[PATCH v18 13/25] tss2: Add TPM2 buffer handling functions

[Gary Lin]

As the prepartion to support TPM2 Software Stack (TSS2), this commit
implements the TPM2 buffer handling functions to pack data for the TPM2
commands and unpack the data from the response.

Cc: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Hernan Gatta <hegatta@linux.microsoft.com>
Signed-off-by: Gary Lin <glin@suse.com>
---
 grub-core/lib/tss2/buffer.c      | 149 +++++++++++++++++++++++++++++++
 grub-core/lib/tss2/tss2_buffer.h |  66 ++++++++++++++
 2 files changed, 215 insertions(+)
 create mode 100644 grub-core/lib/tss2/buffer.c
 create mode 100644 grub-core/lib/tss2/tss2_buffer.h

diff --git a/grub-core/lib/tss2/buffer.c b/grub-core/lib/tss2/buffer.c
new file mode 100644
index 000000000..00a57b464
--- /dev/null
+++ b/grub-core/lib/tss2/buffer.c
@@ -0,0 +1,149 @@
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2024 Free Software Foundation, Inc.
+ *  Copyright (C) 2022 Microsoft 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/misc.h>
+
+#include <tss2_buffer.h>
+
+void grub_tpm2_buffer_init (grub_tpm2_buffer_t buffer)
+{
+  grub_memset (buffer->data, 0, sizeof (buffer->data));
+  buffer->size = 0;
+  buffer->offset = 0;
+  buffer->cap = sizeof (buffer->data);
+  buffer->error = 0;
+}
+
+void
+grub_tpm2_buffer_pack (grub_tpm2_buffer_t buffer, const void* data,
+                      grub_size_t size)
+{
+  grub_uint32_t r = buffer->cap - buffer->size;
+
+  if (buffer->error)
+    return;
+
+  if (size > r)
+    {
+      buffer->error = 1;
+      return;
+    }
+
+  grub_memcpy (&buffer->data[buffer->size], (void*) data, size);
+  buffer->size += size;
+}
+
+void
+grub_tpm2_buffer_pack_u8 (grub_tpm2_buffer_t buffer, grub_uint8_t value)
+{
+  grub_tpm2_buffer_pack (buffer, (const char*) &value, sizeof (value));
+}
+
+void
+grub_tpm2_buffer_pack_u16 (grub_tpm2_buffer_t buffer, grub_uint16_t value)
+{
+  grub_uint16_t tmp = grub_cpu_to_be16 (value);
+
+  grub_tpm2_buffer_pack (buffer, (const char*) &tmp, sizeof (tmp));
+}
+
+void
+grub_tpm2_buffer_pack_u32 (grub_tpm2_buffer_t buffer, grub_uint32_t value)
+{
+  grub_uint32_t tmp = grub_cpu_to_be32 (value);
+
+  grub_tpm2_buffer_pack (buffer, (const char*) &tmp, sizeof (tmp));
+}
+
+void
+grub_tpm2_buffer_unpack (grub_tpm2_buffer_t buffer, void* data,
+                        grub_size_t size)
+{
+  grub_uint32_t r = buffer->size - buffer->offset;
+
+  if (buffer->error)
+    return;
+
+  if (size > r)
+    {
+      buffer->error = 1;
+      return;
+    }
+
+  grub_memcpy (data, &buffer->data[buffer->offset], size);
+  buffer->offset += size;
+}
+
+void
+grub_tpm2_buffer_unpack_u8 (grub_tpm2_buffer_t buffer, grub_uint8_t* value)
+{
+  grub_uint32_t r = buffer->size - buffer->offset;
+
+  if (buffer->error)
+    return;
+
+  if (sizeof (*value) > r)
+    {
+      buffer->error = 1;
+      return;
+    }
+
+  grub_memcpy (value, &buffer->data[buffer->offset], sizeof (*value));
+  buffer->offset += sizeof (*value);
+}
+
+void
+grub_tpm2_buffer_unpack_u16 (grub_tpm2_buffer_t buffer, grub_uint16_t* value)
+{
+  grub_uint16_t tmp;
+  grub_uint32_t r = buffer->size - buffer->offset;
+
+  if (buffer->error)
+    return;
+
+  if (sizeof (tmp) > r)
+    {
+      buffer->error = 1;
+      return;
+    }
+
+  grub_memcpy (&tmp, &buffer->data[buffer->offset], sizeof (tmp));
+  buffer->offset += sizeof (tmp);
+  *value = grub_be_to_cpu16 (tmp);
+}
+
+void
+grub_tpm2_buffer_unpack_u32 (grub_tpm2_buffer_t buffer, grub_uint32_t* value)
+{
+  grub_uint32_t tmp;
+  grub_uint32_t r = buffer->size - buffer->offset;
+
+  if (buffer->error)
+    return;
+
+  if (sizeof (tmp) > r)
+    {
+      buffer->error = 1;
+      return;
+    }
+
+  grub_memcpy (&tmp, &buffer->data[buffer->offset], sizeof (tmp));
+  buffer->offset += sizeof (tmp);
+  *value = grub_be_to_cpu32 (tmp);
+}
diff --git a/grub-core/lib/tss2/tss2_buffer.h b/grub-core/lib/tss2/tss2_buffer.h
new file mode 100644
index 000000000..92648a1cb
--- /dev/null
+++ b/grub-core/lib/tss2/tss2_buffer.h
@@ -0,0 +1,66 @@
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2024 Free Software Foundation, Inc.
+ *  Copyright (C) 2022 Microsoft 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_TPM2_BUFFER_HEADER
+#define GRUB_TPM2_BUFFER_HEADER 1
+
+#include <grub/types.h>
+
+#define GRUB_TPM2_BUFFER_CAPACITY 4096
+
+struct grub_tpm2_buffer
+{
+  grub_uint8_t data[GRUB_TPM2_BUFFER_CAPACITY];
+  grub_size_t size;
+  grub_size_t offset;
+  grub_size_t cap;
+  grub_uint8_t error;
+};
+typedef struct grub_tpm2_buffer *grub_tpm2_buffer_t;
+
+void
+grub_tpm2_buffer_init (grub_tpm2_buffer_t buffer);
+
+void
+grub_tpm2_buffer_pack (grub_tpm2_buffer_t buffer, const void* data,
+                      grub_size_t size);
+
+void
+grub_tpm2_buffer_pack_u8 (grub_tpm2_buffer_t buffer, grub_uint8_t value);
+
+void
+grub_tpm2_buffer_pack_u16 (grub_tpm2_buffer_t buffer, grub_uint16_t value);
+
+void
+grub_tpm2_buffer_pack_u32 (grub_tpm2_buffer_t buffer, grub_uint32_t value);
+
+void
+grub_tpm2_buffer_unpack (grub_tpm2_buffer_t buffer, void* data,
+                        grub_size_t size);
+
+void
+grub_tpm2_buffer_unpack_u8 (grub_tpm2_buffer_t buffer, grub_uint8_t* value);
+
+void
+grub_tpm2_buffer_unpack_u16 (grub_tpm2_buffer_t buffer, grub_uint16_t* value);
+
+void
+grub_tpm2_buffer_unpack_u32 (grub_tpm2_buffer_t buffer, grub_uint32_t* value);
+
+#endif /* ! GRUB_TPM2_BUFFER_HEADER */
-- 
2.35.3