[PATCH v2 3/3] selftests/tdx: Test GetQuote TDX attestation feature

[Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>]

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
integerity of the TDREPORT and sign it with an attestation key.

Intel's TDX attestation driver exposes TDX_CMD_GET_QUOTE IOCTL to
allow user agent 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@xxxxxxxxx>
Reviewed-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Reviewed-by: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx>
Reviewed-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
---
 tools/testing/selftests/tdx/tdx_guest_test.c | 68 ++++++++++++++++++--
 1 file changed, 62 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..2eccde54185b 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 +169,51 @@ TEST(verify_report)
 	ASSERT_EQ(0, close(devfd));
 }
 
+TEST(verify_quote)
+{
+	struct tdx_quote_hdr *quote_hdr;
+	struct tdx_report_req rep_req;
+	struct tdx_quote_req req;
+	__u64 quote_buf_size;
+	__u8 *quote_buf;
+	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_hdr) + QUOTE_SIZE;
+
+	/* Allocate quote buffer */
+	quote_buf = malloc(quote_buf_size);
+	ASSERT_NE(NULL, quote_buf);
+
+	quote_hdr = (struct tdx_quote_hdr *)quote_buf;
+
+	/* Initialize GetQuote header */
+	quote_hdr->version = 1;
+	quote_hdr->status  = GET_QUOTE_SUCCESS;
+	quote_hdr->in_len  = TDX_REPORT_LEN;
+	quote_hdr->out_len = 0;
+
+	/* Get TDREPORT data */
+	ASSERT_EQ(0, get_tdreport0(devfd, &rep_req));
+
+	/* Fill GetQuote request */
+	memcpy(quote_hdr->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_hdr->status);
+
+	free(quote_buf);
+
+	ASSERT_EQ(0, close(devfd));
+}
+
 TEST_HARNESS_MAIN
-- 
2.34.1