From 769660955a62ddcb75a1f9a0d1c6c0f840d533e8 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= Date: Wed, 16 Oct 2024 11:17:22 +0100 Subject: [PATCH] include/crypto: clarify @result/@result_len for hash/hmac APIs MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The @result parameter passed to hash/hmac APIs may either contain a pre-allocated buffer, or a buffer can be allocated on the fly. Clarify these two different usage models in the API docs. Reviewed-by: Dorjoy Chowdhury Signed-off-by: Daniel P. Berrangé --- include/crypto/hash.h | 47 ++++++++++++++++++++++++++++++++----------- include/crypto/hmac.h | 34 ++++++++++++++++++++++--------- 2 files changed, 59 insertions(+), 22 deletions(-) diff --git a/include/crypto/hash.h b/include/crypto/hash.h index b791ca92a4..712cac79ee 100644 --- a/include/crypto/hash.h +++ b/include/crypto/hash.h @@ -73,11 +73,18 @@ size_t qcrypto_hash_digest_len(QCryptoHashAlgo alg); * @errp: pointer to a NULL-initialized error object * * Computes the hash across all the memory regions - * present in @iov. The @result pointer will be - * filled with raw bytes representing the computed - * hash, which will have length @resultlen. The - * memory pointer in @result must be released - * with a call to g_free() when no longer required. + * present in @iov. + * + * If @result_len is set to a non-zero value by the caller, then + * @result must hold a pointer that is @result_len in size, and + * @result_len match the size of the hash output. The digest will + * be written into @result. + * + * If @result_len is set to zero, then this function will allocate + * a buffer to hold the hash output digest, storing a pointer to + * the buffer in @result, and setting @result_len to its size. + * The memory referenced in @result must be released with a call + * to g_free() when no longer required by the caller. * * Returns: 0 on success, -1 on error */ @@ -98,11 +105,18 @@ int qcrypto_hash_bytesv(QCryptoHashAlgo alg, * @errp: pointer to a NULL-initialized error object * * Computes the hash across all the memory region - * @buf of length @len. The @result pointer will be - * filled with raw bytes representing the computed - * hash, which will have length @resultlen. The - * memory pointer in @result must be released - * with a call to g_free() when no longer required. + * @buf of length @len. + * + * If @result_len is set to a non-zero value by the caller, then + * @result must hold a pointer that is @result_len in size, and + * @result_len match the size of the hash output. The digest will + * be written into @result. + * + * If @result_len is set to zero, then this function will allocate + * a buffer to hold the hash output digest, storing a pointer to + * the buffer in @result, and setting @result_len to its size. + * The memory referenced in @result must be released with a call + * to g_free() when no longer required by the caller. * * Returns: 0 on success, -1 on error */ @@ -215,8 +229,17 @@ int qcrypto_hash_finalize_base64(QCryptoHash *hash, * * Computes the hash from the given hash object. Hash object * is expected to have it's data updated from the qcrypto_hash_update function. - * The memory pointer in @result must be released with a call to g_free() - * when no longer required. + * + * If @result_len is set to a non-zero value by the caller, then + * @result must hold a pointer that is @result_len in size, and + * @result_len match the size of the hash output. The digest will + * be written into @result. + * + * If @result_len is set to zero, then this function will allocate + * a buffer to hold the hash output digest, storing a pointer to + * the buffer in @result, and setting @result_len to its size. + * The memory referenced in @result must be released with a call + * to g_free() when no longer required by the caller. * * Returns: 0 on success, -1 on error */ diff --git a/include/crypto/hmac.h b/include/crypto/hmac.h index c69a0dfab3..da8a1e3ceb 100644 --- a/include/crypto/hmac.h +++ b/include/crypto/hmac.h @@ -77,11 +77,18 @@ G_DEFINE_AUTOPTR_CLEANUP_FUNC(QCryptoHmac, qcrypto_hmac_free) * @errp: pointer to a NULL-initialized error object * * Computes the hmac across all the memory regions - * present in @iov. The @result pointer will be - * filled with raw bytes representing the computed - * hmac, which will have length @resultlen. The - * memory pointer in @result must be released - * with a call to g_free() when no longer required. + * present in @iov. + * + * If @result_len is set to a non-zero value by the caller, then + * @result must hold a pointer that is @result_len in size, and + * @result_len match the size of the hash output. The digest will + * be written into @result. + * + * If @result_len is set to zero, then this function will allocate + * a buffer to hold the hash output digest, storing a pointer to + * the buffer in @result, and setting @result_len to its size. + * The memory referenced in @result must be released with a call + * to g_free() when no longer required by the caller. * * Returns: * 0 on success, -1 on error @@ -103,11 +110,18 @@ int qcrypto_hmac_bytesv(QCryptoHmac *hmac, * @errp: pointer to a NULL-initialized error object * * Computes the hmac across all the memory region - * @buf of length @len. The @result pointer will be - * filled with raw bytes representing the computed - * hmac, which will have length @resultlen. The - * memory pointer in @result must be released - * with a call to g_free() when no longer required. + * @buf of length @len. + * + * If @result_len is set to a non-zero value by the caller, then + * @result must hold a pointer that is @result_len in size, and + * @result_len match the size of the hash output. The digest will + * be written into @result. + * + * If @result_len is set to zero, then this function will allocate + * a buffer to hold the hash output digest, storing a pointer to + * the buffer in @result, and setting @result_len to its size. + * The memory referenced in @result must be released with a call + * to g_free() when no longer required by the caller. * * Returns: * 0 on success, -1 on error