29200a8133
To send commands to the TPM device, bhyve can use the host TPM driver by reading and writing from /dev/tpmX. Using this approach, only the host TPM driver has to detect and interact with the physical TPM interface. This simplifies bhyve's code much. As the host TPM driver has to interact with the TPM regardless of bhyve making use of it or not, makes it a good approach. Reviewed by: markj MFC after: 1 week Sponsored by: Beckhoff Automation GmbH & Co. KG Differential Revision: https://reviews.freebsd.org/D40460
108 lines
2.0 KiB
C
108 lines
2.0 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause
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*
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* Copyright (c) 2023 Beckhoff Automation GmbH & Co. KG
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* Author: Corvin Köhne <corvink@FreeBSD.org>
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*/
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#include <sys/types.h>
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#include <err.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <malloc_np.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include "config.h"
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#include "tpm_device.h"
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#include "tpm_emul.h"
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struct tpm_passthru {
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int fd;
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};
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struct tpm_resp_hdr {
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uint16_t tag;
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uint32_t len;
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uint32_t errcode;
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} __packed;
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static int
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tpm_passthru_init(void **sc, nvlist_t *nvl)
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{
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struct tpm_passthru *tpm;
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const char *path;
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tpm = calloc(1, sizeof(struct tpm_passthru));
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if (tpm == NULL) {
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warnx("%s: failed to allocate tpm passthru", __func__);
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return (ENOMEM);
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}
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path = get_config_value_node(nvl, "path");
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tpm->fd = open(path, O_RDWR);
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if (tpm->fd < 0) {
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warnx("%s: unable to open tpm device \"%s\"", __func__, path);
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return (ENOENT);
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}
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*sc = tpm;
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return (0);
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}
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static int
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tpm_passthru_execute_cmd(void *sc, void *cmd, uint32_t cmd_size, void *rsp,
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uint32_t rsp_size)
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{
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struct tpm_passthru *tpm;
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ssize_t len;
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if (rsp_size < (ssize_t)sizeof(struct tpm_resp_hdr)) {
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warn("%s: rsp_size of %u is too small", __func__, rsp_size);
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return (EINVAL);
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}
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tpm = sc;
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len = write(tpm->fd, cmd, cmd_size);
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if (len != cmd_size) {
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warn("%s: cmd write failed (bytes written: %zd / %d)", __func__,
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len, cmd_size);
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return (EFAULT);
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}
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len = read(tpm->fd, rsp, rsp_size);
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if (len < (ssize_t)sizeof(struct tpm_resp_hdr)) {
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warn("%s: rsp read failed (bytes read: %zd / %d)", __func__,
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len, rsp_size);
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return (EFAULT);
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}
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return (0);
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}
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static void
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tpm_passthru_deinit(void *sc)
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{
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struct tpm_passthru *tpm;
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tpm = sc;
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if (tpm == NULL)
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return;
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if (tpm->fd >= 0)
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close(tpm->fd);
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free(tpm);
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}
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static const struct tpm_emul tpm_emul_passthru = {
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.name = "passthru",
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.init = tpm_passthru_init,
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.deinit = tpm_passthru_deinit,
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.execute_cmd = tpm_passthru_execute_cmd,
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};
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TPM_EMUL_SET(tpm_emul_passthru);
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