A regression test to ensure that arc4random returns different sequences

in parent and child processes after a fork.

2 files changed, 91 insertions, 1 deletions

diff --git a/tools/regression/lib/libc/gen/Makefile b/tools/regression/lib/libc/gen/Makefile
index 72a0750..8517913 100644
--- a/tools/regression/lib/libc/gen/Makefile
+++ b/tools/regression/lib/libc/gen/Makefile
@@ -1,6 +1,7 @@
 # $FreeBSD$
 
-TESTS=	test-fmtcheck test-fnmatch test-fpclassify test-posix_spawn test-wordexp
+TESTS=	test-arc4random test-fmtcheck test-fnmatch \
+	test-fpclassify test-posix_spawn test-wordexp
 
 .PHONY: tests
 tests: ${TESTS}
diff --git a/tools/regression/lib/libc/gen/test-arc4random.c b/tools/regression/lib/libc/gen/test-arc4random.c
new file mode 100644
index 0000000..eb3d88c
--- /dev/null
+++ b/tools/regression/lib/libc/gen/test-arc4random.c
@@ -0,0 +1,89 @@
+/*-
+ * Copyright (c) 2011 David Schultz
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+/*
+ * BUFSIZE is the number of bytes of rc4 output to compare.  The probability
+ * that this test fails spuriously is 2**(-BUFSIZE * 8).
+ */
+#define	BUFSIZE		8
+
+/*
+ * Test whether arc4random_buf() returns the same sequence of bytes in both
+ * parent and child processes.  (Hint: It shouldn't.)
+ */
+int main(int argc, char *argv[]) {
+	struct shared_page {
+		char parentbuf[BUFSIZE];
+		char childbuf[BUFSIZE];
+	} *page;
+	pid_t pid;
+	char c;
+
+	printf("1..1\n");
+
+	page = mmap(NULL, sizeof(struct shared_page), PROT_READ | PROT_WRITE,
+		    MAP_ANON | MAP_SHARED, -1, 0);
+	if (page == MAP_FAILED) {
+		printf("fail 1 - mmap\n");
+		exit(1);
+	}
+
+	arc4random_buf(&c, 1);
+
+	pid = fork();
+	if (pid < 0) {
+		printf("fail 1 - fork\n");
+		exit(1);
+	}
+	if (pid == 0) {
+		/* child */
+		arc4random_buf(page->childbuf, BUFSIZE);
+		exit(0);
+	} else {
+		/* parent */
+		int status;
+		arc4random_buf(page->parentbuf, BUFSIZE);
+		wait(&status);
+	}
+	if (memcmp(page->parentbuf, page->childbuf, BUFSIZE) == 0) {
+		printf("fail 1 - sequences are the same\n");
+		exit(1);
+	}
+
+	printf("ok 1 - sequences are different\n");
+	exit(0);
+}