Add output size parameter to signature functions
The functions mbedtls_pk_sign(), mbedtls_pk_sign_restartable(),
mbedtls_ecdsa_write_signature() and mbedtls_ecdsa_write_signature_restartable()
now take an extra parameter indicating the size of the output buffer for the
signature.
No change to RSA because for RSA, the output size is trivial to calculate.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/include/mbedtls/pk.h b/include/mbedtls/pk.h
index ec7fe6e..a8a7a2e 100644
--- a/include/mbedtls/pk.h
+++ b/include/mbedtls/pk.h
@@ -67,6 +67,7 @@
#define MBEDTLS_ERR_PK_UNKNOWN_NAMED_CURVE -0x3A00 /**< Elliptic curve is unsupported (only NIST curves are supported). */
#define MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE -0x3980 /**< Unavailable feature, e.g. RSA disabled for RSA key. */
#define MBEDTLS_ERR_PK_SIG_LEN_MISMATCH -0x3900 /**< The buffer contains a valid signature followed by more data. */
+#define MBEDTLS_ERR_PK_BUFFER_TOO_SMALL -0x3880 /**< The output buffer is too small. */
#ifdef __cplusplus
extern "C" {
@@ -499,6 +500,7 @@
* #MBEDTLS_PK_SIGNATURE_MAX_SIZE is always enough.
* You may use a smaller buffer if it is large enough
* given the key type.
+ * \param sig_size The size of the \p sig buffer in bytes.
* \param sig_len On successful return,
* the number of bytes written to \p sig.
* \param f_rng RNG function, must not be \c NULL.
@@ -515,7 +517,7 @@
*/
int mbedtls_pk_sign( mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg,
const unsigned char *hash, size_t hash_len,
- unsigned char *sig, size_t *sig_len,
+ unsigned char *sig, size_t sig_size, size_t *sig_len,
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng );
/**
@@ -536,6 +538,7 @@
* #MBEDTLS_PK_SIGNATURE_MAX_SIZE is always enough.
* You may use a smaller buffer if it is large enough
* given the key type.
+ * \param sig_size The size of the \p sig buffer in bytes.
* \param sig_len On successful return,
* the number of bytes written to \p sig.
* \param f_rng RNG function, must not be \c NULL.
@@ -549,7 +552,7 @@
int mbedtls_pk_sign_restartable( mbedtls_pk_context *ctx,
mbedtls_md_type_t md_alg,
const unsigned char *hash, size_t hash_len,
- unsigned char *sig, size_t *sig_len,
+ unsigned char *sig, size_t sig_size, size_t *sig_len,
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng,
mbedtls_pk_restart_ctx *rs_ctx );