Clean up and fix int_ctx_new()

Compare explicitly against NULL, ensure the engine is always finished on
error, switch to using calloc() instead of malloc() + forgetting to set
some members to 0, use EVP_PKEY_up_ref() and also use pkey_ctx instead of
ret for the newly created EVP_PKEY_CTX.

ok jsing

1 files changed, 30 insertions, 34 deletions

diff --git a/src/lib/libcrypto/evp/pmeth_lib.c b/src/lib/libcrypto/evp/pmeth_lib.c
index 480a36b9ed..1eb73f57bd 100644
--- a/src/lib/libcrypto/evp/pmeth_lib.c
+++ b/src/lib/libcrypto/evp/pmeth_lib.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: pmeth_lib.c,v 1.28 2023/06/20 14:05:46 tb Exp $ */
+/* $OpenBSD: pmeth_lib.c,v 1.29 2023/06/20 14:10:05 tb Exp $ */
 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
  * project 2006.
  */
@@ -153,19 +153,19 @@ EVP_PKEY_meth_find(int type)
 static EVP_PKEY_CTX *
 int_ctx_new(EVP_PKEY *pkey, ENGINE *e, int id)
 {
-        EVP_PKEY_CTX *ret;
+        EVP_PKEY_CTX *pkey_ctx = NULL;
         const EVP_PKEY_METHOD *pmeth;
 
         if (id == -1) {
-                if (!pkey || !pkey->ameth)
+                if (pkey == NULL || pkey->ameth == NULL)
                         return NULL;
                 id = pkey->ameth->pkey_id;
         }
 #ifndef OPENSSL_NO_ENGINE
-        if (pkey && pkey->engine)
+        if (pkey != NULL && pkey->engine != NULL)
                 e = pkey->engine;
-        /* Try to find an ENGINE which implements this method */
-        if (e) {
+        /* Try to find an ENGINE which implements this method. */
+        if (e != NULL) {
                 if (!ENGINE_init(e)) {
                         EVPerror(ERR_R_ENGINE_LIB);
                         return NULL;
@@ -173,11 +173,8 @@ int_ctx_new(EVP_PKEY *pkey, ENGINE *e, int id)
         } else
                 e = ENGINE_get_pkey_meth_engine(id);
 
-        /* If an ENGINE handled this method look it up. Otherwise
-         * use internal tables.
-         */
-
-        if (e)
+        /* Look up method handler in ENGINE or use internal tables. */
+        if (e != NULL)
                 pmeth = ENGINE_get_pkey_meth(e, id);
         else
 #endif
@@ -185,35 +182,34 @@ int_ctx_new(EVP_PKEY *pkey, ENGINE *e, int id)
 
         if (pmeth == NULL) {
                 EVPerror(EVP_R_UNSUPPORTED_ALGORITHM);
-                return NULL;
+                goto err;
         }
 
-        ret = malloc(sizeof(EVP_PKEY_CTX));
-        if (ret == NULL) {
-#ifndef OPENSSL_NO_ENGINE
-                ENGINE_finish(e);
-#endif
+        if ((pkey_ctx = calloc(1, sizeof(*pkey_ctx))) == NULL) {
                 EVPerror(ERR_R_MALLOC_FAILURE);
-                return NULL;
+                goto err;
         }
-        ret->engine = e;
-        ret->pmeth = pmeth;
-        ret->operation = EVP_PKEY_OP_UNDEFINED;
-        ret->pkey = pkey;
-        ret->peerkey = NULL;
-        ret->pkey_gencb = 0;
-        if (pkey)
-                CRYPTO_add(&pkey->references, 1, CRYPTO_LOCK_EVP_PKEY);
-        ret->data = NULL;
-
-        if (pmeth->init) {
-                if (pmeth->init(ret) <= 0) {
-                        EVP_PKEY_CTX_free(ret);
-                        return NULL;
-                }
+        pkey_ctx->engine = e;
+        e = NULL;
+        pkey_ctx->pmeth = pmeth;
+        pkey_ctx->operation = EVP_PKEY_OP_UNDEFINED;
+        if ((pkey_ctx->pkey = pkey) != NULL)
+                EVP_PKEY_up_ref(pkey_ctx->pkey);
+
+        if (pmeth->init != NULL) {
+                if (pmeth->init(pkey_ctx) <= 0)
+                        goto err;
         }
 
-        return ret;
+        return pkey_ctx;
+
+ err:
+        EVP_PKEY_CTX_free(pkey_ctx);
+#ifndef OPENSSL_NO_ENGINE
+        ENGINE_finish(e);
+#endif
+
+        return NULL;
 }
 
 EVP_PKEY_METHOD*