Clarify warning about mbedtls_pk_ec/rsa()
The previous wording "ensure it holds an XXX" context did not mean
anything without looking at the source.
Looking at the source, the criterion is:
- for mbedtls_pk_rsa(), that the info structure uses rsa_alloc_wrap;
- for mbedtls_pk_ec(), that it uses eckey_alloc_wrap or
ecdsa_alloc_wrap, since mbedtls_ecdsa_context is a typedef for
mbedtls_ecp_keypair. (Note that our test code uses mbedtls_pk_ec() on
contexts of type MBEDTLS_PK_ECDSA.)
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
diff --git a/include/mbedtls/pk.h b/include/mbedtls/pk.h
index 8f2abf2..3851146 100644
--- a/include/mbedtls/pk.h
+++ b/include/mbedtls/pk.h
@@ -221,8 +221,9 @@
/**
* Quick access to an RSA context inside a PK context.
*
- * \warning You must make sure the PK context actually holds an RSA context
- * before using this function!
+ * \warning This function can only be used when the type of the context, as
+ * returned by mbedtls_pk_get_type(), is #MBEDTLS_PK_RSA.
+ * Ensuring that is the caller's responsibility.
*/
static inline mbedtls_rsa_context *mbedtls_pk_rsa( const mbedtls_pk_context pk )
{
@@ -234,8 +235,10 @@
/**
* Quick access to an EC context inside a PK context.
*
- * \warning You must make sure the PK context actually holds an EC context
- * before using this function!
+ * \warning This function can only be used when the type of the context, as
+ * returned by mbedtls_pk_get_type(), is #MBEDTLS_PK_ECKEY,
+ * #MBEDTLS_PK_ECKEY_DH, or #MBEDTLS_PK_ECDSA.
+ * Ensuring that is the caller's responsibility.
*/
static inline mbedtls_ecp_keypair *mbedtls_pk_ec( const mbedtls_pk_context pk )
{