rsa: write documentation of new functions for parse/writing RSA priv/pub keys
Signed-off-by: Valerio Setti <valerio.setti@nordicsemi.no>
diff --git a/library/rsa.c b/library/rsa.c
index 4ff7afa..e0c38c3 100644
--- a/library/rsa.c
+++ b/library/rsa.c
@@ -688,9 +688,6 @@
return 0;
}
-/*
- * Parse a PKCS#1 encoded private RSA key
- */
int mbedtls_rsa_key_parse(mbedtls_rsa_context *rsa, const unsigned char *key, size_t keylen)
{
int ret, version;
@@ -837,18 +834,19 @@
return ret;
}
-/*
- * RSAPublicKey ::= SEQUENCE {
- * modulus INTEGER, -- n
- * publicExponent INTEGER -- e
- * }
- */
int mbedtls_rsa_pubkey_parse(mbedtls_rsa_context *rsa, unsigned char **p,
const unsigned char *end)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
size_t len;
+ /*
+ * RSAPublicKey ::= SEQUENCE {
+ * modulus INTEGER, -- n
+ * publicExponent INTEGER -- e
+ * }
+ */
+
if ((ret = mbedtls_asn1_get_tag(p, end, &len,
MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {
return ret;
diff --git a/library/rsa_internal.h b/library/rsa_internal.h
index dee787f..62972c6 100644
--- a/library/rsa_internal.h
+++ b/library/rsa_internal.h
@@ -17,44 +17,77 @@
#include "mbedtls/rsa.h"
/**
- * \brief
+ * \brief Parse a PKCS#1 (ASN.1) encoded private RSA key.
*
- * \param rsa
- * \param key
- * \param keylen
- * \return int
+ * \param rsa The RSA context where parsed data will be stored.
+ * \param key The buffer that contains the key.
+ * \param keylen The length of the key buffer in bytes.
+ *
+ * \return 0 in success
+ * \return MBEDTLS_ERR_ASN1_xxx in case of ASN.1 parsing errors.
+ * \return MBEDTLS_ERR_RSA_BAD_INPUT_DATA in case of invalid version.
*/
int mbedtls_rsa_key_parse(mbedtls_rsa_context *rsa, const unsigned char *key, size_t keylen);
/**
- * \brief
+ * \brief Parse a PKCS#1 (ASN.1) encoded public RSA key.
*
- * \param rsa
- * \param p
- * \param end
- * \return int
+ * \param rsa The RSA context where parsed data will be stored.
+ * \param p Beginning of the buffer containing the key to be parsed.
+ * On successful return, the referenced pointer will be
+ * updated in order to point to the end of the parsed data.
+ * \param end End of the buffer containing the key to be parsed.
+ *
+ * \return 0 on success.
+ * \return MBEDTLS_ERR_ASN1_xxx in case of ASN.1 parsing errors.
+ * \return MBEDTLS_ERR_RSA_BAD_INPUT_DATA in case of importing or
+ * priv/pub validation errors.
*/
int mbedtls_rsa_pubkey_parse(mbedtls_rsa_context *rsa, unsigned char **p,
const unsigned char *end);
/**
- * \brief
+ * \brief Write a PKCS#1 (ASN.1) encoded private RSA key.
*
- * \param p
- * \param start
- * \param rsa
- * \return int
+ * \param rsa The RSA context which contains the data to be written.
+ * \param start Beginning of the buffer that will be filled with the
+ * private key.
+ * \param p End of the buffer that will be filled with the private key.
+ * On successful return, the referenced pointer will be
+ * updated in order to point to the beginning of written data.
+ *
+ * \return On success, the number of bytes written to the output buffer
+ * (i.e. a value > 0).
+ * \return MBEDTLS_ERR_RSA_BAD_INPUT_DATA is the RSA context does not
+ * cointain valid.
+ * \return MBEDTLS_ERR_ASN1_xxx in case of failure while writing to the
+ * output buffer.
+ *
+ * \note The output buffer is filled backward, i.e. starting from its
+ * end and moving toward its start.
*/
int mbedtls_rsa_key_write(const mbedtls_rsa_context *rsa, unsigned char *start,
unsigned char **p);
/**
- * \brief
+ * \brief Parse a PKCS#1 (ASN.1) encoded public RSA key.
*
- * \param p
- * \param start
- * \param rsa
- * \return int
+ * \param rsa The RSA context which contains the data to be written.
+ * \param start Beginning of the buffer that will be filled with the
+ * private key.
+ * \param p End of the buffer that will be filled with the private key.
+ * On successful return, the referenced pointer will be
+ * updated in order to point to the beginning of written data.
+ *
+ * \return On success, the number of bytes written to the output buffer
+ * (i.e. a value > 0).
+ * \return MBEDTLS_ERR_RSA_BAD_INPUT_DATA is the RSA context does not
+ * cointain valid.
+ * \return MBEDTLS_ERR_ASN1_xxx in case of failure while writing to the
+ * output buffer.
+ *
+ * \note The output buffer is filled backward, i.e. starting from its
+ * end and moving toward its start.
*/
int mbedtls_rsa_pubkey_write(const mbedtls_rsa_context *rsa, unsigned char *start,
unsigned char **p);