[PATCH v2 2/3] selftests/hid: hidraw: forge wrong ioctls and tests them

[Benjamin Tissoires <bentiss@kernel.org>]

We also need coverage for when the malicious user is not using the
proper ioctls definitions and tries to work around the driver.

Suggested-by: Arnd Bergmann <arnd@kernel.org>
Co-developed-by: claude-4-sonnet
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
---
 tools/testing/selftests/hid/hidraw.c | 127 +++++++++++++++++++++++++++++++++++
 1 file changed, 127 insertions(+)

diff --git a/tools/testing/selftests/hid/hidraw.c b/tools/testing/selftests/hid/hidraw.c
index 6d61d03e2ef05e1900fe5a3938d93421717b2621..d625772f8b7cf71fd94956d3a49d54ff44e2b34d 100644
--- a/tools/testing/selftests/hid/hidraw.c
+++ b/tools/testing/selftests/hid/hidraw.c
@@ -332,6 +332,133 @@ TEST_F(hidraw, ioctl_gfeature_invalid)
 	ASSERT_EQ(errno, EIO) TH_LOG("expected EIO, got errno %d", errno);
 }
 
+/*
+ * Test ioctl with incorrect nr bits
+ */
+TEST_F(hidraw, ioctl_invalid_nr)
+{
+	char buf[256] = {0};
+	int err;
+	unsigned int bad_cmd;
+
+	/*
+	 * craft an ioctl command with wrong _IOC_NR bits
+	 */
+	bad_cmd = _IOC(_IOC_WRITE|_IOC_READ, 'H', 0x00, sizeof(buf)); /* 0 is not valid */
+
+	/* test the ioctl */
+	err = ioctl(self->hidraw_fd, bad_cmd, buf);
+	ASSERT_LT(err, 0) TH_LOG("ioctl read-write with wrong _IOC_NR (0) should have failed");
+	ASSERT_EQ(errno, ENOTTY)
+		TH_LOG("expected ENOTTY for wrong read-write _IOC_NR (0), got errno %d", errno);
+
+	/*
+	 * craft an ioctl command with wrong _IOC_NR bits
+	 */
+	bad_cmd = _IOC(_IOC_READ, 'H', 0x00, sizeof(buf)); /* 0 is not valid */
+
+	/* test the ioctl */
+	err = ioctl(self->hidraw_fd, bad_cmd, buf);
+	ASSERT_LT(err, 0) TH_LOG("ioctl read-only with wrong _IOC_NR (0) should have failed");
+	ASSERT_EQ(errno, ENOTTY)
+		TH_LOG("expected ENOTTY for wrong read-only _IOC_NR (0), got errno %d", errno);
+
+	/* also test with bigger number */
+	bad_cmd = _IOC(_IOC_READ, 'H', 0x42, sizeof(buf)); /* 0x42 is not valid as well */
+
+	err = ioctl(self->hidraw_fd, bad_cmd, buf);
+	ASSERT_LT(err, 0) TH_LOG("ioctl read-only with wrong _IOC_NR (0x42) should have failed");
+	ASSERT_EQ(errno, ENOTTY)
+		TH_LOG("expected ENOTTY for wrong read-only _IOC_NR (0x42), got errno %d", errno);
+
+	/* also test with bigger number: 0x42 is not valid as well */
+	bad_cmd = _IOC(_IOC_WRITE|_IOC_READ, 'H', 0x42, sizeof(buf));
+
+	err = ioctl(self->hidraw_fd, bad_cmd, buf);
+	ASSERT_LT(err, 0) TH_LOG("ioctl read-write with wrong _IOC_NR (0x42) should have failed");
+	ASSERT_EQ(errno, ENOTTY)
+		TH_LOG("expected ENOTTY for wrong read-write _IOC_NR (0x42), got errno %d", errno);
+}
+
+/*
+ * Test ioctl with incorrect type bits
+ */
+TEST_F(hidraw, ioctl_invalid_type)
+{
+	char buf[256] = {0};
+	int err;
+	unsigned int bad_cmd;
+
+	/*
+	 * craft an ioctl command with wrong _IOC_TYPE bits
+	 */
+	bad_cmd = _IOC(_IOC_WRITE|_IOC_READ, 'I', 0x01, sizeof(buf)); /* 'I' should be 'H' */
+
+	/* test the ioctl */
+	err = ioctl(self->hidraw_fd, bad_cmd, buf);
+	ASSERT_LT(err, 0) TH_LOG("ioctl with wrong _IOC_TYPE (I) should have failed");
+	ASSERT_EQ(errno, EINVAL) TH_LOG("expected EINVAL for wrong _IOC_NR, got errno %d", errno);
+}
+
+/*
+ * Test HIDIOCGFEATURE ioctl with incorrect _IOC_DIR bits
+ */
+TEST_F(hidraw, ioctl_gfeature_invalid_dir)
+{
+	__u8 buf[10] = {0};
+	int err;
+	unsigned int bad_cmd;
+
+	/* set report ID 1 in first byte */
+	buf[0] = 1;
+
+	/*
+	 * craft an ioctl command with wrong _IOC_DIR bits
+	 * HIDIOCGFEATURE should have _IOC_WRITE|_IOC_READ, let's use only _IOC_WRITE
+	 */
+	bad_cmd = _IOC(_IOC_WRITE, 'H', 0x07, sizeof(buf)); /* should be _IOC_WRITE|_IOC_READ */
+
+	/* try to get feature report with wrong direction bits */
+	err = ioctl(self->hidraw_fd, bad_cmd, buf);
+	ASSERT_LT(err, 0) TH_LOG("HIDIOCGFEATURE with wrong _IOC_DIR should have failed");
+	ASSERT_EQ(errno, EINVAL) TH_LOG("expected EINVAL for wrong _IOC_DIR, got errno %d", errno);
+
+	/* also test with only _IOC_READ */
+	bad_cmd = _IOC(_IOC_READ, 'H', 0x07, sizeof(buf)); /* should be _IOC_WRITE|_IOC_READ */
+
+	err = ioctl(self->hidraw_fd, bad_cmd, buf);
+	ASSERT_LT(err, 0) TH_LOG("HIDIOCGFEATURE with wrong _IOC_DIR should have failed");
+	ASSERT_EQ(errno, EINVAL) TH_LOG("expected EINVAL for wrong _IOC_DIR, got errno %d", errno);
+}
+
+/*
+ * Test read-only ioctl with incorrect _IOC_DIR bits
+ */
+TEST_F(hidraw, ioctl_readonly_invalid_dir)
+{
+	char buf[256] = {0};
+	int err;
+	unsigned int bad_cmd;
+
+	/*
+	 * craft an ioctl command with wrong _IOC_DIR bits
+	 * HIDIOCGRAWNAME should have _IOC_READ, let's use _IOC_WRITE
+	 */
+	bad_cmd = _IOC(_IOC_WRITE, 'H', 0x04, sizeof(buf)); /* should be _IOC_READ */
+
+	/* try to get device name with wrong direction bits */
+	err = ioctl(self->hidraw_fd, bad_cmd, buf);
+	ASSERT_LT(err, 0) TH_LOG("HIDIOCGRAWNAME with wrong _IOC_DIR should have failed");
+	ASSERT_EQ(errno, EINVAL) TH_LOG("expected EINVAL for wrong _IOC_DIR, got errno %d", errno);
+
+	/* also test with _IOC_WRITE|_IOC_READ */
+	bad_cmd = _IOC(_IOC_WRITE|_IOC_READ, 'H', 0x04, sizeof(buf)); /* should be only _IOC_READ */
+
+	err = ioctl(self->hidraw_fd, bad_cmd, buf);
+	ASSERT_LT(err, 0) TH_LOG("HIDIOCGRAWNAME with wrong _IOC_DIR should have failed");
+	ASSERT_EQ(errno, EINVAL) TH_LOG("expected EINVAL for wrong _IOC_DIR, got errno %d", errno);
+}
+
 /*
  * Test HIDIOCSFEATURE ioctl to set feature report
  */

-- 
2.51.0