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
This commit is contained in:
Rohit Ner 2022-05-06 07:58:21 +00:00
parent e682c723cd
commit a283d19f82
2 changed files with 24 additions and 3 deletions

View File

@ -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 @@ static int load_mbr_header(uintptr_t image_handle, mbr_entry_t *mbr_entry)
}
/*
* 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 @@ static int load_gpt_header(uintptr_t image_handle)
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 @@ static int load_gpt_header(uintptr_t image_handle)
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) {

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@ -1,5 +1,5 @@
/*
* Copyright (c) 2016-2018, ARM Limited and Contributors. All rights reserved.
* Copyright (c) 2016-2022, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
@ -29,6 +29,8 @@ CASSERT((PLAT_PARTITION_BLOCK_SIZE == 512) ||
#define LEGACY_PARTITION_BLOCK_SIZE 512
#define DEFAULT_GPT_HEADER_SIZE 92
typedef struct partition_entry {
uint64_t start;
uint64_t length;