[PATCH v3 3/3] selftests/tdx: Test GetQuote TDX attestation feature

Kuppuswamy Sathyanarayanan
2023-05-14T07:24:10Z

In TDX guest, the second stage of the attestation process is Quote
generation. This process is required to convert the locally generated
TDREPORT into a remotely verifiable Quote. It involves sending the
TDREPORT data to a Quoting Enclave (QE) which will verify the
integrity of the TDREPORT and sign it with an attestation key.

Intel's TDX attestation driver exposes TDX_CMD_GET_QUOTE IOCTL to
allow the user agent to get the TD Quote.

Add a kernel selftest module to verify the Quote generation feature.

TD Quote generation involves following steps:

* Get the TDREPORT data using TDX_CMD_GET_REPORT IOCTL.
* Embed the TDREPORT data in quote buffer and request for quote
generation via TDX_CMD_GET_QUOTE IOCTL request.
* Upon completion of the GetQuote request, check for non zero value
in the status field of Quote header to make sure the generated
quote is valid.

Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Erdem Aktas <erdemaktas@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---

Changes since v2:
* Adapted to struct tdx_quote_hdr -> struct tdx_quote_buf rename.

tools/testing/selftests/tdx/tdx_guest_test.c | 65 ++++++++++++++++++--
1 file changed, 59 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/tdx/tdx_guest_test.c b/tools/testing/selftests/tdx/tdx_guest_test.c
index 81d8cb88ea1a..0b4b4293b9cb 100644
--- a/tools/testing/selftests/tdx/tdx_guest_test.c
+++ b/tools/testing/selftests/tdx/tdx_guest_test.c
@@ -18,6 +18,7 @@
#define TDX_GUEST_DEVNAME "/dev/tdx_guest"
#define HEX_DUMP_SIZE 8
#define DEBUG 0
+#define QUOTE_SIZE 8192

/**
* struct tdreport_type - Type header of TDREPORT_STRUCT.
@@ -128,21 +129,29 @@ static void print_array_hex(const char *title, const char *prefix_str,
printf("\n");
}

+/* Helper function to get TDREPORT */
+long get_tdreport0(int devfd, struct tdx_report_req *req)
+{
+ int i;
+
+ /* Generate sample report data */
+ for (i = 0; i < TDX_REPORTDATA_LEN; i++)
+ req->reportdata[i] = i;
+
+ return ioctl(devfd, TDX_CMD_GET_REPORT0, req);
+}
+
TEST(verify_report)
{
struct tdx_report_req req;
struct tdreport *tdreport;
- int devfd, i;
+ int devfd;

devfd = open(TDX_GUEST_DEVNAME, O_RDWR | O_SYNC);
ASSERT_LT(0, devfd);

- /* Generate sample report data */
- for (i = 0; i < TDX_REPORTDATA_LEN; i++)
- req.reportdata[i] = i;
-
/* Get TDREPORT */
- ASSERT_EQ(0, ioctl(devfd, TDX_CMD_GET_REPORT0, &req));
+ ASSERT_EQ(0, get_tdreport0(devfd, &req));

if (DEBUG) {
print_array_hex("\n\t\tTDX report data\n", "",
@@ -160,4 +169,48 @@ TEST(verify_report)
ASSERT_EQ(0, close(devfd));
}

+TEST(verify_quote)
+{
+ struct tdx_quote_buf *quote_buf;
+ struct tdx_report_req rep_req;
+ struct tdx_quote_req req;
+ __u64 quote_buf_size;
+ int devfd;
+
+ /* Open attestation device */
+ devfd = open(TDX_GUEST_DEVNAME, O_RDWR | O_SYNC);
+
+ ASSERT_LT(0, devfd);
+
+ /* Add size for quote header */
+ quote_buf_size = sizeof(*quote_buf) + QUOTE_SIZE;
+
+ /* Allocate quote buffer */
+ quote_buf = (struct tdx_quote_buf *)malloc(quote_buf_size);
+ ASSERT_NE(NULL, quote_buf);
+
+ /* Initialize GetQuote header */
+ quote_buf->version = 1;
+ quote_buf->status = GET_QUOTE_SUCCESS;
+ quote_buf->in_len = TDX_REPORT_LEN;
+ quote_buf->out_len = 0;
+
+ /* Get TDREPORT data */
+ ASSERT_EQ(0, get_tdreport0(devfd, &rep_req));
+
+ /* Fill GetQuote request */
+ memcpy(quote_buf->data, rep_req.tdreport, TDX_REPORT_LEN);
+ req.buf = (__u64)quote_buf;
+ req.len = quote_buf_size;
+
+ ASSERT_EQ(0, ioctl(devfd, TDX_CMD_GET_QUOTE, &req));
+
+ /* Check whether GetQuote request is successful */
+ EXPECT_EQ(0, quote_buf->status);
+
+ free(quote_buf);
+
+ ASSERT_EQ(0, close(devfd));
+}
+
TEST_HARNESS_MAIN
--
2.34.1