tpm: Move backend code under the 'backends/' directory

TPM subsytem is split into backends (see commit f4ede81eed2)
and frontends (see i.e. 3676bc69b35). Keep the emulated
hardware 'frontends' under hw/tpm/, but move the backends
in the backends/tpm/ directory.

Suggested-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20200612085444.8362-13-philmd@redhat.com
Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>

1 files changed, 380 insertions, 0 deletions

diff --git a/backends/tpm/tpm_util.c b/backends/tpm/tpm_util.c
new file mode 100644
index 0000000000..cfc7572a61
--- /dev/null
+++ b/backends/tpm/tpm_util.c
@@ -0,0 +1,380 @@
+/*
+ * TPM utility functions
+ *
+ *  Copyright (c) 2010 - 2015 IBM Corporation
+ *  Authors:
+ *    Stefan Berger <stefanb@us.ibm.com>
+ *
+ * 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 "qapi/error.h"
+#include "qapi/visitor.h"
+#include "tpm_int.h"
+#include "exec/memory.h"
+#include "hw/qdev-properties.h"
+#include "sysemu/tpm_backend.h"
+#include "sysemu/tpm_util.h"
+#include "trace.h"
+
+/* tpm backend property */
+
+static void get_tpm(Object *obj, Visitor *v, const char *name, void *opaque,
+                    Error **errp)
+{
+    DeviceState *dev = DEVICE(obj);
+    TPMBackend **be = qdev_get_prop_ptr(dev, opaque);
+    char *p;
+
+    p = g_strdup(*be ? (*be)->id : "");
+    visit_type_str(v, name, &p, errp);
+    g_free(p);
+}
+
+static void set_tpm(Object *obj, Visitor *v, const char *name, void *opaque,
+                    Error **errp)
+{
+    DeviceState *dev = DEVICE(obj);
+    Error *local_err = NULL;
+    Property *prop = opaque;
+    TPMBackend *s, **be = qdev_get_prop_ptr(dev, prop);
+    char *str;
+
+    if (dev->realized) {
+        qdev_prop_set_after_realize(dev, name, errp);
+        return;
+    }
+
+    visit_type_str(v, name, &str, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        return;
+    }
+
+    s = qemu_find_tpm_be(str);
+    if (s == NULL) {
+        error_setg(errp, "Property '%s.%s' can't find value '%s'",
+                   object_get_typename(obj), prop->name, str);
+    } else if (tpm_backend_init(s, TPM_IF(obj), errp) == 0) {
+        *be = s; /* weak reference, avoid cyclic ref */
+    }
+    g_free(str);
+}
+
+static void release_tpm(Object *obj, const char *name, void *opaque)
+{
+    DeviceState *dev = DEVICE(obj);
+    Property *prop = opaque;
+    TPMBackend **be = qdev_get_prop_ptr(dev, prop);
+
+    if (*be) {
+        tpm_backend_reset(*be);
+    }
+}
+
+const PropertyInfo qdev_prop_tpm = {
+    .name  = "str",
+    .description = "ID of a tpm to use as a backend",
+    .get   = get_tpm,
+    .set   = set_tpm,
+    .release = release_tpm,
+};
+
+/*
+ * Write an error message in the given output buffer.
+ */
+void tpm_util_write_fatal_error_response(uint8_t *out, uint32_t out_len)
+{
+    if (out_len >= sizeof(struct tpm_resp_hdr)) {
+        tpm_cmd_set_tag(out, TPM_TAG_RSP_COMMAND);
+        tpm_cmd_set_size(out, sizeof(struct tpm_resp_hdr));
+        tpm_cmd_set_error(out, TPM_FAIL);
+    }
+}
+
+bool tpm_util_is_selftest(const uint8_t *in, uint32_t in_len)
+{
+    if (in_len >= sizeof(struct tpm_req_hdr)) {
+        return tpm_cmd_get_ordinal(in) == TPM_ORD_ContinueSelfTest;
+    }
+
+    return false;
+}
+
+/*
+ * Send request to a TPM device. We expect a response within one second.
+ */
+static int tpm_util_request(int fd,
+                            const void *request,
+                            size_t requestlen,
+                            void *response,
+                            size_t responselen)
+{
+    fd_set readfds;
+    int n;
+    struct timeval tv = {
+        .tv_sec = 1,
+        .tv_usec = 0,
+    };
+
+    n = write(fd, request, requestlen);
+    if (n < 0) {
+        return -errno;
+    }
+    if (n != requestlen) {
+        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, response, responselen);
+    if (n < sizeof(struct tpm_resp_hdr)) {
+        return -EFAULT;
+    }
+
+    /* check the header */
+    if (tpm_cmd_get_size(response) != n) {
+        return -EMSGSIZE;
+    }
+
+    return 0;
+}
+
+/*
+ * A basic test of a TPM device. We expect a well formatted response header
+ * (error response is fine).
+ */
+static int tpm_util_test(int fd,
+                         const void *request,
+                         size_t requestlen,
+                         uint16_t *return_tag)
+{
+    char buf[1024];
+    ssize_t ret;
+
+    ret = tpm_util_request(fd, request, requestlen,
+                           buf, sizeof(buf));
+    if (ret < 0) {
+        return ret;
+    }
+
+    *return_tag = tpm_cmd_get_tag(buf);
+
+    return 0;
+}
+
+/*
+ * Probe for the TPM device in the back
+ * Returns 0 on success with the version of the probed TPM set, 1 on failure.
+ */
+int tpm_util_test_tpmdev(int tpm_fd, TPMVersion *tpm_version)
+{
+    /*
+     * Sending a TPM1.2 command to a TPM2 should return a TPM1.2
+     * header (tag = 0xc4) and error code (TPM_BADTAG = 0x1e)
+     *
+     * Sending a TPM2 command to a TPM 2 will give a TPM 2 tag in the
+     * header.
+     * Sending a TPM2 command to a TPM 1.2 will give a TPM 1.2 tag
+     * in the header and an error code.
+     */
+    const struct tpm_req_hdr test_req = {
+        .tag = cpu_to_be16(TPM_TAG_RQU_COMMAND),
+        .len = cpu_to_be32(sizeof(test_req)),
+        .ordinal = cpu_to_be32(TPM_ORD_GetTicks),
+    };
+
+    const struct tpm_req_hdr test_req_tpm2 = {
+        .tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
+        .len = cpu_to_be32(sizeof(test_req_tpm2)),
+        .ordinal = cpu_to_be32(TPM2_CC_ReadClock),
+    };
+    uint16_t return_tag;
+    int ret;
+
+    /* Send TPM 2 command */
+    ret = tpm_util_test(tpm_fd, &test_req_tpm2,
+                        sizeof(test_req_tpm2), &return_tag);
+    /* TPM 2 would respond with a tag of TPM2_ST_NO_SESSIONS */
+    if (!ret && return_tag == TPM2_ST_NO_SESSIONS) {
+        *tpm_version = TPM_VERSION_2_0;
+        return 0;
+    }
+
+    /* Send TPM 1.2 command */
+    ret = tpm_util_test(tpm_fd, &test_req,
+                        sizeof(test_req), &return_tag);
+    if (!ret && return_tag == TPM_TAG_RSP_COMMAND) {
+        *tpm_version = TPM_VERSION_1_2;
+        /* this is a TPM 1.2 */
+        return 0;
+    }
+
+    *tpm_version = TPM_VERSION_UNSPEC;
+
+    return 1;
+}
+
+int tpm_util_get_buffer_size(int tpm_fd, TPMVersion tpm_version,
+                             size_t *buffersize)
+{
+    int ret;
+
+    switch (tpm_version) {
+    case TPM_VERSION_1_2: {
+        const struct tpm_req_get_buffer_size {
+            struct tpm_req_hdr hdr;
+            uint32_t capability;
+            uint32_t len;
+            uint32_t subcap;
+        } QEMU_PACKED tpm_get_buffer_size = {
+            .hdr = {
+                .tag = cpu_to_be16(TPM_TAG_RQU_COMMAND),
+                .len = cpu_to_be32(sizeof(tpm_get_buffer_size)),
+                .ordinal = cpu_to_be32(TPM_ORD_GetCapability),
+            },
+            .capability = cpu_to_be32(TPM_CAP_PROPERTY),
+            .len = cpu_to_be32(sizeof(uint32_t)),
+            .subcap = cpu_to_be32(TPM_CAP_PROP_INPUT_BUFFER),
+        };
+        struct tpm_resp_get_buffer_size {
+            struct tpm_resp_hdr hdr;
+            uint32_t len;
+            uint32_t buffersize;
+        } QEMU_PACKED tpm_resp;
+
+        ret = tpm_util_request(tpm_fd, &tpm_get_buffer_size,
+                               sizeof(tpm_get_buffer_size),
+                               &tpm_resp, sizeof(tpm_resp));
+        if (ret < 0) {
+            return ret;
+        }
+
+        if (be32_to_cpu(tpm_resp.hdr.len) != sizeof(tpm_resp) ||
+            be32_to_cpu(tpm_resp.len) != sizeof(uint32_t)) {
+            trace_tpm_util_get_buffer_size_hdr_len(
+                be32_to_cpu(tpm_resp.hdr.len),
+                sizeof(tpm_resp));
+            trace_tpm_util_get_buffer_size_len(be32_to_cpu(tpm_resp.len),
+                                               sizeof(uint32_t));
+            error_report("tpm_util: Got unexpected response to "
+                         "TPM_GetCapability; errcode: 0x%x",
+                         be32_to_cpu(tpm_resp.hdr.errcode));
+            return -EFAULT;
+        }
+        *buffersize = be32_to_cpu(tpm_resp.buffersize);
+        break;
+    }
+    case TPM_VERSION_2_0: {
+        const struct tpm2_req_get_buffer_size {
+            struct tpm_req_hdr hdr;
+            uint32_t capability;
+            uint32_t property;
+            uint32_t count;
+        } QEMU_PACKED tpm2_get_buffer_size = {
+            .hdr = {
+                .tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
+                .len = cpu_to_be32(sizeof(tpm2_get_buffer_size)),
+                .ordinal = cpu_to_be32(TPM2_CC_GetCapability),
+            },
+            .capability = cpu_to_be32(TPM2_CAP_TPM_PROPERTIES),
+            .property = cpu_to_be32(TPM2_PT_MAX_COMMAND_SIZE),
+            .count = cpu_to_be32(2), /* also get TPM2_PT_MAX_RESPONSE_SIZE */
+        };
+        struct tpm2_resp_get_buffer_size {
+            struct tpm_resp_hdr hdr;
+            uint8_t more;
+            uint32_t capability;
+            uint32_t count;
+            uint32_t property1;
+            uint32_t value1;
+            uint32_t property2;
+            uint32_t value2;
+        } QEMU_PACKED tpm2_resp;
+
+        ret = tpm_util_request(tpm_fd, &tpm2_get_buffer_size,
+                               sizeof(tpm2_get_buffer_size),
+                               &tpm2_resp, sizeof(tpm2_resp));
+        if (ret < 0) {
+            return ret;
+        }
+
+        if (be32_to_cpu(tpm2_resp.hdr.len) != sizeof(tpm2_resp) ||
+            be32_to_cpu(tpm2_resp.count) != 2) {
+            trace_tpm_util_get_buffer_size_hdr_len2(
+                be32_to_cpu(tpm2_resp.hdr.len),
+                sizeof(tpm2_resp));
+            trace_tpm_util_get_buffer_size_len2(
+                be32_to_cpu(tpm2_resp.count), 2);
+            error_report("tpm_util: Got unexpected response to "
+                         "TPM2_GetCapability; errcode: 0x%x",
+                         be32_to_cpu(tpm2_resp.hdr.errcode));
+            return -EFAULT;
+        }
+        *buffersize = MAX(be32_to_cpu(tpm2_resp.value1),
+                          be32_to_cpu(tpm2_resp.value2));
+        break;
+    }
+    case TPM_VERSION_UNSPEC:
+        return -EFAULT;
+    }
+
+    trace_tpm_util_get_buffer_size(*buffersize);
+
+    return 0;
+}
+
+void tpm_sized_buffer_reset(TPMSizedBuffer *tsb)
+{
+    g_free(tsb->buffer);
+    tsb->buffer = NULL;
+    tsb->size = 0;
+}
+
+void tpm_util_show_buffer(const unsigned char *buffer,
+                          size_t buffer_size, const char *string)
+{
+    size_t len, i;
+    char *line_buffer, *p;
+
+    if (!trace_event_get_state_backends(TRACE_TPM_UTIL_SHOW_BUFFER)) {
+        return;
+    }
+    len = MIN(tpm_cmd_get_size(buffer), buffer_size);
+
+    /*
+     * allocate enough room for 3 chars per buffer entry plus a
+     * newline after every 16 chars and a final null terminator.
+     */
+    line_buffer = g_malloc(len * 3 + (len / 16) + 1);
+
+    for (i = 0, p = line_buffer; i < len; i++) {
+        if (i && !(i % 16)) {
+            p += sprintf(p, "\n");
+        }
+        p += sprintf(p, "%.2X ", buffer[i]);
+    }
+    trace_tpm_util_show_buffer(string, len, line_buffer);
+
+    g_free(line_buffer);
+}