bn_unit: appease coverity

Apparently, the '0' in memset(a, '0', size - 1); could be a typo for '\0'.
Randomize the decimal digit to make the intent clear.

CID 377009

diff --git a/regress/lib/libcrypto/bn/general/bn_unit.c b/regress/lib/libcrypto/bn/general/bn_unit.c
index f1a2c78..6ae6765 100644 (file)
--- a/regress/lib/libcrypto/bn/general/bn_unit.c
+++ b/regress/lib/libcrypto/bn/general/bn_unit.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: bn_unit.c,v 1.3 2022/11/23 08:01:05 tb Exp $ */
+/*     $OpenBSD: bn_unit.c,v 1.4 2022/11/23 08:58:34 tb Exp $ */
 
 /*
  * Copyright (c) 2022 Theo Buehler <tb@openbsd.org>
@@ -45,6 +45,7 @@ test_bn_print_null_derefs(void)
        size_t size = INT_MAX / 4 + 4;
        size_t datalimit = (size + 500 * 1024) / 1024;
        char *a;
+       char digit;
        int failed = 0;
 
        if ((a = malloc(size)) == NULL) {
@@ -53,7 +54,10 @@ test_bn_print_null_derefs(void)
                return 0;
        }
 
-       memset(a, '0', size - 1);
+       /* Fill with a random digit since coverity doesn't like us using '0'. */
+       digit = '0' + arc4random_uniform(10);
+
+       memset(a, digit, size - 1);
        a[size - 1] = '\0';
 
        failed |= test_bn_print_wrapper(a, size, "BN_dec2bn", BN_dec2bn);