[PATCH v3 1/2] efi/tpcm: Add UEFI interface for TPCM module

[chench246 <chench246@gmail.com>]

TPCM(Trusted Platform Control Module) is a Chinese standard, and
the interface implementation complies with UEFI specification. If
tpcm related protocol is not implemented in UEFI, then tpcm module
directly returns NONE.

Signed-off-by: hao chen <chench246@gmail.com>
---
 grub-core/commands/efi/tpcm.c | 163 ++++++++++++++++++++++++++++++++++
 include/grub/efi/tpcm.h       |  61 +++++++++++++
 include/grub/err.h            |   3 +-
 3 files changed, 226 insertions(+), 1 deletion(-)
 create mode 100755 grub-core/commands/efi/tpcm.c
 create mode 100644 include/grub/efi/tpcm.h

diff --git a/grub-core/commands/efi/tpcm.c b/grub-core/commands/efi/tpcm.c
new file mode 100755
index 000000000..57cd147dc
--- /dev/null
+++ b/grub-core/commands/efi/tpcm.c
@@ -0,0 +1,163 @@
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2025  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/>.
+ *
+ *  EFI TPCM support code.
+ */
+
+#include <grub/err.h>
+#include <grub/efi/tpcm.h>
+
+
+static grub_uint32_t g_measured_id = STAGE_START;
+
+/*
+ * get_tpcm_stage:
+ * TPCM does not make a distinction with the type of
+ * measured target, so we use g_measured_id directly
+ * for the stage.
+ */
+static grub_uint32_t
+get_tpcm_stage (void)
+{
+    grub_uint32_t stage = STAGE_INVALID;
+
+    stage = g_measured_id;
+
+    if (stage < STAGE_START || stage > STAGE_END)
+      stage = STAGE_INVALID;
+
+    return stage;
+}
+
+/*
+ * update_measured_id:
+ * update g_measured_id +1 every time measured, and g_measured_id
+ * will never be decreased.
+ */
+static void
+update_measured_id (void)
+{
+    g_measured_id++;
+}
+
+/*
+ * measure_memory:
+ * measure the memery region--(addr, size) through the TPCM protocol.
+ * if TPCM protocol is not exist in BIOS, it will return SUCC to keep
+ * compatible with non-measurement-support bios; if TPCM protocol is
+ * exist but not enabled, it will also return SUCC.
+ */
+static grub_err_t
+measure_memory (enum grub_file_type type __attribute__((unused)),
+                char *desc, grub_addr_t addr, grub_size_t size)
+{
+    grub_efi_handle_t   *handles = NULL;
+    grub_efi_uintn_t    num_handles;
+    grub_efi_handle_t   grub_c2p_handle = 0;
+    grub_err_t  test_c2p_err = GRUB_ERR_BAD_OS;
+    grub_guid_t         c2p_guid = C2PGUID;
+    grub_uint32_t       measure_result = 0;
+    grub_uint32_t       control_result = 0;
+    grub_efi_boolean_t    verify_enable = false;
+    grub_size_t         desc_len = 0;
+
+    handles = grub_efi_locate_handle (GRUB_EFI_BY_PROTOCOL, &c2p_guid, NULL, &num_handles);
+    if (handles != NULL && num_handles > 0)
+    {
+        struct c2p_protocol *c2p;
+
+        grub_c2p_handle = handles[0];
+        grub_dprintf ("tpcm", "measue memory addr 0x%lx size 0x%lx  \n", addr, size);
+        c2p = grub_efi_open_protocol (grub_c2p_handle, &c2p_guid,
+                                      GRUB_EFI_OPEN_PROTOCOL_GET_PROTOCOL);
+        if (c2p != NULL)
+        {
+            verify_enable = c2p->verify_is_enabled (c2p);
+            if (verify_enable == true)
+            {
+                struct addr_range range;
+                grub_efi_status_t status = 0;
+                grub_uint32_t stage = STAGE_INVALID;
+
+                range.start  = addr;
+                range.length = size;
+
+                stage = get_tpcm_stage ();
+                if (stage != STAGE_INVALID)
+                {
+                    desc_len = grub_strlen (desc) + 1;
+                    status = c2p->verify_raw (c2p, stage, (grub_uint64_t)desc, desc_len, 1, &range, &measure_result, &control_result);
+                    if (status == 0 && (control_result & MEASURE_ACTION_MASK) == 0)
+                    {
+                        grub_dprintf ("tpcm", "verify_raw success. stage[%d]desc:[%s]\n", stage, desc);
+                        test_c2p_err = GRUB_ERR_NONE;
+                    }
+                    else
+                    {
+                        grub_dprintf ("tpcm", "verify_raw error\n");
+                        while (1)
+                        {
+                            grub_error (GRUB_ERR_TPCM_VERIFY, "tpcm verify error. stage[%d]desc[%s]\n", stage, desc);
+                            asm volatile ("hlt");
+                        }
+                    }
+                }
+                else
+                  grub_dprintf ("tpcm", "invalid stage\n");
+
+                update_measured_id ();
+
+            }
+            else
+            {
+                grub_dprintf ("tpcm", "image verify not enabled\n");
+                test_c2p_err = GRUB_ERR_NONE;
+            }
+        }
+        else
+            grub_dprintf ("tpcm", "open c2p protocol failed\n");
+    }
+    else
+    {
+        /* keep compatible with non-measurement-support bios. */
+        grub_dprintf ("tpcm", "not found C2P protocol\n");
+        test_c2p_err = GRUB_ERR_NONE;
+    }
+
+    return test_c2p_err;
+}
+
+/* grub_tpcm_measure_memory */
+grub_err_t
+grub_tpcm_measure_memory (void *context, grub_addr_t buf, grub_size_t size)
+{
+    char *p_context = (char *) context;
+    char *p, *p_desc;
+    char tmp[TPCM_MAX_BUF_SIZE] = {'0'};
+    enum grub_file_type type;
+
+    if (p_context == NULL)
+        return GRUB_ERR_BUG;
+
+    p = grub_strchr (p_context, '|');
+    p_desc = p + 1;
+    grub_memcpy (tmp, p_context, (p - p_context));
+    type = grub_strtoul (tmp, 0, 10);
+
+    return measure_memory (type, p_desc, buf, size);
+}
+
diff --git a/include/grub/efi/tpcm.h b/include/grub/efi/tpcm.h
new file mode 100644
index 000000000..e54aee6c2
--- /dev/null
+++ b/include/grub/efi/tpcm.h
@@ -0,0 +1,61 @@
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2025  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_TPCM_HEADER
+#define GRUB_EFI_TPCM_HEADER 1
+
+#include <grub/file.h>
+#include <grub/efi/api.h>
+#include <grub/efi/efi.h>
+
+#define C2PGUID                          {0xf89ab5cd, 0x2829, 0x422f, {0xa5, 0xf3, 0x03, 0x28, 0xe0, 0x6c, 0xfc, 0xbb}}
+#define MEASURE_RESULT_MASK          (0xff00)
+#define MEASURE_RESULT_SHIFT         (16)
+#define MEASURE_ACTION_MASK          (0x1)
+#define TPCM_MAX_BUF_SIZE            128
+
+/*
+ * stage layout:
+ * 2000~2999: +1 every time
+ */
+
+#define STAGE_START      2000
+#define STAGE_END        2999
+#define STAGE_INVALID    3000
+
+struct addr_range {
+    grub_uint64_t start;
+    grub_uint64_t length;
+};
+struct c2p_protocol {
+    grub_efi_status_t (__grub_efi_api *verify_raw) (struct c2p_protocol *this,
+                                    grub_uint32_t measure_stage,
+                                    grub_uint64_t image_info,
+                                    grub_uint32_t image_info_size,
+                                    grub_uint32_t num_addr_range,
+                                    struct addr_range ranges[],
+                                    grub_uint32_t *measure_result,
+                                    grub_uint32_t *control_result);
+    grub_efi_boolean_t (__grub_efi_api *verify_is_enabled)(struct c2p_protocol *this);
+};
+typedef struct c2p_protocol c2p_protocol_t;
+
+grub_err_t
+grub_tpcm_measure_memory (void *context, grub_addr_t buf, grub_size_t size);
+
+#endif
diff --git a/include/grub/err.h b/include/grub/err.h
index 202fa8a7a..4d2756097 100644
--- a/include/grub/err.h
+++ b/include/grub/err.h
@@ -75,7 +75,8 @@ typedef enum
     GRUB_ERR_BAD_SIGNATURE,
     GRUB_ERR_BAD_FIRMWARE,
     GRUB_ERR_STILL_REFERENCED,
-    GRUB_ERR_RECURSION_DEPTH
+    GRUB_ERR_RECURSION_DEPTH,
+    GRUB_ERR_TPCM_VERIFY
   }
 grub_err_t;
 
-- 
2.17.1


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