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