fuzz/asn1.c: Add check for ASN1_item_i2d

As the potential failure of the ASN1_item_i2d,
it should be better to check the return value.

Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/18647)

diff --git a/fuzz/asn1.c b/fuzz/asn1.c
index 69978cd05436641998c14bb694a71e43236a8427..ee602a08a3d91230c05ed32340b074d668f5a13f 100644 (file)
--- a/fuzz/asn1.c
+++ b/fuzz/asn1.c
@@ -317,8 +317,9 @@ int FuzzerTestOneInput(const uint8_t *buf, size_t len)
                 ASN1_item_print(bio, o, 4, i, pctx);
                 BIO_free(bio);
             }
-            ASN1_item_i2d(o, &der, i);
-            OPENSSL_free(der);
+            if (ASN1_item_i2d(o, &der, i) > 0) {
+                OPENSSL_free(der);
+            }
             ASN1_item_free(o, i);
         }
     }