Fix a few external crypt() issues on musl

ext/standard/crypt.c

@@ -177,7 +177,19 @@ PHPAPI zend_string *php_crypt(const char *password, const int pass_len, const ch
 
 	if (!crypt_res || (salt[0] == '*' && salt[1] == '0')) {
 		return NULL;
-	} else {
+	}
+	else if (!strcmp(crypt_res, "*")) {
+		/* Musl crypt() uses "*" as a failure token rather
+		 * than the "*0" that libxcrypt/PHP use. Our test
+		 * suite in particular looks for "*0" in a few places,
+		 * and it would be annoying to handle both values
+		 * explicitly. It seems wise to abstract this detail
+		 * from the end user: if it's annoying for us, imagine
+		 * how annoying it would be in end-user code; not that
+		 * anyone would think of it. */
+		return NULL;
+	}
+	else {
 		result = zend_string_init(crypt_res, strlen(crypt_res), 0);
 		return result;
 	}

ext/standard/tests/crypt/des_fallback_invalid_salt.phpt

@@ -3,8 +3,11 @@ Test DES with invalid fallback
 --FILE--
 <?php
 
-var_dump(crypt("test", "$#"));
-var_dump(crypt("test", "$5zd$01"));
+// musl tries to support invalid DES salts unless they would violate
+// the /etc/passwd format, so we include colons to ensure that musl
+// crypt() will fail on these inputs as well.
+var_dump(crypt("test", "$:#"));
+var_dump(crypt("test", "$:5zd$01\n"));
 
 ?>
 --EXPECT--

ext/standard/tests/strings/crypt_sha256.phpt

@@ -39,12 +39,10 @@ $tests = array(
         'a short string',
         '$5$rounds=123456$asaltof16chars..$gP3VQ/6X7UUEW3HkBn2w1/Ptq2jxPyzV/cZKmF/wJvD'
     ),
+
+    // The "too many rounds" behavior depends on the crypt()
+    // implementation, but for now everyone agrees on what to do.
     8 => array(
-        '$5$rounds=10$roundstoolow',
-        'the number of rounds is too low',
-        '*0'
-    ),
-    9 => array(
         '$5$rounds=1000000000$roundstoohigh',
         'the number of rounds is too high',
         '*0'