1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2023 Beckhoff Automation GmbH & Co. KG
5 * Author: Corvin Köhne <corvink@FreeBSD.org>
6 */
7
8 #include <sys/types.h>
9
10 #include <err.h>
11 #include <errno.h>
12 #include <fcntl.h>
13 #ifdef __FreeBSD__
14 #include <malloc_np.h>
15 #else
16 #include <sys/vmm.h>
17 #endif
18 #include <stdlib.h>
19 #include <unistd.h>
20
21 #include "config.h"
22 #include "tpm_device.h"
23 #include "tpm_emul.h"
24
25 struct tpm_passthru {
26 int fd;
27 };
28
29 struct tpm_resp_hdr {
30 uint16_t tag;
31 uint32_t len;
32 uint32_t errcode;
33 } __packed;
34
35 static int
tpm_passthru_init(void ** sc,nvlist_t * nvl)36 tpm_passthru_init(void **sc, nvlist_t *nvl)
37 {
38 struct tpm_passthru *tpm;
39 const char *path;
40
41 tpm = calloc(1, sizeof(struct tpm_passthru));
42 if (tpm == NULL) {
43 warnx("%s: failed to allocate tpm passthru", __func__);
44 return (ENOMEM);
45 }
46
47 path = get_config_value_node(nvl, "path");
48 tpm->fd = open(path, O_RDWR);
49 if (tpm->fd < 0) {
50 warnx("%s: unable to open tpm device \"%s\"", __func__, path);
51 return (ENOENT);
52 }
53
54 *sc = tpm;
55
56 return (0);
57 }
58
59 static int
tpm_passthru_execute_cmd(void * sc,void * cmd,uint32_t cmd_size,void * rsp,uint32_t rsp_size)60 tpm_passthru_execute_cmd(void *sc, void *cmd, uint32_t cmd_size, void *rsp,
61 uint32_t rsp_size)
62 {
63 struct tpm_passthru *tpm;
64 ssize_t len;
65
66 if (rsp_size < (ssize_t)sizeof(struct tpm_resp_hdr)) {
67 warn("%s: rsp_size of %u is too small", __func__, rsp_size);
68 return (EINVAL);
69 }
70
71 tpm = sc;
72
73 len = write(tpm->fd, cmd, cmd_size);
74 if (len != cmd_size) {
75 warn("%s: cmd write failed (bytes written: %zd / %d)", __func__,
76 len, cmd_size);
77 return (EFAULT);
78 }
79
80 len = read(tpm->fd, rsp, rsp_size);
81 if (len < (ssize_t)sizeof(struct tpm_resp_hdr)) {
82 warn("%s: rsp read failed (bytes read: %zd / %d)", __func__,
83 len, rsp_size);
84 return (EFAULT);
85 }
86
87 return (0);
88 }
89
90 static void
tpm_passthru_deinit(void * sc)91 tpm_passthru_deinit(void *sc)
92 {
93 struct tpm_passthru *tpm;
94
95 tpm = sc;
96 if (tpm == NULL)
97 return;
98
99 if (tpm->fd >= 0)
100 close(tpm->fd);
101
102 free(tpm);
103 }
104
105 static const struct tpm_emul tpm_emul_passthru = {
106 .name = "passthru",
107 .init = tpm_passthru_init,
108 .deinit = tpm_passthru_deinit,
109 .execute_cmd = tpm_passthru_execute_cmd,
110 };
111 TPM_EMUL_SET(tpm_emul_passthru);
112