[EC] Constify internal EC_KEY pointer usage

A pair of internal functions related to EC_KEY handling could benefit
from declaring `EC_KEY *` variables as `const`, providing clarity for
callers and readers of the code, in addition to enlisting the compiler
in preventing some mistakes.

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/10631)

diff --git a/crypto/ec/ec_ameth.c b/crypto/ec/ec_ameth.c
index d2c8c399deeaacbc325531d831db474734dcef6f..602ff7c557e2f9361b94246fdf7f366d9ca6fa3b 100644 (file)
--- a/crypto/ec/ec_ameth.c
+++ b/crypto/ec/ec_ameth.c
@@ -29,7 +29,7 @@ static int ecdh_cms_decrypt(CMS_RecipientInfo *ri);
 static int ecdh_cms_encrypt(CMS_RecipientInfo *ri);
 #endif
 
-static int eckey_param2type(int *pptype, void **ppval, EC_KEY *ec_key)
+static int eckey_param2type(int *pptype, void **ppval, const EC_KEY *ec_key)
 {
     const EC_GROUP *group;
     int nid;
@@ -63,7 +63,7 @@ static int eckey_param2type(int *pptype, void **ppval, EC_KEY *ec_key)
 
 static int eckey_pub_encode(X509_PUBKEY *pk, const EVP_PKEY *pkey)
 {
-    EC_KEY *ec_key = pkey->pkey.ec;
+    const EC_KEY *ec_key = pkey->pkey.ec;
     void *pval = NULL;
     int ptype;
     unsigned char *penc = NULL, *p;