linux/arch/x86/purgatory/purgatory.c
Eric Biggers b86ced882b lib/crypto: sha256: Make library API use strongly-typed contexts
Currently the SHA-224 and SHA-256 library functions can be mixed
arbitrarily, even in ways that are incorrect, for example using
sha224_init() and sha256_final().  This is because they operate on the
same structure, sha256_state.

Introduce stronger typing, as I did for SHA-384 and SHA-512.

Also as I did for SHA-384 and SHA-512, use the names *_ctx instead of
*_state.  The *_ctx names have the following small benefits:

- They're shorter.
- They avoid an ambiguity with the compression function state.
- They're consistent with the well-known OpenSSL API.
- Users usually name the variable 'sctx' anyway, which suggests that
  *_ctx would be the more natural name for the actual struct.

Therefore: update the SHA-224 and SHA-256 APIs, implementation, and
calling code accordingly.

In the new structs, also strongly-type the compression function state.

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20250630160645.3198-7-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
2025-07-04 10:18:53 -07:00

60 lines
1.2 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* purgatory: Runs between two kernels
*
* Copyright (C) 2014 Red Hat Inc.
*
* Author:
* Vivek Goyal <vgoyal@redhat.com>
*/
#include <linux/bug.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <crypto/sha2.h>
#include <asm/purgatory.h>
#include "../boot/compressed/error.h"
#include "../boot/string.h"
u8 purgatory_sha256_digest[SHA256_DIGEST_SIZE] __section(".kexec-purgatory");
struct kexec_sha_region purgatory_sha_regions[KEXEC_SEGMENT_MAX] __section(".kexec-purgatory");
static int verify_sha256_digest(void)
{
struct kexec_sha_region *ptr, *end;
u8 digest[SHA256_DIGEST_SIZE];
struct sha256_ctx sctx;
sha256_init(&sctx);
end = purgatory_sha_regions + ARRAY_SIZE(purgatory_sha_regions);
for (ptr = purgatory_sha_regions; ptr < end; ptr++)
sha256_update(&sctx, (uint8_t *)(ptr->start), ptr->len);
sha256_final(&sctx, digest);
if (memcmp(digest, purgatory_sha256_digest, sizeof(digest)))
return 1;
return 0;
}
void purgatory(void)
{
int ret;
ret = verify_sha256_digest();
if (ret) {
/* loop forever */
for (;;)
;
}
}
/*
* Defined in order to reuse memcpy() and memset() from
* arch/x86/boot/compressed/string.c
*/
void warn(const char *msg) {}