GH715: ENGINE_finish can take NULL

Simplifies calling code.  Also fixed up any !ptr tests that were
nearby, turning them into NULL tests.

Reviewed-by: Richard Levitte <levitte@openssl.org>

4 files changed, 18 insertions, 39 deletions

diff --git a/crypto/evp/digest.c b/crypto/evp/digest.c
index f7e82db6dd..f89f1c8447 100644
--- a/crypto/evp/digest.c
+++ b/crypto/evp/digest.c
@@ -137,12 +137,7 @@ int EVP_MD_CTX_reset(EVP_MD_CTX *ctx)
     }
     EVP_PKEY_CTX_free(ctx->pctx);
 #ifndef OPENSSL_NO_ENGINE
-    if (ctx->engine)
-        /*
-         * The EVP_MD we used belongs to an ENGINE, release the functional
-         * reference we held for this reason.
-         */
-        ENGINE_finish(ctx->engine);
+    ENGINE_finish(ctx->engine);
 #endif
     memset(ctx, 0, sizeof(*ctx));
 
@@ -187,21 +182,21 @@ int EVP_DigestInit_ex(EVP_MD_CTX *ctx, const EVP_MD *type, ENGINE *impl)
          * previous check attempted to avoid this if the same ENGINE and
          * EVP_MD could be used).
          */
-        if (ctx->engine)
-            ENGINE_finish(ctx->engine);
-        if (impl) {
+        ENGINE_finish(ctx->engine);
+        if (impl != NULL) {
             if (!ENGINE_init(impl)) {
                 EVPerr(EVP_F_EVP_DIGESTINIT_EX, EVP_R_INITIALIZATION_ERROR);
                 return 0;
             }
-        } else
+        } else {
             /* Ask if an ENGINE is reserved for this job */
             impl = ENGINE_get_digest_engine(type->type);
-        if (impl) {
+        }
+        if (impl != NULL) {
             /* There's an ENGINE for this job ... (apparently) */
             const EVP_MD *d = ENGINE_get_digest(impl, type->type);
-            if (!d) {
-                /* Same comment from evp_enc.c */
+
+            if (d == NULL) {
                 EVPerr(EVP_F_EVP_DIGESTINIT_EX, EVP_R_INITIALIZATION_ERROR);
                 ENGINE_finish(impl);
                 return 0;
diff --git a/crypto/evp/evp_enc.c b/crypto/evp/evp_enc.c
index 278e91bada..484b024218 100644
--- a/crypto/evp/evp_enc.c
+++ b/crypto/evp/evp_enc.c
@@ -79,12 +79,7 @@ int EVP_CIPHER_CTX_reset(EVP_CIPHER_CTX *c)
     }
     OPENSSL_free(c->cipher_data);
 #ifndef OPENSSL_NO_ENGINE
-    if (c->engine)
-        /*
-         * The EVP_CIPHER we used belongs to an ENGINE, release the
-         * functional reference we held for this reason.
-         */
-        ENGINE_finish(c->engine);
+    ENGINE_finish(c->engine);
 #endif
     memset(c, 0, sizeof(*c));
     return 1;
diff --git a/crypto/evp/p_lib.c b/crypto/evp/p_lib.c
index 221178dd31..b34a268c89 100644
--- a/crypto/evp/p_lib.c
+++ b/crypto/evp/p_lib.c
@@ -224,10 +224,8 @@ static int pkey_set_type(EVP_PKEY *pkey, int type, const char *str, int len)
             return 1;
 #ifndef OPENSSL_NO_ENGINE
         /* If we have an ENGINE release it */
-        if (pkey->engine) {
-            ENGINE_finish(pkey->engine);
-            pkey->engine = NULL;
-        }
+        ENGINE_finish(pkey->engine);
+        pkey->engine = NULL;
 #endif
     }
     if (str)
@@ -235,10 +233,10 @@ static int pkey_set_type(EVP_PKEY *pkey, int type, const char *str, int len)
     else
         ameth = EVP_PKEY_asn1_find(&e, type);
 #ifndef OPENSSL_NO_ENGINE
-    if (!pkey && e)
+    if (pkey == NULL)
         ENGINE_finish(e);
 #endif
-    if (!ameth) {
+    if (ameth == NULL) {
         EVPerr(EVP_F_PKEY_SET_TYPE, EVP_R_UNSUPPORTED_ALGORITHM);
         return 0;
     }
@@ -396,8 +394,7 @@ int EVP_PKEY_type(int type)
     else
         ret = NID_undef;
 #ifndef OPENSSL_NO_ENGINE
-    if (e)
-        ENGINE_finish(e);
+    ENGINE_finish(e);
 #endif
     return ret;
 }
@@ -437,10 +434,8 @@ static void EVP_PKEY_free_it(EVP_PKEY *x)
         x->pkey.ptr = NULL;
     }
 #ifndef OPENSSL_NO_ENGINE
-    if (x->engine) {
-        ENGINE_finish(x->engine);
-        x->engine = NULL;
-    }
+    ENGINE_finish(x->engine);
+    x->engine = NULL;
 #endif
 }
 
diff --git a/crypto/evp/pmeth_lib.c b/crypto/evp/pmeth_lib.c
index 5b2301431a..72baaa988d 100644
--- a/crypto/evp/pmeth_lib.c
+++ b/crypto/evp/pmeth_lib.c
@@ -162,8 +162,7 @@ static EVP_PKEY_CTX *int_ctx_new(EVP_PKEY *pkey, ENGINE *e, int id)
     ret = OPENSSL_zalloc(sizeof(*ret));
     if (ret == NULL) {
 #ifndef OPENSSL_NO_ENGINE
-        if (e)
-            ENGINE_finish(e);
+        ENGINE_finish(e);
 #endif
         EVPerr(EVP_F_INT_CTX_NEW, ERR_R_MALLOC_FAILURE);
         return NULL;
@@ -329,12 +328,7 @@ void EVP_PKEY_CTX_free(EVP_PKEY_CTX *ctx)
     EVP_PKEY_free(ctx->pkey);
     EVP_PKEY_free(ctx->peerkey);
 #ifndef OPENSSL_NO_ENGINE
-    if (ctx->engine)
-        /*
-         * The EVP_PKEY_CTX we used belongs to an ENGINE, release the
-         * functional reference we held for this reason.
-         */
-        ENGINE_finish(ctx->engine);
+    ENGINE_finish(ctx->engine);
 #endif
     OPENSSL_free(ctx);
 }