Merge pull request #83 from gilles-peskine-arm/psa-api-1.0-beta-beta2_minor_fixes
API: minor corrections after beta 2; specify psa_generator_import_key for most key types
diff --git a/include/psa/crypto.h b/include/psa/crypto.h
index e7d0ecd..bdbbc1f 100644
--- a/include/psa/crypto.h
+++ b/include/psa/crypto.h
@@ -792,12 +792,12 @@
* \retval #PSA_SUCCESS
* \retval #PSA_ERROR_INVALID_HANDLE
* \retval #PSA_ERROR_OCCUPIED_SLOT
- * \p target already contains key material.
+ * \p target_handle already contains key material.
* \retval #PSA_ERROR_EMPTY_SLOT
- * \p source does not contain key material.
+ * \p source_handle does not contain key material.
* \retval #PSA_ERROR_INVALID_ARGUMENT
* The policy constraints on the source, on the target and
- * \p constraints are incompatible.
+ * \p constraint are incompatible.
* \retval #PSA_ERROR_NOT_PERMITTED
* The source key is not exportable and its lifetime does not
* allow copying it to the target's lifetime.
@@ -1152,7 +1152,7 @@
* \retval #PSA_ERROR_EMPTY_SLOT
* \retval #PSA_ERROR_NOT_PERMITTED
* \retval #PSA_ERROR_INVALID_ARGUMENT
- * \p key is not compatible with \p alg.
+ * \p handle is not compatible with \p alg.
* \retval #PSA_ERROR_NOT_SUPPORTED
* \p alg is not supported or is not a MAC algorithm.
* \retval #PSA_ERROR_INSUFFICIENT_MEMORY
@@ -1191,7 +1191,7 @@
* \retval #PSA_ERROR_EMPTY_SLOT
* \retval #PSA_ERROR_NOT_PERMITTED
* \retval #PSA_ERROR_INVALID_ARGUMENT
- * \p key is not compatible with \p alg.
+ * \p handle is not compatible with \p alg.
* \retval #PSA_ERROR_NOT_SUPPORTED
* \p alg is not supported or is not a MAC algorithm.
* \retval #PSA_ERROR_INSUFFICIENT_MEMORY
@@ -1294,7 +1294,7 @@
* \retval #PSA_ERROR_EMPTY_SLOT
* \retval #PSA_ERROR_NOT_PERMITTED
* \retval #PSA_ERROR_INVALID_ARGUMENT
- * \p key is not compatible with \p alg.
+ * \p handle is not compatible with \p alg.
* \retval #PSA_ERROR_NOT_SUPPORTED
* \p alg is not supported or is not a MAC algorithm.
* \retval #PSA_ERROR_INSUFFICIENT_MEMORY
@@ -1532,7 +1532,7 @@
* \retval #PSA_ERROR_EMPTY_SLOT
* \retval #PSA_ERROR_NOT_PERMITTED
* \retval #PSA_ERROR_INVALID_ARGUMENT
- * \p key is not compatible with \p alg.
+ * \p handle is not compatible with \p alg.
* \retval #PSA_ERROR_NOT_SUPPORTED
* \p alg is not supported or is not a cipher algorithm.
* \retval #PSA_ERROR_BUFFER_TOO_SMALL
@@ -1574,7 +1574,7 @@
* \retval #PSA_ERROR_EMPTY_SLOT
* \retval #PSA_ERROR_NOT_PERMITTED
* \retval #PSA_ERROR_INVALID_ARGUMENT
- * \p key is not compatible with \p alg.
+ * \p handle is not compatible with \p alg.
* \retval #PSA_ERROR_NOT_SUPPORTED
* \p alg is not supported or is not a cipher algorithm.
* \retval #PSA_ERROR_BUFFER_TOO_SMALL
@@ -1680,7 +1680,7 @@
* \retval #PSA_ERROR_EMPTY_SLOT
* \retval #PSA_ERROR_NOT_PERMITTED
* \retval #PSA_ERROR_INVALID_ARGUMENT
- * \p key is not compatible with \p alg.
+ * \p handle is not compatible with \p alg.
* \retval #PSA_ERROR_NOT_SUPPORTED
* \p alg is not supported or is not a cipher algorithm.
* \retval #PSA_ERROR_INSUFFICIENT_MEMORY
@@ -1739,7 +1739,7 @@
* \retval #PSA_ERROR_EMPTY_SLOT
* \retval #PSA_ERROR_NOT_PERMITTED
* \retval #PSA_ERROR_INVALID_ARGUMENT
- * \p key is not compatible with \p alg.
+ * \p handle is not compatible with \p alg.
* \retval #PSA_ERROR_NOT_SUPPORTED
* \p alg is not supported or is not a cipher algorithm.
* \retval #PSA_ERROR_INSUFFICIENT_MEMORY
@@ -1967,7 +1967,7 @@
* \retval #PSA_ERROR_EMPTY_SLOT
* \retval #PSA_ERROR_NOT_PERMITTED
* \retval #PSA_ERROR_INVALID_ARGUMENT
- * \p key is not compatible with \p alg.
+ * \p handle is not compatible with \p alg.
* \retval #PSA_ERROR_NOT_SUPPORTED
* \p alg is not supported or is not an AEAD algorithm.
* \retval #PSA_ERROR_INSUFFICIENT_MEMORY
@@ -2025,7 +2025,7 @@
* The ciphertext is not authentic.
* \retval #PSA_ERROR_NOT_PERMITTED
* \retval #PSA_ERROR_INVALID_ARGUMENT
- * \p key is not compatible with \p alg.
+ * \p handle is not compatible with \p alg.
* \retval #PSA_ERROR_NOT_SUPPORTED
* \p alg is not supported or is not an AEAD algorithm.
* \retval #PSA_ERROR_INSUFFICIENT_MEMORY
@@ -2144,7 +2144,7 @@
* \retval #PSA_ERROR_EMPTY_SLOT
* \retval #PSA_ERROR_NOT_PERMITTED
* \retval #PSA_ERROR_INVALID_ARGUMENT
- * \p key is not compatible with \p alg.
+ * \p handle is not compatible with \p alg.
* \retval #PSA_ERROR_NOT_SUPPORTED
* \p alg is not supported or is not an AEAD algorithm.
* \retval #PSA_ERROR_INSUFFICIENT_MEMORY
@@ -2206,7 +2206,7 @@
* \retval #PSA_ERROR_EMPTY_SLOT
* \retval #PSA_ERROR_NOT_PERMITTED
* \retval #PSA_ERROR_INVALID_ARGUMENT
- * \p key is not compatible with \p alg.
+ * \p handle is not compatible with \p alg.
* \retval #PSA_ERROR_NOT_SUPPORTED
* \p alg is not supported or is not an AEAD algorithm.
* \retval #PSA_ERROR_INSUFFICIENT_MEMORY
@@ -2444,7 +2444,7 @@
* psa_aead_update() does not buffer any output and therefore \p ciphertext
* will not contain any output and can be a 0-sized buffer.
* - \p tag contains the authentication tag. Its length is always
- * #PSA_AEAD_TAG_LENGTH(\p alg) where \p alg is the AEAD algorithm
+ * #PSA_AEAD_TAG_LENGTH(\c alg) where \c alg is the AEAD algorithm
* that the operation performs.
*
* When this function returns, the operation becomes inactive.
@@ -2467,7 +2467,7 @@
* The operation state is not valid (not set up, nonce not set,
* decryption, or already completed).
* \retval #PSA_ERROR_BUFFER_TOO_SMALL
- * The size of the \p output buffer is too small.
+ * The size of the \p ciphertext or \p tag buffer is too small.
* \retval #PSA_ERROR_INVALID_ARGUMENT
* The total length of input to psa_aead_update_ad() so far is
* less than the additional data length that was previously
@@ -2509,8 +2509,6 @@
* \retval #PSA_ERROR_BAD_STATE
* The operation state is not valid (not set up, nonce not set,
* encryption, or already completed).
- * \retval #PSA_ERROR_BUFFER_TOO_SMALL
- * The size of the \p output buffer is too small.
* \retval #PSA_ERROR_INVALID_ARGUMENT
* The total length of input to psa_aead_update_ad() so far is
* less than the additional data length that was previously
@@ -2576,7 +2574,7 @@
* \param handle Handle to the key to use for the operation.
* It must be an asymmetric key pair.
* \param alg A signature algorithm that is compatible with
- * the type of \p key.
+ * the type of \p handle.
* \param[in] hash The hash or message to sign.
* \param hash_length Size of the \p hash buffer in bytes.
* \param[out] signature Buffer where the signature is to be written.
@@ -2590,7 +2588,7 @@
* determine a sufficient buffer size by calling
* #PSA_ASYMMETRIC_SIGN_OUTPUT_SIZE(\c key_type, \c key_bits, \p alg)
* where \c key_type and \c key_bits are the type and bit-size
- * respectively of \p key.
+ * respectively of \p handle.
* \retval #PSA_ERROR_NOT_SUPPORTED
* \retval #PSA_ERROR_INVALID_ARGUMENT
* \retval #PSA_ERROR_INSUFFICIENT_MEMORY
@@ -2623,7 +2621,7 @@
* \param handle Handle to the key to use for the operation.
* It must be a public key or an asymmetric key pair.
* \param alg A signature algorithm that is compatible with
- * the type of \p key.
+ * the type of \p handle.
* \param[in] hash The hash or message whose signature is to be
* verified.
* \param hash_length Size of the \p hash buffer in bytes.
@@ -2660,7 +2658,7 @@
* It must be a public key or an asymmetric
* key pair.
* \param alg An asymmetric encryption algorithm that is
- * compatible with the type of \p key.
+ * compatible with the type of \p handle.
* \param[in] input The message to encrypt.
* \param input_length Size of the \p input buffer in bytes.
* \param[in] salt A salt or label, if supported by the
@@ -2687,7 +2685,7 @@
* determine a sufficient buffer size by calling
* #PSA_ASYMMETRIC_ENCRYPT_OUTPUT_SIZE(\c key_type, \c key_bits, \p alg)
* where \c key_type and \c key_bits are the type and bit-size
- * respectively of \p key.
+ * respectively of \p handle.
* \retval #PSA_ERROR_NOT_SUPPORTED
* \retval #PSA_ERROR_INVALID_ARGUMENT
* \retval #PSA_ERROR_INSUFFICIENT_MEMORY
@@ -2716,7 +2714,7 @@
* \param handle Handle to the key to use for the operation.
* It must be an asymmetric key pair.
* \param alg An asymmetric encryption algorithm that is
- * compatible with the type of \p key.
+ * compatible with the type of \p handle.
* \param[in] input The message to decrypt.
* \param input_length Size of the \p input buffer in bytes.
* \param[in] salt A salt or label, if supported by the
@@ -2743,7 +2741,7 @@
* determine a sufficient buffer size by calling
* #PSA_ASYMMETRIC_DECRYPT_OUTPUT_SIZE(\c key_type, \c key_bits, \p alg)
* where \c key_type and \c key_bits are the type and bit-size
- * respectively of \p key.
+ * respectively of \p handle.
* \retval #PSA_ERROR_NOT_SUPPORTED
* \retval #PSA_ERROR_INVALID_ARGUMENT
* \retval #PSA_ERROR_INSUFFICIENT_MEMORY
@@ -2880,24 +2878,89 @@
uint8_t *output,
size_t output_length);
-/** Create a symmetric key from data read from a generator.
+/** Generate a key deterministically from data read from a generator.
*
- * This function reads a sequence of bytes from a generator and imports
- * these bytes as a key.
- * The data that is read is discarded from the generator. The generator's
- * capacity is decreased by the number of bytes read.
+ * This function uses the output of a generator to derive a key.
+ * How much output it consumes and how the key is derived depends on the
+ * key type.
*
- * This function is equivalent to calling #psa_generator_read and
- * passing the resulting output to #psa_import_key, but
- * if the implementation provides an isolation boundary then
- * the key material is not exposed outside the isolation boundary.
+ * - For key types for which the key is an arbitrary sequence of bytes
+ * of a given size,
+ * this function is functionally equivalent to calling #psa_generator_read
+ * and passing the resulting output to #psa_import_key.
+ * However, this function has a security benefit:
+ * if the implementation provides an isolation boundary then
+ * the key material is not exposed outside the isolation boundary.
+ * As a consequence, for these key types, this function always consumes
+ * exactly (\p bits / 8) bytes from the generator.
+ * The following key types defined in this specification follow this scheme:
+ *
+ * - #PSA_KEY_TYPE_AES;
+ * - #PSA_KEY_TYPE_ARC4;
+ * - #PSA_KEY_TYPE_CAMELLIA;
+ * - #PSA_KEY_TYPE_DERIVE;
+ * - #PSA_KEY_TYPE_HMAC.
+ *
+ * - For ECC keys on a Montgomery elliptic curve
+ * (#PSA_KEY_TYPE_ECC_KEYPAIR(\c curve) where \c curve designates a
+ * Montgomery curve), this function always draws a byte string whose
+ * length is determined by the curve, and sets the mandatory bits
+ * accordingly. That is:
+ *
+ * - #PSA_ECC_CURVE_CURVE25519: draw a 32-byte string
+ * and process it as specified in RFC 7748 §5.
+ * - #PSA_ECC_CURVE_CURVE448: draw a 56-byte string
+ * and process it as specified in RFC 7748 §5.
+ *
+ * - For key types for which the key is represented by a single sequence of
+ * \p bits bits with constraints as to which bit sequences are acceptable,
+ * this function draws a byte string of length (\p bits / 8) bytes rounded
+ * up to the nearest whole number of bytes. If the resulting byte string
+ * is acceptable, it becomes the key, otherwise the drawn bytes are discarded.
+ * This process is repeated until an acceptable byte string is drawn.
+ * The byte string drawn from the generator is interpreted as specified
+ * for the output produced by psa_export_key().
+ * The following key types defined in this specification follow this scheme:
+ *
+ * - #PSA_KEY_TYPE_DES.
+ * Force-set the parity bits, but discard forbidden weak keys.
+ * For 2-key and 3-key triple-DES, the three keys are generated
+ * successively (for example, for 3-key triple-DES,
+ * if the first 8 bytes specify a weak key and the next 8 bytes do not,
+ * discard the first 8 bytes, use the next 8 bytes as the first key,
+ * and continue reading output from the generator to derive the other
+ * two keys).
+ * - Finite-field Diffie-Hellman keys (#PSA_KEY_TYPE_DH_KEYPAIR),
+ * DSA keys (#PSA_KEY_TYPE_DSA_KEYPAIR), and
+ * ECC keys on a Weierstrass elliptic curve
+ * (#PSA_KEY_TYPE_ECC_KEYPAIR(\c curve) where \c curve designates a
+ * Weierstrass curve).
+ * For these key types, interpret the byte string as integer
+ * in big-endian order. Discard it if it is not in the range
+ * [0, *N* - 2] where *N* is the boundary of the private key domain
+ * (the prime *p* for Diffie-Hellman, the subprime *q* for DSA,
+ * or the order of the curve's base point for ECC).
+ * Add 1 to the resulting integer and use this as the private key *x*.
+ * This method allows compliance to NIST standards, specifically
+ * the methods titled "key-pair generation by testing candidates"
+ * in NIST SP 800-56A §5.6.1.1.4 for Diffie-Hellman,
+ * in FIPS 186-4 §B.1.2 for DSA, and
+ * in NIST SP 800-56A §5.6.1.2.2 or
+ * FIPS 186-4 §B.4.2 for elliptic curve keys.
+ *
+ * - For other key types, including #PSA_KEY_TYPE_RSA_KEYPAIR,
+ * the way in which the generator output is consumed is
+ * implementation-defined.
+ *
+ * In all cases, the data that is read is discarded from the generator.
+ * The generator's capacity is decreased by the number of bytes read.
*
* \param handle Handle to the slot where the key will be stored.
* It must have been obtained by calling
* psa_allocate_key() or psa_create_key() and must
* not contain key material yet.
* \param type Key type (a \c PSA_KEY_TYPE_XXX value).
- * This must be a symmetric key type.
+ * This must be a secret key type or a key pair type.
* \param bits Key size in bits.
* \param[in,out] generator The generator object to read from.
*
@@ -2906,12 +2969,10 @@
* If the key is persistent, the key material and the key's metadata
* have been saved to persistent storage.
* \retval #PSA_ERROR_INSUFFICIENT_CAPACITY
- * There were fewer than \p output_length bytes
- * in the generator. Note that in this case, no
- * output is written to the output buffer.
- * The generator's capacity is set to 0, thus
- * subsequent calls to this function will not
- * succeed, even with a smaller output buffer.
+ * There was not enough data to create the desired key.
+ * Note that in this case, no output is written to the output buffer.
+ * The generator's capacity is set to 0, thus subsequent calls to
+ * this function will not succeed, even with a smaller output buffer.
* \retval #PSA_ERROR_NOT_SUPPORTED
* The key type or key size is not supported, either by the
* implementation in general or in this particular slot.
@@ -3114,8 +3175,8 @@
* psa_key_derivation_setup() with a
* key agreement and derivation algorithm
* \c alg (\c PSA_ALG_XXX value such that
- * #PSA_ALG_IS_KEY_AGREEMENT(\p alg) is true
- * and #PSA_ALG_IS_RAW_KEY_AGREEMENT(\p alg)
+ * #PSA_ALG_IS_KEY_AGREEMENT(\c alg) is true
+ * and #PSA_ALG_IS_RAW_KEY_AGREEMENT(\c alg)
* is false).
* The generator must be ready for an
* input of the type given by \p step.
diff --git a/include/psa/crypto_extra.h b/include/psa/crypto_extra.h
index a0eac4d..d14edd9 100644
--- a/include/psa/crypto_extra.h
+++ b/include/psa/crypto_extra.h
@@ -125,7 +125,7 @@
* FIMXE This function is no longer part of the official API. Its prototype
* is only kept around for the sake of tests that haven't been updated yet.
*
- * A key derivation algorithm takes three inputs: a secret input \p key and
+ * A key derivation algorithm takes three inputs: a secret input \p handle and
* two non-secret inputs \p label and p salt.
* The result of this function is a byte generator which can
* be used to produce keys and other cryptographic material.
diff --git a/include/psa/crypto_values.h b/include/psa/crypto_values.h
index e0cc544..f6ce04e 100644
--- a/include/psa/crypto_values.h
+++ b/include/psa/crypto_values.h
@@ -691,7 +691,7 @@
*
* This value may not be used to build other algorithms that are
* parametrized over a hash. For any valid use of this macro to build
- * an algorithm `\p alg`, #PSA_ALG_IS_HASH_AND_SIGN(\p alg) is true.
+ * an algorithm \c alg, #PSA_ALG_IS_HASH_AND_SIGN(\c alg) is true.
*
* This value may not be used to build an algorithm specification to
* perform an operation. It is only valid to build policies.
@@ -708,7 +708,7 @@
* #PSA_ALG_IS_HASH(\p hash_alg) is true).
*
* \return The corresponding HMAC algorithm.
- * \return Unspecified if \p alg is not a supported
+ * \return Unspecified if \p hash_alg is not a supported
* hash algorithm.
*/
#define PSA_ALG_HMAC(hash_alg) \
@@ -954,7 +954,7 @@
* when specifying the algorithm in a usage policy.
*
* \return The corresponding RSA PKCS#1 v1.5 signature algorithm.
- * \return Unspecified if \p alg is not a supported
+ * \return Unspecified if \p hash_alg is not a supported
* hash algorithm.
*/
#define PSA_ALG_RSA_PKCS1V15_SIGN(hash_alg) \
@@ -985,7 +985,7 @@
* when specifying the algorithm in a usage policy.
*
* \return The corresponding RSA PSS signature algorithm.
- * \return Unspecified if \p alg is not a supported
+ * \return Unspecified if \p hash_alg is not a supported
* hash algorithm.
*/
#define PSA_ALG_RSA_PSS(hash_alg) \
@@ -1005,7 +1005,7 @@
* when specifying the algorithm in a usage policy.
*
* \return The corresponding DSA signature algorithm.
- * \return Unspecified if \p alg is not a supported
+ * \return Unspecified if \p hash_alg is not a supported
* hash algorithm.
*/
#define PSA_ALG_DSA(hash_alg) \
@@ -1023,7 +1023,7 @@
* when specifying the algorithm in a usage policy.
*
* \return The corresponding DSA signature algorithm.
- * \return Unspecified if \p alg is not a supported
+ * \return Unspecified if \p hash_alg is not a supported
* hash algorithm.
*/
#define PSA_ALG_DETERMINISTIC_DSA(hash_alg) \
@@ -1056,7 +1056,7 @@
* when specifying the algorithm in a usage policy.
*
* \return The corresponding ECDSA signature algorithm.
- * \return Unspecified if \p alg is not a supported
+ * \return Unspecified if \p hash_alg is not a supported
* hash algorithm.
*/
#define PSA_ALG_ECDSA(hash_alg) \
@@ -1091,7 +1091,7 @@
*
* \return The corresponding deterministic ECDSA signature
* algorithm.
- * \return Unspecified if \p alg is not a supported
+ * \return Unspecified if \p hash_alg is not a supported
* hash algorithm.
*/
#define PSA_ALG_DETERMINISTIC_ECDSA(hash_alg) \
@@ -1163,7 +1163,7 @@
* for MGF1.
*
* \return The corresponding RSA OAEP signature algorithm.
- * \return Unspecified if \p alg is not a supported
+ * \return Unspecified if \p hash_alg is not a supported
* hash algorithm.
*/
#define PSA_ALG_RSA_OAEP(hash_alg) \
@@ -1193,7 +1193,7 @@
* #PSA_ALG_IS_HASH(\p hash_alg) is true).
*
* \return The corresponding HKDF algorithm.
- * \return Unspecified if \p alg is not a supported
+ * \return Unspecified if \p hash_alg is not a supported
* hash algorithm.
*/
#define PSA_ALG_HKDF(hash_alg) \
@@ -1234,7 +1234,7 @@
* #PSA_ALG_IS_HASH(\p hash_alg) is true).
*
* \return The corresponding TLS-1.2 PRF algorithm.
- * \return Unspecified if \p alg is not a supported
+ * \return Unspecified if \p hash_alg is not a supported
* hash algorithm.
*/
#define PSA_ALG_TLS12_PRF(hash_alg) \
@@ -1274,7 +1274,7 @@
* #PSA_ALG_IS_HASH(\p hash_alg) is true).
*
* \return The corresponding TLS-1.2 PSK to MS algorithm.
- * \return Unspecified if \p alg is not a supported
+ * \return Unspecified if \p hash_alg is not a supported
* hash algorithm.
*/
#define PSA_ALG_TLS12_PSK_TO_MS(hash_alg) \
@@ -1342,8 +1342,7 @@
/** The finite-field Diffie-Hellman (DH) key agreement algorithm.
*
- * The shared secret produced by key agreement and passed as input to the
- * derivation or selection algorithm \p kdf_alg is the shared secret
+ * The shared secret produced by key agreement is
* `g^{ab}` in big-endian format.
* It is `ceiling(m / 8)` bytes long where `m` is the size of the prime `p`
* in bits.
@@ -1352,8 +1351,9 @@
/** Whether the specified algorithm is a finite field Diffie-Hellman algorithm.
*
- * This includes every supported key selection or key agreement algorithm
- * for the output of the Diffie-Hellman calculation.
+ * This includes the raw finite field Diffie-Hellman algorithm as well as
+ * finite-field Diffie-Hellman followed by any supporter key derivation
+ * algorithm.
*
* \param alg An algorithm identifier (value of type #psa_algorithm_t).
*
@@ -1394,8 +1394,9 @@
/** Whether the specified algorithm is an elliptic curve Diffie-Hellman
* algorithm.
*
- * This includes every supported key selection or key agreement algorithm
- * for the output of the Diffie-Hellman calculation.
+ * This includes the raw elliptic curve Diffie-Hellman algorithm as well as
+ * elliptic curve Diffie-Hellman followed by any supporter key derivation
+ * algorithm.
*
* \param alg An algorithm identifier (value of type #psa_algorithm_t).
*