[Qemu-devel] [PATCH V8 14/14] Allow to provide inital TPM state

[Stefan Berger]

This patch adds a -tpm ...,initstate=...,... command line option to the
TPM's existing options and enables the TPM to be initialized with an
existing state blob. This in turn allows us to simulate TPM manufacturing
and equip the TPM with an endorsement key, certificates and initialize its
NVRAM areas etc.. This step is typically done during manufacturng of the TPM
and/or the (physical) machine.

The initial state can be passed either as file or via a file descriptor. The
encoding of the state can either be binary or in form of a base64-encoded
blob surrounded by tags indicating the start and end.

The intial state can be produced through a yet-to-be-published tpm-authoring
tool.

Signed-off-by: Stefan Berger <address@hidden>

---
 hw/tpm_builtin.c |  123 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 qemu-config.c    |   12 +++++
 qemu-options.hx  |   40 ++++++++++++++++-
 3 files changed, 172 insertions(+), 3 deletions(-)

Index: qemu-git/hw/tpm_builtin.c
===================================================================
--- qemu-git.orig/hw/tpm_builtin.c
+++ qemu-git/hw/tpm_builtin.c
@@ -170,9 +170,16 @@ static struct enckey {
     AES_KEY tpm_dec_key;
 } enckey;
 
+static int tpm_initstatefd = -1;
+static bool tpm_initstate_bin;
+
 static int tpm_builtin_load_sized_data_from_bs(BlockDriverState *bs,
                                                enum BSEntryType be,
                                                TPMSizedBuffer *tsb);
+static TPM_RESULT tpm_builtin_get_initial_state(unsigned char **data,
+                                                uint32_t *length,
+                                                size_t tpm_number,
+                                                const char *name);
 
 
 
@@ -1269,7 +1276,7 @@ static TPM_RESULT tpm_builtin_nvram_load
         *length = permanent_state.size;
 
         if (*length == 0) {
-            rc = TPM_RETRY;
+            rc = tpm_builtin_get_initial_state(data, length, tpm_number, name);
         } else {
             /* keep a copy of the last permanent state */
             rc = TPM_Malloc(data, *length);
@@ -1452,6 +1459,94 @@ static TPM_RESULT tpm_builtin_io_getphys
 }
 
 
+static TPM_RESULT tpm_builtin_get_initial_state(unsigned char **data,
+                                                uint32_t *length,
+                                                size_t tpm_number,
+                                                const char *name)
+{
+    TPM_RESULT rc = TPM_RETRY;
+    uint32_t allocated = 0;
+    int len, flags;
+    unsigned char buf[1024];
+    unsigned char *result = NULL;
+    size_t result_len;
+
+    if (tpm_initstatefd >= 0) {
+        *data = NULL;
+        *length = 0;
+
+        flags = fcntl(tpm_initstatefd, F_GETFL);
+        if (flags < 0 ||
+            fcntl(tpm_initstatefd, F_SETFL, flags & ~O_NONBLOCK) < 0) {
+            return TPM_FAIL;
+        }
+
+        while (TRUE) {
+            len = read(tpm_initstatefd, buf, sizeof(buf));
+
+            if (len > 0) {
+                if (len > allocated - *length) {
+                    allocated = *length + len + 1024;
+                    if (TPM_Realloc(data, allocated) != TPM_SUCCESS) {
+                        goto err_exit;
+                    }
+                }
+                memcpy(&(*data)[*length], buf, len);
+                *length += len;
+                (*data)[*length] = 0;
+            } else if (len == 0) {
+                rc = TPM_SUCCESS;
+                break;
+            } else if (len < 0) {
+                if (errno == EINTR) {
+                    continue;
+                }
+                goto err_exit;
+            }
+        }
+
+        if (*data == NULL) {
+            /* nothing read */
+            rc = TPM_FAIL;
+            goto err_exit;
+        }
+
+        if (!tpm_initstate_bin) {
+            if (TPMLIB_DecodeBlob((char *)*data, TPMLIB_BLOB_TYPE_INITSTATE,
+                                  &result, &result_len) != TPM_SUCCESS) {
+                goto err_exit;
+            }
+            TPM_Free(*data);
+            *data = result;
+            *length = result_len;
+            result = NULL;
+        }
+        /* sanity check for the size of the blob */
+        if (*length > tpmlib_get_prop(TPMPROP_TPM_MAX_NV_SPACE)) {
+            goto err_exit;
+        }
+        /* have it written into the BlockStorage */
+        rc = tpm_builtin_nvram_storedata(*data, *length, tpm_number, name);
+        if (rc != TPM_SUCCESS) {
+            goto err_exit;
+        }
+    }
+
+norm_exit:
+    close(tpm_initstatefd);
+    tpm_initstatefd = -1;
+
+    return rc;
+
+err_exit:
+    TPM_Free(*data);
+    *data = NULL;
+    *length = 0;
+    TPM_Free(result);
+
+    goto norm_exit;
+}
+
 /*****************************************************************/
 
 
@@ -1748,6 +1843,7 @@ static TPMBackend *tpm_builtin_create(Qe
     const char *value;
     unsigned char keyvalue[256/8];
     int keysize = sizeof(keyvalue);
+    unsigned int offset;
 
     driver = g_malloc(sizeof(TPMBackend));
     if (!driver) {
@@ -1801,6 +1897,28 @@ static TPMBackend *tpm_builtin_create(Qe
         enckey.enctype = BS_DIR_ENCTYPE_NONE;
     }
 
+    value = qemu_opt_get(opts, "initstate");
+    if (value) {
+        offset = 0;
+
+        if (!strncmp(value, "bin:", 4)) {
+            tpm_initstate_bin = true;
+            offset = 4;
+        } else if (!strncmp(value, "base64:", 7)) {
+            tpm_initstate_bin = false;
+            offset = 7;
+        }
+
+        if (sscanf(&value[offset], "fd:%d", &tpm_initstatefd) != 1) {
+            tpm_initstatefd = open(&value[offset], O_RDONLY);
+            if (tpm_initstatefd < 0) {
+                fprintf(stderr, "tpm: could not open file '%s' for reading.\n",
+                        value);
+                goto err_exit;
+            }
+        }
+    }
+
     return driver;
 
 err_exit:
@@ -1816,6 +1934,9 @@ static void tpm_builtin_destroy(TPMBacke
     g_free(driver->id);
     g_free(driver->model);
     g_free(driver);
+
+    close(tpm_initstatefd);
+    tpm_initstatefd = -1;
 }
 
 
Index: qemu-git/qemu-config.c
===================================================================
--- qemu-git.orig/qemu-config.c
+++ qemu-git/qemu-config.c
@@ -527,6 +527,12 @@ static QemuOptsList qemu_tpmdev_opts = {
             .type = QEMU_OPT_STRING,
             .help = "Data encryption key",
         },
+        {
+            .name = "initstate",
+            .type = QEMU_OPT_STRING,
+            .help = "File or file descriptor for reading initial TPM state "
+                    "from",
+        },
         { /* end of list */ }
     },
 };
@@ -556,6 +562,12 @@ static QemuOptsList qemu_tpm_opts = {
             .type = QEMU_OPT_STRING,
             .help = "Data encryption key",
         },
+        {
+            .name = "initstate",
+            .type = QEMU_OPT_STRING,
+            .help = "File or file descriptor for reading initial TPM state "
+                    "from",
+        },
         { /* end of list */ }
     },
 };
Index: qemu-git/qemu-options.hx
===================================================================
--- qemu-git.orig/qemu-options.hx
+++ qemu-git/qemu-options.hx
@@ -1767,8 +1767,10 @@ DEFHEADING(TPM device options:)
 DEF("tpm", HAS_ARG, QEMU_OPTION_tpm, \
     "" \
     "-tpm builtin,path=<path>[,model=<model>][,key=<aes key>]\n" \
+    "     [,initstate=[bin:|base64:]fd:<fd>|<path>]\n" \
     "                enable a builtin TPM with state in file in path\n" \
     "                and encrypt the TPM's state with the given AES key\n" \
+    "                initstate= path to initial state of TPM; default is 
base64\n" \
     "-tpm null       enable a TPM null driver that responds with a fault\n" \
     "                message to every TPM request\n" \
     "-tpm model=?    to list available TPM device models\n" \
@@ -1800,7 +1802,7 @@ Use ? to print all available TPM backend
 qemu -tpmdev ?
 @end example
 
address@hidden -tpmdev builtin ,address@hidden, address@hidden [,address@hidden
address@hidden -tpmdev builtin ,address@hidden, address@hidden [,address@hidden 
[,address@hidden
 
 Creates an instance of the built-in TPM.
 
@@ -1830,6 +1832,40 @@ using AES-CBC encryption scheme supply t
 -tpmdev 
builtin,id=tpm0,path=<path_to_qcow2>,key=aes-cbc:0x1234567890abcdef01234567890abcdef
 -device tpm-tis,tpmdev=tpm0
 @end example
 
address@hidden specifies the path to a file containing the initial
+state of the TPM. It can be used to provide the TPM with an EK and certificates
+for the EK, TPM and Platform. Since the file contains binary data that
+have to conform to the TPM's layout of data, it must have been created using
+an approriate authoring tool.
+
+The initstate option allows to provide a binary state blob or one that is
+encode in base 64. The base64-encode state blob must have the format
+
address@hidden
+-----BEGIN INITSTATE-----
+<base 64 encoded state>
+-----END INITSTATE-----
address@hidden example
+
+The initstate option is only effective when Qemu is started with blank
+state.
+
+The initstate option supports several formats:
+
address@hidden @option
+ @item  [base64:]<path_to_blob>
+ Provide the path to the TPM's initial state blob in base64 format.
+ @item  bin:<path to blob>
+ Provide the path to the TPM's initial state blob in binary format.
+ @item  [base64:]fd:<fd>
+ Provide the base64 formatted initial state via a file descriptor to read from.
+ @item  bin:fd:<fd>
+ Provide the binary initial state via a file descriptor to read from.
address@hidden table
+
address@hidden is optional.
+
+
 @item -tpmdev null
 
 Creates an instance of a TPM null driver that responds to every command
@@ -1840,7 +1876,7 @@ with a fault message.
 The short form of a TPM device option is:
 @table @option
 
address@hidden -tpm @var{backend-type}, address@hidden [,address@hidden 
[,address@hidden
address@hidden -tpm @var{backend-type}, address@hidden [,address@hidden 
[,address@hidden [,address@hidden
 @findex -tpm
 
 @option{model} specifies the device model. The default device model is a