test/gensalt-bcrypt_x: Add testcase for bcrypt "$2x$" variant.

Simple testcase to ensure crypt_gensalt(3) always returns "NULL",
and sets the error number to "EINVAL" for the bcrypt "$2x" variant.

Author: besser82

.gitignore

@@ -85,6 +85,7 @@ test/des-obsolete_r
 test/explicit-bzero
 test/fcrypt-enosys
 test/gensalt
+test/gensalt-bcrypt_x
 test/gensalt-nthash
 test/gensalt-extradata
 test/getrandom-fallbacks

Makefile.am

@@ -388,6 +388,7 @@ check_PROGRAMS = \
 	test/crypt-sm3-yescrypt \
 	test/explicit-bzero \
 	test/gensalt \
+	test/gensalt-bcrypt_x \
 	test/gensalt-extradata \
 	test/gensalt-nthash \
 	test/getrandom-fallbacks \
@@ -497,6 +498,7 @@ COMMON_TEST_OBJECTS = libcrypt.la
 
 test_badsalt_LDADD = $(COMMON_TEST_OBJECTS)
 test_badsetting_LDADD = $(COMMON_TEST_OBJECTS)
+test_gensalt_bcrypt_x_LDADD = $(COMMON_TEST_OBJECTS)
 test_gensalt_nthash_LDADD = $(COMMON_TEST_OBJECTS)
 test_gensalt_extradata_LDADD = $(COMMON_TEST_OBJECTS)
 test_checksalt_LDADD = $(COMMON_TEST_OBJECTS)

test/gensalt-bcrypt_x.c

@@ -0,0 +1,54 @@
+/* Copyright (C) 2025 Björn Esser <[email protected]>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include "crypt-port.h"
+
+#if INCLUDE_bcrypt_x
+
+#include <errno.h>
+#include <stdio.h>
+
+int
+main (void)
+{
+  char *retval;
+
+  errno = 0;
+  retval = crypt_gensalt ("$2x$", 0, NULL, 0);
+
+  if (retval || errno != EINVAL)
+    {
+      fprintf (stderr, "gensalt: expected \"NULL\", got \"%s\" "
+                       "with errno == %i, instead of %i.\n",
+               retval ? retval : "NULL", errno, EINVAL);
+
+      return 1;
+    }
+
+  return 0;
+}
+
+#else
+
+int
+main (void)
+{
+  return 77; /* UNSUPPORTED */
+}
+
+#endif /* INCLUDE_bcrypt_x */