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.
Signed-off-by: Daniel P. Berrangé <berra...@redhat.com> --- include/crypto/hash.h | 30 +++++++++++++++++++++++------- include/crypto/hmac.h | 17 ++++++++++++----- 2 files changed, 35 insertions(+), 12 deletions(-) diff --git a/include/crypto/hash.h b/include/crypto/hash.h index b791ca92a4..317bf9ecde 100644 --- a/include/crypto/hash.h +++ b/include/crypto/hash.h @@ -98,11 +98,18 @@ 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 +222,17 @@ 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..aaff95f7db 100644 --- a/include/crypto/hmac.h +++ b/include/crypto/hmac.h @@ -103,11 +103,18 @@ 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 -- 2.46.0
