Avoid NULL dereference in EVP_PKEY_paramgen()

If EVP_PKEY_new() returns NULL, it would be passed to the paramgen() pmeth
which would typically dereference it. This is identical to a recent change
in keygen().

ok jsing

1 files changed, 8 insertions, 6 deletions

diff --git a/src/lib/libcrypto/evp/pmeth_gn.c b/src/lib/libcrypto/evp/pmeth_gn.c
index b8b51ced3d..1c355e594a 100644
--- a/src/lib/libcrypto/evp/pmeth_gn.c
+++ b/src/lib/libcrypto/evp/pmeth_gn.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: pmeth_gn.c,v 1.18 2024/04/12 09:41:39 tb Exp $ */
+/* $OpenBSD: pmeth_gn.c,v 1.19 2024/04/17 08:24:11 tb Exp $ */
 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
  * project 2006.
  */
@@ -87,7 +87,7 @@ EVP_PKEY_paramgen(EVP_PKEY_CTX *ctx, EVP_PKEY **ppkey)
 {
         int ret;
 
-        if (!ctx || !ctx->pmeth || !ctx->pmeth->paramgen) {
+        if (ctx == NULL || ctx->pmeth == NULL || ctx->pmeth->paramgen == NULL) {
                 EVPerror(EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
                 return -2;
         }
@@ -97,17 +97,19 @@ EVP_PKEY_paramgen(EVP_PKEY_CTX *ctx, EVP_PKEY **ppkey)
                 return -1;
         }
 
-        if (!ppkey)
+        if (ppkey == NULL)
                 return -1;
 
-        if (!*ppkey)
+        if (*ppkey == NULL)
                 *ppkey = EVP_PKEY_new();
+        if (*ppkey == NULL)
+                return -1;
 
-        ret = ctx->pmeth->paramgen(ctx, *ppkey);
-        if (ret <= 0) {
+        if ((ret = ctx->pmeth->paramgen(ctx, *ppkey)) <= 0) {
                 EVP_PKEY_free(*ppkey);
                 *ppkey = NULL;
         }
+
         return ret;
 }
 LCRYPTO_ALIAS(EVP_PKEY_paramgen);