Map QCRYPTO_CIPHER_MODE_GCM to GCRY_CIPHER_MODE_GCM and advertise it in qcrypto_cipher_supports() for 128-bit block ciphers. Add a GCM driver whose setiv accepts the (typically 96-bit) nonce, whose encrypt/decrypt do not require block-aligned lengths, and which implements setaad via gcry_cipher_authenticate() and gettag via gcry_cipher_gettag().
Signed-off-by: Jamin Lin <[email protected]> Reviewed-by: Daniel P. Berrangé <[email protected]> Acked-by: Daniel P. Berrangé <[email protected]> --- crypto/cipher-gcrypt.c.inc | 101 +++++++++++++++++++++++++++++++++++++ 1 file changed, 101 insertions(+) diff --git a/crypto/cipher-gcrypt.c.inc b/crypto/cipher-gcrypt.c.inc index 12eb9ddb5a..fce09a3c77 100644 --- a/crypto/cipher-gcrypt.c.inc +++ b/crypto/cipher-gcrypt.c.inc @@ -65,6 +65,8 @@ static int qcrypto_cipher_mode_to_gcry_mode(QCryptoCipherMode mode) return GCRY_CIPHER_MODE_CBC; case QCRYPTO_CIPHER_MODE_CTR: return GCRY_CIPHER_MODE_CTR; + case QCRYPTO_CIPHER_MODE_GCM: + return GCRY_CIPHER_MODE_GCM; default: return GCRY_CIPHER_MODE_NONE; } @@ -104,6 +106,10 @@ bool qcrypto_cipher_supports(QCryptoCipherAlgo alg, case QCRYPTO_CIPHER_MODE_XTS: case QCRYPTO_CIPHER_MODE_CTR: return true; + case QCRYPTO_CIPHER_MODE_GCM: + /* GCM requires a 128-bit block cipher. */ + return gcry_cipher_get_algo_blklen( + qcrypto_cipher_alg_to_gcry_alg(alg)) == 16; default: return false; } @@ -228,6 +234,99 @@ static const struct QCryptoCipherDriver qcrypto_gcrypt_ctr_driver = { .cipher_free = qcrypto_gcrypt_ctx_free, }; +/* + * GCM is an AEAD stream mode: the IV/nonce need not match the block size, + * the message length need not be a multiple of the block size, associated + * data is fed with gcry_cipher_authenticate() and the authentication tag is + * read back with gcry_cipher_gettag(). + */ +static int qcrypto_gcrypt_gcm_setiv(QCryptoCipher *cipher, + const uint8_t *iv, size_t niv, + Error **errp) +{ + QCryptoCipherGcrypt *ctx = container_of(cipher, QCryptoCipherGcrypt, base); + gcry_error_t err; + + gcry_cipher_reset(ctx->handle); + err = gcry_cipher_setiv(ctx->handle, iv, niv); + if (err != 0) { + error_setg(errp, "Cannot set IV: %s", gcry_strerror(err)); + return -1; + } + + return 0; +} + +static int qcrypto_gcrypt_gcm_setaad(QCryptoCipher *cipher, + const uint8_t *aad, size_t len, + Error **errp) +{ + QCryptoCipherGcrypt *ctx = container_of(cipher, QCryptoCipherGcrypt, base); + gcry_error_t err; + + err = gcry_cipher_authenticate(ctx->handle, aad, len); + if (err != 0) { + error_setg(errp, "Cannot set AAD: %s", gcry_strerror(err)); + return -1; + } + + return 0; +} + +static int qcrypto_gcrypt_gcm_encrypt(QCryptoCipher *cipher, const void *in, + void *out, size_t len, Error **errp) +{ + QCryptoCipherGcrypt *ctx = container_of(cipher, QCryptoCipherGcrypt, base); + gcry_error_t err; + + err = gcry_cipher_encrypt(ctx->handle, out, len, in, len); + if (err != 0) { + error_setg(errp, "Cannot encrypt data: %s", gcry_strerror(err)); + return -1; + } + + return 0; +} + +static int qcrypto_gcrypt_gcm_decrypt(QCryptoCipher *cipher, const void *in, + void *out, size_t len, Error **errp) +{ + QCryptoCipherGcrypt *ctx = container_of(cipher, QCryptoCipherGcrypt, base); + gcry_error_t err; + + err = gcry_cipher_decrypt(ctx->handle, out, len, in, len); + if (err != 0) { + error_setg(errp, "Cannot decrypt data: %s", gcry_strerror(err)); + return -1; + } + + return 0; +} + +static int qcrypto_gcrypt_gcm_gettag(QCryptoCipher *cipher, + uint8_t *tag, size_t len, Error **errp) +{ + QCryptoCipherGcrypt *ctx = container_of(cipher, QCryptoCipherGcrypt, base); + gcry_error_t err; + + err = gcry_cipher_gettag(ctx->handle, tag, len); + if (err != 0) { + error_setg(errp, "Cannot get tag: %s", gcry_strerror(err)); + return -1; + } + + return 0; +} + +static const struct QCryptoCipherDriver qcrypto_gcrypt_gcm_driver = { + .cipher_encrypt = qcrypto_gcrypt_gcm_encrypt, + .cipher_decrypt = qcrypto_gcrypt_gcm_decrypt, + .cipher_setiv = qcrypto_gcrypt_gcm_setiv, + .cipher_setaad = qcrypto_gcrypt_gcm_setaad, + .cipher_gettag = qcrypto_gcrypt_gcm_gettag, + .cipher_free = qcrypto_gcrypt_ctx_free, +}; + static QCryptoCipher *qcrypto_cipher_ctx_new(QCryptoCipherAlgo alg, QCryptoCipherMode mode, const uint8_t *key, @@ -259,6 +358,8 @@ static QCryptoCipher *qcrypto_cipher_ctx_new(QCryptoCipherAlgo alg, if (mode == QCRYPTO_CIPHER_MODE_CTR) { drv = &qcrypto_gcrypt_ctr_driver; + } else if (mode == QCRYPTO_CIPHER_MODE_GCM) { + drv = &qcrypto_gcrypt_gcm_driver; } else { drv = &qcrypto_gcrypt_driver; } -- 2.43.0
