Give unused param a name.

Fixes builds on platforms that do have fido2 but don't have
fido_dev_is_winhello.

openbsd-compat/Makefile.in

@@ -17,7 +17,9 @@ INSTALL=@INSTALL@
 LDFLAGS=-L. @LDFLAGS@
 LDFLAGS_NOPIE=-L. -Lopenbsd-compat/ @LDFLAGS_NOPIE@
 
-OPENBSD=base64.o \
+OPENBSD=arc4random.o \
+	arc4random_uniform.o \
+	base64.o \
 	basename.o \
 	bcrypt_pbkdf.o \
 	bindresvport.o \
@@ -64,8 +66,7 @@ OPENBSD=base64.o \
 	timingsafe_bcmp.o \
 	vis.o
 
-COMPAT=	arc4random.o \
-	bsd-asprintf.o \
+COMPAT= bsd-asprintf.o \
 	bsd-closefrom.o \
 	bsd-cygwin_util.o \
 	bsd-err.o \

openbsd-compat/arc4random_uniform.c

@@ -0,0 +1,64 @@
+/* OPENBSD ORIGINAL: lib/libc/crypt/arc4random_uniform.c */
+
+/*	$OpenBSD: arc4random_uniform.c,v 1.3 2019/01/20 02:59:07 bcook Exp $	*/
+
+/*
+ * Copyright (c) 2008, Damien Miller <djm@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include "includes.h"
+
+#include <stdint.h>
+#ifdef HAVE_STDINT_H
+# include <stdlib.h>
+#endif
+
+#ifndef HAVE_ARC4RANDOM_UNIFORM
+/*
+ * Calculate a uniformly distributed random number less than upper_bound
+ * avoiding "modulo bias".
+ *
+ * Uniformity is achieved by generating new random numbers until the one
+ * returned is outside the range [0, 2**32 % upper_bound).  This
+ * guarantees the selected random number will be inside
+ * [2**32 % upper_bound, 2**32) which maps back to [0, upper_bound)
+ * after reduction modulo upper_bound.
+ */
+uint32_t
+arc4random_uniform(uint32_t upper_bound)
+{
+	uint32_t r, min;
+
+	if (upper_bound < 2)
+		return 0;
+
+	/* 2**32 % x == (2**32 - x) % x */
+	min = -upper_bound % upper_bound;
+
+	/*
+	 * This could theoretically loop forever but each retry has
+	 * p > 0.5 (worst case, usually far better) of selecting a
+	 * number inside the range we need, so it should rarely need
+	 * to re-roll.
+	 */
+	for (;;) {
+		r = arc4random();
+		if (r >= min)
+			break;
+	}
+
+	return r % upper_bound;
+}
+#endif /* !HAVE_ARC4RANDOM_UNIFORM */

openbsd-compat/openbsd-compat.h

@@ -232,7 +232,7 @@ void arc4random_buf(void *, size_t);
 #endif
 
 #ifndef HAVE_ARC4RANDOM_UNIFORM
-u_int32_t arc4random_uniform(u_int32_t);
+uint32_t arc4random_uniform(uint32_t);
 #endif
 
 #ifndef HAVE_ASPRINTF

sk-usbhid.c

@@ -383,7 +383,7 @@ fido_assert_set_clientdata(fido_assert_t *assert, const u_char *ptr, size_t len)
 
 #ifndef HAVE_FIDO_DEV_IS_WINHELLO
 static bool
-fido_dev_is_winhello(const fido_dev_t *)
+fido_dev_is_winhello(const fido_dev_t *fdev)
 {
 	return false;
 }