Add macros for output buffer sizes
Signed-off-by: gabor-mezei-arm <gabor.mezei@arm.com>
diff --git a/include/psa/crypto_sizes.h b/include/psa/crypto_sizes.h
index d52f85f..119acaa 100644
--- a/include/psa/crypto_sizes.h
+++ b/include/psa/crypto_sizes.h
@@ -141,6 +141,13 @@
(((alg) & PSA_ALG_AEAD_TAG_LENGTH_MASK) >> PSA_AEAD_TAG_LENGTH_OFFSET) : \
0)
+/** The maximum tag size for all supported AEAD algorithms, in bytes.
+ *
+ * See also #PSA_AEAD_TAG_LENGTH(\p alg).
+ */
+#define PSA_AEAD_TAG_MAX_SIZE \
+ (PSA_ALG_AEAD_TAG_LENGTH_MASK >> PSA_AEAD_TAG_LENGTH_OFFSET)
+
/* The maximum size of an RSA key on this implementation, in bits.
* This is a vendor-specific macro.
*
@@ -259,6 +266,24 @@
(plaintext_length) + PSA_AEAD_TAG_LENGTH(alg) : \
0)
+/** A sufficient output buffer size for psa_aead_encrypt(), for any of the
+ * supported key types and AEAD algorithms.
+ *
+ * If the size of the ciphertext buffer is at least this large, it is guaranteed
+ * that psa_aead_encrypt() will not fail due to an insufficient buffer size.
+ *
+ * See also #PSA_AEAD_ENCRYPT_OUTPUT_SIZE(\p alg, \p plaintext_length).
+ *
+ * \param plaintext_length Size of the plaintext in bytes.
+ *
+ * \return A sufficient output buffer size for any of the
+ * supported key types and AEAD algorithms.
+ *
+ */
+#define PSA_AEAD_ENCRYPT_OUTPUT_MAX_SIZE(plaintext_length) \
+ ((plaintext_length) + PSA_AEAD_TAG_MAX_SIZE)
+
+
/** The maximum size of the output of psa_aead_decrypt(), in bytes.
*
* If the size of the plaintext buffer is at least this large, it is
@@ -283,6 +308,23 @@
(ciphertext_length) - PSA_AEAD_TAG_LENGTH(alg) : \
0)
+/** A sufficient output buffer size for psa_aead_decrypt(), for any of the
+ * supported key types and AEAD algorithms.
+ *
+ * If the size of the plaintext buffer is at least this large, it is guaranteed
+ * that psa_aead_decrypt() will not fail due to an insufficient buffer size.
+ *
+ * See also #PSA_AEAD_DECRYPT_OUTPUT_SIZE(\p alg, \p ciphertext_length).
+ *
+ * \param ciphertext_length Size of the ciphertext in bytes.
+ *
+ * \return A sufficient output buffer size for any of the
+ * supported key types and AEAD algorithms.
+ *
+ */
+#define PSA_AEAD_DECRYPT_OUTPUT_MAX_SIZE(ciphertext_length) \
+ (ciphertext_length)
+
/** The default nonce size for an AEAD algorithm, in bytes.
*
* This macro can be used to allocate a buffer of sufficient size to
@@ -382,6 +424,14 @@
PSA_BLOCK_CIPHER_BLOCK_MAX_SIZE : \
0)
+/** A sufficient ciphertext buffer size for psa_aead_finish(), for any of the
+ * supported key types and AEAD algorithms.
+ *
+ * See also #PSA_AEAD_FINISH_OUTPUT_SIZE(\p alg).
+ */
+#define PSA_AEAD_FINISH_OUTPUT_MAX_SIZE (PSA_MAX_BLOCK_CIPHER_BLOCK_SIZE)
+
+
/** A sufficient plaintext buffer size for psa_aead_verify().
*
* If the size of the plaintext buffer is at least this large, it is
