Make the EVP_PKEY_get0* functions have a const return type

OTC have decided that the EVP_PKEY_get0* functions should have a const
return type. This is a breaking change to emphasise that these values
should be considered as immutable.

Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/14319)

8 files changed, 64 insertions, 33 deletions

diff --git a/crypto/dh/dh_ameth.c b/crypto/dh/dh_ameth.c
index 338f308934..18f4c9955e 100644
--- a/crypto/dh/dh_ameth.c
+++ b/crypto/dh/dh_ameth.c
@@ -433,7 +433,10 @@ static int dh_pkey_ctrl(EVP_PKEY *pkey, int op, long arg1, void *arg2)
 {
     switch (op) {
     case ASN1_PKEY_CTRL_SET1_TLS_ENCPT:
-        return ossl_dh_buf2key(EVP_PKEY_get0_DH(pkey), arg2, arg1);
+        /* We should only be here if we have a legacy key */
+        if (!ossl_assert(evp_pkey_is_legacy(pkey)))
+            return 0;
+        return ossl_dh_buf2key(evp_pkey_get0_DH_int(pkey), arg2, arg1);
     case ASN1_PKEY_CTRL_GET1_TLS_ENCPT:
         return ossl_dh_key2buf(EVP_PKEY_get0_DH(pkey), arg2, 0, 1);
     default:
diff --git a/crypto/ec/ec_ameth.c b/crypto/ec/ec_ameth.c
index 89241b97c1..694fcb3789 100644
--- a/crypto/ec/ec_ameth.c
+++ b/crypto/ec/ec_ameth.c
@@ -482,7 +482,10 @@ static int ec_pkey_ctrl(EVP_PKEY *pkey, int op, long arg1, void *arg2)
         return 1;
 
     case ASN1_PKEY_CTRL_SET1_TLS_ENCPT:
-        return EC_KEY_oct2key(EVP_PKEY_get0_EC_KEY(pkey), arg2, arg1, NULL);
+        /* We should only be here if we have a legacy key */
+        if (!ossl_assert(evp_pkey_is_legacy(pkey)))
+            return 0;
+        return EC_KEY_oct2key(evp_pkey_get0_EC_KEY_int(pkey), arg2, arg1, NULL);
 
     case ASN1_PKEY_CTRL_GET1_TLS_ENCPT:
         return EC_KEY_key2buf(EVP_PKEY_get0_EC_KEY(pkey),
diff --git a/crypto/evp/ctrl_params_translate.c b/crypto/evp/ctrl_params_translate.c
index ae3340395d..966278171c 100644
--- a/crypto/evp/ctrl_params_translate.c
+++ b/crypto/evp/ctrl_params_translate.c
@@ -1481,7 +1481,7 @@ static int get_payload_group_name(enum state state,
 #ifndef OPENSSL_NO_DH
     case EVP_PKEY_DH:
         {
-            DH *dh = EVP_PKEY_get0_DH(pkey);
+            const DH *dh = EVP_PKEY_get0_DH(pkey);
             int uid = DH_get_nid(dh);
 
             if (uid != NID_undef) {
@@ -1531,7 +1531,7 @@ static int get_payload_private_key(enum state state,
 #ifndef OPENSSL_NO_DH
     case EVP_PKEY_DH:
         {
-            DH *dh = EVP_PKEY_get0_DH(pkey);
+            const DH *dh = EVP_PKEY_get0_DH(pkey);
 
             ctx->p2 = (BIGNUM *)DH_get0_priv_key(dh);
         }
@@ -1540,7 +1540,7 @@ static int get_payload_private_key(enum state state,
 #ifndef OPENSSL_NO_EC
     case EVP_PKEY_EC:
         {
-            EC_KEY *ec = EVP_PKEY_get0_EC_KEY(pkey);
+            const EC_KEY *ec = EVP_PKEY_get0_EC_KEY(pkey);
 
             ctx->p2 = (BIGNUM *)EC_KEY_get0_private_key(ec);
         }
@@ -1590,7 +1590,7 @@ static int get_payload_public_key(enum state state,
 #ifndef OPENSSL_NO_EC
     case EVP_PKEY_EC:
         if (ctx->params->data_type == OSSL_PARAM_OCTET_STRING) {
-            EC_KEY *eckey = EVP_PKEY_get0_EC_KEY(pkey);
+            const EC_KEY *eckey = EVP_PKEY_get0_EC_KEY(pkey);
             BN_CTX *bnctx = BN_CTX_new_ex(ossl_ec_key_get_libctx(eckey));
             const EC_GROUP *ecg = EC_KEY_get0_group(eckey);
             const EC_POINT *point = EC_KEY_get0_public_key(eckey);
diff --git a/crypto/evp/p_dec.c b/crypto/evp/p_dec.c
index 6ac344e394..2e90705656 100644
--- a/crypto/evp/p_dec.c
+++ b/crypto/evp/p_dec.c
@@ -16,6 +16,7 @@
 #include <openssl/evp.h>
 #include <openssl/objects.h>
 #include <openssl/x509.h>
+#include "crypto/evp.h"
 
 int EVP_PKEY_decrypt_old(unsigned char *key, const unsigned char *ek, int ekl,
                          EVP_PKEY *priv)
@@ -28,7 +29,7 @@ int EVP_PKEY_decrypt_old(unsigned char *key, const unsigned char *ek, int ekl,
     }
 
     ret =
-        RSA_private_decrypt(ekl, ek, key, EVP_PKEY_get0_RSA(priv),
+        RSA_private_decrypt(ekl, ek, key, evp_pkey_get0_RSA_int(priv),
                             RSA_PKCS1_PADDING);
  err:
     return ret;
diff --git a/crypto/evp/p_enc.c b/crypto/evp/p_enc.c
index bdc490d884..5881153dbb 100644
--- a/crypto/evp/p_enc.c
+++ b/crypto/evp/p_enc.c
@@ -16,6 +16,7 @@
 #include <openssl/evp.h>
 #include <openssl/objects.h>
 #include <openssl/x509.h>
+#include "crypto/evp.h"
 
 int EVP_PKEY_encrypt_old(unsigned char *ek, const unsigned char *key,
                          int key_len, EVP_PKEY *pubk)
@@ -26,8 +27,9 @@ int EVP_PKEY_encrypt_old(unsigned char *ek, const unsigned char *key,
         ERR_raise(ERR_LIB_EVP, EVP_R_PUBLIC_KEY_NOT_RSA);
         goto err;
     }
+
     ret =
-        RSA_public_encrypt(key_len, key, ek, EVP_PKEY_get0_RSA(pubk),
+        RSA_public_encrypt(key_len, key, ek, evp_pkey_get0_RSA_int(pubk),
                            RSA_PKCS1_PADDING);
  err:
     return ret;
diff --git a/crypto/evp/p_legacy.c b/crypto/evp/p_legacy.c
index e478814065..af93288dcb 100644
--- a/crypto/evp/p_legacy.c
+++ b/crypto/evp/p_legacy.c
@@ -31,7 +31,7 @@ int EVP_PKEY_set1_RSA(EVP_PKEY *pkey, RSA *key)
     return ret;
 }
 
-RSA *EVP_PKEY_get0_RSA(const EVP_PKEY *pkey)
+RSA *evp_pkey_get0_RSA_int(const EVP_PKEY *pkey)
 {
     if (pkey->type != EVP_PKEY_RSA && pkey->type != EVP_PKEY_RSA_PSS) {
         ERR_raise(ERR_LIB_EVP, EVP_R_EXPECTING_AN_RSA_KEY);
@@ -40,9 +40,14 @@ RSA *EVP_PKEY_get0_RSA(const EVP_PKEY *pkey)
     return evp_pkey_get_legacy((EVP_PKEY *)pkey);
 }
 
+const RSA *EVP_PKEY_get0_RSA(const EVP_PKEY *pkey)
+{
+    return evp_pkey_get0_RSA_int(pkey);
+}
+
 RSA *EVP_PKEY_get1_RSA(EVP_PKEY *pkey)
 {
-    RSA *ret = EVP_PKEY_get0_RSA(pkey);
+    RSA *ret = evp_pkey_get0_RSA_int(pkey);
 
     if (ret != NULL)
         RSA_up_ref(ret);
@@ -59,18 +64,23 @@ int EVP_PKEY_set1_EC_KEY(EVP_PKEY *pkey, EC_KEY *key)
     return ret;
 }
 
-EC_KEY *EVP_PKEY_get0_EC_KEY(const EVP_PKEY *pkey)
+EC_KEY *evp_pkey_get0_EC_KEY_int(const EVP_PKEY *pkey)
 {
     if (EVP_PKEY_base_id(pkey) != EVP_PKEY_EC) {
-        EVPerr(EVP_F_EVP_PKEY_GET0_EC_KEY, EVP_R_EXPECTING_A_EC_KEY);
+        ERR_raise(ERR_LIB_EVP, EVP_R_EXPECTING_A_EC_KEY);
         return NULL;
     }
     return evp_pkey_get_legacy((EVP_PKEY *)pkey);
 }
 
+const EC_KEY *EVP_PKEY_get0_EC_KEY(const EVP_PKEY *pkey)
+{
+    return evp_pkey_get0_EC_KEY_int(pkey);
+}
+
 EC_KEY *EVP_PKEY_get1_EC_KEY(EVP_PKEY *pkey)
 {
-    EC_KEY *ret = EVP_PKEY_get0_EC_KEY(pkey);
+    EC_KEY *ret = evp_pkey_get0_EC_KEY_int(pkey);
 
     if (ret != NULL)
         EC_KEY_up_ref(ret);
diff --git a/crypto/evp/p_lib.c b/crypto/evp/p_lib.c
index 55214dd3d6..21fbc2ea4c 100644
--- a/crypto/evp/p_lib.c
+++ b/crypto/evp/p_lib.c
@@ -740,7 +740,7 @@ int EVP_PKEY_assign(EVP_PKEY *pkey, int type, void *key)
 }
 # endif
 
-void *EVP_PKEY_get0(const EVP_PKEY *pkey)
+const void *EVP_PKEY_get0(const EVP_PKEY *pkey)
 {
     if (pkey == NULL)
         return NULL;
@@ -750,7 +750,7 @@ void *EVP_PKEY_get0(const EVP_PKEY *pkey)
 
 const unsigned char *EVP_PKEY_get0_hmac(const EVP_PKEY *pkey, size_t *len)
 {
-    ASN1_OCTET_STRING *os = NULL;
+    const ASN1_OCTET_STRING *os = NULL;
     if (pkey->type != EVP_PKEY_HMAC) {
         ERR_raise(ERR_LIB_EVP, EVP_R_EXPECTING_AN_HMAC_KEY);
         return NULL;
@@ -763,7 +763,7 @@ const unsigned char *EVP_PKEY_get0_hmac(const EVP_PKEY *pkey, size_t *len)
 # ifndef OPENSSL_NO_POLY1305
 const unsigned char *EVP_PKEY_get0_poly1305(const EVP_PKEY *pkey, size_t *len)
 {
-    ASN1_OCTET_STRING *os = NULL;
+    const ASN1_OCTET_STRING *os = NULL;
     if (pkey->type != EVP_PKEY_POLY1305) {
         ERR_raise(ERR_LIB_EVP, EVP_R_EXPECTING_A_POLY1305_KEY);
         return NULL;
@@ -777,7 +777,7 @@ const unsigned char *EVP_PKEY_get0_poly1305(const EVP_PKEY *pkey, size_t *len)
 # ifndef OPENSSL_NO_SIPHASH
 const unsigned char *EVP_PKEY_get0_siphash(const EVP_PKEY *pkey, size_t *len)
 {
-    ASN1_OCTET_STRING *os = NULL;
+    const ASN1_OCTET_STRING *os = NULL;
 
     if (pkey->type != EVP_PKEY_SIPHASH) {
         ERR_raise(ERR_LIB_EVP, EVP_R_EXPECTING_A_SIPHASH_KEY);
@@ -790,7 +790,7 @@ const unsigned char *EVP_PKEY_get0_siphash(const EVP_PKEY *pkey, size_t *len)
 # endif
 
 # ifndef OPENSSL_NO_DSA
-DSA *EVP_PKEY_get0_DSA(const EVP_PKEY *pkey)
+static DSA *evp_pkey_get0_DSA_int(const EVP_PKEY *pkey)
 {
     if (pkey->type != EVP_PKEY_DSA) {
         ERR_raise(ERR_LIB_EVP, EVP_R_EXPECTING_A_DSA_KEY);
@@ -799,6 +799,11 @@ DSA *EVP_PKEY_get0_DSA(const EVP_PKEY *pkey)
     return evp_pkey_get_legacy((EVP_PKEY *)pkey);
 }
 
+const DSA *EVP_PKEY_get0_DSA(const EVP_PKEY *pkey)
+{
+    return evp_pkey_get0_DSA_int(pkey);
+}
+
 int EVP_PKEY_set1_DSA(EVP_PKEY *pkey, DSA *key)
 {
     int ret = EVP_PKEY_assign_DSA(pkey, key);
@@ -808,7 +813,8 @@ int EVP_PKEY_set1_DSA(EVP_PKEY *pkey, DSA *key)
 }
 DSA *EVP_PKEY_get1_DSA(EVP_PKEY *pkey)
 {
-    DSA *ret = EVP_PKEY_get0_DSA(pkey);
+    DSA *ret = evp_pkey_get0_DSA_int(pkey);
+
     if (ret != NULL)
         DSA_up_ref(ret);
     return ret;
@@ -818,7 +824,7 @@ DSA *EVP_PKEY_get1_DSA(EVP_PKEY *pkey)
 
 #ifndef FIPS_MODULE
 # ifndef OPENSSL_NO_EC
-static ECX_KEY *evp_pkey_get0_ECX_KEY(const EVP_PKEY *pkey, int type)
+static const ECX_KEY *evp_pkey_get0_ECX_KEY(const EVP_PKEY *pkey, int type)
 {
     if (EVP_PKEY_base_id(pkey) != type) {
         ERR_raise(ERR_LIB_EVP, EVP_R_EXPECTING_A_ECX_KEY);
@@ -829,7 +835,7 @@ static ECX_KEY *evp_pkey_get0_ECX_KEY(const EVP_PKEY *pkey, int type)
 
 static ECX_KEY *evp_pkey_get1_ECX_KEY(EVP_PKEY *pkey, int type)
 {
-    ECX_KEY *ret = evp_pkey_get0_ECX_KEY(pkey, type);
+    ECX_KEY *ret = (ECX_KEY *)evp_pkey_get0_ECX_KEY(pkey, type);
     if (ret != NULL)
         ossl_ecx_key_up_ref(ret);
     return ret;
@@ -859,7 +865,7 @@ int EVP_PKEY_set1_DH(EVP_PKEY *pkey, DH *key)
     return ret;
 }
 
-DH *EVP_PKEY_get0_DH(const EVP_PKEY *pkey)
+DH *evp_pkey_get0_DH_int(const EVP_PKEY *pkey)
 {
     if (pkey->type != EVP_PKEY_DH && pkey->type != EVP_PKEY_DHX) {
         ERR_raise(ERR_LIB_EVP, EVP_R_EXPECTING_A_DH_KEY);
@@ -868,9 +874,15 @@ DH *EVP_PKEY_get0_DH(const EVP_PKEY *pkey)
     return evp_pkey_get_legacy((EVP_PKEY *)pkey);
 }
 
+const DH *EVP_PKEY_get0_DH(const EVP_PKEY *pkey)
+{
+    return evp_pkey_get0_DH_int(pkey);
+}
+
 DH *EVP_PKEY_get1_DH(EVP_PKEY *pkey)
 {
-    DH *ret = EVP_PKEY_get0_DH(pkey);
+    DH *ret = evp_pkey_get0_DH_int(pkey);
+
     if (ret != NULL)
         DH_up_ref(ret);
     return ret;
@@ -2166,7 +2178,7 @@ int EVP_PKEY_get_ec_point_conv_form(const EVP_PKEY *pkey)
             || pkey->keydata == NULL) {
 #ifndef OPENSSL_NO_EC
         /* Might work through the legacy route */
-        EC_KEY *ec = EVP_PKEY_get0_EC_KEY(pkey);
+        const EC_KEY *ec = EVP_PKEY_get0_EC_KEY(pkey);
 
         if (ec == NULL)
             return 0;
@@ -2206,7 +2218,7 @@ int EVP_PKEY_get_field_type(const EVP_PKEY *pkey)
             || pkey->keydata == NULL) {
 #ifndef OPENSSL_NO_EC
         /* Might work through the legacy route */
-        EC_KEY *ec = EVP_PKEY_get0_EC_KEY(pkey);
+        const EC_KEY *ec = EVP_PKEY_get0_EC_KEY(pkey);
         const EC_GROUP *grp;
 
         if (ec == NULL)
diff --git a/crypto/pem/pvkfmt.c b/crypto/pem/pvkfmt.c
index de673be005..8006c64b3a 100644
--- a/crypto/pem/pvkfmt.c
+++ b/crypto/pem/pvkfmt.c
@@ -450,12 +450,12 @@ static void write_lebn(unsigned char **out, const BIGNUM *bn, int len)
     *out += len;
 }
 
-static int check_bitlen_rsa(RSA *rsa, int ispub, unsigned int *magic);
-static void write_rsa(unsigned char **out, RSA *rsa, int ispub);
+static int check_bitlen_rsa(const RSA *rsa, int ispub, unsigned int *magic);
+static void write_rsa(unsigned char **out, const RSA *rsa, int ispub);
 
 #ifndef OPENSSL_NO_DSA
-static int check_bitlen_dsa(DSA *dsa, int ispub, unsigned int *magic);
-static void write_dsa(unsigned char **out, DSA *dsa, int ispub);
+static int check_bitlen_dsa(const DSA *dsa, int ispub, unsigned int *magic);
+static void write_dsa(unsigned char **out, const DSA *dsa, int ispub);
 #endif
 
 static int do_i2b(unsigned char **out, const EVP_PKEY *pk, int ispub)
@@ -542,7 +542,7 @@ static int do_i2b_bio(BIO *out, const EVP_PKEY *pk, int ispub)
     return -1;
 }
 
-static int check_bitlen_rsa(RSA *rsa, int ispub, unsigned int *pmagic)
+static int check_bitlen_rsa(const RSA *rsa, int ispub, unsigned int *pmagic)
 {
     int nbyte, hnbyte, bitlen;
     const BIGNUM *e;
@@ -582,7 +582,7 @@ static int check_bitlen_rsa(RSA *rsa, int ispub, unsigned int *pmagic)
     return 0;
 }
 
-static void write_rsa(unsigned char **out, RSA *rsa, int ispub)
+static void write_rsa(unsigned char **out, const RSA *rsa, int ispub)
 {
     int nbyte, hnbyte;
     const BIGNUM *n, *d, *e, *p, *q, *iqmp, *dmp1, *dmq1;
@@ -605,7 +605,7 @@ static void write_rsa(unsigned char **out, RSA *rsa, int ispub)
 }
 
 #ifndef OPENSSL_NO_DSA
-static int check_bitlen_dsa(DSA *dsa, int ispub, unsigned int *pmagic)
+static int check_bitlen_dsa(const DSA *dsa, int ispub, unsigned int *pmagic)
 {
     int bitlen;
     const BIGNUM *p = NULL, *q = NULL, *g = NULL;
@@ -633,7 +633,7 @@ static int check_bitlen_dsa(DSA *dsa, int ispub, unsigned int *pmagic)
     return 0;
 }
 
-static void write_dsa(unsigned char **out, DSA *dsa, int ispub)
+static void write_dsa(unsigned char **out, const DSA *dsa, int ispub)
 {
     int nbyte;
     const BIGNUM *p = NULL, *q = NULL, *g = NULL;