feat(partition): verify crc while loading gpt header
This change makes use of 32-bit crc for calculating gpt header crc
and compares it with the given value.
Signed-off-by: Rohit Ner <rohitner@google.com>
Change-Id: I49bca7aab2c3884881c4b7d90d31786a895290e6
diff --git a/drivers/partition/partition.c b/drivers/partition/partition.c
index 7706f88..c84816f 100644
--- a/drivers/partition/partition.c
+++ b/drivers/partition/partition.c
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2016-2019, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2016-2022, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
@@ -10,6 +10,7 @@
#include <string.h>
#include <common/debug.h>
+#include <common/tf_crc32.h>
#include <drivers/io/io_storage.h>
#include <drivers/partition/efi.h>
#include <drivers/partition/partition.h>
@@ -76,7 +77,7 @@
}
/*
- * Load GPT header and check the GPT signature.
+ * Load GPT header and check the GPT signature and header CRC.
* If partition numbers could be found, check & update it.
*/
static int load_gpt_header(uintptr_t image_handle)
@@ -84,6 +85,7 @@
gpt_header_t header;
size_t bytes_read;
int result;
+ uint32_t header_crc, calc_crc;
result = io_seek(image_handle, IO_SEEK_SET, GPT_HEADER_OFFSET);
if (result != 0) {
@@ -99,6 +101,23 @@
return -EINVAL;
}
+ /*
+ * UEFI Spec 2.8 March 2019 Page 119: HeaderCRC32 value is
+ * computed by setting this field to 0, and computing the
+ * 32-bit CRC for HeaderSize bytes.
+ */
+ header_crc = header.header_crc;
+ header.header_crc = 0U;
+
+ calc_crc = tf_crc32(0U, (uint8_t *)&header, DEFAULT_GPT_HEADER_SIZE);
+ if (header_crc != calc_crc) {
+ ERROR("Invalid GPT Header CRC: Expected 0x%x but got 0x%x.\n",
+ header_crc, calc_crc);
+ return -EINVAL;
+ }
+
+ header.header_crc = header_crc;
+
/* partition numbers can't exceed PLAT_PARTITION_MAX_ENTRIES */
list.entry_count = header.list_num;
if (list.entry_count > PLAT_PARTITION_MAX_ENTRIES) {