73 lines
1.4 KiB
C
73 lines
1.4 KiB
C
|
/*
|
||
|
|
* purgatory: Runs between two kernels
|
||
|
|
*
|
||
|
|
* Copyright (C) 2014 Red Hat Inc.
|
||
|
|
*
|
||
|
|
* Author:
|
||
|
|
* Vivek Goyal <vgoyal@redhat.com>
|
||
|
|
*
|
||
|
|
* This source code is licensed under the GNU General Public License,
|
||
|
|
* Version 2. See the file COPYING for more details.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include "sha256.h"
|
||
|
|
#include "../boot/string.h"
|
||
|
|
|
||
|
|
struct sha_region {
|
||
|
|
unsigned long start;
|
||
|
|
unsigned long len;
|
||
|
|
};
|
||
|
|
|
||
|
|
unsigned long backup_dest = 0;
|
||
|
|
unsigned long backup_src = 0;
|
||
|
|
unsigned long backup_sz = 0;
|
||
|
|
|
||
|
|
u8 sha256_digest[SHA256_DIGEST_SIZE] = { 0 };
|
||
|
|
|
||
|
|
struct sha_region sha_regions[16] = {};
|
||
|
|
|
||
|
|
/*
|
||
|
|
* On x86, second kernel requries first 640K of memory to boot. Copy
|
||
|
|
* first 640K to a backup region in reserved memory range so that second
|
||
|
|
* kernel can use first 640K.
|
||
|
|
*/
|
||
|
|
static int copy_backup_region(void)
|
||
|
|
{
|
||
|
|
if (backup_dest)
|
||
|
|
memcpy((void *)backup_dest, (void *)backup_src, backup_sz);
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
int verify_sha256_digest(void)
|
||
|
|
{
|
||
|
|
struct sha_region *ptr, *end;
|
||
|
|
u8 digest[SHA256_DIGEST_SIZE];
|
||
|
|
struct sha256_state sctx;
|
||
|
|
|
||
|
|
sha256_init(&sctx);
|
||
|
|
end = &sha_regions[sizeof(sha_regions)/sizeof(sha_regions[0])];
|
||
|
|
for (ptr = sha_regions; ptr < end; ptr++)
|
||
|
|
sha256_update(&sctx, (uint8_t *)(ptr->start), ptr->len);
|
||
|
|
|
||
|
|
sha256_final(&sctx, digest);
|
||
|
|
|
||
|
|
if (memcmp(digest, sha256_digest, sizeof(digest)))
|
||
|
|
return 1;
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
void purgatory(void)
|
||
|
|
{
|
||
|
|
int ret;
|
||
|
|
|
||
|
|
ret = verify_sha256_digest();
|
||
|
|
if (ret) {
|
||
|
|
/* loop forever */
|
||
|
|
for (;;)
|
||
|
|
;
|
||
|
|
}
|
||
|
|
copy_backup_region();
|
||
|
|
}
|