[PATCH] ibmvtpm: Add support for trusted boot using a vTPM 2.0

[Stefan Berger]

From: Stefan Berger <stefanb@linux.ibm.com>

Add support for trusted boot using a vTPM 2.0 on the IBM ieee1275
platform. With this patch grub now measures text and binary data
into the TPM's PCRs 8 and 9 in the same way as the x86_64 platform
does.

This patch requires Daniel Axtens's patches for claiming more memory.

Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
---
 grub-core/Makefile.core.def           |   8 ++
 grub-core/commands/ieee1275/ibmvtpm.c | 118 ++++++++++++++++++++++++++
 grub-core/kern/ieee1275/ibmvtpm.c     |  62 ++++++++++++++
 include/grub/ieee1275/ibmvtpm.h       |  32 +++++++
 4 files changed, 220 insertions(+)
 create mode 100644 grub-core/commands/ieee1275/ibmvtpm.c
 create mode 100644 grub-core/kern/ieee1275/ibmvtpm.c
 create mode 100644 include/grub/ieee1275/ibmvtpm.h

diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
index 3f3459b2c..e2a64f8ff 100644
--- a/grub-core/Makefile.core.def
+++ b/grub-core/Makefile.core.def
@@ -1166,6 +1166,14 @@ module = {
   enable = powerpc_ieee1275;
 };
 
+module = {
+  name = tpm;
+  common = commands/tpm.c;
+  common = kern/ieee1275/ibmvtpm.c;
+  ieee1275 = commands/ieee1275/ibmvtpm.c;
+  enable = powerpc_ieee1275;
+};
+
 module = {
   name = terminal;
   common = commands/terminal.c;
diff --git a/grub-core/commands/ieee1275/ibmvtpm.c 
b/grub-core/commands/ieee1275/ibmvtpm.c
new file mode 100644
index 000000000..9b06c76d9
--- /dev/null
+++ b/grub-core/commands/ieee1275/ibmvtpm.c
@@ -0,0 +1,118 @@
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2021  IBM Corporation
+ *
+ *  GRUB is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  GRUB 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 General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  IBM vTPM support code.
+ */
+
+#include <grub/err.h>
+#include <grub/types.h>
+#include <grub/tpm.h>
+#include <grub/ieee1275/ieee1275.h>
+#include <grub/ieee1275/ibmvtpm.h>
+#include <grub/mm.h>
+#include <grub/misc.h>
+
+static grub_ieee1275_ihandle_t grub_tpm_ihandle;
+static grub_uint8_t grub_tpm_version;
+
+static void grub_ieee1275_tpm_init (grub_ieee1275_ihandle_t *tpm_ihandle)
+{
+  static int init_called = 0;
+
+  if (!init_called) {
+      init_called = 1;
+      grub_ieee1275_open ("/vdevice/vtpm", &grub_tpm_ihandle);
+  }
+
+  *tpm_ihandle = grub_tpm_ihandle;
+}
+
+static grub_err_t
+grub_tpm_get_tpm_version (grub_uint8_t *protocol_version)
+{
+  static int version_probed = 0;
+  grub_ieee1275_phandle_t vtpm;
+  char buffer[20];
+  grub_ssize_t buffer_size;
+
+  if (!version_probed) {
+     version_probed = 1;
+     if (!grub_ieee1275_finddevice ("/vdevice/vtpm", &vtpm) &&
+         !grub_ieee1275_get_property (vtpm, "compatible", buffer,
+                                      sizeof buffer, &buffer_size) &&
+         !grub_strcmp (buffer, "IBM,vtpm20")) {
+       grub_tpm_version = 2;
+    }
+  }
+  *protocol_version = grub_tpm_version;
+
+  return 0;
+}
+
+static grub_int8_t
+grub_tpm_handle_find (grub_ieee1275_ihandle_t *tpm_handle,
+                     grub_uint8_t *protocol_version)
+{
+  grub_ieee1275_tpm_init (tpm_handle);
+  if (*tpm_handle == NULL)
+      return 0;
+
+  grub_tpm_get_tpm_version (protocol_version);
+
+  return 1;
+}
+
+static grub_err_t
+grub_tpm2_log_event (grub_ieee1275_ihandle_t tpm_handle, unsigned char *buf,
+                    grub_size_t size, grub_uint8_t pcr,
+                    const char *description)
+{
+  static int error_displayed;
+  bool succ;
+
+  succ = grub_ieee1275_ibmvtpm_2hash_ext_log (tpm_handle,
+                                           pcr, EV_IPL,
+                                           description,
+                                           grub_strlen(description) + 1,
+                                           buf, size);
+  if (!succ && !error_displayed) {
+    error_displayed = 1;
+    grub_printf("2HASH-EXT-LOG failed: Firmware is likely too old.\n");
+  }
+
+  return 0;
+}
+
+grub_err_t
+grub_tpm_measure (unsigned char *buf, grub_size_t size, grub_uint8_t pcr,
+                   const char *description)
+{
+  grub_ieee1275_ihandle_t tpm_handle;
+  grub_uint8_t protocol_version = 0;
+
+  /* Absence of a TPM isn't a failure. */
+  if (!grub_tpm_handle_find (&tpm_handle, &protocol_version))
+    return 0;
+
+  grub_dprintf ("tpm", "log_event, pcr = %d, size = 0x%" PRIxGRUB_SIZE ", 
%s\n",
+                pcr, size, description);
+
+  if (protocol_version == 2)
+      return grub_tpm2_log_event (tpm_handle, buf, size, pcr, description);
+
+  return 0;
+}
diff --git a/grub-core/kern/ieee1275/ibmvtpm.c 
b/grub-core/kern/ieee1275/ibmvtpm.c
new file mode 100644
index 000000000..525a792b4
--- /dev/null
+++ b/grub-core/kern/ieee1275/ibmvtpm.c
@@ -0,0 +1,62 @@
+/* ibmvtpm.c - Client interface to access the IBM vTPM */
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2021  IBM Corporation
+ *
+ *  GRUB is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  GRUB 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 General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <grub/types.h>
+#include <grub/misc.h>
+#include <grub/ieee1275/ieee1275.h>
+#include <grub/ieee1275/ibmvtpm.h>
+
+bool
+grub_ieee1275_ibmvtpm_2hash_ext_log (grub_uint32_t ihandle,
+                                grub_uint8_t pcrindex,
+                                grub_uint32_t eventtype,
+                                const char *description,
+                                grub_size_t description_size,
+                                void *buf, grub_size_t size)
+{
+  struct tpm_2hash_ext_log
+  {
+    struct grub_ieee1275_common_hdr common;
+    grub_ieee1275_cell_t method;
+    grub_ieee1275_cell_t ihandle;
+    grub_ieee1275_cell_t size;
+    void *buf;
+    grub_ieee1275_cell_t description_size;
+    const char *description;
+    grub_ieee1275_cell_t eventtype;
+    grub_ieee1275_cell_t pcrindex;
+    grub_ieee1275_cell_t catch_result;
+    grub_ieee1275_cell_t rc;
+  }
+  args;
+
+  INIT_IEEE1275_COMMON (&args.common, "call-method", 8, 2);
+  args.method = (grub_ieee1275_cell_t) "2hash-ext-log";
+  args.ihandle = ihandle;
+  args.pcrindex = pcrindex;
+  args.eventtype = eventtype;
+  args.description = description;
+  args.description_size = description_size;
+  args.buf = buf;
+  args.size = (grub_ieee1275_cell_t) size;
+
+  if (IEEE1275_CALL_ENTRY_FN (&args) == -1)
+    return false;
+  return !!args.rc;
+}
diff --git a/include/grub/ieee1275/ibmvtpm.h b/include/grub/ieee1275/ibmvtpm.h
new file mode 100644
index 000000000..bde4f9e69
--- /dev/null
+++ b/include/grub/ieee1275/ibmvtpm.h
@@ -0,0 +1,32 @@
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2021  IBM Corporation
+ *
+ *  GRUB is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  GRUB 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 General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef GRUB_IEEE1275_IBMVTPM_HEADER
+#define GRUB_IEEE1275_IBMVTPM_HEADER 1
+
+#include <stdbool.h>
+
+bool EXPORT_FUNC(grub_ieee1275_ibmvtpm_2hash_ext_log) (
+                                  grub_uint32_t ihandle,
+                                  grub_uint8_t pcrindex,
+                                  grub_uint32_t eventtype,
+                                  const char *description,
+                                  grub_size_t description_size,
+                                  void *buf, grub_size_t size);
+
+#endif
-- 
2.31.1