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selftests/tdx: Test TDX attestation GetReport support

Attestation is used to verify the trustworthiness of a TDX guest. During the guest bring-up, the Intel TDX module measures and records the initial contents and configuration of the guest, and at runtime, guest software uses runtime measurement registers (RMTRs) to measure and record details related to kernel image, command line params, ACPI tables, initrd, etc. At guest runtime, the attestation process is used to attest to these measurements. The first step in the TDX attestation process is to get the TDREPORT data. It is a fixed size data structure generated by the TDX module which includes the above mentioned measurements data, a MAC ID to protect the integrity of the TDREPORT, and a 64-Byte of user specified data passed during TDREPORT request which can uniquely identify the TDREPORT. Intel's TDX guest driver exposes TDX_CMD_GET_REPORT0 IOCTL interface to enable guest userspace to get the TDREPORT subtype 0. Add a kernel self test module to test this ABI and verify the validity of the generated TDREPORT.

Kuppuswamy Sathyanarayanan committed 3 years ago

Commit 00e07cf1 parent 6c8c1404 files · +172 −0Browse files

Unified · Split

4 files
  1. tools/testing/selftests/Makefile +1 −0
  2. tools/testing/selftests/tdx/Makefile +7 −0
  3. tools/testing/selftests/tdx/config +1 −0
  4. tools/testing/selftests/tdx/tdx_guest_test.c +163 −0
tools/testing/selftests/Makefile+1−0
@@ -74,6 +74,7 @@ TARGETS += sync · 73 unmodified lines
74TARGETS += syscall_user_dispatch74TARGETS += syscall_user_dispatch
75TARGETS += sysctl75TARGETS += sysctl
76TARGETS += tc-testing76TARGETS += tc-testing
77TARGETS += tdx
77TARGETS += timens78TARGETS += timens
78ifneq (1, $(quicktest))79ifneq (1, $(quicktest))
79TARGETS += timers80TARGETS += timers
tools/testing/selftests/tdx/Makefile+7−0
@@ -0,0 +1,7 @@
1# SPDX-License-Identifier: GPL-2.0
2
3CFLAGS += -O3 -Wl,-no-as-needed -Wall -static
4
5TEST_GEN_PROGS := tdx_guest_test
6
7include ../lib.mk
tools/testing/selftests/tdx/config+1−0
@@ -0,0 +1 @@
1CONFIG_TDX_GUEST_DRIVER=y
tools/testing/selftests/tdx/tdx_guest_test.c+163−0
@@ -0,0 +1,163 @@
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Test TDX guest features
4 *
5 * Copyright (C) 2022 Intel Corporation.
6 *
7 * Author: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
8 */
9
10#include <sys/ioctl.h>
11
12#include <errno.h>
13#include <fcntl.h>
14
15#include "../kselftest_harness.h"
16#include "../../../../include/uapi/linux/tdx-guest.h"
17
18#define TDX_GUEST_DEVNAME "/dev/tdx_guest"
19#define HEX_DUMP_SIZE 8
20#define DEBUG 0
21
22/**
23 * struct tdreport_type - Type header of TDREPORT_STRUCT.
24 * @type: Type of the TDREPORT (0 - SGX, 81 - TDX, rest are reserved)
25 * @sub_type: Subtype of the TDREPORT (Default value is 0).
26 * @version: TDREPORT version (Default value is 0).
27 * @reserved: Added for future extension.
28 *
29 * More details can be found in TDX v1.0 module specification, sec
30 * titled "REPORTTYPE".
31 */
32struct tdreport_type {
33 __u8 type;
34 __u8 sub_type;
35 __u8 version;
36 __u8 reserved;
37};
38
39/**
40 * struct reportmac - TDX guest report data, MAC and TEE hashes.
41 * @type: TDREPORT type header.
42 * @reserved1: Reserved for future extension.
43 * @cpu_svn: CPU security version.
44 * @tee_tcb_info_hash: SHA384 hash of TEE TCB INFO.
45 * @tee_td_info_hash: SHA384 hash of TDINFO_STRUCT.
46 * @reportdata: User defined unique data passed in TDG.MR.REPORT request.
47 * @reserved2: Reserved for future extension.
48 * @mac: CPU MAC ID.
49 *
50 * It is MAC-protected and contains hashes of the remainder of the
51 * report structure along with user provided report data. More details can
52 * be found in TDX v1.0 Module specification, sec titled "REPORTMACSTRUCT"
53 */
54struct reportmac {
55 struct tdreport_type type;
56 __u8 reserved1[12];
57 __u8 cpu_svn[16];
58 __u8 tee_tcb_info_hash[48];
59 __u8 tee_td_info_hash[48];
60 __u8 reportdata[64];
61 __u8 reserved2[32];
62 __u8 mac[32];
63};
64
65/**
66 * struct td_info - TDX guest measurements and configuration.
67 * @attr: TDX Guest attributes (like debug, spet_disable, etc).
68 * @xfam: Extended features allowed mask.
69 * @mrtd: Build time measurement register.
70 * @mrconfigid: Software-defined ID for non-owner-defined configuration
71 * of the guest - e.g., run-time or OS configuration.
72 * @mrowner: Software-defined ID for the guest owner.
73 * @mrownerconfig: Software-defined ID for owner-defined configuration of
74 * the guest - e.g., specific to the workload.
75 * @rtmr: Run time measurement registers.
76 * @reserved: Added for future extension.
77 *
78 * It contains the measurements and initial configuration of the TDX guest
79 * that was locked at initialization and a set of measurement registers
80 * that are run-time extendable. More details can be found in TDX v1.0
81 * Module specification, sec titled "TDINFO_STRUCT".
82 */
83struct td_info {
84 __u8 attr[8];
85 __u64 xfam;
86 __u64 mrtd[6];
87 __u64 mrconfigid[6];
88 __u64 mrowner[6];
89 __u64 mrownerconfig[6];
90 __u64 rtmr[24];
91 __u64 reserved[14];
92};
93
94/*
95 * struct tdreport - Output of TDCALL[TDG.MR.REPORT].
96 * @reportmac: Mac protected header of size 256 bytes.
97 * @tee_tcb_info: Additional attestable elements in the TCB are not
98 * reflected in the reportmac.
99 * @reserved: Added for future extension.
100 * @tdinfo: Measurements and configuration data of size 512 bytes.
101 *
102 * More details can be found in TDX v1.0 Module specification, sec
103 * titled "TDREPORT_STRUCT".
104 */
105struct tdreport {
106 struct reportmac reportmac;
107 __u8 tee_tcb_info[239];
108 __u8 reserved[17];
109 struct td_info tdinfo;
110};
111
112static void print_array_hex(const char *title, const char *prefix_str,
113 const void *buf, int len)
114{
115 int i, j, line_len, rowsize = HEX_DUMP_SIZE;
116 const __u8 *ptr = buf;
117
118 printf("\t\t%s", title);
119
120 for (j = 0; j < len; j += rowsize) {
121 line_len = rowsize < (len - j) ? rowsize : (len - j);
122 printf("%s%.8x:", prefix_str, j);
123 for (i = 0; i < line_len; i++)
124 printf(" %.2x", ptr[j + i]);
125 printf("\n");
126 }
127
128 printf("\n");
129}
130
131TEST(verify_report)
132{
133 struct tdx_report_req req;
134 struct tdreport *tdreport;
135 int devfd, i;
136
137 devfd = open(TDX_GUEST_DEVNAME, O_RDWR | O_SYNC);
138 ASSERT_LT(0, devfd);
139
140 /* Generate sample report data */
141 for (i = 0; i < TDX_REPORTDATA_LEN; i++)
142 req.reportdata[i] = i;
143
144 /* Get TDREPORT */
145 ASSERT_EQ(0, ioctl(devfd, TDX_CMD_GET_REPORT0, &req));
146
147 if (DEBUG) {
148 print_array_hex("\n\t\tTDX report data\n", "",
149 req.reportdata, sizeof(req.reportdata));
150
151 print_array_hex("\n\t\tTDX tdreport data\n", "",
152 req.tdreport, sizeof(req.tdreport));
153 }
154
155 /* Make sure TDREPORT data includes the REPORTDATA passed */
156 tdreport = (struct tdreport *)req.tdreport;
157 ASSERT_EQ(0, memcmp(&tdreport->reportmac.reportdata[0],
158 req.reportdata, sizeof(req.reportdata)));
159
160 ASSERT_EQ(0, close(devfd));
161}
162
163TEST_HARNESS_MAIN