Revision 35cdcbfc5cfc30012b790d9b077bd949ad46f1dd authored by Peng Wang on 26 February 2021, 01:21:44 UTC, committed by Linus Torvalds on 26 February 2021, 17:41:04 UTC
Some max_length wants to hold as large room as possible to ensure enough
size to tackle with the biggest NR_CPUS.  An example below:

kernel/cgroup/cpuset.c:
static struct cftype legacy_files[] = {
        {
                .name = "cpus",
                .seq_show = cpuset_common_seq_show,
                .write = cpuset_write_resmask,
                .max_write_len = (100U + 6 * NR_CPUS),
                .private = FILE_CPULIST,
        },
	...
}

Link: https://lkml.kernel.org/r/5d4998aa8a8ac7efada2c7daffa9e73559f8b186.1609331255.git.rocking@linux.alibaba.com
Signed-off-by: Peng Wang <rocking@linux.alibaba.com>
Acked-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent b5e8736
Raw File
sha1_generic.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Cryptographic API.
 *
 * SHA1 Secure Hash Algorithm.
 *
 * Derived from cryptoapi implementation, adapted for in-place
 * scatterlist interface.
 *
 * Copyright (c) Alan Smithee.
 * Copyright (c) Andrew McDonald <andrew@mcdonald.org.uk>
 * Copyright (c) Jean-Francois Dive <jef@linuxbe.org>
 */
#include <crypto/internal/hash.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/types.h>
#include <crypto/sha1.h>
#include <crypto/sha1_base.h>
#include <asm/byteorder.h>

const u8 sha1_zero_message_hash[SHA1_DIGEST_SIZE] = {
	0xda, 0x39, 0xa3, 0xee, 0x5e, 0x6b, 0x4b, 0x0d,
	0x32, 0x55, 0xbf, 0xef, 0x95, 0x60, 0x18, 0x90,
	0xaf, 0xd8, 0x07, 0x09
};
EXPORT_SYMBOL_GPL(sha1_zero_message_hash);

static void sha1_generic_block_fn(struct sha1_state *sst, u8 const *src,
				  int blocks)
{
	u32 temp[SHA1_WORKSPACE_WORDS];

	while (blocks--) {
		sha1_transform(sst->state, src, temp);
		src += SHA1_BLOCK_SIZE;
	}
	memzero_explicit(temp, sizeof(temp));
}

int crypto_sha1_update(struct shash_desc *desc, const u8 *data,
		       unsigned int len)
{
	return sha1_base_do_update(desc, data, len, sha1_generic_block_fn);
}
EXPORT_SYMBOL(crypto_sha1_update);

static int sha1_final(struct shash_desc *desc, u8 *out)
{
	sha1_base_do_finalize(desc, sha1_generic_block_fn);
	return sha1_base_finish(desc, out);
}

int crypto_sha1_finup(struct shash_desc *desc, const u8 *data,
		      unsigned int len, u8 *out)
{
	sha1_base_do_update(desc, data, len, sha1_generic_block_fn);
	return sha1_final(desc, out);
}
EXPORT_SYMBOL(crypto_sha1_finup);

static struct shash_alg alg = {
	.digestsize	=	SHA1_DIGEST_SIZE,
	.init		=	sha1_base_init,
	.update		=	crypto_sha1_update,
	.final		=	sha1_final,
	.finup		=	crypto_sha1_finup,
	.descsize	=	sizeof(struct sha1_state),
	.base		=	{
		.cra_name	=	"sha1",
		.cra_driver_name=	"sha1-generic",
		.cra_priority	=	100,
		.cra_blocksize	=	SHA1_BLOCK_SIZE,
		.cra_module	=	THIS_MODULE,
	}
};

static int __init sha1_generic_mod_init(void)
{
	return crypto_register_shash(&alg);
}

static void __exit sha1_generic_mod_fini(void)
{
	crypto_unregister_shash(&alg);
}

subsys_initcall(sha1_generic_mod_init);
module_exit(sha1_generic_mod_fini);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("SHA1 Secure Hash Algorithm");

MODULE_ALIAS_CRYPTO("sha1");
MODULE_ALIAS_CRYPTO("sha1-generic");
back to top