[PATCH v9 6/6] selftests: tdx: Test GetQuote TDX attestation feature

Kuppuswamy Sathyanarayanan
2022-07-28T03:45:05Z

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@intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---
tools/testing/selftests/tdx/tdx_attest_test.c | 74 ++++++++++++++++---
1 file changed, 64 insertions(+), 10 deletions(-)

diff --git a/tools/testing/selftests/tdx/tdx_attest_test.c b/tools/testing/selftests/tdx/tdx_attest_test.c
index 7155cc751eaa..14125b97e308 100644
--- a/tools/testing/selftests/tdx/tdx_attest_test.c
+++ b/tools/testing/selftests/tdx/tdx_attest_test.c
@@ -23,6 +23,7 @@

#define devname "/dev/tdx-guest"
#define HEX_DUMP_SIZE 8
+#define QUOTE_SIZE 8192

/*
* struct td_info - It contains the measurements and initial configuration of
@@ -114,17 +115,11 @@ static void print_array_hex(const char *title, const char *prefix_str,
}
#endif

-TEST(verify_report)
+/* Helper function to get TDREPORT */
+long get_tdreport(int devfd, __u8 *reportdata, __u8 *tdreport)
{
- __u8 reportdata[TDX_REPORTDATA_LEN];
- struct tdreport_data *tdr_data;
- __u8 tdreport[TDX_REPORT_LEN];
struct tdx_report_req req;
- int devfd, i;
-
- devfd = open(devname, O_RDWR | O_SYNC);
-
- ASSERT_LT(0, devfd);
+ int i;

/* Generate sample report data */
for (i = 0; i < TDX_REPORTDATA_LEN; i++)
@@ -137,8 +132,22 @@ TEST(verify_report)
req.tdreport = (__u64)tdreport;
req.tdr_len = TDX_REPORT_LEN;

+ return ioctl(devfd, TDX_CMD_GET_REPORT, &req);
+}
+
+TEST(verify_report)
+{
+ __u8 reportdata[TDX_REPORTDATA_LEN];
+ struct tdreport_data *tdr_data;
+ __u8 tdreport[TDX_REPORT_LEN];
+ int devfd;
+
+ devfd = open(devname, O_RDWR | O_SYNC);
+
+ ASSERT_LT(0, devfd);
+
/* Get TDREPORT */
- ASSERT_EQ(0, ioctl(devfd, TDX_CMD_GET_REPORT, &req));
+ ASSERT_EQ(0, get_tdreport(devfd, reportdata, tdreport));

tdr_data = (struct tdreport_data *)tdreport;

@@ -157,4 +166,49 @@ TEST(verify_report)
ASSERT_EQ(0, close(devfd));
}

+TEST(verify_quote)
+{
+ __u8 reportdata[TDX_REPORTDATA_LEN];
+ struct tdx_quote_hdr *quote_hdr;
+ struct tdx_quote_req quote_req;
+ __u8 *quote_buf = NULL;
+ __u64 quote_buf_size;
+ int devfd;
+
+ /* Open attestation device */
+ devfd = open(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_tdreport(devfd, reportdata,
+ (__u8 *)&quote_hdr->data));
+
+ /* Fill GetQuote request */
+ quote_req.buf = (__u64)quote_buf;
+ quote_req.len = quote_buf_size;
+
+ ASSERT_EQ(0, ioctl(devfd, TDX_CMD_GET_QUOTE, &quote_req));
+
+ /* Check whether GetQuote request is successful */
+ EXPECT_EQ(0, quote_hdr->status);
+
+ free(quote_buf);
+}
+
TEST_HARNESS_MAIN
--
2.25.1