[LTP] [PATCH v3 4/9] Test for uname26 exploit CVE-2012-0957

[Richard Palethorpe <rpalethorpe@suse.com>]

Attempt to exploit the uname kernel memory leak which occurred when the
UNAME26 personality was set.

Signed-off-by: Richard Palethorpe <rpalethorpe@suse.com>
---
 configure.ac                  |  1 +
 m4/ltp-uname.m4               | 20 ++++++++++
 testcases/cve/cve-2012-0957.c | 89 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 110 insertions(+)
 create mode 100644 m4/ltp-uname.m4
 create mode 100644 testcases/cve/cve-2012-0957.c

diff --git a/configure.ac b/configure.ac
index 326da8ece..658003972 100644
--- a/configure.ac
+++ b/configure.ac
@@ -193,5 +193,6 @@ LTP_CHECK_KEYUTILS_SUPPORT
 LTP_CHECK_SYNC_ADD_AND_FETCH
 LTP_CHECK_BUILTIN_CLEAR_CACHE
 LTP_CHECK_MMSGHDR
+LTP_CHECK_UNAME_DOMAINNAME
 
 AC_OUTPUT
diff --git a/m4/ltp-uname.m4 b/m4/ltp-uname.m4
new file mode 100644
index 000000000..5a3002200
--- /dev/null
+++ b/m4/ltp-uname.m4
@@ -0,0 +1,20 @@
+dnl Copyright (c) 2017 Richard Palethorpe <rpalethorpe@suse.com>
+dnl
+dnl This program is free software;  you can redistribute it and/or modify
+dnl it under the terms of the GNU General Public License as published by
+dnl the Free Software Foundation; either version 2 of the License, or
+dnl (at your option) any later version.
+dnl
+dnl This program is distributed in the hope that it will be useful,
+dnl but WITHOUT ANY WARRANTY;  without even the implied warranty of
+dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
+dnl the GNU General Public License for more details.
+dnl
+dnl You should have received a copy of the GNU General Public License
+dnl along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+AC_DEFUN([LTP_CHECK_UNAME_DOMAINNAME],[
+AC_CHECK_MEMBERS([struct utsname.domainname],,,[
+#define _GNU_SOURCE
+#include <sys/utsname.h>
+])])
diff --git a/testcases/cve/cve-2012-0957.c b/testcases/cve/cve-2012-0957.c
new file mode 100644
index 000000000..f065735a1
--- /dev/null
+++ b/testcases/cve/cve-2012-0957.c
@@ -0,0 +1,89 @@
+/*
+ * Copyright (c) 2017 Richard Palethorpe <rpalethorpe@suse.com>
+ * Copyright (c) 2012, Kees Cook <keescook@chromium.org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+/*
+ * Check that memory after the string terminator in all the utsname fields has
+ * been zeroed. cve-2012-0957 leaked kernel memory through the release field
+ * when the UNAME26 personality was set.
+ *
+ * Thanks to Kees Cook for the original proof of concept:
+ * http://www.securityfocus.com/bid/55855/info
+ */
+
+#include <string.h>
+#include <sys/utsname.h>
+#include <sys/personality.h>
+#include "tst_test.h"
+
+#define UNAME26 0x0020000
+
+static int check_field(char *bytes, size_t length, char *field)
+{
+	size_t i = strlen(bytes) + 1;
+
+	for (; i < length; i++) {
+		if (bytes[i]) {
+			tst_res(TFAIL, "Bytes leaked in %s!", field);
+			return 1;
+		}
+	}
+	return 0;
+}
+
+
+static void try_leak_bytes(void)
+{
+	struct utsname buf;
+
+	if (uname(&buf))
+		tst_brk(TBROK | TERRNO, "Call to uname failed");
+
+#define CHECK_FIELD(field_name) \
+	(check_field(buf.field_name, ARRAY_SIZE(buf.field_name), #field_name))
+
+	if (!(CHECK_FIELD(release) |
+	    CHECK_FIELD(sysname) |
+	    CHECK_FIELD(nodename) |
+	    CHECK_FIELD(version) |
+	    CHECK_FIELD(machine) |
+#ifdef HAVE_STRUCT_UTSNAME_DOMAINNAME
+	    CHECK_FIELD(domainname) |
+#endif
+		    0)) {
+		tst_res(TPASS, "All fields zeroed after string terminator");
+	}
+#undef CHECK_FIELD
+}
+
+static void run(unsigned int test_nr)
+{
+	if (!test_nr) {
+		tst_res(TINFO, "Calling uname with default personality");
+		try_leak_bytes();
+	} else {
+		if (personality(PER_LINUX | UNAME26) < 0)
+			tst_brk(TCONF | TERRNO,
+				"Could not change personality to UNAME26");
+		tst_res(TINFO, "Calling uname with UNAME26 personality");
+		try_leak_bytes();
+	}
+}
+
+static struct tst_test test = {
+	.test = run,
+	.tcnt = 2,
+};
-- 
2.12.2