2F_MAX_KH_SIZE 128 /* Max size of key handle */ #define U2F_MAX_ATT_CERT_SIZE 2048 /* Max size of attestation certificate */ @@ -30,8 +38,15 @@ extern "C" { #define U2F_CHAL_SIZE 32 /* Size of challenge */ #define U2F_MAX_ATTEST_SIZE 256 /* Size of largest blob to sign */ #define U2F_P256_SIZE 32 +/* Origin seed is a random nonce generated during key handle creation. */ +#define U2F_ORIGIN_SEED_SIZE 32 +#define U2F_USER_SECRET_SIZE 32 /* Size of user secret */ + +#define U2F_AUTH_TIME_SECRET_SIZE 32 #define SHA256_DIGEST_SIZE 32 +#define U2F_MESSAGE_DIGEST_SIZE SHA256_DIGEST_SIZE + #define ENC_SIZE(x) ((x + 7) & 0xfff8) @@ -56,15 +71,29 @@ struct u2f_ec_point { #define U2F_KH_VERSION_1 0x01 #define U2F_AUTHORIZATION_SALT_SIZE 16 +#define U2F_V0_KH_SIZE 64 + +/** + * Key handle version = 1 for WebAuthn, bound to device and user. + */ +#define U2F_V1_KH_SIZE 113 + +/* Header is composed of version || origin_seed || kh_hmac */ +#define U2F_V1_KH_HEADER_SIZE (U2F_ORIGIN_SEED_SIZE + SHA256_DIGEST_SIZE + 1) + +struct u2f_signature { + uint8_t sig_r[U2F_EC_KEY_SIZE]; /* Signature */ + uint8_t sig_s[U2F_EC_KEY_SIZE]; /* Signature */ +}; struct u2f_key_handle { - uint8_t origin_seed[U2F_P256_SIZE]; + uint8_t origin_seed[U2F_ORIGIN_SEED_SIZE]; uint8_t hmac[SHA256_DIGEST_SIZE]; }; struct u2f_versioned_key_handle_header { uint8_t version; - uint8_t origin_seed[U2F_P256_SIZE]; + uint8_t origin_seed[U2F_ORIGIN_SEED_SIZE]; uint8_t kh_hmac[SHA256_DIGEST_SIZE]; }; @@ -75,17 +104,46 @@ struct u2f_versioned_key_handle { uint8_t authorization_hmac[SHA256_DIGEST_SIZE]; }; +/** + * Alternative definitions of key handles. + * + * struct u2f_key_handle_v0 == struct u2f_key_handle + * struct u2f_key_handle_v1 == struct u2f_versioned_key_handle + * + */ + +/* Key handle version = 0, only bound to device. */ +struct u2f_key_handle_v0 { + uint8_t origin_seed[U2F_ORIGIN_SEED_SIZE]; + uint8_t hmac[SHA256_DIGEST_SIZE]; +}; + +/* Key handle version = 1, bound to device and user. */ +struct u2f_key_handle_v1 { + uint8_t version; + uint8_t origin_seed[U2F_ORIGIN_SEED_SIZE]; + uint8_t kh_hmac[SHA256_DIGEST_SIZE]; + /* Optionally checked in u2f_sign. */ + uint8_t authorization_salt[U2F_AUTHORIZATION_SALT_SIZE]; + uint8_t authorization_hmac[SHA256_DIGEST_SIZE]; +}; + +union u2f_key_handle_variant { + struct u2f_key_handle_v0 v0; + struct u2f_key_handle_v1 v1; +}; + /* TODO(louiscollard): Add Descriptions. */ struct u2f_generate_req { uint8_t appId[U2F_APPID_SIZE]; /* Application id */ - uint8_t userSecret[U2F_P256_SIZE]; + uint8_t userSecret[U2F_USER_SECRET_SIZE]; uint8_t flags; /* * If generating versioned KH, derive an hmac from it and append to * the key handle. Otherwise unused. */ - uint8_t authTimeSecretHash[SHA256_DIGEST_SIZE]; + uint8_t authTimeSecretHash[U2F_AUTH_TIME_SECRET_SIZE]; }; struct u2f_generate_resp { @@ -100,7 +158,7 @@ struct u2f_generate_versioned_resp { struct u2f_sign_req { uint8_t appId[U2F_APPID_SIZE]; /* Application id */ - uint8_t userSecret[U2F_P256_SIZE]; + uint8_t userSecret[U2F_USER_SECRET_SIZE]; struct u2f_key_handle keyHandle; uint8_t hash[U2F_P256_SIZE]; uint8_t flags; @@ -108,8 +166,8 @@ struct u2f_sign_req { struct u2f_sign_versioned_req { uint8_t appId[U2F_APPID_SIZE]; /* Application id */ - uint8_t userSecret[U2F_P256_SIZE]; - uint8_t authTimeSecret[U2F_P256_SIZE]; + uint8_t userSecret[U2F_USER_SECRET_SIZE]; + uint8_t authTimeSecret[U2F_AUTH_TIME_SECRET_SIZE]; uint8_t hash[U2F_P256_SIZE]; uint8_t flags; struct u2f_versioned_key_handle keyHandle; @@ -121,7 +179,7 @@ struct u2f_sign_resp { }; struct u2f_attest_req { - uint8_t userSecret[U2F_P256_SIZE]; + uint8_t userSecret[U2F_USER_SECRET_SIZE]; uint8_t format; uint8_t dataLen; uint8_t data[U2F_MAX_ATTEST_SIZE]; |