[LTP] RFC:[PATCH v1] Added testcase to test mmap with MAP_SHARED_VALIDATE flag

[LTP] RFC:[PATCH v1] Added testcase to test mmap with MAP_SHARED_VALIDATE flag

[Paulson Raja L]

This patch adds a new test case for mmap syscall. It tests the
MAP_SHARED_VALIDATE flag of mmap. The code checks of the
MAP_SHARED_VALIDATE flag return EOPNOTSUPP when mapped with an invalid flag
value. It does so by setting the unused bits of the flag argument.

Signed-off-by: Paulson Raja L. <lpaulsonraja@gmail.com>

diff --git a/testcases/kernel/syscalls/mmap/mmap20.c
b/testcases/kernel/syscalls/mmap/mmap20.c
new file mode 100644
index 000000000..2f6dd5d4d
--- /dev/null
+++ b/testcases/kernel/syscalls/mmap/mmap20.c
@@ -0,0 +1,61 @@
+//SPDX-License-Identifier: GPL-2.0-or-later
+
+/*
+ * Test mmap with MAP_SHARED_VALIDATE flag
+ *
+ * We are testing the MAP_SHARED_VALIDATE flag of mmap() syscall. To check
+ * if there is an invalid flag value, the MAP_SHARED_VALIDATE return
+ * EOPNOTSUPP. The unused bit in the MAP_SHARED_VALIDATE is found, and by
+ * setting the unused bits of the flag argument the flag value becomes
+ * invalid and the error EOPNOTSUPP is produced as expected.
+ */
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <linux/mman.h>
+#include <errno.h>
+#include "tst_test.h"
+
+#define TEST_FILE "file_to_mmap"
+#define TEST_FILE_SIZE 1024
+#define TEST_FILE_MODE 0600
+
+static int fd_file;
+static void *mapped_address = NULL;
+
+static void setup(void)
+{
+ fd_file = SAFE_OPEN(TEST_FILE, O_CREAT | O_RDWR, TEST_FILE_MODE);
+ if (tst_fill_file(TEST_FILE, 'a', TEST_FILE_SIZE, 1))
+ tst_brk(TBROK, "Could not fill the testfile.");
+}
+
+static void cleanup(void)
+{
+ if (fd_file > 0)
+ SAFE_CLOSE(fd_file);
+ if (mapped_address != NULL && mapped_address != MAP_FAILED)
+ SAFE_MUNMAP(mapped_address, TEST_FILE_SIZE);
+}
+
+static void test_mmap(void)
+{
+ mapped_address = mmap(NULL, TEST_FILE_SIZE, PROT_READ | PROT_WRITE,
+      (1 << 7) | (1 << 9) | MAP_SHARED_VALIDATE, fd_file, 0);
+ if (mapped_address != MAP_FAILED)
+ tst_res(TFAIL | TERRNO, "mmap() is successful, but it should have
failed.");
+ else if (errno == EOPNOTSUPP)
+ tst_res(TPASS, "mmap() failed with errno set to EOPNOTSUPP.");
+ else
+ tst_res(TFAIL | TERRNO, "mmap() failed with unexpected error.");
+}
+
+static struct tst_test test = {
+ .min_kver = "4.15",
+ .setup = setup,
+ .cleanup = cleanup,
+ .test_all = test_mmap,
+ .needs_tmpdir = 1,
+};

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Re: [LTP] RFC:[PATCH v1] Added testcase to test mmap with MAP_SHARED_VALIDATE flag

[Cyril Hrubis]

Hi!
> +static void test_mmap(void)
> +{
> + mapped_address = mmap(NULL, TEST_FILE_SIZE, PROT_READ | PROT_WRITE,
> +      (1 << 7) | (1 << 9) | MAP_SHARED_VALIDATE, fd_file, 0);
> + if (mapped_address != MAP_FAILED)
> + tst_res(TFAIL | TERRNO, "mmap() is successful, but it should have
> failed.");
> + else if (errno == EOPNOTSUPP)
> + tst_res(TPASS, "mmap() failed with errno set to EOPNOTSUPP.");
> + else
> + tst_res(TFAIL | TERRNO, "mmap() failed with unexpected error.");
> +}
> +
> +static struct tst_test test = {
> + .min_kver = "4.15",
> + .setup = setup,
> + .cleanup = cleanup,
> + .test_all = test_mmap,
> + .needs_tmpdir = 1,
> +};

First of all all the whitespaces are messed up and some of the lines are
wrapped, quite likely this was done by your email client. Please make
sure to send patches so that they do not get mangled like this.

See: https://www.kernel.org/doc/html/v4.17/process/email-clients.html

-- 
Cyril Hrubis
chrubis@suse.cz

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Re: [LTP] RFC:[PATCH v1] Added testcase to test mmap with MAP_SHARED_VALIDATE flag

[Richard Palethorpe]

Hello,

In principal the test is good, you can remove the RFC.

Please see comments below (in addition to Cyril's).

Paulson Raja L <lpaulsonraja@gmail.com> writes:

> This patch adds a new test case for mmap syscall. It tests the
> MAP_SHARED_VALIDATE flag of mmap. The code checks of the
> MAP_SHARED_VALIDATE flag return EOPNOTSUPP when mapped with an invalid flag
> value. It does so by setting the unused bits of the flag argument.

Would it be possible to use two incompatible flags together instead?

Unused flags can become valid at a later date.

>
> Signed-off-by: Paulson Raja L. <lpaulsonraja@gmail.com>
>
> diff --git a/testcases/kernel/syscalls/mmap/mmap20.c
> b/testcases/kernel/syscalls/mmap/mmap20.c
> new file mode 100644
> index 000000000..2f6dd5d4d
> --- /dev/null
> +++ b/testcases/kernel/syscalls/mmap/mmap20.c
> @@ -0,0 +1,61 @@
> +//SPDX-License-Identifier: GPL-2.0-or-later
> +
> +/*
> + * Test mmap with MAP_SHARED_VALIDATE flag
> + *
> + * We are testing the MAP_SHARED_VALIDATE flag of mmap() syscall. To check
> + * if there is an invalid flag value, the MAP_SHARED_VALIDATE return
> + * EOPNOTSUPP. The unused bit in the MAP_SHARED_VALIDATE is found, and by
> + * setting the unused bits of the flag argument the flag value becomes
> + * invalid and the error EOPNOTSUPP is produced as expected.
> + */
> +#include <stdio.h>
> +#include <sys/types.h>
> +#include <sys/stat.h>
> +#include <fcntl.h>
> +#include <sys/mman.h>
> +#include <linux/mman.h>
> +#include <errno.h>
> +#include "tst_test.h"
> +
> +#define TEST_FILE "file_to_mmap"
> +#define TEST_FILE_SIZE 1024
> +#define TEST_FILE_MODE 0600
> +
> +static int fd_file;
> +static void *mapped_address = NULL;
> +
> +static void setup(void)
> +{
> + fd_file = SAFE_OPEN(TEST_FILE, O_CREAT | O_RDWR, TEST_FILE_MODE);
> + if (tst_fill_file(TEST_FILE, 'a', TEST_FILE_SIZE, 1))
> + tst_brk(TBROK, "Could not fill the testfile.");
> +}
> +
> +static void cleanup(void)
> +{
> + if (fd_file > 0)

It's unlikely, but possible that fd_file is 0, so it should be
initialised to -1 and we check it is > -1.

> + SAFE_CLOSE(fd_file);
> + if (mapped_address != NULL && mapped_address != MAP_FAILED)
> + SAFE_MUNMAP(mapped_address, TEST_FILE_SIZE);
> +}
> +
> +static void test_mmap(void)
> +{
> + mapped_address = mmap(NULL, TEST_FILE_SIZE, PROT_READ | PROT_WRITE,
> +      (1 << 7) | (1 << 9) | MAP_SHARED_VALIDATE, fd_file, 0);

The TEST macro can be used here, which will set errno=0. Possibly errno
is already set to some previous error. (also note you need to then use
TTERRNO below)

> + if (mapped_address != MAP_FAILED)
> + tst_res(TFAIL | TERRNO, "mmap() is successful, but it should have
> failed.");
> + else if (errno == EOPNOTSUPP)
> + tst_res(TPASS, "mmap() failed with errno set to EOPNOTSUPP.");
> + else
> + tst_res(TFAIL | TERRNO, "mmap() failed with unexpected error.");
> +}
> +
> +static struct tst_test test = {
> + .min_kver = "4.15",
> + .setup = setup,
> + .cleanup = cleanup,
> + .test_all = test_mmap,
> + .needs_tmpdir = 1,
> +};



-- 
Thank you,
Richard.

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