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// SPDX-License-Identifier: GPL-2.0
/*
* This file is part of UBIFS.
*
* Copyright (C) 2018 Pengutronix, Sascha Hauer <s.hauer@pengutronix.de>
*/
/*
* This file implements various helper functions for UBIFS authentication support
*/
#include "linux_err.h"
#include "ubifs.h"
#include "sign.h"
#include "defs.h"
int ubifs_shash_init(const struct ubifs_info *c,
__unused struct shash_desc *desc)
{
if (ubifs_authenticated(c))
return hash_digest_init();
else
return 0;
}
int ubifs_shash_update(const struct ubifs_info *c,
__unused struct shash_desc *desc,
const void *buf, unsigned int len)
{
int err = 0;
if (ubifs_authenticated(c)) {
err = hash_digest_update(buf, len);
if (err < 0)
return err;
}
return 0;
}
int ubifs_shash_final(const struct ubifs_info *c,
__unused struct shash_desc *desc, u8 *out)
{
return ubifs_authenticated(c) ? hash_digest_final(out) : 0;
}
struct shash_desc *ubifs_hash_get_desc(const struct ubifs_info *c)
{
int err;
err = ubifs_shash_init(c, NULL);
if (err)
return ERR_PTR(err);
return NULL;
}
/**
* ubifs_node_calc_hash - calculate the hash of a UBIFS node
* @c: UBIFS file-system description object
* @node: the node to calculate a hash for
* @hash: the returned hash
*
* Returns 0 for success or a negative error code otherwise.
*/
int __ubifs_node_calc_hash(__unused const struct ubifs_info *c,
const void *node, u8 *hash)
{
const struct ubifs_ch *ch = node;
return hash_digest(node, le32_to_cpu(ch->len), hash);
}
/**
* ubifs_master_node_calc_hash - calculate the hash of a UBIFS master node
* @node: the node to calculate a hash for
* @hash: the returned hash
*/
int ubifs_master_node_calc_hash(const struct ubifs_info *c, const void *node,
uint8_t *hash)
{
if (!ubifs_authenticated(c))
return 0;
return hash_digest(node + sizeof(struct ubifs_ch),
UBIFS_MST_NODE_SZ - sizeof(struct ubifs_ch), hash);
}
int ubifs_sign_superblock_node(struct ubifs_info *c, void *node)
{
int err, len;
struct ubifs_sig_node *sig = node + UBIFS_SB_NODE_SZ;
if (!ubifs_authenticated(c))
return 0;
err = hash_sign_node(c->auth_key_filename, c->auth_cert_filename, node,
&len, sig + 1);
if (err)
return err;
sig->type = UBIFS_SIGNATURE_TYPE_PKCS7;
sig->len = cpu_to_le32(len);
sig->ch.node_type = UBIFS_SIG_NODE;
return 0;
}
/**
* ubifs_bad_hash - Report hash mismatches
* @c: UBIFS file-system description object
* @node: the node
* @hash: the expected hash
* @lnum: the LEB @node was read from
* @offs: offset in LEB @node was read from
*
* This function reports a hash mismatch when a node has a different hash than
* expected.
*/
void ubifs_bad_hash(const struct ubifs_info *c, const void *node, const u8 *hash,
int lnum, int offs)
{
int len = min(c->hash_len, 20);
int cropped = len != c->hash_len;
const char *cont = cropped ? "..." : "";
u8 calc[UBIFS_HASH_ARR_SZ];
__ubifs_node_calc_hash(c, node, calc);
ubifs_err(c, "hash mismatch on node at LEB %d:%d", lnum, offs);
ubifs_err(c, "hash expected: %*ph%s", len, hash, cont);
ubifs_err(c, "hash calculated: %*ph%s", len, calc, cont);
}
/**
* ubifs_init_authentication - initialize UBIFS authentication support
* @c: UBIFS file-system description object
*
* This function returns 0 for success or a negative error code otherwise.
*/
int ubifs_init_authentication(struct ubifs_info *c)
{
int err, hash_len, hash_algo;
if (!c->auth_key_filename && !c->auth_cert_filename && !c->hash_algo_name)
return 0;
if (!c->auth_key_filename) {
ubifs_err(c, "authentication key not given (--auth-key)");
return -EINVAL;
}
if (!c->hash_algo_name) {
ubifs_err(c, "Hash algorithm not given (--hash-algo)");
return -EINVAL;
}
err = init_authentication(c->hash_algo_name, &hash_len, &hash_algo);
if (err) {
ubifs_err(c, "Init authentication failed");
return err;
}
c->hash_len = hash_len;
c->hash_algo = hash_algo;
c->authenticated = 1;
return 0;
}
void __ubifs_exit_authentication(__unused struct ubifs_info *c)
{
exit_authentication();
}
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