make ENGINE_finish() succeed on NULL and simplify callers as in

OpenSSL commit 7c96dbcdab9 by Rich Salz.

This cleans up the caller side quite a bit and reduces the number of
lines enclosed in #ifndef OPENSSL_NO_ENGINE.  codesearch.debian.net
shows that almost nothing checks the return value of ENGINE_finish().
While there, replace a few nearby 'if (!ptr)' with 'if (ptr == NULL)'.

ok jsing, tested by & ok inoguchi

4 files changed, 19 insertions, 36 deletions

diff --git a/src/lib/libcrypto/evp/digest.c b/src/lib/libcrypto/evp/digest.c
index b69a928ab8..6a7d86d702 100644
--- a/src/lib/libcrypto/evp/digest.c
+++ b/src/lib/libcrypto/evp/digest.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: digest.c,v 1.29 2018/02/17 14:55:31 jsing Exp $ */
+/* $OpenBSD: digest.c,v 1.30 2018/04/14 07:09:21 tb Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -146,9 +146,8 @@ EVP_DigestInit_ex(EVP_MD_CTX *ctx, const EVP_MD *type, ENGINE *impl)
                 /* Ensure an ENGINE left lying around from last time is cleared
                  * (the 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)) {
                                 EVPerror(EVP_R_INITIALIZATION_ERROR);
                                 return 0;
@@ -156,10 +155,10 @@ EVP_DigestInit_ex(EVP_MD_CTX *ctx, const EVP_MD *type, ENGINE *impl)
                 } 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) {
+                        if (d == NULL) {
                                 /* Same comment from evp_enc.c */
                                 EVPerror(EVP_R_INITIALIZATION_ERROR);
                                 ENGINE_finish(impl);
@@ -384,10 +383,7 @@ EVP_MD_CTX_cleanup(EVP_MD_CTX *ctx)
                 freezero(ctx->md_data, ctx->digest->ctx_size);
         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));
 
diff --git a/src/lib/libcrypto/evp/evp_enc.c b/src/lib/libcrypto/evp/evp_enc.c
index de7c690ca7..db2deb6905 100644
--- a/src/lib/libcrypto/evp/evp_enc.c
+++ b/src/lib/libcrypto/evp/evp_enc.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: evp_enc.c,v 1.38 2018/02/17 16:54:08 jsing Exp $ */
+/* $OpenBSD: evp_enc.c,v 1.39 2018/04/14 07:09:21 tb Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -577,10 +577,7 @@ EVP_CIPHER_CTX_cleanup(EVP_CIPHER_CTX *c)
         }
         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
         explicit_bzero(c, sizeof(EVP_CIPHER_CTX));
         return 1;
diff --git a/src/lib/libcrypto/evp/p_lib.c b/src/lib/libcrypto/evp/p_lib.c
index 811fe0c86d..b14c95f14d 100644
--- a/src/lib/libcrypto/evp/p_lib.c
+++ b/src/lib/libcrypto/evp/p_lib.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: p_lib.c,v 1.20 2018/02/20 18:05:28 tb Exp $ */
+/* $OpenBSD: p_lib.c,v 1.21 2018/04/14 07:09:21 tb Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -229,11 +229,8 @@ pkey_set_type(EVP_PKEY *pkey, int type, const char *str, int len)
                 if ((type == pkey->save_type) && pkey->ameth)
                         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)
@@ -241,7 +238,7 @@ 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) {
@@ -426,8 +423,7 @@ EVP_PKEY_type(int type)
         else
                 ret = NID_undef;
 #ifndef OPENSSL_NO_ENGINE
-        if (e)
-                ENGINE_finish(e);
+        ENGINE_finish(e);
 #endif
         return ret;
 }
@@ -470,10 +466,8 @@ 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/src/lib/libcrypto/evp/pmeth_lib.c b/src/lib/libcrypto/evp/pmeth_lib.c
index fc5f4ef91e..6b86a0ecfb 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 1.13 2017/01/29 17:49:23 beck Exp $ */
+/* $OpenBSD: pmeth_lib.c,v 1.14 2018/04/14 07:09:21 tb Exp $ */
 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
  * project 2006.
  */
@@ -188,10 +188,9 @@ int_ctx_new(EVP_PKEY *pkey, ENGINE *e, int id)
         }
 
         ret = malloc(sizeof(EVP_PKEY_CTX));
-        if (!ret) {
+        if (ret == NULL) {
 #ifndef OPENSSL_NO_ENGINE
-                if (e)
-                        ENGINE_finish(e);
+                ENGINE_finish(e);
 #endif
                 EVPerror(ERR_R_MALLOC_FAILURE);
                 return NULL;
@@ -394,10 +393,7 @@ 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
         free(ctx);
 }