tpm: reorganize headers and split hardware part

The TPM subsystem does not have a full front-end/back-end separation. The sole available backend, tpm_passthrough, depends on the data structures of the sole available frontend, tpm_tis. However, we can at least try to split the user interface (tpm.c) from the implementation (hw/tpm). The patches makes tpm.c not include tpm_int.h, which is shared between tpm_tis.c and tpm_passthrough.c; instead it moves more stuff to tpm_backend.h. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2025-08-06 17:23:56 -06:00 · 2013-04-02 18:28:41 +02:00 · 2013-04-02 18:28:41 +02:00 · bdee56f546
commit bdee56f546
parent 3b8acc11d3
15 changed files with 103 additions and 128 deletions
--- a/hw/tpm/tpm_passthrough.c
+++ b/hw/tpm/tpm_passthrough.c
@ -0,0 +1,576 @@
+/*
+ *  passthrough TPM driver
+ *
+ *  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 <dirent.h>
+
+#include "qemu-common.h"
+#include "qapi/error.h"
+#include "qemu/sockets.h"
+#include "backends/tpm.h"
+#include "tpm_int.h"
+#include "hw/hw.h"
+#include "hw/i386/pc.h"
+#include "sysemu/tpm_backend_int.h"
+#include "tpm_tis.h"
+
+/* #define DEBUG_TPM */
+
+#ifdef DEBUG_TPM
+#define DPRINTF(fmt, ...) \
+    do { fprintf(stderr, fmt, ## __VA_ARGS__); } while (0)
+#else
+#define DPRINTF(fmt, ...) \
+    do { } while (0)
+#endif
+
+#define TYPE_TPM_PASSTHROUGH "tpm-passthrough"
+#define TPM_PASSTHROUGH(obj) \
+    OBJECT_CHECK(TPMPassthruState, (obj), TYPE_TPM_PASSTHROUGH)
+
+static const TPMDriverOps tpm_passthrough_driver;
+
+/* data structures */
+typedef struct TPMPassthruThreadParams {
+    TPMState *tpm_state;
+
+    TPMRecvDataCB *recv_data_callback;
+    TPMBackend *tb;
+} TPMPassthruThreadParams;
+
+struct TPMPassthruState {
+    TPMBackend parent;
+
+    TPMBackendThread tbt;
+
+    TPMPassthruThreadParams tpm_thread_params;
+
+    char *tpm_dev;
+    int tpm_fd;
+    bool tpm_executing;
+    bool tpm_op_canceled;
+    int cancel_fd;
+    bool had_startup_error;
+};
+
+typedef struct TPMPassthruState TPMPassthruState;
+
+#define TPM_PASSTHROUGH_DEFAULT_DEVICE "/dev/tpm0"
+
+/* functions */
+
+static void tpm_passthrough_cancel_cmd(TPMBackend *tb);
+
+static int tpm_passthrough_unix_write(int fd, const uint8_t *buf, uint32_t len)
+{
+    return send_all(fd, buf, len);
+}
+
+static int tpm_passthrough_unix_read(int fd, uint8_t *buf, uint32_t len)
+{
+    return recv_all(fd, buf, len, true);
+}
+
+static uint32_t tpm_passthrough_get_size_from_buffer(const uint8_t *buf)
+{
+    struct tpm_resp_hdr *resp = (struct tpm_resp_hdr *)buf;
+
+    return be32_to_cpu(resp->len);
+}
+
+/*
+ * Write an error message in the given output buffer.
+ */
+static void tpm_write_fatal_error_response(uint8_t *out, uint32_t out_len)
+{
+    if (out_len >= sizeof(struct tpm_resp_hdr)) {
+        struct tpm_resp_hdr *resp = (struct tpm_resp_hdr *)out;
+
+        resp->tag = cpu_to_be16(TPM_TAG_RSP_COMMAND);
+        resp->len = cpu_to_be32(sizeof(struct tpm_resp_hdr));
+        resp->errcode = cpu_to_be32(TPM_FAIL);
+    }
+}
+
+static int tpm_passthrough_unix_tx_bufs(TPMPassthruState *tpm_pt,
+                                        const uint8_t *in, uint32_t in_len,
+                                        uint8_t *out, uint32_t out_len)
+{
+    int ret;
+
+    tpm_pt->tpm_op_canceled = false;
+    tpm_pt->tpm_executing = true;
+
+    ret = tpm_passthrough_unix_write(tpm_pt->tpm_fd, in, in_len);
+    if (ret != in_len) {
+        if (!tpm_pt->tpm_op_canceled ||
+            (tpm_pt->tpm_op_canceled && errno != ECANCELED)) {
+            error_report("tpm_passthrough: error while transmitting data "
+                         "to TPM: %s (%i)\n",
+                         strerror(errno), errno);
+        }
+        goto err_exit;
+    }
+
+    tpm_pt->tpm_executing = false;
+
+    ret = tpm_passthrough_unix_read(tpm_pt->tpm_fd, out, out_len);
+    if (ret < 0) {
+        if (!tpm_pt->tpm_op_canceled ||
+            (tpm_pt->tpm_op_canceled && errno != ECANCELED)) {
+            error_report("tpm_passthrough: error while reading data from "
+                         "TPM: %s (%i)\n",
+                         strerror(errno), errno);
+        }
+    } else if (ret < sizeof(struct tpm_resp_hdr) ||
+               tpm_passthrough_get_size_from_buffer(out) != ret) {
+        ret = -1;
+        error_report("tpm_passthrough: received invalid response "
+                     "packet from TPM\n");
+    }
+
+err_exit:
+    if (ret < 0) {
+        tpm_write_fatal_error_response(out, out_len);
+    }
+
+    tpm_pt->tpm_executing = false;
+
+    return ret;
+}
+
+static int tpm_passthrough_unix_transfer(TPMPassthruState *tpm_pt,
+                                         const TPMLocality *locty_data)
+{
+    return tpm_passthrough_unix_tx_bufs(tpm_pt,
+                                        locty_data->w_buffer.buffer,
+                                        locty_data->w_offset,
+                                        locty_data->r_buffer.buffer,
+                                        locty_data->r_buffer.size);
+}
+
+static void tpm_passthrough_worker_thread(gpointer data,
+                                          gpointer user_data)
+{
+    TPMPassthruThreadParams *thr_parms = user_data;
+    TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(thr_parms->tb);
+    TPMBackendCmd cmd = (TPMBackendCmd)data;
+
+    DPRINTF("tpm_passthrough: processing command type %d\n", cmd);
+
+    switch (cmd) {
+    case TPM_BACKEND_CMD_PROCESS_CMD:
+        tpm_passthrough_unix_transfer(tpm_pt,
+                                      thr_parms->tpm_state->locty_data);
+
+        thr_parms->recv_data_callback(thr_parms->tpm_state,
+                                      thr_parms->tpm_state->locty_number);
+        break;
+    case TPM_BACKEND_CMD_INIT:
+    case TPM_BACKEND_CMD_END:
+    case TPM_BACKEND_CMD_TPM_RESET:
+        /* nothing to do */
+        break;
+    }
+}
+
+/*
+ * Start the TPM (thread). If it had been started before, then terminate
+ * and start it again.
+ */
+static int tpm_passthrough_startup_tpm(TPMBackend *tb)
+{
+    TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
+
+    /* terminate a running TPM */
+    tpm_backend_thread_end(&tpm_pt->tbt);
+
+    tpm_backend_thread_create(&tpm_pt->tbt,
+                              tpm_passthrough_worker_thread,
+                              &tpm_pt->tpm_thread_params);
+
+    return 0;
+}
+
+static void tpm_passthrough_reset(TPMBackend *tb)
+{
+    TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
+
+    DPRINTF("tpm_passthrough: CALL TO TPM_RESET!\n");
+
+    tpm_passthrough_cancel_cmd(tb);
+
+    tpm_backend_thread_end(&tpm_pt->tbt);
+
+    tpm_pt->had_startup_error = false;
+}
+
+static int tpm_passthrough_init(TPMBackend *tb, TPMState *s,
+                                TPMRecvDataCB *recv_data_cb)
+{
+    TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
+
+    tpm_pt->tpm_thread_params.tpm_state = s;
+    tpm_pt->tpm_thread_params.recv_data_callback = recv_data_cb;
+    tpm_pt->tpm_thread_params.tb = tb;
+
+    return 0;
+}
+
+static bool tpm_passthrough_get_tpm_established_flag(TPMBackend *tb)
+{
+    return false;
+}
+
+static bool tpm_passthrough_get_startup_error(TPMBackend *tb)
+{
+    TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
+
+    return tpm_pt->had_startup_error;
+}
+
+static size_t tpm_passthrough_realloc_buffer(TPMSizedBuffer *sb)
+{
+    size_t wanted_size = 4096; /* Linux tpm.c buffer size */
+
+    if (sb->size != wanted_size) {
+        sb->buffer = g_realloc(sb->buffer, wanted_size);
+        sb->size = wanted_size;
+    }
+    return sb->size;
+}
+
+static void tpm_passthrough_deliver_request(TPMBackend *tb)
+{
+    TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
+
+    tpm_backend_thread_deliver_request(&tpm_pt->tbt);
+}
+
+static void tpm_passthrough_cancel_cmd(TPMBackend *tb)
+{
+    TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
+    int n;
+
+    /*
+     * As of Linux 3.7 the tpm_tis driver does not properly cancel
+     * commands on all TPM manufacturers' TPMs.
+     * Only cancel if we're busy so we don't cancel someone else's
+     * command, e.g., a command executed on the host.
+     */
+    if (tpm_pt->tpm_executing) {
+        if (tpm_pt->cancel_fd >= 0) {
+            n = write(tpm_pt->cancel_fd, "-", 1);
+            if (n != 1) {
+                error_report("Canceling TPM command failed: %s\n",
+                             strerror(errno));
+            } else {
+                tpm_pt->tpm_op_canceled = true;
+            }
+        } else {
+            error_report("Cannot cancel TPM command due to missing "
+                         "TPM sysfs cancel entry");
+        }
+    }
+}
+
+static const char *tpm_passthrough_create_desc(void)
+{
+    return "Passthrough TPM backend driver";
+}
+
+/*
+ * A basic test of a TPM device. We expect a well formatted response header
+ * (error response is fine) within one second.
+ */
+static int tpm_passthrough_test_tpmdev(int fd)
+{
+    struct tpm_req_hdr req = {
+        .tag = cpu_to_be16(TPM_TAG_RQU_COMMAND),
+        .len = cpu_to_be32(sizeof(req)),
+        .ordinal = cpu_to_be32(TPM_ORD_GetTicks),
+    };
+    struct tpm_resp_hdr *resp;
+    fd_set readfds;
+    int n;
+    struct timeval tv = {
+        .tv_sec = 1,
+        .tv_usec = 0,
+    };
+    unsigned char buf[1024];
+
+    n = write(fd, &req, sizeof(req));
+    if (n < 0) {
+        return errno;
+    }
+    if (n != sizeof(req)) {
+        return EFAULT;
+    }
+
+    FD_ZERO(&readfds);
+    FD_SET(fd, &readfds);
+
+    /* wait for a second */
+    n = select(fd + 1, &readfds, NULL, NULL, &tv);
+    if (n != 1) {
+        return errno;
+    }
+
+    n = read(fd, &buf, sizeof(buf));
+    if (n < sizeof(struct tpm_resp_hdr)) {
+        return EFAULT;
+    }
+
+    resp = (struct tpm_resp_hdr *)buf;
+    /* check the header */
+    if (be16_to_cpu(resp->tag) != TPM_TAG_RSP_COMMAND ||
+        be32_to_cpu(resp->len) != n) {
+        return EBADMSG;
+    }
+
+    return 0;
+}
+
+/*
+ * Check whether the given base path, e.g.,  /sys/class/misc/tpm0/device,
+ * is the sysfs directory of a TPM. A TPM sysfs directory should be uniquely
+ * recognizable by the file entries 'pcrs' and 'cancel'.
+ * Upon success 'true' is returned and the basebath buffer has '/cancel'
+ * appended.
+ */
+static bool tpm_passthrough_check_sysfs_cancel(char *basepath, size_t bufsz)
+{
+    char path[PATH_MAX];
+    struct stat statbuf;
+
+    snprintf(path, sizeof(path), "%s/pcrs", basepath);
+    if (stat(path, &statbuf) == -1 || !S_ISREG(statbuf.st_mode)) {
+        return false;
+    }
+
+    snprintf(path, sizeof(path), "%s/cancel", basepath);
+    if (stat(path, &statbuf) == -1 || !S_ISREG(statbuf.st_mode)) {
+        return false;
+    }
+
+    strncpy(basepath, path, bufsz);
+
+    return true;
+}
+
+/*
+ * Unless path or file descriptor set has been provided by user,
+ * determine the sysfs cancel file following kernel documentation
+ * in Documentation/ABI/stable/sysfs-class-tpm.
+ */
+static int tpm_passthrough_open_sysfs_cancel(TPMBackend *tb)
+{
+    int fd = -1;
+    unsigned int idx;
+    DIR *pnp_dir;
+    char path[PATH_MAX];
+    struct dirent entry, *result;
+    int len;
+
+    if (tb->cancel_path) {
+        fd = qemu_open(tb->cancel_path, O_WRONLY);
+        if (fd < 0) {
+            error_report("Could not open TPM cancel path : %s",
+                         strerror(errno));
+        }
+        return fd;
+    }
+
+    snprintf(path, sizeof(path), "/sys/class/misc");
+    pnp_dir = opendir(path);
+    if (pnp_dir != NULL) {
+        while (readdir_r(pnp_dir, &entry, &result) == 0 &&
+               result != NULL) {
+            /*
+             * only allow /sys/class/misc/tpm%u type of paths
+             */
+            if (sscanf(entry.d_name, "tpm%u%n", &idx, &len) < 1 ||
+                len <= strlen("tpm") ||
+                len != strlen(entry.d_name)) {
+                continue;
+            }
+
+            snprintf(path, sizeof(path), "/sys/class/misc/%s/device",
+                     entry.d_name);
+            if (!tpm_passthrough_check_sysfs_cancel(path, sizeof(path))) {
+                continue;
+            }
+
+            fd = qemu_open(path, O_WRONLY);
+            break;
+        }
+        closedir(pnp_dir);
+    }
+
+    if (fd >= 0) {
+        tb->cancel_path = g_strdup(path);
+    }
+
+    return fd;
+}
+
+static int tpm_passthrough_handle_device_opts(QemuOpts *opts, TPMBackend *tb)
+{
+    TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
+    const char *value;
+
+    value = qemu_opt_get(opts, "cancel-path");
+    if (value) {
+        tb->cancel_path = g_strdup(value);
+    }
+
+    value = qemu_opt_get(opts, "path");
+    if (!value) {
+        value = TPM_PASSTHROUGH_DEFAULT_DEVICE;
+    }
+
+    tpm_pt->tpm_dev = g_strdup(value);
+
+    tb->path = g_strdup(tpm_pt->tpm_dev);
+
+    tpm_pt->tpm_fd = qemu_open(tpm_pt->tpm_dev, O_RDWR);
+    if (tpm_pt->tpm_fd < 0) {
+        error_report("Cannot access TPM device using '%s': %s\n",
+                     tpm_pt->tpm_dev, strerror(errno));
+        goto err_free_parameters;
+    }
+
+    if (tpm_passthrough_test_tpmdev(tpm_pt->tpm_fd)) {
+        error_report("'%s' is not a TPM device.\n",
+                     tpm_pt->tpm_dev);
+        goto err_close_tpmdev;
+    }
+
+    return 0;
+
+ err_close_tpmdev:
+    qemu_close(tpm_pt->tpm_fd);
+    tpm_pt->tpm_fd = -1;
+
+ err_free_parameters:
+    g_free(tb->path);
+    tb->path = NULL;
+
+    g_free(tpm_pt->tpm_dev);
+    tpm_pt->tpm_dev = NULL;
+
+    return 1;
+}
+
+static TPMBackend *tpm_passthrough_create(QemuOpts *opts, const char *id)
+{
+    Object *obj = object_new(TYPE_TPM_PASSTHROUGH);
+    TPMBackend *tb = TPM_BACKEND(obj);
+    TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
+
+    tb->id = g_strdup(id);
+    /* let frontend set the fe_model to proper value */
+    tb->fe_model = -1;
+
+    tb->ops = &tpm_passthrough_driver;
+
+    if (tpm_passthrough_handle_device_opts(opts, tb)) {
+        goto err_exit;
+    }
+
+    tpm_pt->cancel_fd = tpm_passthrough_open_sysfs_cancel(tb);
+    if (tpm_pt->cancel_fd < 0) {
+        goto err_exit;
+    }
+
+    return tb;
+
+err_exit:
+    g_free(tb->id);
+
+    return NULL;
+}
+
+static void tpm_passthrough_destroy(TPMBackend *tb)
+{
+    TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
+
+    tpm_passthrough_cancel_cmd(tb);
+
+    tpm_backend_thread_end(&tpm_pt->tbt);
+
+    qemu_close(tpm_pt->tpm_fd);
+    qemu_close(tpm_pt->cancel_fd);
+
+    g_free(tb->id);
+    g_free(tb->path);
+    g_free(tb->cancel_path);
+    g_free(tpm_pt->tpm_dev);
+}
+
+static const TPMDriverOps tpm_passthrough_driver = {
+    .type                     = TPM_TYPE_PASSTHROUGH,
+    .desc                     = tpm_passthrough_create_desc,
+    .create                   = tpm_passthrough_create,
+    .destroy                  = tpm_passthrough_destroy,
+    .init                     = tpm_passthrough_init,
+    .startup_tpm              = tpm_passthrough_startup_tpm,
+    .realloc_buffer           = tpm_passthrough_realloc_buffer,
+    .reset                    = tpm_passthrough_reset,
+    .had_startup_error        = tpm_passthrough_get_startup_error,
+    .deliver_request          = tpm_passthrough_deliver_request,
+    .cancel_cmd               = tpm_passthrough_cancel_cmd,
+    .get_tpm_established_flag = tpm_passthrough_get_tpm_established_flag,
+};
+
+static void tpm_passthrough_inst_init(Object *obj)
+{
+}
+
+static void tpm_passthrough_inst_finalize(Object *obj)
+{
+}
+
+static void tpm_passthrough_class_init(ObjectClass *klass, void *data)
+{
+    TPMBackendClass *tbc = TPM_BACKEND_CLASS(klass);
+
+    tbc->ops = &tpm_passthrough_driver;
+}
+
+static const TypeInfo tpm_passthrough_info = {
+    .name = TYPE_TPM_PASSTHROUGH,
+    .parent = TYPE_TPM_BACKEND,
+    .instance_size = sizeof(TPMPassthruState),
+    .class_init = tpm_passthrough_class_init,
+    .instance_init = tpm_passthrough_inst_init,
+    .instance_finalize = tpm_passthrough_inst_finalize,
+};
+
+static void tpm_passthrough_register(void)
+{
+    type_register_static(&tpm_passthrough_info);
+    tpm_register_driver(&tpm_passthrough_driver);
+}
+
+type_init(tpm_passthrough_register)