Discussion:
[PATCH 1/3] verifiers: Verify commands executed by grub
(too old to reply)
Matthew Garrett
2018-11-09 23:50:41 UTC
Permalink
From: Matthew Garrett <***@google.com>

Pass all commands executed by grub to the verifiers layer. Most
verifiers will ignore this, but some (such as the TPM verifier) want to
be able to measure and log each command executed in order to ensure that
the boot state is as expected.
---
grub-core/script/execute.c | 27 ++++++++++++++++++++++++---
include/grub/verify.h | 1 +
2 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/grub-core/script/execute.c b/grub-core/script/execute.c
index a8502d907..ee299fd0e 100644
--- a/grub-core/script/execute.c
+++ b/grub-core/script/execute.c
@@ -27,6 +27,7 @@
#include <grub/normal.h>
#include <grub/extcmd.h>
#include <grub/i18n.h>
+#include <grub/verify.h>

/* Max digits for a char is 3 (0xFF is 255), similarly for an int it
is sizeof (int) * 3, and one extra for a possible -ve sign. */
@@ -929,8 +930,9 @@ grub_script_execute_cmdline (struct grub_script_cmd *cmd)
grub_err_t ret = 0;
grub_script_function_t func = 0;
char errnobuf[18];
- char *cmdname;
- int argc;
+ char *cmdname, *cmdstring;
+ int argc, offset = 0, cmdlen = 0;
+ unsigned int i;
char **args;
int invert;
struct grub_script_argv argv = { 0, 0, 0 };
@@ -939,6 +941,26 @@ grub_script_execute_cmdline (struct grub_script_cmd *cmd)
if (grub_script_arglist_to_argv (cmdline->arglist, &argv) || ! argv.args[0])
return grub_errno;

+ for (i = 0; i < argv.argc; i++)
+ {
+ cmdlen += grub_strlen (argv.args[i]) + 1;
+ }
+
+ cmdstring = grub_malloc (cmdlen);
+ if (!cmdstring)
+ {
+ return grub_error (GRUB_ERR_OUT_OF_MEMORY,
+ N_("cannot allocate command buffer"));
+ }
+
+ for (i = 0; i < argv.argc; i++)
+ {
+ offset += grub_snprintf (cmdstring + offset, cmdlen - offset, "%s ",
+ argv.args[i]);
+ }
+ cmdstring[cmdlen - 1] = '\0';
+ grub_verify_string (cmdstring, GRUB_VERIFY_COMMAND);
+ grub_free (cmdstring);
invert = 0;
argc = argv.argc - 1;
args = argv.args + 1;
@@ -1163,4 +1185,3 @@ grub_script_execute (struct grub_script *script)

return grub_script_execute_cmd (script->cmd);
}
-
diff --git a/include/grub/verify.h b/include/grub/verify.h
index 79022b422..460f2e20a 100644
--- a/include/grub/verify.h
+++ b/include/grub/verify.h
@@ -31,6 +31,7 @@ enum grub_verify_string_type
{
GRUB_VERIFY_KERNEL_CMDLINE,
GRUB_VERIFY_MODULE_CMDLINE,
+ GRUB_VERIFY_COMMAND,
};

struct grub_file_verifier
--
2.19.1.930.g4563a0d9d0-goog
Matthew Garrett
2018-11-09 23:50:43 UTC
Permalink
Describe the behaviour of grub when the TPM module is in use.
---
docs/grub.texi | 38 ++++++++++++++++++++++++++++++++++++++
1 file changed, 38 insertions(+)

diff --git a/docs/grub.texi b/docs/grub.texi
index 471d97c95..6bd3783a4 100644
--- a/docs/grub.texi
+++ b/docs/grub.texi
@@ -5545,6 +5545,7 @@ environment variables and commands are listed in the same order.
* Authentication and authorisation:: Users and access control
* Using digital signatures:: Booting digitally signed code
* UEFI secure boot and shim:: Booting digitally signed PE files
+* Measured Boot:: Measuring boot components
@end menu

@node Authentication and authorisation
@@ -5721,6 +5722,43 @@ mentioned requirements are enforced by the shim_lock module. And itself it
is a persistent module which means that it cannot be unloaded if it was
loaded into the memory.

+@node Measured Boot
+@section Measuring boot components
+
+If the tpm module is loaded and the platform has a Trusted Platform Module
+installed, GRUB will log each command executed and each file loaded into the
+TPM event log and extend the PCR values in the TPM correspondingly. All events
+will be logged into the PCR described below with a type of EV_IPL and an
+event description as described below.
+
+@multitable @columnfractions 0.3 0.1 0.6
+@headitem Event type @tab PCR @tab Description
+@item Command
+@tab 8
+@tab All executed commands (including those from configuration files) will be
+logged and measured as entered with a prefix of ``grub_cmd: ``
+@item Module command line
+@tab 8
+@tab Any command line passed to a kernel module will be logged and measured as
+entered with a prefix of ``module_cmdline: ``
+@item Kernel command line
+@tab 8
+@tab Any command line passed to a kernel will be logged and measured as entered
+with a prefix of ``kernel_cmdline: ''
+@item Files
+@tab 9
+@tab Any file read by GRUB will be logged and measured with a descriptive text
+corresponding to the filename.
+@end multitable
+
+GRUB will not measure its own @file{core.img} - it is expected that firmware
+will carry this out. GRUB will also not perform any measurements until the
+tpm module is loaded. As such it is recommended that the tpm module be built
+into @file{core.img} in order to avoid a potential gap in measurement between
+@file{core.img} being loaded and the tpm module being loaded.
+
+Measured boot is currently only supported on EFI platforms.
+
@node Platform limitations
@chapter Platform limitations
--
2.19.1.930.g4563a0d9d0-goog
Matthew Garrett
2018-11-09 23:50:42 UTC
Permalink
From: Matthew Garrett <***@google.com>

Add support for performing basic TPM measurements. Right now this only
supports extending PCRs statically and only on UEFI. In future we might
want to have some sort of mechanism for choosing which events get logged
to which PCRs, but this seems like a good default policy and we can wait
to see whether anyone has a use case before adding more complexity.
---
grub-core/Makefile.core.def | 7 +
grub-core/commands/efi/tpm.c | 310 +++++++++++++++++++++++++++++++++
grub-core/commands/tpm.c | 87 +++++++++
grub-core/kern/i386/efi/init.c | 1 +
include/grub/efi/tpm.h | 153 ++++++++++++++++
include/grub/tpm.h | 74 ++++++++
6 files changed, 632 insertions(+)
create mode 100644 grub-core/commands/efi/tpm.c
create mode 100644 grub-core/commands/tpm.c
create mode 100644 include/grub/efi/tpm.h
create mode 100644 include/grub/tpm.h

diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
index 6e2cc8444..a485f9186 100644
--- a/grub-core/Makefile.core.def
+++ b/grub-core/Makefile.core.def
@@ -2377,6 +2377,13 @@ module = {
common = commands/testspeed.c;
};

+module = {
+ name = tpm;
+ common = commands/tpm.c;
+ efi = commands/efi/tpm.c;
+ enable = efi;
+};
+
module = {
name = tr;
common = commands/tr.c;
diff --git a/grub-core/commands/efi/tpm.c b/grub-core/commands/efi/tpm.c
new file mode 100644
index 000000000..f03464d96
--- /dev/null
+++ b/grub-core/commands/efi/tpm.c
@@ -0,0 +1,310 @@
+#include <grub/err.h>
+#include <grub/i18n.h>
+#include <grub/efi/api.h>
+#include <grub/efi/efi.h>
+#include <grub/efi/tpm.h>
+#include <grub/mm.h>
+#include <grub/tpm.h>
+#include <grub/term.h>
+
+static grub_efi_guid_t tpm_guid = EFI_TPM_GUID;
+static grub_efi_guid_t tpm2_guid = EFI_TPM2_GUID;
+
+static grub_efi_handle_t *grub_tpm_handle;
+static grub_uint8_t grub_tpm_version;
+
+static grub_int8_t tpm1_present = -1;
+static grub_int8_t tpm2_present = -1;
+
+static grub_efi_boolean_t grub_tpm1_present(grub_efi_tpm_protocol_t *tpm)
+{
+ grub_efi_status_t status;
+ TCG_EFI_BOOT_SERVICE_CAPABILITY caps;
+ grub_uint32_t flags;
+ grub_efi_physical_address_t eventlog, lastevent;
+
+ if (tpm1_present != -1)
+ return (grub_efi_boolean_t)tpm1_present;
+
+ caps.Size = (grub_uint8_t)sizeof(caps);
+
+ status = efi_call_5(tpm->status_check, tpm, &caps, &flags, &eventlog,
+ &lastevent);
+
+ if (status != GRUB_EFI_SUCCESS || caps.TPMDeactivatedFlag
+ || !caps.TPMPresentFlag) {
+ tpm1_present = 0;
+ return tpm1_present;
+ }
+
+ tpm1_present = 1;
+ return tpm1_present;
+}
+
+static grub_efi_boolean_t grub_tpm2_present(grub_efi_tpm2_protocol_t *tpm)
+{
+ grub_efi_status_t status;
+ EFI_TCG2_BOOT_SERVICE_CAPABILITY caps;
+
+ caps.Size = (grub_uint8_t)sizeof(caps);
+
+ if (tpm2_present != -1)
+ return (grub_efi_boolean_t)tpm2_present;
+
+ status = efi_call_2(tpm->get_capability, tpm, &caps);
+
+ if (status != GRUB_EFI_SUCCESS || !caps.TPMPresentFlag) {
+ tpm2_present = 0;
+ return tpm2_present;
+ }
+
+ tpm2_present = 1;
+ return tpm2_present;
+}
+
+static grub_efi_boolean_t grub_tpm_handle_find(grub_efi_handle_t *tpm_handle,
+ grub_efi_uint8_t *protocol_version)
+{
+ grub_efi_handle_t *handles;
+ grub_efi_uintn_t num_handles;
+
+ if (grub_tpm_handle != NULL) {
+ *tpm_handle = &grub_tpm_handle;
+ *protocol_version = grub_tpm_version;
+ return 1;
+ }
+
+ handles = grub_efi_locate_handle (GRUB_EFI_BY_PROTOCOL, &tpm_guid, NULL,
+ &num_handles);
+ if (handles && num_handles > 0) {
+ grub_tpm_handle = handles[0];
+ *tpm_handle = handles[0];
+ grub_tpm_version = 1;
+ *protocol_version = 1;
+ return 1;
+ }
+
+ handles = grub_efi_locate_handle (GRUB_EFI_BY_PROTOCOL, &tpm2_guid, NULL,
+ &num_handles);
+ if (handles && num_handles > 0) {
+ grub_tpm_handle = handles[0];
+ *tpm_handle = handles[0];
+ grub_tpm_version = 2;
+ *protocol_version = 2;
+ return 1;
+ }
+
+ return 0;
+}
+
+static grub_err_t
+grub_tpm1_execute(grub_efi_handle_t tpm_handle,
+ PassThroughToTPM_InputParamBlock *inbuf,
+ PassThroughToTPM_OutputParamBlock *outbuf)
+{
+ grub_efi_status_t status;
+ grub_efi_tpm_protocol_t *tpm;
+ grub_uint32_t inhdrsize = sizeof(*inbuf) - sizeof(inbuf->TPMOperandIn);
+ grub_uint32_t outhdrsize = sizeof(*outbuf) - sizeof(outbuf->TPMOperandOut);
+
+ tpm = grub_efi_open_protocol (tpm_handle, &tpm_guid,
+ GRUB_EFI_OPEN_PROTOCOL_GET_PROTOCOL);
+
+ if (!grub_tpm1_present(tpm))
+ return 0;
+
+ /* UEFI TPM protocol takes the raw operand block, no param block header */
+ status = efi_call_5 (tpm->pass_through_to_tpm, tpm,
+ inbuf->IPBLength - inhdrsize, inbuf->TPMOperandIn,
+ outbuf->OPBLength - outhdrsize, outbuf->TPMOperandOut);
+
+ switch (status) {
+ case GRUB_EFI_SUCCESS:
+ return 0;
+ case GRUB_EFI_DEVICE_ERROR:
+ return grub_error (GRUB_ERR_IO, N_("Command failed"));
+ case GRUB_EFI_INVALID_PARAMETER:
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("Invalid parameter"));
+ case GRUB_EFI_BUFFER_TOO_SMALL:
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("Output buffer too small"));
+ case GRUB_EFI_NOT_FOUND:
+ return grub_error (GRUB_ERR_UNKNOWN_DEVICE, N_("TPM unavailable"));
+ default:
+ return grub_error (GRUB_ERR_UNKNOWN_DEVICE, N_("Unknown TPM error"));
+ }
+}
+
+static grub_err_t
+grub_tpm2_execute(grub_efi_handle_t tpm_handle,
+ PassThroughToTPM_InputParamBlock *inbuf,
+ PassThroughToTPM_OutputParamBlock *outbuf)
+{
+ grub_efi_status_t status;
+ grub_efi_tpm2_protocol_t *tpm;
+ grub_uint32_t inhdrsize = sizeof(*inbuf) - sizeof(inbuf->TPMOperandIn);
+ grub_uint32_t outhdrsize = sizeof(*outbuf) - sizeof(outbuf->TPMOperandOut);
+
+ tpm = grub_efi_open_protocol (tpm_handle, &tpm2_guid,
+ GRUB_EFI_OPEN_PROTOCOL_GET_PROTOCOL);
+
+ if (!grub_tpm2_present(tpm))
+ return 0;
+
+ /* UEFI TPM protocol takes the raw operand block, no param block header */
+ status = efi_call_5 (tpm->submit_command, tpm,
+ inbuf->IPBLength - inhdrsize, inbuf->TPMOperandIn,
+ outbuf->OPBLength - outhdrsize, outbuf->TPMOperandOut);
+
+ switch (status) {
+ case GRUB_EFI_SUCCESS:
+ return 0;
+ case GRUB_EFI_DEVICE_ERROR:
+ return grub_error (GRUB_ERR_IO, N_("Command failed"));
+ case GRUB_EFI_INVALID_PARAMETER:
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("Invalid parameter"));
+ case GRUB_EFI_BUFFER_TOO_SMALL:
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("Output buffer too small"));
+ case GRUB_EFI_NOT_FOUND:
+ return grub_error (GRUB_ERR_UNKNOWN_DEVICE, N_("TPM unavailable"));
+ default:
+ return grub_error (GRUB_ERR_UNKNOWN_DEVICE, N_("Unknown TPM error"));
+ }
+}
+
+grub_err_t
+grub_tpm_execute(PassThroughToTPM_InputParamBlock *inbuf,
+ PassThroughToTPM_OutputParamBlock *outbuf)
+{
+ grub_efi_handle_t tpm_handle;
+ grub_uint8_t protocol_version;
+
+ /* Absence of a TPM isn't a failure */
+ if (!grub_tpm_handle_find(&tpm_handle, &protocol_version))
+ return 0;
+
+ if (protocol_version == 1) {
+ return grub_tpm1_execute(tpm_handle, inbuf, outbuf);
+ } else {
+ return grub_tpm2_execute(tpm_handle, inbuf, outbuf);
+ }
+}
+
+typedef struct {
+ grub_uint32_t pcrindex;
+ grub_uint32_t eventtype;
+ grub_uint8_t digest[20];
+ grub_uint32_t eventsize;
+ grub_uint8_t event[1];
+} Event;
+
+
+static grub_err_t
+grub_tpm1_log_event(grub_efi_handle_t tpm_handle, unsigned char *buf,
+ grub_size_t size, grub_uint8_t pcr,
+ const char *description)
+{
+ Event *event;
+ grub_efi_status_t status;
+ grub_efi_tpm_protocol_t *tpm;
+ grub_efi_physical_address_t lastevent;
+ grub_uint32_t algorithm;
+ grub_uint32_t eventnum = 0;
+
+ tpm = grub_efi_open_protocol (tpm_handle, &tpm_guid,
+ GRUB_EFI_OPEN_PROTOCOL_GET_PROTOCOL);
+
+ if (!grub_tpm1_present(tpm))
+ return 0;
+
+ event = grub_zalloc(sizeof (Event) + grub_strlen(description) + 1);
+ if (!event)
+ return grub_error (GRUB_ERR_OUT_OF_MEMORY,
+ N_("cannot allocate TPM event buffer"));
+
+ event->pcrindex = pcr;
+ event->eventtype = EV_IPL;
+ event->eventsize = grub_strlen(description) + 1;
+ grub_memcpy(event->event, description, event->eventsize);
+
+ algorithm = TCG_ALG_SHA;
+ status = efi_call_7 (tpm->log_extend_event, tpm, buf, (grub_uint64_t) size,
+ algorithm, event, &eventnum, &lastevent);
+
+ switch (status) {
+ case GRUB_EFI_SUCCESS:
+ return 0;
+ case GRUB_EFI_DEVICE_ERROR:
+ return grub_error (GRUB_ERR_IO, N_("Command failed"));
+ case GRUB_EFI_INVALID_PARAMETER:
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("Invalid parameter"));
+ case GRUB_EFI_BUFFER_TOO_SMALL:
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("Output buffer too small"));
+ case GRUB_EFI_NOT_FOUND:
+ return grub_error (GRUB_ERR_UNKNOWN_DEVICE, N_("TPM unavailable"));
+ default:
+ return grub_error (GRUB_ERR_UNKNOWN_DEVICE, N_("Unknown TPM error"));
+ }
+}
+
+static grub_err_t
+grub_tpm2_log_event(grub_efi_handle_t tpm_handle, unsigned char *buf,
+ grub_size_t size, grub_uint8_t pcr,
+ const char *description)
+{
+ EFI_TCG2_EVENT *event;
+ grub_efi_status_t status;
+ grub_efi_tpm2_protocol_t *tpm;
+
+ tpm = grub_efi_open_protocol (tpm_handle, &tpm2_guid,
+ GRUB_EFI_OPEN_PROTOCOL_GET_PROTOCOL);
+
+ if (!grub_tpm2_present(tpm))
+ return 0;
+
+ event = grub_zalloc(sizeof (EFI_TCG2_EVENT) + grub_strlen(description) + 1);
+ if (!event)
+ return grub_error (GRUB_ERR_OUT_OF_MEMORY,
+ N_("cannot allocate TPM event buffer"));
+
+ event->Header.HeaderSize = sizeof(EFI_TCG2_EVENT_HEADER);
+ event->Header.HeaderVersion = 1;
+ event->Header.PCRIndex = pcr;
+ event->Header.EventType = EV_IPL;
+ event->Size = sizeof(*event) - sizeof(event->Event) + grub_strlen(description) + 1;
+ grub_memcpy(event->Event, description, grub_strlen(description) + 1);
+
+ status = efi_call_5 (tpm->hash_log_extend_event, tpm, 0, buf,
+ (grub_uint64_t) size, event);
+
+ switch (status) {
+ case GRUB_EFI_SUCCESS:
+ return 0;
+ case GRUB_EFI_DEVICE_ERROR:
+ return grub_error (GRUB_ERR_IO, N_("Command failed"));
+ case GRUB_EFI_INVALID_PARAMETER:
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("Invalid parameter"));
+ case GRUB_EFI_BUFFER_TOO_SMALL:
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("Output buffer too small"));
+ case GRUB_EFI_NOT_FOUND:
+ return grub_error (GRUB_ERR_UNKNOWN_DEVICE, N_("TPM unavailable"));
+ default:
+ return grub_error (GRUB_ERR_UNKNOWN_DEVICE, N_("Unknown TPM error"));
+ }
+}
+
+grub_err_t
+grub_tpm_log_event(unsigned char *buf, grub_size_t size, grub_uint8_t pcr,
+ const char *description)
+{
+ grub_efi_handle_t tpm_handle;
+ grub_efi_uint8_t protocol_version;
+
+ if (!grub_tpm_handle_find(&tpm_handle, &protocol_version))
+ return 0;
+
+ if (protocol_version == 1) {
+ return grub_tpm1_log_event(tpm_handle, buf, size, pcr, description);
+ } else {
+ return grub_tpm2_log_event(tpm_handle, buf, size, pcr, description);
+ }
+}
diff --git a/grub-core/commands/tpm.c b/grub-core/commands/tpm.c
new file mode 100644
index 000000000..e047b5fe0
--- /dev/null
+++ b/grub-core/commands/tpm.c
@@ -0,0 +1,87 @@
+#include <grub/err.h>
+#include <grub/i18n.h>
+#include <grub/misc.h>
+#include <grub/mm.h>
+#include <grub/tpm.h>
+#include <grub/term.h>
+#include <grub/verify.h>
+#include <grub/dl.h>
+
+GRUB_MOD_LICENSE ("GPLv3+")
+
+grub_err_t
+grub_tpm_measure (unsigned char *buf, grub_size_t size, grub_uint8_t pcr,
+ const char *description)
+{
+ return grub_tpm_log_event (buf, size, pcr, description);
+}
+
+static grub_err_t
+grub_tpm_verify_init (grub_file_t io,
+ enum grub_file_type type __attribute__ ((unused)),
+ void **context, enum grub_verify_flags *flags)
+{
+ *context = io->name;
+ *flags |= GRUB_VERIFY_FLAGS_SINGLE_CHUNK;
+ return GRUB_ERR_NONE;
+}
+
+static grub_err_t
+grub_tpm_verify_write (void *context, void *buf, grub_size_t size)
+{
+ return grub_tpm_measure (buf, size, 9, context);
+}
+
+static void
+grub_tpm_verify_close (void *ctxt __attribute__ ((unused)))
+{
+ return;
+}
+
+static grub_err_t
+grub_tpm_verify_string (char *str, enum grub_verify_string_type type)
+{
+ const char *prefix = NULL;
+ char *description;
+ grub_err_t status;
+
+ switch (type)
+ {
+ case GRUB_VERIFY_KERNEL_CMDLINE:
+ prefix = "kernel_cmdline: ";
+ break;
+ case GRUB_VERIFY_MODULE_CMDLINE:
+ prefix = "module_cmdline: ";
+ break;
+ case GRUB_VERIFY_COMMAND:
+ prefix = "grub_cmd: ";
+ break;
+ }
+ description = grub_malloc(grub_strlen(str) + grub_strlen(prefix) + 1);
+ if (!description)
+ return grub_errno;
+ grub_memcpy(description, prefix, grub_strlen(prefix));
+ grub_memcpy(description + grub_strlen(prefix), str, grub_strlen(str) + 1);
+ status = grub_tpm_measure ((unsigned char *) str, grub_strlen (str), 8,
+ description);
+ grub_free(description);
+ return status;
+}
+
+struct grub_file_verifier grub_tpm_verifier = {
+ .name = "tpm",
+ .init = grub_tpm_verify_init,
+ .write = grub_tpm_verify_write,
+ .close = grub_tpm_verify_close,
+ .verify_string = grub_tpm_verify_string,
+};
+
+GRUB_MOD_INIT(tpm)
+{
+ grub_verifier_register (&grub_tpm_verifier);
+}
+
+GRUB_MOD_FINI(tpm)
+{
+ grub_verifier_unregister (&grub_tpm_verifier);
+}
diff --git a/grub-core/kern/i386/efi/init.c b/grub-core/kern/i386/efi/init.c
index a28316cc6..da499aba0 100644
--- a/grub-core/kern/i386/efi/init.c
+++ b/grub-core/kern/i386/efi/init.c
@@ -27,6 +27,7 @@
#include <grub/efi/efi.h>
#include <grub/i386/tsc.h>
#include <grub/loader.h>
+#include <grub/tpm.h>

void
grub_machine_init (void)
diff --git a/include/grub/efi/tpm.h b/include/grub/efi/tpm.h
new file mode 100644
index 000000000..e2aff4a3c
--- /dev/null
+++ b/include/grub/efi/tpm.h
@@ -0,0 +1,153 @@
+/*
+ * GRUB -- GRand Unified Bootloader
+ * Copyright (C) 2015 Free Software Foundation, Inc.
+ *
+ * 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_EFI_TPM_HEADER
+#define GRUB_EFI_TPM_HEADER 1
+
+#define EFI_TPM_GUID {0xf541796d, 0xa62e, 0x4954, {0xa7, 0x75, 0x95, 0x84, 0xf6, 0x1b, 0x9c, 0xdd }};
+#define EFI_TPM2_GUID {0x607f766c, 0x7455, 0x42be, {0x93, 0x0b, 0xe4, 0xd7, 0x6d, 0xb2, 0x72, 0x0f }};
+
+typedef struct {
+ grub_efi_uint8_t Major;
+ grub_efi_uint8_t Minor;
+ grub_efi_uint8_t RevMajor;
+ grub_efi_uint8_t RevMinor;
+} TCG_VERSION;
+
+typedef struct _TCG_EFI_BOOT_SERVICE_CAPABILITY {
+ grub_efi_uint8_t Size; /// Size of this structure.
+ TCG_VERSION StructureVersion;
+ TCG_VERSION ProtocolSpecVersion;
+ grub_efi_uint8_t HashAlgorithmBitmap; /// Hash algorithms .
+ char TPMPresentFlag; /// 00h = TPM not present.
+ char TPMDeactivatedFlag; /// 01h = TPM currently deactivated.
+} TCG_EFI_BOOT_SERVICE_CAPABILITY;
+
+typedef struct {
+ grub_efi_uint32_t PCRIndex;
+ grub_efi_uint32_t EventType;
+ grub_efi_uint8_t digest[20];
+ grub_efi_uint32_t EventSize;
+ grub_efi_uint8_t Event[1];
+} TCG_PCR_EVENT;
+
+struct grub_efi_tpm_protocol
+{
+ grub_efi_status_t (*status_check) (struct grub_efi_tpm_protocol *this,
+ TCG_EFI_BOOT_SERVICE_CAPABILITY *ProtocolCapability,
+ grub_efi_uint32_t *TCGFeatureFlags,
+ grub_efi_physical_address_t *EventLogLocation,
+ grub_efi_physical_address_t *EventLogLastEntry);
+ grub_efi_status_t (*hash_all) (struct grub_efi_tpm_protocol *this,
+ grub_efi_uint8_t *HashData,
+ grub_efi_uint64_t HashLen,
+ grub_efi_uint32_t AlgorithmId,
+ grub_efi_uint64_t *HashedDataLen,
+ grub_efi_uint8_t **HashedDataResult);
+ grub_efi_status_t (*log_event) (struct grub_efi_tpm_protocol *this,
+ TCG_PCR_EVENT *TCGLogData,
+ grub_efi_uint32_t *EventNumber,
+ grub_efi_uint32_t Flags);
+ grub_efi_status_t (*pass_through_to_tpm) (struct grub_efi_tpm_protocol *this,
+ grub_efi_uint32_t TpmInputParameterBlockSize,
+ grub_efi_uint8_t *TpmInputParameterBlock,
+ grub_efi_uint32_t TpmOutputParameterBlockSize,
+ grub_efi_uint8_t *TpmOutputParameterBlock);
+ grub_efi_status_t (*log_extend_event) (struct grub_efi_tpm_protocol *this,
+ grub_efi_physical_address_t HashData,
+ grub_efi_uint64_t HashDataLen,
+ grub_efi_uint32_t AlgorithmId,
+ TCG_PCR_EVENT *TCGLogData,
+ grub_efi_uint32_t *EventNumber,
+ grub_efi_physical_address_t *EventLogLastEntry);
+};
+
+typedef struct grub_efi_tpm_protocol grub_efi_tpm_protocol_t;
+
+typedef grub_efi_uint32_t EFI_TCG2_EVENT_LOG_BITMAP;
+typedef grub_efi_uint32_t EFI_TCG2_EVENT_LOG_FORMAT;
+typedef grub_efi_uint32_t EFI_TCG2_EVENT_ALGORITHM_BITMAP;
+
+typedef struct tdEFI_TCG2_VERSION {
+ grub_efi_uint8_t Major;
+ grub_efi_uint8_t Minor;
+} GRUB_PACKED EFI_TCG2_VERSION;
+
+typedef struct tdEFI_TCG2_BOOT_SERVICE_CAPABILITY {
+ grub_efi_uint8_t Size;
+ EFI_TCG2_VERSION StructureVersion;
+ EFI_TCG2_VERSION ProtocolVersion;
+ EFI_TCG2_EVENT_ALGORITHM_BITMAP HashAlgorithmBitmap;
+ EFI_TCG2_EVENT_LOG_BITMAP SupportedEventLogs;
+ grub_efi_boolean_t TPMPresentFlag;
+ grub_efi_uint16_t MaxCommandSize;
+ grub_efi_uint16_t MaxResponseSize;
+ grub_efi_uint32_t ManufacturerID;
+ grub_efi_uint32_t NumberOfPcrBanks;
+ EFI_TCG2_EVENT_ALGORITHM_BITMAP ActivePcrBanks;
+} EFI_TCG2_BOOT_SERVICE_CAPABILITY;
+
+typedef grub_efi_uint32_t TCG_PCRINDEX;
+typedef grub_efi_uint32_t TCG_EVENTTYPE;
+
+typedef struct tdEFI_TCG2_EVENT_HEADER {
+ grub_efi_uint32_t HeaderSize;
+ grub_efi_uint16_t HeaderVersion;
+ TCG_PCRINDEX PCRIndex;
+ TCG_EVENTTYPE EventType;
+} GRUB_PACKED EFI_TCG2_EVENT_HEADER;
+
+typedef struct tdEFI_TCG2_EVENT {
+ grub_efi_uint32_t Size;
+ EFI_TCG2_EVENT_HEADER Header;
+ grub_efi_uint8_t Event[1];
+} GRUB_PACKED EFI_TCG2_EVENT;
+
+struct grub_efi_tpm2_protocol
+{
+ grub_efi_status_t (*get_capability) (struct grub_efi_tpm2_protocol *this,
+ EFI_TCG2_BOOT_SERVICE_CAPABILITY *ProtocolCapability);
+ grub_efi_status_t (*get_event_log) (struct grub_efi_tpm2_protocol *this,
+ EFI_TCG2_EVENT_LOG_FORMAT EventLogFormat,
+ grub_efi_physical_address_t *EventLogLocation,
+ grub_efi_physical_address_t *EventLogLastEntry,
+ grub_efi_boolean_t *EventLogTruncated);
+ grub_efi_status_t (*hash_log_extend_event) (struct grub_efi_tpm2_protocol *this,
+ grub_efi_uint64_t Flags,
+ grub_efi_physical_address_t *DataToHash,
+ grub_efi_uint64_t DataToHashLen,
+ EFI_TCG2_EVENT *EfiTcgEvent);
+ grub_efi_status_t (*submit_command) (struct grub_efi_tpm2_protocol *this,
+ grub_efi_uint32_t InputParameterBlockSize,
+ grub_efi_uint8_t *InputParameterBlock,
+ grub_efi_uint32_t OutputParameterBlockSize,
+ grub_efi_uint8_t *OutputParameterBlock);
+ grub_efi_status_t (*get_active_pcr_blanks) (struct grub_efi_tpm2_protocol *this,
+ grub_efi_uint32_t *ActivePcrBanks);
+ grub_efi_status_t (*set_active_pcr_banks) (struct grub_efi_tpm2_protocol *this,
+ grub_efi_uint32_t ActivePcrBanks);
+ grub_efi_status_t (*get_result_of_set_active_pcr_banks) (struct grub_efi_tpm2_protocol *this,
+ grub_efi_uint32_t *OperationPresent,
+ grub_efi_uint32_t *Response);
+};
+
+typedef struct grub_efi_tpm2_protocol grub_efi_tpm2_protocol_t;
+
+#define TCG_ALG_SHA 0x00000004
+
+#endif
diff --git a/include/grub/tpm.h b/include/grub/tpm.h
new file mode 100644
index 000000000..d6757b57b
--- /dev/null
+++ b/include/grub/tpm.h
@@ -0,0 +1,74 @@
+/*
+ * GRUB -- GRand Unified Bootloader
+ * Copyright (C) 2015 Free Software Foundation, Inc.
+ *
+ * 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_TPM_HEADER
+#define GRUB_TPM_HEADER 1
+
+#define SHA1_DIGEST_SIZE 20
+
+#define TPM_BASE 0x0
+#define TPM_SUCCESS TPM_BASE
+#define TPM_AUTHFAIL (TPM_BASE + 0x1)
+#define TPM_BADINDEX (TPM_BASE + 0x2)
+
+#define TPM_TAG_RQU_COMMAND 0x00C1
+#define TPM_ORD_Extend 0x14
+
+#define EV_IPL 0x0d
+
+/* TCG_PassThroughToTPM Input Parameter Block */
+typedef struct {
+ grub_uint16_t IPBLength;
+ grub_uint16_t Reserved1;
+ grub_uint16_t OPBLength;
+ grub_uint16_t Reserved2;
+ grub_uint8_t TPMOperandIn[1];
+} GRUB_PACKED PassThroughToTPM_InputParamBlock;
+
+/* TCG_PassThroughToTPM Output Parameter Block */
+typedef struct {
+ grub_uint16_t OPBLength;
+ grub_uint16_t Reserved;
+ grub_uint8_t TPMOperandOut[1];
+} GRUB_PACKED PassThroughToTPM_OutputParamBlock;
+
+typedef struct {
+ grub_uint16_t tag;
+ grub_uint32_t paramSize;
+ grub_uint32_t ordinal;
+ grub_uint32_t pcrNum;
+ grub_uint8_t inDigest[SHA1_DIGEST_SIZE]; /* The 160 bit value representing the event to be recorded. */
+} GRUB_PACKED ExtendIncoming;
+
+/* TPM_Extend Outgoing Operand */
+typedef struct {
+ grub_uint16_t tag;
+ grub_uint32_t paramSize;
+ grub_uint32_t returnCode;
+ grub_uint8_t outDigest[SHA1_DIGEST_SIZE]; /* The PCR value after execution of the command. */
+} GRUB_PACKED ExtendOutgoing;
+
+grub_err_t grub_tpm_measure (unsigned char *buf, grub_size_t size,
+ grub_uint8_t pcr,
+ const char *description);
+grub_err_t grub_tpm_init(void);
+grub_err_t grub_tpm_execute(PassThroughToTPM_InputParamBlock *inbuf,
+ PassThroughToTPM_OutputParamBlock *outbuf);
+grub_err_t grub_tpm_log_event(unsigned char *buf, grub_size_t size,
+ grub_uint8_t pcr, const char *description);
+#endif
--
2.19.1.930.g4563a0d9d0-goog
Matthew Garrett
2018-11-09 23:41:02 UTC
Permalink
From: Matthew Garrett <***@google.com>

Add support for performing basic TPM measurements. Right now this only
supports extending PCRs statically and only on UEFI. In future we might
want to have some sort of mechanism for choosing which events get logged
to which PCRs, but this seems like a good default policy and we can wait
to see whether anyone has a use case before adding more complexity.
---
grub-core/Makefile.core.def | 7 +
grub-core/commands/efi/tpm.c | 310 +++++++++++++++++++++++++++++++++
grub-core/commands/tpm.c | 87 +++++++++
grub-core/kern/i386/efi/init.c | 1 +
include/grub/efi/tpm.h | 153 ++++++++++++++++
include/grub/tpm.h | 74 ++++++++
6 files changed, 632 insertions(+)
create mode 100644 grub-core/commands/efi/tpm.c
create mode 100644 grub-core/commands/tpm.c
create mode 100644 include/grub/efi/tpm.h
create mode 100644 include/grub/tpm.h

diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
index 6e2cc8444..a485f9186 100644
--- a/grub-core/Makefile.core.def
+++ b/grub-core/Makefile.core.def
@@ -2377,6 +2377,13 @@ module = {
common = commands/testspeed.c;
};

+module = {
+ name = tpm;
+ common = commands/tpm.c;
+ efi = commands/efi/tpm.c;
+ enable = efi;
+};
+
module = {
name = tr;
common = commands/tr.c;
diff --git a/grub-core/commands/efi/tpm.c b/grub-core/commands/efi/tpm.c
new file mode 100644
index 000000000..f03464d96
--- /dev/null
+++ b/grub-core/commands/efi/tpm.c
@@ -0,0 +1,310 @@
+#include <grub/err.h>
+#include <grub/i18n.h>
+#include <grub/efi/api.h>
+#include <grub/efi/efi.h>
+#include <grub/efi/tpm.h>
+#include <grub/mm.h>
+#include <grub/tpm.h>
+#include <grub/term.h>
+
+static grub_efi_guid_t tpm_guid = EFI_TPM_GUID;
+static grub_efi_guid_t tpm2_guid = EFI_TPM2_GUID;
+
+static grub_efi_handle_t *grub_tpm_handle;
+static grub_uint8_t grub_tpm_version;
+
+static grub_int8_t tpm1_present = -1;
+static grub_int8_t tpm2_present = -1;
+
+static grub_efi_boolean_t grub_tpm1_present(grub_efi_tpm_protocol_t *tpm)
+{
+ grub_efi_status_t status;
+ TCG_EFI_BOOT_SERVICE_CAPABILITY caps;
+ grub_uint32_t flags;
+ grub_efi_physical_address_t eventlog, lastevent;
+
+ if (tpm1_present != -1)
+ return (grub_efi_boolean_t)tpm1_present;
+
+ caps.Size = (grub_uint8_t)sizeof(caps);
+
+ status = efi_call_5(tpm->status_check, tpm, &caps, &flags, &eventlog,
+ &lastevent);
+
+ if (status != GRUB_EFI_SUCCESS || caps.TPMDeactivatedFlag
+ || !caps.TPMPresentFlag) {
+ tpm1_present = 0;
+ return tpm1_present;
+ }
+
+ tpm1_present = 1;
+ return tpm1_present;
+}
+
+static grub_efi_boolean_t grub_tpm2_present(grub_efi_tpm2_protocol_t *tpm)
+{
+ grub_efi_status_t status;
+ EFI_TCG2_BOOT_SERVICE_CAPABILITY caps;
+
+ caps.Size = (grub_uint8_t)sizeof(caps);
+
+ if (tpm2_present != -1)
+ return (grub_efi_boolean_t)tpm2_present;
+
+ status = efi_call_2(tpm->get_capability, tpm, &caps);
+
+ if (status != GRUB_EFI_SUCCESS || !caps.TPMPresentFlag) {
+ tpm2_present = 0;
+ return tpm2_present;
+ }
+
+ tpm2_present = 1;
+ return tpm2_present;
+}
+
+static grub_efi_boolean_t grub_tpm_handle_find(grub_efi_handle_t *tpm_handle,
+ grub_efi_uint8_t *protocol_version)
+{
+ grub_efi_handle_t *handles;
+ grub_efi_uintn_t num_handles;
+
+ if (grub_tpm_handle != NULL) {
+ *tpm_handle = &grub_tpm_handle;
+ *protocol_version = grub_tpm_version;
+ return 1;
+ }
+
+ handles = grub_efi_locate_handle (GRUB_EFI_BY_PROTOCOL, &tpm_guid, NULL,
+ &num_handles);
+ if (handles && num_handles > 0) {
+ grub_tpm_handle = handles[0];
+ *tpm_handle = handles[0];
+ grub_tpm_version = 1;
+ *protocol_version = 1;
+ return 1;
+ }
+
+ handles = grub_efi_locate_handle (GRUB_EFI_BY_PROTOCOL, &tpm2_guid, NULL,
+ &num_handles);
+ if (handles && num_handles > 0) {
+ grub_tpm_handle = handles[0];
+ *tpm_handle = handles[0];
+ grub_tpm_version = 2;
+ *protocol_version = 2;
+ return 1;
+ }
+
+ return 0;
+}
+
+static grub_err_t
+grub_tpm1_execute(grub_efi_handle_t tpm_handle,
+ PassThroughToTPM_InputParamBlock *inbuf,
+ PassThroughToTPM_OutputParamBlock *outbuf)
+{
+ grub_efi_status_t status;
+ grub_efi_tpm_protocol_t *tpm;
+ grub_uint32_t inhdrsize = sizeof(*inbuf) - sizeof(inbuf->TPMOperandIn);
+ grub_uint32_t outhdrsize = sizeof(*outbuf) - sizeof(outbuf->TPMOperandOut);
+
+ tpm = grub_efi_open_protocol (tpm_handle, &tpm_guid,
+ GRUB_EFI_OPEN_PROTOCOL_GET_PROTOCOL);
+
+ if (!grub_tpm1_present(tpm))
+ return 0;
+
+ /* UEFI TPM protocol takes the raw operand block, no param block header */
+ status = efi_call_5 (tpm->pass_through_to_tpm, tpm,
+ inbuf->IPBLength - inhdrsize, inbuf->TPMOperandIn,
+ outbuf->OPBLength - outhdrsize, outbuf->TPMOperandOut);
+
+ switch (status) {
+ case GRUB_EFI_SUCCESS:
+ return 0;
+ case GRUB_EFI_DEVICE_ERROR:
+ return grub_error (GRUB_ERR_IO, N_("Command failed"));
+ case GRUB_EFI_INVALID_PARAMETER:
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("Invalid parameter"));
+ case GRUB_EFI_BUFFER_TOO_SMALL:
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("Output buffer too small"));
+ case GRUB_EFI_NOT_FOUND:
+ return grub_error (GRUB_ERR_UNKNOWN_DEVICE, N_("TPM unavailable"));
+ default:
+ return grub_error (GRUB_ERR_UNKNOWN_DEVICE, N_("Unknown TPM error"));
+ }
+}
+
+static grub_err_t
+grub_tpm2_execute(grub_efi_handle_t tpm_handle,
+ PassThroughToTPM_InputParamBlock *inbuf,
+ PassThroughToTPM_OutputParamBlock *outbuf)
+{
+ grub_efi_status_t status;
+ grub_efi_tpm2_protocol_t *tpm;
+ grub_uint32_t inhdrsize = sizeof(*inbuf) - sizeof(inbuf->TPMOperandIn);
+ grub_uint32_t outhdrsize = sizeof(*outbuf) - sizeof(outbuf->TPMOperandOut);
+
+ tpm = grub_efi_open_protocol (tpm_handle, &tpm2_guid,
+ GRUB_EFI_OPEN_PROTOCOL_GET_PROTOCOL);
+
+ if (!grub_tpm2_present(tpm))
+ return 0;
+
+ /* UEFI TPM protocol takes the raw operand block, no param block header */
+ status = efi_call_5 (tpm->submit_command, tpm,
+ inbuf->IPBLength - inhdrsize, inbuf->TPMOperandIn,
+ outbuf->OPBLength - outhdrsize, outbuf->TPMOperandOut);
+
+ switch (status) {
+ case GRUB_EFI_SUCCESS:
+ return 0;
+ case GRUB_EFI_DEVICE_ERROR:
+ return grub_error (GRUB_ERR_IO, N_("Command failed"));
+ case GRUB_EFI_INVALID_PARAMETER:
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("Invalid parameter"));
+ case GRUB_EFI_BUFFER_TOO_SMALL:
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("Output buffer too small"));
+ case GRUB_EFI_NOT_FOUND:
+ return grub_error (GRUB_ERR_UNKNOWN_DEVICE, N_("TPM unavailable"));
+ default:
+ return grub_error (GRUB_ERR_UNKNOWN_DEVICE, N_("Unknown TPM error"));
+ }
+}
+
+grub_err_t
+grub_tpm_execute(PassThroughToTPM_InputParamBlock *inbuf,
+ PassThroughToTPM_OutputParamBlock *outbuf)
+{
+ grub_efi_handle_t tpm_handle;
+ grub_uint8_t protocol_version;
+
+ /* Absence of a TPM isn't a failure */
+ if (!grub_tpm_handle_find(&tpm_handle, &protocol_version))
+ return 0;
+
+ if (protocol_version == 1) {
+ return grub_tpm1_execute(tpm_handle, inbuf, outbuf);
+ } else {
+ return grub_tpm2_execute(tpm_handle, inbuf, outbuf);
+ }
+}
+
+typedef struct {
+ grub_uint32_t pcrindex;
+ grub_uint32_t eventtype;
+ grub_uint8_t digest[20];
+ grub_uint32_t eventsize;
+ grub_uint8_t event[1];
+} Event;
+
+
+static grub_err_t
+grub_tpm1_log_event(grub_efi_handle_t tpm_handle, unsigned char *buf,
+ grub_size_t size, grub_uint8_t pcr,
+ const char *description)
+{
+ Event *event;
+ grub_efi_status_t status;
+ grub_efi_tpm_protocol_t *tpm;
+ grub_efi_physical_address_t lastevent;
+ grub_uint32_t algorithm;
+ grub_uint32_t eventnum = 0;
+
+ tpm = grub_efi_open_protocol (tpm_handle, &tpm_guid,
+ GRUB_EFI_OPEN_PROTOCOL_GET_PROTOCOL);
+
+ if (!grub_tpm1_present(tpm))
+ return 0;
+
+ event = grub_zalloc(sizeof (Event) + grub_strlen(description) + 1);
+ if (!event)
+ return grub_error (GRUB_ERR_OUT_OF_MEMORY,
+ N_("cannot allocate TPM event buffer"));
+
+ event->pcrindex = pcr;
+ event->eventtype = EV_IPL;
+ event->eventsize = grub_strlen(description) + 1;
+ grub_memcpy(event->event, description, event->eventsize);
+
+ algorithm = TCG_ALG_SHA;
+ status = efi_call_7 (tpm->log_extend_event, tpm, buf, (grub_uint64_t) size,
+ algorithm, event, &eventnum, &lastevent);
+
+ switch (status) {
+ case GRUB_EFI_SUCCESS:
+ return 0;
+ case GRUB_EFI_DEVICE_ERROR:
+ return grub_error (GRUB_ERR_IO, N_("Command failed"));
+ case GRUB_EFI_INVALID_PARAMETER:
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("Invalid parameter"));
+ case GRUB_EFI_BUFFER_TOO_SMALL:
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("Output buffer too small"));
+ case GRUB_EFI_NOT_FOUND:
+ return grub_error (GRUB_ERR_UNKNOWN_DEVICE, N_("TPM unavailable"));
+ default:
+ return grub_error (GRUB_ERR_UNKNOWN_DEVICE, N_("Unknown TPM error"));
+ }
+}
+
+static grub_err_t
+grub_tpm2_log_event(grub_efi_handle_t tpm_handle, unsigned char *buf,
+ grub_size_t size, grub_uint8_t pcr,
+ const char *description)
+{
+ EFI_TCG2_EVENT *event;
+ grub_efi_status_t status;
+ grub_efi_tpm2_protocol_t *tpm;
+
+ tpm = grub_efi_open_protocol (tpm_handle, &tpm2_guid,
+ GRUB_EFI_OPEN_PROTOCOL_GET_PROTOCOL);
+
+ if (!grub_tpm2_present(tpm))
+ return 0;
+
+ event = grub_zalloc(sizeof (EFI_TCG2_EVENT) + grub_strlen(description) + 1);
+ if (!event)
+ return grub_error (GRUB_ERR_OUT_OF_MEMORY,
+ N_("cannot allocate TPM event buffer"));
+
+ event->Header.HeaderSize = sizeof(EFI_TCG2_EVENT_HEADER);
+ event->Header.HeaderVersion = 1;
+ event->Header.PCRIndex = pcr;
+ event->Header.EventType = EV_IPL;
+ event->Size = sizeof(*event) - sizeof(event->Event) + grub_strlen(description) + 1;
+ grub_memcpy(event->Event, description, grub_strlen(description) + 1);
+
+ status = efi_call_5 (tpm->hash_log_extend_event, tpm, 0, buf,
+ (grub_uint64_t) size, event);
+
+ switch (status) {
+ case GRUB_EFI_SUCCESS:
+ return 0;
+ case GRUB_EFI_DEVICE_ERROR:
+ return grub_error (GRUB_ERR_IO, N_("Command failed"));
+ case GRUB_EFI_INVALID_PARAMETER:
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("Invalid parameter"));
+ case GRUB_EFI_BUFFER_TOO_SMALL:
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("Output buffer too small"));
+ case GRUB_EFI_NOT_FOUND:
+ return grub_error (GRUB_ERR_UNKNOWN_DEVICE, N_("TPM unavailable"));
+ default:
+ return grub_error (GRUB_ERR_UNKNOWN_DEVICE, N_("Unknown TPM error"));
+ }
+}
+
+grub_err_t
+grub_tpm_log_event(unsigned char *buf, grub_size_t size, grub_uint8_t pcr,
+ const char *description)
+{
+ grub_efi_handle_t tpm_handle;
+ grub_efi_uint8_t protocol_version;
+
+ if (!grub_tpm_handle_find(&tpm_handle, &protocol_version))
+ return 0;
+
+ if (protocol_version == 1) {
+ return grub_tpm1_log_event(tpm_handle, buf, size, pcr, description);
+ } else {
+ return grub_tpm2_log_event(tpm_handle, buf, size, pcr, description);
+ }
+}
diff --git a/grub-core/commands/tpm.c b/grub-core/commands/tpm.c
new file mode 100644
index 000000000..e047b5fe0
--- /dev/null
+++ b/grub-core/commands/tpm.c
@@ -0,0 +1,87 @@
+#include <grub/err.h>
+#include <grub/i18n.h>
+#include <grub/misc.h>
+#include <grub/mm.h>
+#include <grub/tpm.h>
+#include <grub/term.h>
+#include <grub/verify.h>
+#include <grub/dl.h>
+
+GRUB_MOD_LICENSE ("GPLv3+")
+
+grub_err_t
+grub_tpm_measure (unsigned char *buf, grub_size_t size, grub_uint8_t pcr,
+ const char *description)
+{
+ return grub_tpm_log_event (buf, size, pcr, description);
+}
+
+static grub_err_t
+grub_tpm_verify_init (grub_file_t io,
+ enum grub_file_type type __attribute__ ((unused)),
+ void **context, enum grub_verify_flags *flags)
+{
+ *context = io->name;
+ *flags |= GRUB_VERIFY_FLAGS_SINGLE_CHUNK;
+ return GRUB_ERR_NONE;
+}
+
+static grub_err_t
+grub_tpm_verify_write (void *context, void *buf, grub_size_t size)
+{
+ return grub_tpm_measure (buf, size, 9, context);
+}
+
+static void
+grub_tpm_verify_close (void *ctxt __attribute__ ((unused)))
+{
+ return;
+}
+
+static grub_err_t
+grub_tpm_verify_string (char *str, enum grub_verify_string_type type)
+{
+ const char *prefix = NULL;
+ char *description;
+ grub_err_t status;
+
+ switch (type)
+ {
+ case GRUB_VERIFY_KERNEL_CMDLINE:
+ prefix = "kernel_cmdline: ";
+ break;
+ case GRUB_VERIFY_MODULE_CMDLINE:
+ prefix = "module_cmdline: ";
+ break;
+ case GRUB_VERIFY_COMMAND:
+ prefix = "grub_cmd: ";
+ break;
+ }
+ description = grub_malloc(grub_strlen(str) + grub_strlen(prefix) + 1);
+ if (!description)
+ return grub_errno;
+ grub_memcpy(description, prefix, grub_strlen(prefix));
+ grub_memcpy(description + grub_strlen(prefix), str, grub_strlen(str) + 1);
+ status = grub_tpm_measure ((unsigned char *) str, grub_strlen (str), 8,
+ description);
+ grub_free(description);
+ return status;
+}
+
+struct grub_file_verifier grub_tpm_verifier = {
+ .name = "tpm",
+ .init = grub_tpm_verify_init,
+ .write = grub_tpm_verify_write,
+ .close = grub_tpm_verify_close,
+ .verify_string = grub_tpm_verify_string,
+};
+
+GRUB_MOD_INIT(tpm)
+{
+ grub_verifier_register (&grub_tpm_verifier);
+}
+
+GRUB_MOD_FINI(tpm)
+{
+ grub_verifier_unregister (&grub_tpm_verifier);
+}
diff --git a/grub-core/kern/i386/efi/init.c b/grub-core/kern/i386/efi/init.c
index a28316cc6..da499aba0 100644
--- a/grub-core/kern/i386/efi/init.c
+++ b/grub-core/kern/i386/efi/init.c
@@ -27,6 +27,7 @@
#include <grub/efi/efi.h>
#include <grub/i386/tsc.h>
#include <grub/loader.h>
+#include <grub/tpm.h>

void
grub_machine_init (void)
diff --git a/include/grub/efi/tpm.h b/include/grub/efi/tpm.h
new file mode 100644
index 000000000..e2aff4a3c
--- /dev/null
+++ b/include/grub/efi/tpm.h
@@ -0,0 +1,153 @@
+/*
+ * GRUB -- GRand Unified Bootloader
+ * Copyright (C) 2015 Free Software Foundation, Inc.
+ *
+ * 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_EFI_TPM_HEADER
+#define GRUB_EFI_TPM_HEADER 1
+
+#define EFI_TPM_GUID {0xf541796d, 0xa62e, 0x4954, {0xa7, 0x75, 0x95, 0x84, 0xf6, 0x1b, 0x9c, 0xdd }};
+#define EFI_TPM2_GUID {0x607f766c, 0x7455, 0x42be, {0x93, 0x0b, 0xe4, 0xd7, 0x6d, 0xb2, 0x72, 0x0f }};
+
+typedef struct {
+ grub_efi_uint8_t Major;
+ grub_efi_uint8_t Minor;
+ grub_efi_uint8_t RevMajor;
+ grub_efi_uint8_t RevMinor;
+} TCG_VERSION;
+
+typedef struct _TCG_EFI_BOOT_SERVICE_CAPABILITY {
+ grub_efi_uint8_t Size; /// Size of this structure.
+ TCG_VERSION StructureVersion;
+ TCG_VERSION ProtocolSpecVersion;
+ grub_efi_uint8_t HashAlgorithmBitmap; /// Hash algorithms .
+ char TPMPresentFlag; /// 00h = TPM not present.
+ char TPMDeactivatedFlag; /// 01h = TPM currently deactivated.
+} TCG_EFI_BOOT_SERVICE_CAPABILITY;
+
+typedef struct {
+ grub_efi_uint32_t PCRIndex;
+ grub_efi_uint32_t EventType;
+ grub_efi_uint8_t digest[20];
+ grub_efi_uint32_t EventSize;
+ grub_efi_uint8_t Event[1];
+} TCG_PCR_EVENT;
+
+struct grub_efi_tpm_protocol
+{
+ grub_efi_status_t (*status_check) (struct grub_efi_tpm_protocol *this,
+ TCG_EFI_BOOT_SERVICE_CAPABILITY *ProtocolCapability,
+ grub_efi_uint32_t *TCGFeatureFlags,
+ grub_efi_physical_address_t *EventLogLocation,
+ grub_efi_physical_address_t *EventLogLastEntry);
+ grub_efi_status_t (*hash_all) (struct grub_efi_tpm_protocol *this,
+ grub_efi_uint8_t *HashData,
+ grub_efi_uint64_t HashLen,
+ grub_efi_uint32_t AlgorithmId,
+ grub_efi_uint64_t *HashedDataLen,
+ grub_efi_uint8_t **HashedDataResult);
+ grub_efi_status_t (*log_event) (struct grub_efi_tpm_protocol *this,
+ TCG_PCR_EVENT *TCGLogData,
+ grub_efi_uint32_t *EventNumber,
+ grub_efi_uint32_t Flags);
+ grub_efi_status_t (*pass_through_to_tpm) (struct grub_efi_tpm_protocol *this,
+ grub_efi_uint32_t TpmInputParameterBlockSize,
+ grub_efi_uint8_t *TpmInputParameterBlock,
+ grub_efi_uint32_t TpmOutputParameterBlockSize,
+ grub_efi_uint8_t *TpmOutputParameterBlock);
+ grub_efi_status_t (*log_extend_event) (struct grub_efi_tpm_protocol *this,
+ grub_efi_physical_address_t HashData,
+ grub_efi_uint64_t HashDataLen,
+ grub_efi_uint32_t AlgorithmId,
+ TCG_PCR_EVENT *TCGLogData,
+ grub_efi_uint32_t *EventNumber,
+ grub_efi_physical_address_t *EventLogLastEntry);
+};
+
+typedef struct grub_efi_tpm_protocol grub_efi_tpm_protocol_t;
+
+typedef grub_efi_uint32_t EFI_TCG2_EVENT_LOG_BITMAP;
+typedef grub_efi_uint32_t EFI_TCG2_EVENT_LOG_FORMAT;
+typedef grub_efi_uint32_t EFI_TCG2_EVENT_ALGORITHM_BITMAP;
+
+typedef struct tdEFI_TCG2_VERSION {
+ grub_efi_uint8_t Major;
+ grub_efi_uint8_t Minor;
+} GRUB_PACKED EFI_TCG2_VERSION;
+
+typedef struct tdEFI_TCG2_BOOT_SERVICE_CAPABILITY {
+ grub_efi_uint8_t Size;
+ EFI_TCG2_VERSION StructureVersion;
+ EFI_TCG2_VERSION ProtocolVersion;
+ EFI_TCG2_EVENT_ALGORITHM_BITMAP HashAlgorithmBitmap;
+ EFI_TCG2_EVENT_LOG_BITMAP SupportedEventLogs;
+ grub_efi_boolean_t TPMPresentFlag;
+ grub_efi_uint16_t MaxCommandSize;
+ grub_efi_uint16_t MaxResponseSize;
+ grub_efi_uint32_t ManufacturerID;
+ grub_efi_uint32_t NumberOfPcrBanks;
+ EFI_TCG2_EVENT_ALGORITHM_BITMAP ActivePcrBanks;
+} EFI_TCG2_BOOT_SERVICE_CAPABILITY;
+
+typedef grub_efi_uint32_t TCG_PCRINDEX;
+typedef grub_efi_uint32_t TCG_EVENTTYPE;
+
+typedef struct tdEFI_TCG2_EVENT_HEADER {
+ grub_efi_uint32_t HeaderSize;
+ grub_efi_uint16_t HeaderVersion;
+ TCG_PCRINDEX PCRIndex;
+ TCG_EVENTTYPE EventType;
+} GRUB_PACKED EFI_TCG2_EVENT_HEADER;
+
+typedef struct tdEFI_TCG2_EVENT {
+ grub_efi_uint32_t Size;
+ EFI_TCG2_EVENT_HEADER Header;
+ grub_efi_uint8_t Event[1];
+} GRUB_PACKED EFI_TCG2_EVENT;
+
+struct grub_efi_tpm2_protocol
+{
+ grub_efi_status_t (*get_capability) (struct grub_efi_tpm2_protocol *this,
+ EFI_TCG2_BOOT_SERVICE_CAPABILITY *ProtocolCapability);
+ grub_efi_status_t (*get_event_log) (struct grub_efi_tpm2_protocol *this,
+ EFI_TCG2_EVENT_LOG_FORMAT EventLogFormat,
+ grub_efi_physical_address_t *EventLogLocation,
+ grub_efi_physical_address_t *EventLogLastEntry,
+ grub_efi_boolean_t *EventLogTruncated);
+ grub_efi_status_t (*hash_log_extend_event) (struct grub_efi_tpm2_protocol *this,
+ grub_efi_uint64_t Flags,
+ grub_efi_physical_address_t *DataToHash,
+ grub_efi_uint64_t DataToHashLen,
+ EFI_TCG2_EVENT *EfiTcgEvent);
+ grub_efi_status_t (*submit_command) (struct grub_efi_tpm2_protocol *this,
+ grub_efi_uint32_t InputParameterBlockSize,
+ grub_efi_uint8_t *InputParameterBlock,
+ grub_efi_uint32_t OutputParameterBlockSize,
+ grub_efi_uint8_t *OutputParameterBlock);
+ grub_efi_status_t (*get_active_pcr_blanks) (struct grub_efi_tpm2_protocol *this,
+ grub_efi_uint32_t *ActivePcrBanks);
+ grub_efi_status_t (*set_active_pcr_banks) (struct grub_efi_tpm2_protocol *this,
+ grub_efi_uint32_t ActivePcrBanks);
+ grub_efi_status_t (*get_result_of_set_active_pcr_banks) (struct grub_efi_tpm2_protocol *this,
+ grub_efi_uint32_t *OperationPresent,
+ grub_efi_uint32_t *Response);
+};
+
+typedef struct grub_efi_tpm2_protocol grub_efi_tpm2_protocol_t;
+
+#define TCG_ALG_SHA 0x00000004
+
+#endif
diff --git a/include/grub/tpm.h b/include/grub/tpm.h
new file mode 100644
index 000000000..d6757b57b
--- /dev/null
+++ b/include/grub/tpm.h
@@ -0,0 +1,74 @@
+/*
+ * GRUB -- GRand Unified Bootloader
+ * Copyright (C) 2015 Free Software Foundation, Inc.
+ *
+ * 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_TPM_HEADER
+#define GRUB_TPM_HEADER 1
+
+#define SHA1_DIGEST_SIZE 20
+
+#define TPM_BASE 0x0
+#define TPM_SUCCESS TPM_BASE
+#define TPM_AUTHFAIL (TPM_BASE + 0x1)
+#define TPM_BADINDEX (TPM_BASE + 0x2)
+
+#define TPM_TAG_RQU_COMMAND 0x00C1
+#define TPM_ORD_Extend 0x14
+
+#define EV_IPL 0x0d
+
+/* TCG_PassThroughToTPM Input Parameter Block */
+typedef struct {
+ grub_uint16_t IPBLength;
+ grub_uint16_t Reserved1;
+ grub_uint16_t OPBLength;
+ grub_uint16_t Reserved2;
+ grub_uint8_t TPMOperandIn[1];
+} GRUB_PACKED PassThroughToTPM_InputParamBlock;
+
+/* TCG_PassThroughToTPM Output Parameter Block */
+typedef struct {
+ grub_uint16_t OPBLength;
+ grub_uint16_t Reserved;
+ grub_uint8_t TPMOperandOut[1];
+} GRUB_PACKED PassThroughToTPM_OutputParamBlock;
+
+typedef struct {
+ grub_uint16_t tag;
+ grub_uint32_t paramSize;
+ grub_uint32_t ordinal;
+ grub_uint32_t pcrNum;
+ grub_uint8_t inDigest[SHA1_DIGEST_SIZE]; /* The 160 bit value representing the event to be recorded. */
+} GRUB_PACKED ExtendIncoming;
+
+/* TPM_Extend Outgoing Operand */
+typedef struct {
+ grub_uint16_t tag;
+ grub_uint32_t paramSize;
+ grub_uint32_t returnCode;
+ grub_uint8_t outDigest[SHA1_DIGEST_SIZE]; /* The PCR value after execution of the command. */
+} GRUB_PACKED ExtendOutgoing;
+
+grub_err_t grub_tpm_measure (unsigned char *buf, grub_size_t size,
+ grub_uint8_t pcr,
+ const char *description);
+grub_err_t grub_tpm_init(void);
+grub_err_t grub_tpm_execute(PassThroughToTPM_InputParamBlock *inbuf,
+ PassThroughToTPM_OutputParamBlock *outbuf);
+grub_err_t grub_tpm_log_event(unsigned char *buf, grub_size_t size,
+ grub_uint8_t pcr, const char *description);
+#endif
--
2.19.1.930.g4563a0d9d0-goog
Daniel Kiper
2018-11-14 17:38:51 UTC
Permalink
On Fri, Nov 09, 2018 at 03:41:02PM -0800, Matthew Garrett wrote:

Hmmm... Here it is a bit better...
Post by Matthew Garrett
Add support for performing basic TPM measurements. Right now this only
supports extending PCRs statically and only on UEFI. In future we might
want to have some sort of mechanism for choosing which events get logged
to which PCRs, but this seems like a good default policy and we can wait
to see whether anyone has a use case before adding more complexity.
---
grub-core/Makefile.core.def | 7 +
grub-core/commands/efi/tpm.c | 310 +++++++++++++++++++++++++++++++++
grub-core/commands/tpm.c | 87 +++++++++
grub-core/kern/i386/efi/init.c | 1 +
include/grub/efi/tpm.h | 153 ++++++++++++++++
include/grub/tpm.h | 74 ++++++++
6 files changed, 632 insertions(+)
create mode 100644 grub-core/commands/efi/tpm.c
create mode 100644 grub-core/commands/tpm.c
create mode 100644 include/grub/efi/tpm.h
create mode 100644 include/grub/tpm.h
diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
index 6e2cc8444..a485f9186 100644
--- a/grub-core/Makefile.core.def
+++ b/grub-core/Makefile.core.def
@@ -2377,6 +2377,13 @@ module = {
common = commands/testspeed.c;
};
+module = {
+ name = tpm;
+ common = commands/tpm.c;
+ efi = commands/efi/tpm.c;
+ enable = efi;
+};
+
module = {
name = tr;
common = commands/tr.c;
diff --git a/grub-core/commands/efi/tpm.c b/grub-core/commands/efi/tpm.c
new file mode 100644
index 000000000..f03464d96
--- /dev/null
+++ b/grub-core/commands/efi/tpm.c
Lack of license header. You can copy it from, e.g.,
grub-core/commands/efi/shim_lock.c.
Post by Matthew Garrett
@@ -0,0 +1,310 @@
+#include <grub/err.h>
+#include <grub/i18n.h>
+#include <grub/efi/api.h>
+#include <grub/efi/efi.h>
+#include <grub/efi/tpm.h>
+#include <grub/mm.h>
+#include <grub/tpm.h>
+#include <grub/term.h>
+
+static grub_efi_guid_t tpm_guid = EFI_TPM_GUID;
+static grub_efi_guid_t tpm2_guid = EFI_TPM2_GUID;
+
+static grub_efi_handle_t *grub_tpm_handle;
+static grub_uint8_t grub_tpm_version;
+
+static grub_int8_t tpm1_present = -1;
+static grub_int8_t tpm2_present = -1;
+
+static grub_efi_boolean_t grub_tpm1_present(grub_efi_tpm_protocol_t *tpm)
static
grub_efi_boolean_t grub_tpm1_present (grub_efi_tpm_protocol_t *tpm)
...and missing space -> ^

And below please...
Post by Matthew Garrett
+{
+ grub_efi_status_t status;
+ TCG_EFI_BOOT_SERVICE_CAPABILITY caps;
+ grub_uint32_t flags;
+ grub_efi_physical_address_t eventlog, lastevent;
+
+ if (tpm1_present != -1)
+ return (grub_efi_boolean_t)tpm1_present;
return (grub_efi_boolean_t) tpm1_present;
Missing space -> ^

Some say that this is more common form in the GRUB2 code.
Post by Matthew Garrett
+ caps.Size = (grub_uint8_t)sizeof(caps);
+
+ status = efi_call_5(tpm->status_check, tpm, &caps, &flags, &eventlog,
status = efi_call_5 (tpm->status_check, ...
Missing space -> ^

And below...
Post by Matthew Garrett
+ &lastevent);
+
+ if (status != GRUB_EFI_SUCCESS || caps.TPMDeactivatedFlag
+ || !caps.TPMPresentFlag) {
Curly bracket is in wrong place...
Post by Matthew Garrett
+ tpm1_present = 0;
+ return tpm1_present;
+ }
...here and below...
Post by Matthew Garrett
+
+ tpm1_present = 1;
+ return tpm1_present;
+}
+
+static grub_efi_boolean_t grub_tpm2_present(grub_efi_tpm2_protocol_t *tpm)
+{
+ grub_efi_status_t status;
+ EFI_TCG2_BOOT_SERVICE_CAPABILITY caps;
+
+ caps.Size = (grub_uint8_t)sizeof(caps);
+
+ if (tpm2_present != -1)
+ return (grub_efi_boolean_t)tpm2_present;
+
+ status = efi_call_2(tpm->get_capability, tpm, &caps);
+
+ if (status != GRUB_EFI_SUCCESS || !caps.TPMPresentFlag) {
+ tpm2_present = 0;
+ return tpm2_present;
Could not you assign the value and return it in one line?
Post by Matthew Garrett
+ }
+
+ tpm2_present = 1;
+ return tpm2_present;
+}
+
+static grub_efi_boolean_t grub_tpm_handle_find(grub_efi_handle_t *tpm_handle,
+ grub_efi_uint8_t *protocol_version)
+{
+ grub_efi_handle_t *handles;
+ grub_efi_uintn_t num_handles;
+
+ if (grub_tpm_handle != NULL) {
+ *tpm_handle = &grub_tpm_handle;
+ *protocol_version = grub_tpm_version;
+ return 1;
+ }
+
+ handles = grub_efi_locate_handle (GRUB_EFI_BY_PROTOCOL, &tpm_guid, NULL,
+ &num_handles);
+ if (handles && num_handles > 0) {
+ grub_tpm_handle = handles[0];
+ *tpm_handle = handles[0];
+ grub_tpm_version = 1;
+ *protocol_version = 1;
+ return 1;
+ }
+
+ handles = grub_efi_locate_handle (GRUB_EFI_BY_PROTOCOL, &tpm2_guid, NULL,
+ &num_handles);
+ if (handles && num_handles > 0) {
+ grub_tpm_handle = handles[0];
+ *tpm_handle = handles[0];
+ grub_tpm_version = 2;
+ *protocol_version = 2;
+ return 1;
+ }
+
+ return 0;
+}
+
+static grub_err_t
+grub_tpm1_execute(grub_efi_handle_t tpm_handle,
+ PassThroughToTPM_InputParamBlock *inbuf,
+ PassThroughToTPM_OutputParamBlock *outbuf)
Hmmm... Here it is a bit better... A bit...
Post by Matthew Garrett
+{
+ grub_efi_status_t status;
+ grub_efi_tpm_protocol_t *tpm;
+ grub_uint32_t inhdrsize = sizeof(*inbuf) - sizeof(inbuf->TPMOperandIn);
+ grub_uint32_t outhdrsize = sizeof(*outbuf) - sizeof(outbuf->TPMOperandOut);
+
+ tpm = grub_efi_open_protocol (tpm_handle, &tpm_guid,
+ GRUB_EFI_OPEN_PROTOCOL_GET_PROTOCOL);
+
+ if (!grub_tpm1_present(tpm))
+ return 0;
+
+ /* UEFI TPM protocol takes the raw operand block, no param block header */
+ status = efi_call_5 (tpm->pass_through_to_tpm, tpm,
+ inbuf->IPBLength - inhdrsize, inbuf->TPMOperandIn,
+ outbuf->OPBLength - outhdrsize, outbuf->TPMOperandOut);
+
+ switch (status) {
+ return 0;
+ return grub_error (GRUB_ERR_IO, N_("Command failed"));
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("Invalid parameter"));
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("Output buffer too small"));
+ return grub_error (GRUB_ERR_UNKNOWN_DEVICE, N_("TPM unavailable"));
+ return grub_error (GRUB_ERR_UNKNOWN_DEVICE, N_("Unknown TPM error"));
+ }
+}
+
+static grub_err_t
+grub_tpm2_execute(grub_efi_handle_t tpm_handle,
+ PassThroughToTPM_InputParamBlock *inbuf,
+ PassThroughToTPM_OutputParamBlock *outbuf)
+{
+ grub_efi_status_t status;
+ grub_efi_tpm2_protocol_t *tpm;
+ grub_uint32_t inhdrsize = sizeof(*inbuf) - sizeof(inbuf->TPMOperandIn);
+ grub_uint32_t outhdrsize = sizeof(*outbuf) - sizeof(outbuf->TPMOperandOut);
+
+ tpm = grub_efi_open_protocol (tpm_handle, &tpm2_guid,
+ GRUB_EFI_OPEN_PROTOCOL_GET_PROTOCOL);
+
+ if (!grub_tpm2_present(tpm))
+ return 0;
+
+ /* UEFI TPM protocol takes the raw operand block, no param block header */
+ status = efi_call_5 (tpm->submit_command, tpm,
+ inbuf->IPBLength - inhdrsize, inbuf->TPMOperandIn,
+ outbuf->OPBLength - outhdrsize, outbuf->TPMOperandOut);
+
+ switch (status) {
+ return 0;
+ return grub_error (GRUB_ERR_IO, N_("Command failed"));
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("Invalid parameter"));
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("Output buffer too small"));
+ return grub_error (GRUB_ERR_UNKNOWN_DEVICE, N_("TPM unavailable"));
+ return grub_error (GRUB_ERR_UNKNOWN_DEVICE, N_("Unknown TPM error"));
+ }
+}
+
+grub_err_t
+grub_tpm_execute(PassThroughToTPM_InputParamBlock *inbuf,
+ PassThroughToTPM_OutputParamBlock *outbuf)
+{
+ grub_efi_handle_t tpm_handle;
+ grub_uint8_t protocol_version;
+
+ /* Absence of a TPM isn't a failure */
+ if (!grub_tpm_handle_find(&tpm_handle, &protocol_version))
+ return 0;
+
+ if (protocol_version == 1) {
+ return grub_tpm1_execute(tpm_handle, inbuf, outbuf);
+ } else {
+ return grub_tpm2_execute(tpm_handle, inbuf, outbuf);
+ }
+}
+
+typedef struct {
+ grub_uint32_t pcrindex;
+ grub_uint32_t eventtype;
+ grub_uint8_t digest[20];
+ grub_uint32_t eventsize;
+ grub_uint8_t event[1];
Could you align member names that they start in one column.
Post by Matthew Garrett
+} Event;
I would prefer if you define types in GRUB2 way. And please put all
structs/types definitions immediately after includes.
Post by Matthew Garrett
+
Please drop this extra new line.
Post by Matthew Garrett
+
+static grub_err_t
+grub_tpm1_log_event(grub_efi_handle_t tpm_handle, unsigned char *buf,
+ grub_size_t size, grub_uint8_t pcr,
+ const char *description)
+{
+ Event *event;
+ grub_efi_status_t status;
+ grub_efi_tpm_protocol_t *tpm;
+ grub_efi_physical_address_t lastevent;
+ grub_uint32_t algorithm;
+ grub_uint32_t eventnum = 0;
+
+ tpm = grub_efi_open_protocol (tpm_handle, &tpm_guid,
+ GRUB_EFI_OPEN_PROTOCOL_GET_PROTOCOL);
+
+ if (!grub_tpm1_present(tpm))
+ return 0;
+
+ event = grub_zalloc(sizeof (Event) + grub_strlen(description) + 1);
+ if (!event)
+ return grub_error (GRUB_ERR_OUT_OF_MEMORY,
+ N_("cannot allocate TPM event buffer"));
+
+ event->pcrindex = pcr;
+ event->eventtype = EV_IPL;
+ event->eventsize = grub_strlen(description) + 1;
+ grub_memcpy(event->event, description, event->eventsize);
+
+ algorithm = TCG_ALG_SHA;
+ status = efi_call_7 (tpm->log_extend_event, tpm, buf, (grub_uint64_t) size,
+ algorithm, event, &eventnum, &lastevent);
+
+ switch (status) {
+ return 0;
+ return grub_error (GRUB_ERR_IO, N_("Command failed"));
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("Invalid parameter"));
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("Output buffer too small"));
+ return grub_error (GRUB_ERR_UNKNOWN_DEVICE, N_("TPM unavailable"));
+ return grub_error (GRUB_ERR_UNKNOWN_DEVICE, N_("Unknown TPM error"));
+ }
+}
+
+static grub_err_t
+grub_tpm2_log_event(grub_efi_handle_t tpm_handle, unsigned char *buf,
+ grub_size_t size, grub_uint8_t pcr,
+ const char *description)
+{
+ EFI_TCG2_EVENT *event;
+ grub_efi_status_t status;
+ grub_efi_tpm2_protocol_t *tpm;
+
+ tpm = grub_efi_open_protocol (tpm_handle, &tpm2_guid,
+ GRUB_EFI_OPEN_PROTOCOL_GET_PROTOCOL);
+
+ if (!grub_tpm2_present(tpm))
+ return 0;
+
+ event = grub_zalloc(sizeof (EFI_TCG2_EVENT) + grub_strlen(description) + 1);
+ if (!event)
+ return grub_error (GRUB_ERR_OUT_OF_MEMORY,
+ N_("cannot allocate TPM event buffer"));
+
+ event->Header.HeaderSize = sizeof(EFI_TCG2_EVENT_HEADER);
+ event->Header.HeaderVersion = 1;
+ event->Header.PCRIndex = pcr;
+ event->Header.EventType = EV_IPL;
+ event->Size = sizeof(*event) - sizeof(event->Event) + grub_strlen(description) + 1;
+ grub_memcpy(event->Event, description, grub_strlen(description) + 1);
+
+ status = efi_call_5 (tpm->hash_log_extend_event, tpm, 0, buf,
+ (grub_uint64_t) size, event);
+
+ switch (status) {
+ return 0;
+ return grub_error (GRUB_ERR_IO, N_("Command failed"));
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("Invalid parameter"));
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("Output buffer too small"));
+ return grub_error (GRUB_ERR_UNKNOWN_DEVICE, N_("TPM unavailable"));
+ return grub_error (GRUB_ERR_UNKNOWN_DEVICE, N_("Unknown TPM error"));
+ }
+}
+
+grub_err_t
+grub_tpm_log_event(unsigned char *buf, grub_size_t size, grub_uint8_t pcr,
+ const char *description)
+{
+ grub_efi_handle_t tpm_handle;
+ grub_efi_uint8_t protocol_version;
+
+ if (!grub_tpm_handle_find(&tpm_handle, &protocol_version))
+ return 0;
+
+ if (protocol_version == 1) {
+ return grub_tpm1_log_event(tpm_handle, buf, size, pcr, description);
+ } else {
+ return grub_tpm2_log_event(tpm_handle, buf, size, pcr, description);
+ }
+}
diff --git a/grub-core/commands/tpm.c b/grub-core/commands/tpm.c
new file mode 100644
index 000000000..e047b5fe0
--- /dev/null
+++ b/grub-core/commands/tpm.c
Lack of license header.
Post by Matthew Garrett
@@ -0,0 +1,87 @@
+#include <grub/err.h>
+#include <grub/i18n.h>
+#include <grub/misc.h>
+#include <grub/mm.h>
+#include <grub/tpm.h>
+#include <grub/term.h>
+#include <grub/verify.h>
+#include <grub/dl.h>
+
+GRUB_MOD_LICENSE ("GPLv3+")
+
+grub_err_t
+grub_tpm_measure (unsigned char *buf, grub_size_t size, grub_uint8_t pcr,
+ const char *description)
+{
+ return grub_tpm_log_event (buf, size, pcr, description);
+}
+
+static grub_err_t
+grub_tpm_verify_init (grub_file_t io,
+ enum grub_file_type type __attribute__ ((unused)),
+ void **context, enum grub_verify_flags *flags)
+{
+ *context = io->name;
+ *flags |= GRUB_VERIFY_FLAGS_SINGLE_CHUNK;
+ return GRUB_ERR_NONE;
+}
+
+static grub_err_t
+grub_tpm_verify_write (void *context, void *buf, grub_size_t size)
+{
+ return grub_tpm_measure (buf, size, 9, context);
Hmmm... Could you define a constant, e.g. PCR_9?
Post by Matthew Garrett
+}
+
+static void
+grub_tpm_verify_close (void *ctxt __attribute__ ((unused)))
+{
+ return;
+}
close() calls are no longer required by verifiers. You can drop it.
Post by Matthew Garrett
+
+static grub_err_t
+grub_tpm_verify_string (char *str, enum grub_verify_string_type type)
+{
+ const char *prefix = NULL;
+ char *description;
+ grub_err_t status;
+
+ switch (type)
+ {
+ prefix = "kernel_cmdline: ";
+ break;
+ prefix = "module_cmdline: ";
+ break;
+ prefix = "grub_cmd: ";
+ break;
+ }
+ description = grub_malloc(grub_strlen(str) + grub_strlen(prefix) + 1);
+ if (!description)
+ return grub_errno;
+ grub_memcpy(description, prefix, grub_strlen(prefix));
+ grub_memcpy(description + grub_strlen(prefix), str, grub_strlen(str) + 1);
+ status = grub_tpm_measure ((unsigned char *) str, grub_strlen (str), 8,
s/8/PCR_8/?
Post by Matthew Garrett
+ description);
+ grub_free(description);
+ return status;
+}
+
+struct grub_file_verifier grub_tpm_verifier = {
+ .name = "tpm",
+ .init = grub_tpm_verify_init,
+ .write = grub_tpm_verify_write,
+ .close = grub_tpm_verify_close,
Please drop .close. It is no longer needed.
Post by Matthew Garrett
+ .verify_string = grub_tpm_verify_string,
+};
+
+GRUB_MOD_INIT(tpm)
+{
+ grub_verifier_register (&grub_tpm_verifier);
+}
+
+GRUB_MOD_FINI(tpm)
+{
+ grub_verifier_unregister (&grub_tpm_verifier);
+}
diff --git a/grub-core/kern/i386/efi/init.c b/grub-core/kern/i386/efi/init.c
index a28316cc6..da499aba0 100644
--- a/grub-core/kern/i386/efi/init.c
+++ b/grub-core/kern/i386/efi/init.c
@@ -27,6 +27,7 @@
#include <grub/efi/efi.h>
#include <grub/i386/tsc.h>
#include <grub/loader.h>
+#include <grub/tpm.h>
void
grub_machine_init (void)
diff --git a/include/grub/efi/tpm.h b/include/grub/efi/tpm.h
new file mode 100644
index 000000000..e2aff4a3c
--- /dev/null
+++ b/include/grub/efi/tpm.h
@@ -0,0 +1,153 @@
+/*
+ * GRUB -- GRand Unified Bootloader
+ * Copyright (C) 2015 Free Software Foundation, Inc.
s/2015/2018/
Post by Matthew Garrett
+ *
+ * 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_EFI_TPM_HEADER
+#define GRUB_EFI_TPM_HEADER 1
+
+#define EFI_TPM_GUID {0xf541796d, 0xa62e, 0x4954, {0xa7, 0x75, 0x95, 0x84, 0xf6, 0x1b, 0x9c, 0xdd }};
+#define EFI_TPM2_GUID {0x607f766c, 0x7455, 0x42be, {0x93, 0x0b, 0xe4, 0xd7, 0x6d, 0xb2, 0x72, 0x0f }};
+
+typedef struct {
+ grub_efi_uint8_t Major;
+ grub_efi_uint8_t Minor;
+ grub_efi_uint8_t RevMajor;
+ grub_efi_uint8_t RevMinor;
+} TCG_VERSION;
Could you be more C-ish? E.g. s/Major/major/, s/Minor/minor/, etc.
Post by Matthew Garrett
+
+typedef struct _TCG_EFI_BOOT_SERVICE_CAPABILITY {
+ grub_efi_uint8_t Size; /// Size of this structure.
+ TCG_VERSION StructureVersion;
+ TCG_VERSION ProtocolSpecVersion;
+ grub_efi_uint8_t HashAlgorithmBitmap; /// Hash algorithms .
+ char TPMPresentFlag; /// 00h = TPM not present.
+ char TPMDeactivatedFlag; /// 01h = TPM currently deactivated.
Same as above. However, if these are standard names from somewhere than
I am OK with them. Though I would ask you for proper members alignment.
Post by Matthew Garrett
+} TCG_EFI_BOOT_SERVICE_CAPABILITY;
+
+typedef struct {
+ grub_efi_uint32_t PCRIndex;
+ grub_efi_uint32_t EventType;
+ grub_efi_uint8_t digest[20];
+ grub_efi_uint32_t EventSize;
+ grub_efi_uint8_t Event[1];
Ditto and below...
Post by Matthew Garrett
+} TCG_PCR_EVENT;
+
+struct grub_efi_tpm_protocol
+{
+ grub_efi_status_t (*status_check) (struct grub_efi_tpm_protocol *this,
+ TCG_EFI_BOOT_SERVICE_CAPABILITY *ProtocolCapability,
+ grub_efi_uint32_t *TCGFeatureFlags,
+ grub_efi_physical_address_t *EventLogLocation,
+ grub_efi_physical_address_t *EventLogLastEntry);
+ grub_efi_status_t (*hash_all) (struct grub_efi_tpm_protocol *this,
+ grub_efi_uint8_t *HashData,
+ grub_efi_uint64_t HashLen,
+ grub_efi_uint32_t AlgorithmId,
+ grub_efi_uint64_t *HashedDataLen,
+ grub_efi_uint8_t **HashedDataResult);
+ grub_efi_status_t (*log_event) (struct grub_efi_tpm_protocol *this,
+ TCG_PCR_EVENT *TCGLogData,
+ grub_efi_uint32_t *EventNumber,
+ grub_efi_uint32_t Flags);
+ grub_efi_status_t (*pass_through_to_tpm) (struct grub_efi_tpm_protocol *this,
+ grub_efi_uint32_t TpmInputParameterBlockSize,
+ grub_efi_uint8_t *TpmInputParameterBlock,
+ grub_efi_uint32_t TpmOutputParameterBlockSize,
+ grub_efi_uint8_t *TpmOutputParameterBlock);
+ grub_efi_status_t (*log_extend_event) (struct grub_efi_tpm_protocol *this,
+ grub_efi_physical_address_t HashData,
+ grub_efi_uint64_t HashDataLen,
+ grub_efi_uint32_t AlgorithmId,
+ TCG_PCR_EVENT *TCGLogData,
+ grub_efi_uint32_t *EventNumber,
+ grub_efi_physical_address_t *EventLogLastEntry);
+};
+
+typedef struct grub_efi_tpm_protocol grub_efi_tpm_protocol_t;
+
+typedef grub_efi_uint32_t EFI_TCG2_EVENT_LOG_BITMAP;
+typedef grub_efi_uint32_t EFI_TCG2_EVENT_LOG_FORMAT;
+typedef grub_efi_uint32_t EFI_TCG2_EVENT_ALGORITHM_BITMAP;
+
+typedef struct tdEFI_TCG2_VERSION {
+ grub_efi_uint8_t Major;
+ grub_efi_uint8_t Minor;
+} GRUB_PACKED EFI_TCG2_VERSION;
+
+typedef struct tdEFI_TCG2_BOOT_SERVICE_CAPABILITY {
+ grub_efi_uint8_t Size;
+ EFI_TCG2_VERSION StructureVersion;
+ EFI_TCG2_VERSION ProtocolVersion;
+ EFI_TCG2_EVENT_ALGORITHM_BITMAP HashAlgorithmBitmap;
+ EFI_TCG2_EVENT_LOG_BITMAP SupportedEventLogs;
+ grub_efi_boolean_t TPMPresentFlag;
+ grub_efi_uint16_t MaxCommandSize;
+ grub_efi_uint16_t MaxResponseSize;
+ grub_efi_uint32_t ManufacturerID;
+ grub_efi_uint32_t NumberOfPcrBanks;
+ EFI_TCG2_EVENT_ALGORITHM_BITMAP ActivePcrBanks;
+} EFI_TCG2_BOOT_SERVICE_CAPABILITY;
+
+typedef grub_efi_uint32_t TCG_PCRINDEX;
+typedef grub_efi_uint32_t TCG_EVENTTYPE;
+
+typedef struct tdEFI_TCG2_EVENT_HEADER {
+ grub_efi_uint32_t HeaderSize;
+ grub_efi_uint16_t HeaderVersion;
+ TCG_PCRINDEX PCRIndex;
+ TCG_EVENTTYPE EventType;
+} GRUB_PACKED EFI_TCG2_EVENT_HEADER;
+
+typedef struct tdEFI_TCG2_EVENT {
+ grub_efi_uint32_t Size;
+ EFI_TCG2_EVENT_HEADER Header;
+ grub_efi_uint8_t Event[1];
+} GRUB_PACKED EFI_TCG2_EVENT;
+
+struct grub_efi_tpm2_protocol
+{
+ grub_efi_status_t (*get_capability) (struct grub_efi_tpm2_protocol *this,
+ EFI_TCG2_BOOT_SERVICE_CAPABILITY *ProtocolCapability);
+ grub_efi_status_t (*get_event_log) (struct grub_efi_tpm2_protocol *this,
+ EFI_TCG2_EVENT_LOG_FORMAT EventLogFormat,
+ grub_efi_physical_address_t *EventLogLocation,
+ grub_efi_physical_address_t *EventLogLastEntry,
+ grub_efi_boolean_t *EventLogTruncated);
+ grub_efi_status_t (*hash_log_extend_event) (struct grub_efi_tpm2_protocol *this,
+ grub_efi_uint64_t Flags,
+ grub_efi_physical_address_t *DataToHash,
+ grub_efi_uint64_t DataToHashLen,
+ EFI_TCG2_EVENT *EfiTcgEvent);
+ grub_efi_status_t (*submit_command) (struct grub_efi_tpm2_protocol *this,
+ grub_efi_uint32_t InputParameterBlockSize,
+ grub_efi_uint8_t *InputParameterBlock,
+ grub_efi_uint32_t OutputParameterBlockSize,
+ grub_efi_uint8_t *OutputParameterBlock);
+ grub_efi_status_t (*get_active_pcr_blanks) (struct grub_efi_tpm2_protocol *this,
+ grub_efi_uint32_t *ActivePcrBanks);
+ grub_efi_status_t (*set_active_pcr_banks) (struct grub_efi_tpm2_protocol *this,
+ grub_efi_uint32_t ActivePcrBanks);
+ grub_efi_status_t (*get_result_of_set_active_pcr_banks) (struct grub_efi_tpm2_protocol *this,
+ grub_efi_uint32_t *OperationPresent,
+ grub_efi_uint32_t *Response);
+};
+
+typedef struct grub_efi_tpm2_protocol grub_efi_tpm2_protocol_t;
+
+#define TCG_ALG_SHA 0x00000004
I would prefer if you define all constants at the beginning of the file.
Post by Matthew Garrett
+
+#endif
diff --git a/include/grub/tpm.h b/include/grub/tpm.h
new file mode 100644
index 000000000..d6757b57b
--- /dev/null
+++ b/include/grub/tpm.h
@@ -0,0 +1,74 @@
+/*
+ * GRUB -- GRand Unified Bootloader
+ * Copyright (C) 2015 Free Software Foundation, Inc.
s/2015/2018/
Post by Matthew Garrett
+ *
+ * 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_TPM_HEADER
+#define GRUB_TPM_HEADER 1
+
+#define SHA1_DIGEST_SIZE 20
+
+#define TPM_BASE 0x0
+#define TPM_SUCCESS TPM_BASE
+#define TPM_AUTHFAIL (TPM_BASE + 0x1)
+#define TPM_BADINDEX (TPM_BASE + 0x2)
Alignment please.
Post by Matthew Garrett
+
+#define TPM_TAG_RQU_COMMAND 0x00C1
+#define TPM_ORD_Extend 0x14
+
+#define EV_IPL 0x0d
+
+/* TCG_PassThroughToTPM Input Parameter Block */
+typedef struct {
+ grub_uint16_t IPBLength;
+ grub_uint16_t Reserved1;
+ grub_uint16_t OPBLength;
+ grub_uint16_t Reserved2;
+ grub_uint8_t TPMOperandIn[1];
+} GRUB_PACKED PassThroughToTPM_InputParamBlock;
+
+/* TCG_PassThroughToTPM Output Parameter Block */
+typedef struct {
+ grub_uint16_t OPBLength;
+ grub_uint16_t Reserved;
+ grub_uint8_t TPMOperandOut[1];
+} GRUB_PACKED PassThroughToTPM_OutputParamBlock;
+
+typedef struct {
+ grub_uint16_t tag;
+ grub_uint32_t paramSize;
+ grub_uint32_t ordinal;
+ grub_uint32_t pcrNum;
+ grub_uint8_t inDigest[SHA1_DIGEST_SIZE]; /* The 160 bit value representing the event to be recorded. */
+} GRUB_PACKED ExtendIncoming;
+
+/* TPM_Extend Outgoing Operand */
+typedef struct {
+ grub_uint16_t tag;
+ grub_uint32_t paramSize;
+ grub_uint32_t returnCode;
+ grub_uint8_t outDigest[SHA1_DIGEST_SIZE]; /* The PCR value after execution of the command. */
Please put the comments before the member names.

Daniel
Matthew Garrett
2018-11-14 23:23:32 UTC
Permalink
Post by Daniel Kiper
Could you be more C-ish? E.g. s/Major/major/, s/Minor/minor/, etc.
These are the spec-defined member names, so I've a mild preference for
keeping them that way - it makes it easier to compare with the spec
and update stuff with later spec revisions. I've updated everything
else, I'll resend now.
Daniel Kiper
2018-11-23 10:50:53 UTC
Permalink
Post by Matthew Garrett
Post by Daniel Kiper
Could you be more C-ish? E.g. s/Major/major/, s/Minor/minor/, etc.
These are the spec-defined member names, so I've a mild preference for
keeping them that way - it makes it easier to compare with the spec
and update stuff with later spec revisions. I've updated everything
else, I'll resend now.
OK, but please add the title of spec which you are referring to into the
comment before these structs. This way it will be much easier to
understand why you diverge from the common naming convention.

Daniel

Matthew Garrett
2018-11-09 23:41:03 UTC
Permalink
Describe the behaviour of grub when the TPM module is in use.
---
docs/grub.texi | 38 ++++++++++++++++++++++++++++++++++++++
1 file changed, 38 insertions(+)

diff --git a/docs/grub.texi b/docs/grub.texi
index 471d97c95..6bd3783a4 100644
--- a/docs/grub.texi
+++ b/docs/grub.texi
@@ -5545,6 +5545,7 @@ environment variables and commands are listed in the same order.
* Authentication and authorisation:: Users and access control
* Using digital signatures:: Booting digitally signed code
* UEFI secure boot and shim:: Booting digitally signed PE files
+* Measured Boot:: Measuring boot components
@end menu

@node Authentication and authorisation
@@ -5721,6 +5722,43 @@ mentioned requirements are enforced by the shim_lock module. And itself it
is a persistent module which means that it cannot be unloaded if it was
loaded into the memory.

+@node Measured Boot
+@section Measuring boot components
+
+If the tpm module is loaded and the platform has a Trusted Platform Module
+installed, GRUB will log each command executed and each file loaded into the
+TPM event log and extend the PCR values in the TPM correspondingly. All events
+will be logged into the PCR described below with a type of EV_IPL and an
+event description as described below.
+
+@multitable @columnfractions 0.3 0.1 0.6
+@headitem Event type @tab PCR @tab Description
+@item Command
+@tab 8
+@tab All executed commands (including those from configuration files) will be
+logged and measured as entered with a prefix of ``grub_cmd: ``
+@item Module command line
+@tab 8
+@tab Any command line passed to a kernel module will be logged and measured as
+entered with a prefix of ``module_cmdline: ``
+@item Kernel command line
+@tab 8
+@tab Any command line passed to a kernel will be logged and measured as entered
+with a prefix of ``kernel_cmdline: ''
+@item Files
+@tab 9
+@tab Any file read by GRUB will be logged and measured with a descriptive text
+corresponding to the filename.
+@end multitable
+
+GRUB will not measure its own @file{core.img} - it is expected that firmware
+will carry this out. GRUB will also not perform any measurements until the
+tpm module is loaded. As such it is recommended that the tpm module be built
+into @file{core.img} in order to avoid a potential gap in measurement between
+@file{core.img} being loaded and the tpm module being loaded.
+
+Measured boot is currently only supported on EFI platforms.
+
@node Platform limitations
@chapter Platform limitations
--
2.19.1.930.g4563a0d9d0-goog
Daniel Kiper
2018-11-14 17:41:13 UTC
Permalink
Post by Matthew Garrett
Describe the behaviour of grub when the TPM module is in use.
Lack of SOB. Otherwise Reviewed-by: Daniel Kiper <***@oracle.com>

Daniel
Daniel Kiper
2018-11-14 16:45:12 UTC
Permalink
Post by Matthew Garrett
Pass all commands executed by grub to the verifiers layer. Most
verifiers will ignore this, but some (such as the TPM verifier) want to
be able to measure and log each command executed in order to ensure that
the boot state is as expected.
Except lack of SOB patch LGTM. May I add your SOB before pushing this
patch. Or you can repost it with
Reviewed-by: Daniel Kiper <***@oracle.com>

Daniel
Matthew Garrett
2018-11-14 19:37:07 UTC
Permalink
Post by Daniel Kiper
Except lack of SOB patch LGTM. May I add your SOB before pushing this
patch. Or you can repost it with
Feel free to add my SOB.
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