[LTP] [PATCH] syscalls/add_key02: update to test fix for nonempty NULL payload

[Eric Biggers]

From: Eric Biggers <ebiggers@google.com>

add_key02 was supposed to be a "Basic test for the add_key() syscall",
but it actually happened to test the obscure case of passing a NULL
payload with nonzero length.  This case was mishandled by the kernel,
which either returned EINVAL or crashed with a NULL pointer dereference,
depending on the key type.  (The former applied to the test, as it used
the "user" key type.)  The expected behavior in this case is that the
syscall fail with EFAULT.

Update the test to expect the fixed behavior from v4.12-rc5, and make
the test more thorough by testing additional key types, including ones
that caused a NULL pointer dereference in unfixed kernels.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 testcases/kernel/syscalls/add_key/add_key02.c | 69 ++++++++++++++++++++-------
 1 file changed, 51 insertions(+), 18 deletions(-)

diff --git a/testcases/kernel/syscalls/add_key/add_key02.c b/testcases/kernel/syscalls/add_key/add_key02.c
index 866800d6f..a0ccbdeb1 100644
--- a/testcases/kernel/syscalls/add_key/add_key02.c
+++ b/testcases/kernel/syscalls/add_key/add_key02.c
@@ -1,5 +1,6 @@
 /******************************************************************************
  * Copyright (c) Crackerjack Project., 2007				      *
+ * Copyright (c) 2017 Google, Inc.
  *									      *
  * 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       *
@@ -18,10 +19,17 @@
  ******************************************************************************/
 
 /*
- * Basic test for the add_key() syscall.
+ * Test that the add_key() syscall correctly handles a NULL payload with nonzero
+ * length.  Specifically, it should fail with EFAULT rather than oopsing the
+ * kernel with a NULL pointer dereference or failing with EINVAL, as it did
+ * before (depending on the key type).  This is a regression test for commit
+ * 5649645d725c ("KEYS: fix dereferencing NULL payload with nonzero length").
  *
- * History:   Porting from Crackerjack to LTP is done by
- *	      Manas Kumar Nayak maknayak@in.ibm.com>
+ * Note that none of the key types that exhibited the NULL pointer dereference
+ * are guaranteed to be built into the kernel, so we just test as many as we
+ * can, in the hope of catching one.  We also test with the "user" key type for
+ * good measure, although it was one of the types that failed with EINVAL rather
+ * than dereferencing NULL.
  */
 
 #include "config.h"
@@ -33,36 +41,61 @@
 
 #ifdef HAVE_LINUX_KEYCTL_H
 struct tcase {
-	char *type;
-	char *desc;
-	void *payload;
-	int plen;
-	int exp_errno;
+	const char *type;
+	size_t plen;
 } tcases[] = {
-	{"user", "firstkey", NULL, 1, EINVAL}
+	/*
+	 * The payload length we test for each key type needs to pass initial
+	 * validation but is otherwise arbitrary.  Note: the "rxrpc_s" key type
+	 * requires a payload of exactly 8 bytes.
+	 */
+	{ "asymmetric",		64 },
+	{ "cifs.idmap",		64 },
+	{ "cifs.spnego",	64 },
+	{ "pkcs7_test",		64 },
+	{ "rxrpc",		64 },
+	{ "rxrpc_s",		 8 },
+	{ "user",		64 },
 };
 #endif /* HAVE_LINUX_KEYCTL_H */
 
 static void verify_add_key(unsigned int i)
 {
 #ifdef HAVE_LINUX_KEYCTL_H
-	TEST(tst_syscall(__NR_add_key, tcases[i].type, tcases[i].desc,
-	                 tcases[i].payload, tcases[i].plen,
-	                 KEY_SPEC_USER_KEYRING));
+	TEST(tst_syscall(__NR_add_key, tcases[i].type, "abc:def",
+			 NULL, tcases[i].plen, KEY_SPEC_PROCESS_KEYRING));
 
 	if (TEST_RETURN != -1) {
-		tst_res(TFAIL, "add_key() passed unexpectedly");
+		tst_res(TFAIL,
+			"add_key() with key type '%s' unexpectedly succeeded",
+			tcases[i].type);
 		return;
 	}
 
-	if (TEST_ERRNO == tcases[i].exp_errno) {
-		tst_res(TPASS | TTERRNO, "add_key() failed expectedly");
+	if (TEST_ERRNO == EFAULT) {
+		tst_res(TPASS, "received expected EFAULT with key type '%s'",
+			tcases[i].type);
 		return;
 	}
 
-	tst_res(TFAIL | TTERRNO,
-	        "add_key() failed unexpectedly, expected %s",
-	        tst_strerrno(tcases[i].exp_errno));
+	if (TEST_ERRNO == ENODEV) {
+		tst_res(TCONF, "kernel doesn't support key type '%s'",
+			tcases[i].type);
+		return;
+	}
+
+	/*
+	 * It's possible for the "asymmetric" key type to be supported, but with
+	 * no asymmetric key parsers registered.  In that case, attempting to
+	 * add a key of type asymmetric will fail with EBADMSG.
+	 */
+	if (TEST_ERRNO == EBADMSG && !strcmp(tcases[i].type, "asymmetric")) {
+		tst_res(TCONF, "no asymmetric key parsers are registered");
+		return;
+	}
+
+	tst_res(TFAIL | TTERRNO, "unexpected error with key type '%s'",
+		tcases[i].type);
 #else
 	tst_brk(TCONF, "linux/keyctl.h was missing upon compilation.");
 #endif /* HAVE_LINUX_KEYCTL_H */
-- 
2.13.1.508.gb3defc5cc-goog