[LTP] [PATCH v2 3/3] syscalls/capset04: add new EPERM error test with vfs cap support

Yang Xu
2020-01-10T10:21:42Z

Now, most linux distributions has VFS capabilities supports, so
modifying other process cap is never permitted. This case from old
capset02.c.

Signed-off-by: Yang Xu <xuyang2018.jy@cn.fujitsu.com>
---
runtest/syscalls | 1 +
testcases/kernel/syscalls/capset/.gitignore | 1 +
testcases/kernel/syscalls/capset/capset04.c | 81 +++++++++++++++++++++
3 files changed, 83 insertions(+)
create mode 100644 testcases/kernel/syscalls/capset/capset04.c

diff --git a/runtest/syscalls b/runtest/syscalls
index 4f481be6d..f58fefe17 100644
--- a/runtest/syscalls
+++ b/runtest/syscalls
@@ -45,6 +45,7 @@ capget02 capget02
capset01 capset01
capset02 capset02
capset03 capset03
+capset04 capset04

cacheflush01 cacheflush01

diff --git a/testcases/kernel/syscalls/capset/.gitignore b/testcases/kernel/syscalls/capset/.gitignore
index 3f9a4d5e8..d0a7a13a4 100644
--- a/testcases/kernel/syscalls/capset/.gitignore
+++ b/testcases/kernel/syscalls/capset/.gitignore
@@ -1,3 +1,4 @@
/capset01
/capset02
/capset03
+/capset04
diff --git a/testcases/kernel/syscalls/capset/capset04.c b/testcases/kernel/syscalls/capset/capset04.c
new file mode 100644
index 000000000..895b62e17
--- /dev/null
+++ b/testcases/kernel/syscalls/capset/capset04.c
@@ -0,0 +1,81 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) Wipro Technologies Ltd, 2002. All Rights Reserved.
+ * Author: Saji Kumar.V.R <saji.kumar@wipro.com>
+ *
+ * Tests whether we can use capset() to modify the capabilities of a thread
+ * other than itself. Now, most linux distributions with kernel supporting
+ * VFS capabilities, this should be never permitted.
+ */
+#include <stdlib.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include "tst_test.h"
+#include "lapi/syscalls.h"
+#include <linux/capability.h>
+
+static struct __user_cap_header_struct *header;
+static struct __user_cap_data_struct *data;
+static pid_t child_pid;
+static int clean_nflag;
+static void cleanup(void);
+
+static void child_func(void)
+{
+ for (;;)
+ sleep(10);
+}
+
+static void verify_capset(void)
+{
+ child_pid = SAFE_FORK();
+ if (child_pid == 0) {
+ child_func();
+ exit(0);
+ }
+
+ clean_nflag = 0;
+ header->pid = child_pid;
+
+ TEST(tst_syscall(__NR_capset, header, data));
+ if (TST_RET == 0) {
+ tst_res(TFAIL, "capset succeed unexpectedly");
+ cleanup();
+ return;
+ }
+ if (TST_ERR == EPERM)
+ tst_res(TPASS, "capset doesn't can modify other process capabilities");
+ else
+ tst_res(TFAIL | TTERRNO, "capset expected EPERM, bug got");
+
+ cleanup();
+}
+
+static void setup(void)
+{
+ header->version = 0x20080522;
+ TEST(tst_syscall(__NR_capget, header, data));
+ if (TST_RET == -1)
+ tst_brk(TBROK | TTERRNO, "capget data failed");
+}
+
+static void cleanup(void)
+{
+ if (child_pid > 0 && !clean_nflag) {
+ SAFE_KILL(child_pid, SIGTERM);
+ SAFE_WAIT(NULL);
+ clean_nflag = 1;
+ }
+}
+
+static struct tst_test test = {
+ .setup = setup,
+ .cleanup = cleanup,
+ .test_all = verify_capset,
+ .forks_child = 1,
+ .bufs = (struct tst_buffers []) {
+ {&header, .size = sizeof(*header)},
+ {&data, .size = 2 * sizeof(*data)},
+ {},
+ }
+};
--
2.18.0