tpm: Added support for TPM emulator

This change introduces a new TPM backend driver that can communicate with
swtpm(software TPM emulator) using unix domain socket interface. QEMU talks to
the TPM emulator using QEMU's socket-based chardev backend device.

Swtpm uses two Unix sockets for communications, one for plain TPM commands and
responses, and one for out-of-band control messages. QEMU passes the data
socket to be used over the control channel.

The swtpm and associated tools can be found here:
    https://github.com/stefanberger/swtpm

The swtpm's control channel protocol specification can be found here:
    https://github.com/stefanberger/swtpm/wiki/Control-Channel-Specification

Usage:
    # setup TPM state directory
    mkdir /tmp/mytpm
    chown -R tss:root /tmp/mytpm
    /usr/bin/swtpm_setup --tpm-state /tmp/mytpm --createek

    # Ask qemu to use TPM emulator with given tpm state directory
    qemu-system-x86_64 \
        [...] \
        -chardev socket,id=chrtpm,path=/tmp/swtpm-sock \
        -tpmdev emulator,id=tpm0,chardev=chrtpm \
        -device tpm-tis,tpmdev=tpm0 \
        [...]

Signed-off-by: Amarnath Valluri <amarnath.valluri@intel.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Tested-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>

1 files changed, 587 insertions, 0 deletions

diff --git a/hw/tpm/tpm_emulator.c b/hw/tpm/tpm_emulator.c
new file mode 100644
index 0000000000..95e1e041cf
--- /dev/null
+++ b/hw/tpm/tpm_emulator.c
@@ -0,0 +1,587 @@
+/*
+ *  Emulator TPM driver
+ *
+ *  Copyright (c) 2017 Intel Corporation
+ *  Author: Amarnath Valluri <amarnath.valluri@intel.com>
+ *
+ *  Copyright (c) 2010 - 2013 IBM Corporation
+ *  Authors:
+ *    Stefan Berger <stefanb@us.ibm.com>
+ *
+ *  Copyright (C) 2011 IAIK, Graz University of Technology
+ *    Author: Andreas Niederl
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/error-report.h"
+#include "qemu/sockets.h"
+#include "io/channel-socket.h"
+#include "sysemu/tpm_backend.h"
+#include "tpm_int.h"
+#include "hw/hw.h"
+#include "hw/i386/pc.h"
+#include "tpm_util.h"
+#include "tpm_ioctl.h"
+#include "migration/blocker.h"
+#include "qapi/error.h"
+#include "qapi/clone-visitor.h"
+#include "chardev/char-fe.h"
+
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <stdio.h>
+
+#define DEBUG_TPM 0
+
+#define DPRINTF(fmt, ...) do { \
+    if (DEBUG_TPM) { \
+        fprintf(stderr, "tpm-emulator:"fmt"\n", ## __VA_ARGS__); \
+    } \
+} while (0)
+
+#define TYPE_TPM_EMULATOR "tpm-emulator"
+#define TPM_EMULATOR(obj) \
+    OBJECT_CHECK(TPMEmulator, (obj), TYPE_TPM_EMULATOR)
+
+#define TPM_EMULATOR_IMPLEMENTS_ALL_CAPS(S, cap) (((S)->caps & (cap)) == (cap))
+
+static const TPMDriverOps tpm_emulator_driver;
+
+/* data structures */
+typedef struct TPMEmulator {
+    TPMBackend parent;
+
+    TPMEmulatorOptions *options;
+    CharBackend ctrl_chr;
+    QIOChannel *data_ioc;
+    TPMVersion tpm_version;
+    ptm_cap caps; /* capabilities of the TPM */
+    uint8_t cur_locty_number; /* last set locality */
+    Error *migration_blocker;
+} TPMEmulator;
+
+
+static int tpm_emulator_ctrlcmd(CharBackend *dev, unsigned long cmd, void *msg,
+                                size_t msg_len_in, size_t msg_len_out)
+{
+    uint32_t cmd_no = cpu_to_be32(cmd);
+    ssize_t n = sizeof(uint32_t) + msg_len_in;
+    uint8_t *buf = NULL;
+
+    buf = g_alloca(n);
+    memcpy(buf, &cmd_no, sizeof(cmd_no));
+    memcpy(buf + sizeof(cmd_no), msg, msg_len_in);
+
+    n = qemu_chr_fe_write_all(dev, buf, n);
+    if (n <= 0) {
+        return -1;
+    }
+
+    if (msg_len_out != 0) {
+        n = qemu_chr_fe_read_all(dev, msg, msg_len_out);
+        if (n <= 0) {
+            return -1;
+        }
+    }
+
+    return 0;
+}
+
+static int tpm_emulator_unix_tx_bufs(TPMEmulator *tpm_emu,
+                                     const uint8_t *in, uint32_t in_len,
+                                     uint8_t *out, uint32_t out_len,
+                                     bool *selftest_done,
+                                     Error **err)
+{
+    ssize_t ret;
+    bool is_selftest = false;
+    const struct tpm_resp_hdr *hdr = NULL;
+
+    if (selftest_done) {
+        *selftest_done = false;
+        is_selftest = tpm_util_is_selftest(in, in_len);
+    }
+
+    ret = qio_channel_write_all(tpm_emu->data_ioc, (char *)in, in_len, err);
+    if (ret != 0) {
+        return -1;
+    }
+
+    ret = qio_channel_read_all(tpm_emu->data_ioc, (char *)out, sizeof(*hdr),
+                               err);
+    if (ret != 0) {
+        return -1;
+    }
+
+    hdr = (struct tpm_resp_hdr *)out;
+    out += sizeof(*hdr);
+    ret = qio_channel_read_all(tpm_emu->data_ioc, (char *)out,
+                               be32_to_cpu(hdr->len) - sizeof(*hdr) , err);
+    if (ret != 0) {
+        return -1;
+    }
+
+    if (is_selftest) {
+        *selftest_done = (be32_to_cpu(hdr->errcode) == 0);
+    }
+
+    return 0;
+}
+
+static int tpm_emulator_set_locality(TPMEmulator *tpm_emu, uint8_t locty_number)
+{
+    ptm_loc loc;
+
+    DPRINTF("%s : locality: 0x%x", __func__, locty_number);
+
+    if (tpm_emu->cur_locty_number == locty_number) {
+        return 0;
+    }
+
+    DPRINTF("setting locality : 0x%x", locty_number);
+    loc.u.req.loc = locty_number;
+    if (tpm_emulator_ctrlcmd(&tpm_emu->ctrl_chr, CMD_SET_LOCALITY, &loc,
+                             sizeof(loc), sizeof(loc)) < 0) {
+        error_report("tpm-emulator: could not set locality : %s",
+                     strerror(errno));
+        return -1;
+    }
+
+    loc.u.resp.tpm_result = be32_to_cpu(loc.u.resp.tpm_result);
+    if (loc.u.resp.tpm_result != 0) {
+        error_report("tpm-emulator: TPM result for set locality : 0x%x",
+                     loc.u.resp.tpm_result);
+        return -1;
+    }
+
+    tpm_emu->cur_locty_number = locty_number;
+
+    return 0;
+}
+
+static void tpm_emulator_handle_request(TPMBackend *tb, TPMBackendCmd cmd)
+{
+    TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
+    TPMLocality *locty = NULL;
+    bool selftest_done = false;
+    Error *err = NULL;
+
+    DPRINTF("processing command type %d", cmd);
+
+    switch (cmd) {
+    case TPM_BACKEND_CMD_PROCESS_CMD:
+        locty = tb->tpm_state->locty_data;
+        if (tpm_emulator_set_locality(tpm_emu,
+                                      tb->tpm_state->locty_number) < 0 ||
+            tpm_emulator_unix_tx_bufs(tpm_emu, locty->w_buffer.buffer,
+                                      locty->w_offset, locty->r_buffer.buffer,
+                                      locty->r_buffer.size, &selftest_done,
+                                      &err) < 0) {
+            tpm_util_write_fatal_error_response(locty->r_buffer.buffer,
+                                                locty->r_buffer.size);
+            error_report_err(err);
+        }
+
+        tb->recv_data_callback(tb->tpm_state, tb->tpm_state->locty_number,
+                               selftest_done);
+
+        break;
+    case TPM_BACKEND_CMD_INIT:
+    case TPM_BACKEND_CMD_END:
+    case TPM_BACKEND_CMD_TPM_RESET:
+        /* nothing to do */
+        break;
+    }
+}
+
+static int tpm_emulator_probe_caps(TPMEmulator *tpm_emu)
+{
+    DPRINTF("%s", __func__);
+    if (tpm_emulator_ctrlcmd(&tpm_emu->ctrl_chr, CMD_GET_CAPABILITY,
+                         &tpm_emu->caps, 0, sizeof(tpm_emu->caps)) < 0) {
+        error_report("tpm-emulator: probing failed : %s", strerror(errno));
+        return -1;
+    }
+
+    tpm_emu->caps = be64_to_cpu(tpm_emu->caps);
+
+    DPRINTF("capabilities : 0x%"PRIx64, tpm_emu->caps);
+
+    return 0;
+}
+
+static int tpm_emulator_check_caps(TPMEmulator *tpm_emu)
+{
+    ptm_cap caps = 0;
+    const char *tpm = NULL;
+
+    /* check for min. required capabilities */
+    switch (tpm_emu->tpm_version) {
+    case TPM_VERSION_1_2:
+        caps = PTM_CAP_INIT | PTM_CAP_SHUTDOWN | PTM_CAP_GET_TPMESTABLISHED |
+               PTM_CAP_SET_LOCALITY | PTM_CAP_SET_DATAFD;
+        tpm = "1.2";
+        break;
+    case TPM_VERSION_2_0:
+        caps = PTM_CAP_INIT | PTM_CAP_SHUTDOWN | PTM_CAP_GET_TPMESTABLISHED |
+               PTM_CAP_SET_LOCALITY | PTM_CAP_RESET_TPMESTABLISHED |
+               PTM_CAP_SET_DATAFD;
+        tpm = "2";
+        break;
+    case TPM_VERSION_UNSPEC:
+        error_report("tpm-emulator: TPM version has not been set");
+        return -1;
+    }
+
+    if (!TPM_EMULATOR_IMPLEMENTS_ALL_CAPS(tpm_emu, caps)) {
+        error_report("tpm-emulator: TPM does not implement minimum set of "
+                     "required capabilities for TPM %s (0x%x)", tpm, (int)caps);
+        return -1;
+    }
+
+    return 0;
+}
+
+static int tpm_emulator_startup_tpm(TPMBackend *tb)
+{
+    TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
+    ptm_init init;
+    ptm_res res;
+
+    DPRINTF("%s", __func__);
+    if (tpm_emulator_ctrlcmd(&tpm_emu->ctrl_chr, CMD_INIT, &init, sizeof(init),
+                         sizeof(init)) < 0) {
+        error_report("tpm-emulator: could not send INIT: %s",
+                     strerror(errno));
+        goto err_exit;
+    }
+
+    res = be32_to_cpu(init.u.resp.tpm_result);
+    if (res) {
+        error_report("tpm-emulator: TPM result for CMD_INIT: 0x%x", res);
+        goto err_exit;
+    }
+    return 0;
+
+err_exit:
+    return -1;
+}
+
+static bool tpm_emulator_get_tpm_established_flag(TPMBackend *tb)
+{
+    TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
+    ptm_est est;
+
+    DPRINTF("%s", __func__);
+    if (tpm_emulator_ctrlcmd(&tpm_emu->ctrl_chr, CMD_GET_TPMESTABLISHED, &est,
+                             0, sizeof(est)) < 0) {
+        error_report("tpm-emulator: Could not get the TPM established flag: %s",
+                     strerror(errno));
+        return false;
+    }
+    DPRINTF("established flag: %0x", est.u.resp.bit);
+
+    return (est.u.resp.bit != 0);
+}
+
+static int tpm_emulator_reset_tpm_established_flag(TPMBackend *tb,
+                                                   uint8_t locty)
+{
+    TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
+    ptm_reset_est reset_est;
+    ptm_res res;
+
+    /* only a TPM 2.0 will support this */
+    if (tpm_emu->tpm_version != TPM_VERSION_2_0) {
+        return 0;
+    }
+
+    reset_est.u.req.loc = tpm_emu->cur_locty_number;
+    if (tpm_emulator_ctrlcmd(&tpm_emu->ctrl_chr, CMD_RESET_TPMESTABLISHED,
+                             &reset_est, sizeof(reset_est),
+                             sizeof(reset_est)) < 0) {
+        error_report("tpm-emulator: Could not reset the establishment bit: %s",
+                     strerror(errno));
+        return -1;
+    }
+
+    res = be32_to_cpu(reset_est.u.resp.tpm_result);
+    if (res) {
+        error_report("tpm-emulator: TPM result for rest establixhed flag: 0x%x",
+                     res);
+        return -1;
+    }
+
+    return 0;
+}
+
+static void tpm_emulator_cancel_cmd(TPMBackend *tb)
+{
+    TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
+    ptm_res res;
+
+    if (!TPM_EMULATOR_IMPLEMENTS_ALL_CAPS(tpm_emu, PTM_CAP_CANCEL_TPM_CMD)) {
+        DPRINTF("Backend does not support CANCEL_TPM_CMD");
+        return;
+    }
+
+    if (tpm_emulator_ctrlcmd(&tpm_emu->ctrl_chr, CMD_CANCEL_TPM_CMD, &res, 0,
+                             sizeof(res)) < 0) {
+        error_report("tpm-emulator: Could not cancel command: %s",
+                     strerror(errno));
+    } else if (res != 0) {
+        error_report("tpm-emulator: Failed to cancel TPM: 0x%x",
+                     be32_to_cpu(res));
+    }
+}
+
+static TPMVersion tpm_emulator_get_tpm_version(TPMBackend *tb)
+{
+    TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
+
+    return tpm_emu->tpm_version;
+}
+
+static int tpm_emulator_block_migration(TPMEmulator *tpm_emu)
+{
+    Error *err = NULL;
+
+    error_setg(&tpm_emu->migration_blocker,
+               "Migration disabled: TPM emulator not yet migratable");
+    migrate_add_blocker(tpm_emu->migration_blocker, &err);
+    if (err) {
+        error_report_err(err);
+        error_free(tpm_emu->migration_blocker);
+        tpm_emu->migration_blocker = NULL;
+
+        return -1;
+    }
+
+    return 0;
+}
+
+static int tpm_emulator_prepare_data_fd(TPMEmulator *tpm_emu)
+{
+    ptm_res res;
+    Error *err = NULL;
+    int fds[2] = { -1, -1 };
+
+    if (socketpair(AF_UNIX, SOCK_STREAM, 0, fds) < 0) {
+        error_report("tpm-emulator: Failed to create socketpair");
+        return -1;
+    }
+
+    qemu_chr_fe_set_msgfds(&tpm_emu->ctrl_chr, fds + 1, 1);
+
+    if (tpm_emulator_ctrlcmd(&tpm_emu->ctrl_chr, CMD_SET_DATAFD, &res, 0,
+                    sizeof(res)) || res != 0) {
+        error_report("tpm-emulator: Failed to send CMD_SET_DATAFD: %s",
+                     strerror(errno));
+        goto err_exit;
+    }
+
+    tpm_emu->data_ioc = QIO_CHANNEL(qio_channel_socket_new_fd(fds[0], &err));
+    if (err) {
+        error_prepend(&err, "tpm-emulator: Failed to create io channel: ");
+        error_report_err(err);
+        goto err_exit;
+    }
+
+    closesocket(fds[1]);
+
+    return 0;
+
+err_exit:
+    closesocket(fds[0]);
+    closesocket(fds[1]);
+    return -1;
+}
+
+static int tpm_emulator_handle_device_opts(TPMEmulator *tpm_emu, QemuOpts *opts)
+{
+    const char *value;
+
+    value = qemu_opt_get(opts, "chardev");
+    if (value) {
+        Error *err = NULL;
+        Chardev *dev = qemu_chr_find(value);
+
+        if (!dev) {
+            error_report("tpm-emulator: tpm chardev '%s' not found.", value);
+            goto err;
+        }
+
+        if (!qemu_chr_fe_init(&tpm_emu->ctrl_chr, dev, &err)) {
+            error_prepend(&err, "tpm-emulator: No valid chardev found at '%s':",
+                          value);
+            error_report_err(err);
+            goto err;
+        }
+
+        tpm_emu->options->chardev = g_strdup(value);
+    }
+
+    if (tpm_emulator_prepare_data_fd(tpm_emu) < 0) {
+        goto err;
+    }
+
+    /* FIXME: tpm_util_test_tpmdev() accepts only on socket fd, as it also used
+     * by passthrough driver, which not yet using GIOChannel.
+     */
+    if (tpm_util_test_tpmdev(QIO_CHANNEL_SOCKET(tpm_emu->data_ioc)->fd,
+                             &tpm_emu->tpm_version)) {
+        error_report("'%s' is not emulating TPM device. Error: %s",
+                      tpm_emu->options->chardev, strerror(errno));
+        goto err;
+    }
+
+    DPRINTF("TPM Version %s", tpm_emu->tpm_version == TPM_VERSION_1_2 ? "1.2" :
+            (tpm_emu->tpm_version == TPM_VERSION_2_0 ?  "2.0" : "Unspecified"));
+
+    if (tpm_emulator_probe_caps(tpm_emu) ||
+        tpm_emulator_check_caps(tpm_emu)) {
+        goto err;
+    }
+
+    return tpm_emulator_block_migration(tpm_emu);
+
+err:
+    DPRINTF("Startup error");
+    return -1;
+}
+
+static TPMBackend *tpm_emulator_create(QemuOpts *opts, const char *id)
+{
+    TPMBackend *tb = TPM_BACKEND(object_new(TYPE_TPM_EMULATOR));
+
+    tb->id = g_strdup(id);
+
+    if (tpm_emulator_handle_device_opts(TPM_EMULATOR(tb), opts)) {
+        goto err_exit;
+    }
+
+    return tb;
+
+err_exit:
+    object_unref(OBJECT(tb));
+
+    return NULL;
+}
+
+static TpmTypeOptions *tpm_emulator_get_tpm_options(TPMBackend *tb)
+{
+    TPMEmulator *tpm_emu = TPM_EMULATOR(tb);
+    TpmTypeOptions *options = g_new0(TpmTypeOptions, 1);
+
+    options->type = TPM_TYPE_OPTIONS_KIND_EMULATOR;
+    options->u.emulator.data = QAPI_CLONE(TPMEmulatorOptions, tpm_emu->options);
+
+    return options;
+}
+
+static const QemuOptDesc tpm_emulator_cmdline_opts[] = {
+    TPM_STANDARD_CMDLINE_OPTS,
+    {
+        .name = "chardev",
+        .type = QEMU_OPT_STRING,
+        .help = "Character device to use for out-of-band control messages",
+    },
+    { /* end of list */ },
+};
+
+static const TPMDriverOps tpm_emulator_driver = {
+    .type                     = TPM_TYPE_EMULATOR,
+    .opts                     = tpm_emulator_cmdline_opts,
+    .desc                     = "TPM emulator backend driver",
+
+    .create                   = tpm_emulator_create,
+    .startup_tpm              = tpm_emulator_startup_tpm,
+    .cancel_cmd               = tpm_emulator_cancel_cmd,
+    .get_tpm_established_flag = tpm_emulator_get_tpm_established_flag,
+    .reset_tpm_established_flag = tpm_emulator_reset_tpm_established_flag,
+    .get_tpm_version          = tpm_emulator_get_tpm_version,
+    .get_tpm_options          = tpm_emulator_get_tpm_options,
+};
+
+static void tpm_emulator_inst_init(Object *obj)
+{
+    TPMEmulator *tpm_emu = TPM_EMULATOR(obj);
+
+    DPRINTF("%s", __func__);
+    tpm_emu->options = g_new0(TPMEmulatorOptions, 1);
+    tpm_emu->cur_locty_number = ~0;
+}
+
+/*
+ * Gracefully shut down the external TPM
+ */
+static void tpm_emulator_shutdown(TPMEmulator *tpm_emu)
+{
+    ptm_res res;
+
+    if (tpm_emulator_ctrlcmd(&tpm_emu->ctrl_chr, CMD_SHUTDOWN, &res, 0,
+                             sizeof(res)) < 0) {
+        error_report("tpm-emulator: Could not cleanly shutdown the TPM: %s",
+                     strerror(errno));
+    } else if (res != 0) {
+        error_report("tpm-emulator: TPM result for sutdown: 0x%x",
+                     be32_to_cpu(res));
+    }
+}
+
+static void tpm_emulator_inst_finalize(Object *obj)
+{
+    TPMEmulator *tpm_emu = TPM_EMULATOR(obj);
+
+    tpm_emulator_shutdown(tpm_emu);
+
+    object_unref(OBJECT(tpm_emu->data_ioc));
+
+    qemu_chr_fe_deinit(&tpm_emu->ctrl_chr, false);
+
+    qapi_free_TPMEmulatorOptions(tpm_emu->options);
+
+    if (tpm_emu->migration_blocker) {
+        migrate_del_blocker(tpm_emu->migration_blocker);
+        error_free(tpm_emu->migration_blocker);
+    }
+}
+
+static void tpm_emulator_class_init(ObjectClass *klass, void *data)
+{
+    TPMBackendClass *tbc = TPM_BACKEND_CLASS(klass);
+    tbc->ops = &tpm_emulator_driver;
+    tbc->handle_request = tpm_emulator_handle_request;
+}
+
+static const TypeInfo tpm_emulator_info = {
+    .name = TYPE_TPM_EMULATOR,
+    .parent = TYPE_TPM_BACKEND,
+    .instance_size = sizeof(TPMEmulator),
+    .class_init = tpm_emulator_class_init,
+    .instance_init = tpm_emulator_inst_init,
+    .instance_finalize = tpm_emulator_inst_finalize,
+};
+
+static void tpm_emulator_register(void)
+{
+    type_register_static(&tpm_emulator_info);
+    tpm_register_driver(&tpm_emulator_driver);
+}
+
+type_init(tpm_emulator_register)