lib: crypto: add public key utility

Imported from linux kernel v5.3:
 asymmetric-type.h with changes marked as __UBOOT__
 asymmetric_type.c with changes marked as __UBOOT__
 public_key.h with changes marked as __UBOOT__
 public_key.c with changes marked as __UBOOT__

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
This commit is contained in:
AKASHI Takahiro 2019-11-13 09:44:58 +09:00 committed by Tom Rini
parent a9b45e6e83
commit c4e961ecec
6 changed files with 1251 additions and 0 deletions

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/* SPDX-License-Identifier: GPL-2.0-or-later */
/* Asymmetric public-key algorithm definitions
*
* See Documentation/crypto/asymmetric-keys.txt
*
* Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#ifndef _LINUX_PUBLIC_KEY_H
#define _LINUX_PUBLIC_KEY_H
#ifdef __UBOOT__
#include <linux/types.h>
#else
#include <linux/keyctl.h>
#endif
#include <linux/oid_registry.h>
/*
* Cryptographic data for the public-key subtype of the asymmetric key type.
*
* Note that this may include private part of the key as well as the public
* part.
*/
struct public_key {
void *key;
u32 keylen;
enum OID algo;
void *params;
u32 paramlen;
bool key_is_private;
const char *id_type;
const char *pkey_algo;
};
extern void public_key_free(struct public_key *key);
/*
* Public key cryptography signature data
*/
struct public_key_signature {
struct asymmetric_key_id *auth_ids[2];
u8 *s; /* Signature */
u32 s_size; /* Number of bytes in signature */
u8 *digest;
u8 digest_size; /* Number of bytes in digest */
const char *pkey_algo;
const char *hash_algo;
const char *encoding;
};
extern void public_key_signature_free(struct public_key_signature *sig);
#ifndef __UBOOT__
extern struct asymmetric_key_subtype public_key_subtype;
struct key;
struct key_type;
union key_payload;
extern int restrict_link_by_signature(struct key *dest_keyring,
const struct key_type *type,
const union key_payload *payload,
struct key *trust_keyring);
extern int restrict_link_by_key_or_keyring(struct key *dest_keyring,
const struct key_type *type,
const union key_payload *payload,
struct key *trusted);
extern int restrict_link_by_key_or_keyring_chain(struct key *trust_keyring,
const struct key_type *type,
const union key_payload *payload,
struct key *trusted);
extern int query_asymmetric_key(const struct kernel_pkey_params *,
struct kernel_pkey_query *);
extern int encrypt_blob(struct kernel_pkey_params *, const void *, void *);
extern int decrypt_blob(struct kernel_pkey_params *, const void *, void *);
extern int create_signature(struct kernel_pkey_params *, const void *, void *);
extern int verify_signature(const struct key *,
const struct public_key_signature *);
int public_key_verify_signature(const struct public_key *pkey,
const struct public_key_signature *sig);
#endif /* !__UBOOT__ */
#endif /* _LINUX_PUBLIC_KEY_H */

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/* SPDX-License-Identifier: GPL-2.0-or-later */
/* Asymmetric Public-key cryptography key type interface
*
* See Documentation/crypto/asymmetric-keys.txt
*
* Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#ifndef _KEYS_ASYMMETRIC_TYPE_H
#define _KEYS_ASYMMETRIC_TYPE_H
#ifndef __UBOOT__
#include <linux/key-type.h>
#include <linux/verification.h>
extern struct key_type key_type_asymmetric;
/*
* The key payload is four words. The asymmetric-type key uses them as
* follows:
*/
enum asymmetric_payload_bits {
asym_crypto, /* The data representing the key */
asym_subtype, /* Pointer to an asymmetric_key_subtype struct */
asym_key_ids, /* Pointer to an asymmetric_key_ids struct */
asym_auth /* The key's authorisation (signature, parent key ID) */
};
#endif /* !__UBOOT__ */
/*
* Identifiers for an asymmetric key ID. We have three ways of looking up a
* key derived from an X.509 certificate:
*
* (1) Serial Number & Issuer. Non-optional. This is the only valid way to
* map a PKCS#7 signature to an X.509 certificate.
*
* (2) Issuer & Subject Unique IDs. Optional. These were the original way to
* match X.509 certificates, but have fallen into disuse in favour of (3).
*
* (3) Auth & Subject Key Identifiers. Optional. SKIDs are only provided on
* CA keys that are intended to sign other keys, so don't appear in end
* user certificates unless forced.
*
* We could also support an PGP key identifier, which is just a SHA1 sum of the
* public key and certain parameters, but since we don't support PGP keys at
* the moment, we shall ignore those.
*
* What we actually do is provide a place where binary identifiers can be
* stashed and then compare against them when checking for an id match.
*/
struct asymmetric_key_id {
unsigned short len;
unsigned char data[];
};
struct asymmetric_key_ids {
void *id[2];
};
extern bool asymmetric_key_id_same(const struct asymmetric_key_id *kid1,
const struct asymmetric_key_id *kid2);
extern bool asymmetric_key_id_partial(const struct asymmetric_key_id *kid1,
const struct asymmetric_key_id *kid2);
extern struct asymmetric_key_id *asymmetric_key_generate_id(const void *val_1,
size_t len_1,
const void *val_2,
size_t len_2);
#ifndef __UBOOT__
static inline
const struct asymmetric_key_ids *asymmetric_key_ids(const struct key *key)
{
return key->payload.data[asym_key_ids];
}
extern struct key *find_asymmetric_key(struct key *keyring,
const struct asymmetric_key_id *id_0,
const struct asymmetric_key_id *id_1,
bool partial);
#endif
/*
* The payload is at the discretion of the subtype.
*/
#endif /* _KEYS_ASYMMETRIC_TYPE_H */

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lib/crypto/Kconfig Normal file
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menuconfig ASYMMETRIC_KEY_TYPE
bool "Asymmetric (public-key cryptographic) key Support"
help
This option provides support for a key type that holds the data for
the asymmetric keys used for public key cryptographic operations such
as encryption, decryption, signature generation and signature
verification.
if ASYMMETRIC_KEY_TYPE
config ASYMMETRIC_PUBLIC_KEY_SUBTYPE
bool "Asymmetric public-key crypto algorithm subtype"
help
This option provides support for asymmetric public key type handling.
If signature generation and/or verification are to be used,
appropriate hash algorithms (such as SHA-1) must be available.
ENOPKG will be reported if the requisite algorithm is unavailable.
endif # ASYMMETRIC_KEY_TYPE

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lib/crypto/Makefile Normal file
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# SPDX-License-Identifier: GPL-2.0+
#
# Makefile for asymmetric cryptographic keys
#
obj-$(CONFIG_ASYMMETRIC_KEY_TYPE) += asymmetric_keys.o
asymmetric_keys-y := asymmetric_type.o
obj-$(CONFIG_ASYMMETRIC_PUBLIC_KEY_SUBTYPE) += public_key.o

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// SPDX-License-Identifier: GPL-2.0-or-later
/* Asymmetric public-key cryptography key type
*
* See Documentation/crypto/asymmetric-keys.txt
*
* Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#ifndef __UBOOT__
#include <keys/asymmetric-subtype.h>
#include <keys/asymmetric-parser.h>
#endif
#include <crypto/public_key.h>
#ifdef __UBOOT__
#include <linux/compat.h>
#include <linux/ctype.h>
#include <linux/string.h>
#else
#include <linux/seq_file.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/ctype.h>
#endif
#ifdef __UBOOT__
#include <keys/asymmetric-type.h>
#else
#include <keys/system_keyring.h>
#include <keys/user-type.h>
#include "asymmetric_keys.h"
#endif
MODULE_LICENSE("GPL");
#ifndef __UBOOT__
const char *const key_being_used_for[NR__KEY_BEING_USED_FOR] = {
[VERIFYING_MODULE_SIGNATURE] = "mod sig",
[VERIFYING_FIRMWARE_SIGNATURE] = "firmware sig",
[VERIFYING_KEXEC_PE_SIGNATURE] = "kexec PE sig",
[VERIFYING_KEY_SIGNATURE] = "key sig",
[VERIFYING_KEY_SELF_SIGNATURE] = "key self sig",
[VERIFYING_UNSPECIFIED_SIGNATURE] = "unspec sig",
};
EXPORT_SYMBOL_GPL(key_being_used_for);
static LIST_HEAD(asymmetric_key_parsers);
static DECLARE_RWSEM(asymmetric_key_parsers_sem);
/**
* find_asymmetric_key - Find a key by ID.
* @keyring: The keys to search.
* @id_0: The first ID to look for or NULL.
* @id_1: The second ID to look for or NULL.
* @partial: Use partial match if true, exact if false.
*
* Find a key in the given keyring by identifier. The preferred identifier is
* the id_0 and the fallback identifier is the id_1. If both are given, the
* lookup is by the former, but the latter must also match.
*/
struct key *find_asymmetric_key(struct key *keyring,
const struct asymmetric_key_id *id_0,
const struct asymmetric_key_id *id_1,
bool partial)
{
struct key *key;
key_ref_t ref;
const char *lookup;
char *req, *p;
int len;
BUG_ON(!id_0 && !id_1);
if (id_0) {
lookup = id_0->data;
len = id_0->len;
} else {
lookup = id_1->data;
len = id_1->len;
}
/* Construct an identifier "id:<keyid>". */
p = req = kmalloc(2 + 1 + len * 2 + 1, GFP_KERNEL);
if (!req)
return ERR_PTR(-ENOMEM);
if (partial) {
*p++ = 'i';
*p++ = 'd';
} else {
*p++ = 'e';
*p++ = 'x';
}
*p++ = ':';
p = bin2hex(p, lookup, len);
*p = 0;
pr_debug("Look up: \"%s\"\n", req);
ref = keyring_search(make_key_ref(keyring, 1),
&key_type_asymmetric, req, true);
if (IS_ERR(ref))
pr_debug("Request for key '%s' err %ld\n", req, PTR_ERR(ref));
kfree(req);
if (IS_ERR(ref)) {
switch (PTR_ERR(ref)) {
/* Hide some search errors */
case -EACCES:
case -ENOTDIR:
case -EAGAIN:
return ERR_PTR(-ENOKEY);
default:
return ERR_CAST(ref);
}
}
key = key_ref_to_ptr(ref);
if (id_0 && id_1) {
const struct asymmetric_key_ids *kids = asymmetric_key_ids(key);
if (!kids->id[1]) {
pr_debug("First ID matches, but second is missing\n");
goto reject;
}
if (!asymmetric_key_id_same(id_1, kids->id[1])) {
pr_debug("First ID matches, but second does not\n");
goto reject;
}
}
pr_devel("<==%s() = 0 [%x]\n", __func__, key_serial(key));
return key;
reject:
key_put(key);
return ERR_PTR(-EKEYREJECTED);
}
EXPORT_SYMBOL_GPL(find_asymmetric_key);
#endif /* !__UBOOT__ */
/**
* asymmetric_key_generate_id: Construct an asymmetric key ID
* @val_1: First binary blob
* @len_1: Length of first binary blob
* @val_2: Second binary blob
* @len_2: Length of second binary blob
*
* Construct an asymmetric key ID from a pair of binary blobs.
*/
struct asymmetric_key_id *asymmetric_key_generate_id(const void *val_1,
size_t len_1,
const void *val_2,
size_t len_2)
{
struct asymmetric_key_id *kid;
kid = kmalloc(sizeof(struct asymmetric_key_id) + len_1 + len_2,
GFP_KERNEL);
if (!kid)
return ERR_PTR(-ENOMEM);
kid->len = len_1 + len_2;
memcpy(kid->data, val_1, len_1);
memcpy(kid->data + len_1, val_2, len_2);
return kid;
}
EXPORT_SYMBOL_GPL(asymmetric_key_generate_id);
/**
* asymmetric_key_id_same - Return true if two asymmetric keys IDs are the same.
* @kid_1, @kid_2: The key IDs to compare
*/
bool asymmetric_key_id_same(const struct asymmetric_key_id *kid1,
const struct asymmetric_key_id *kid2)
{
if (!kid1 || !kid2)
return false;
if (kid1->len != kid2->len)
return false;
return memcmp(kid1->data, kid2->data, kid1->len) == 0;
}
EXPORT_SYMBOL_GPL(asymmetric_key_id_same);
/**
* asymmetric_key_id_partial - Return true if two asymmetric keys IDs
* partially match
* @kid_1, @kid_2: The key IDs to compare
*/
bool asymmetric_key_id_partial(const struct asymmetric_key_id *kid1,
const struct asymmetric_key_id *kid2)
{
if (!kid1 || !kid2)
return false;
if (kid1->len < kid2->len)
return false;
return memcmp(kid1->data + (kid1->len - kid2->len),
kid2->data, kid2->len) == 0;
}
EXPORT_SYMBOL_GPL(asymmetric_key_id_partial);
#ifndef __UBOOT__
/**
* asymmetric_match_key_ids - Search asymmetric key IDs
* @kids: The list of key IDs to check
* @match_id: The key ID we're looking for
* @match: The match function to use
*/
static bool asymmetric_match_key_ids(
const struct asymmetric_key_ids *kids,
const struct asymmetric_key_id *match_id,
bool (*match)(const struct asymmetric_key_id *kid1,
const struct asymmetric_key_id *kid2))
{
int i;
if (!kids || !match_id)
return false;
for (i = 0; i < ARRAY_SIZE(kids->id); i++)
if (match(kids->id[i], match_id))
return true;
return false;
}
/* helper function can be called directly with pre-allocated memory */
inline int __asymmetric_key_hex_to_key_id(const char *id,
struct asymmetric_key_id *match_id,
size_t hexlen)
{
match_id->len = hexlen;
return hex2bin(match_id->data, id, hexlen);
}
/**
* asymmetric_key_hex_to_key_id - Convert a hex string into a key ID.
* @id: The ID as a hex string.
*/
struct asymmetric_key_id *asymmetric_key_hex_to_key_id(const char *id)
{
struct asymmetric_key_id *match_id;
size_t asciihexlen;
int ret;
if (!*id)
return ERR_PTR(-EINVAL);
asciihexlen = strlen(id);
if (asciihexlen & 1)
return ERR_PTR(-EINVAL);
match_id = kmalloc(sizeof(struct asymmetric_key_id) + asciihexlen / 2,
GFP_KERNEL);
if (!match_id)
return ERR_PTR(-ENOMEM);
ret = __asymmetric_key_hex_to_key_id(id, match_id, asciihexlen / 2);
if (ret < 0) {
kfree(match_id);
return ERR_PTR(-EINVAL);
}
return match_id;
}
/*
* Match asymmetric keys by an exact match on an ID.
*/
static bool asymmetric_key_cmp(const struct key *key,
const struct key_match_data *match_data)
{
const struct asymmetric_key_ids *kids = asymmetric_key_ids(key);
const struct asymmetric_key_id *match_id = match_data->preparsed;
return asymmetric_match_key_ids(kids, match_id,
asymmetric_key_id_same);
}
/*
* Match asymmetric keys by a partial match on an IDs.
*/
static bool asymmetric_key_cmp_partial(const struct key *key,
const struct key_match_data *match_data)
{
const struct asymmetric_key_ids *kids = asymmetric_key_ids(key);
const struct asymmetric_key_id *match_id = match_data->preparsed;
return asymmetric_match_key_ids(kids, match_id,
asymmetric_key_id_partial);
}
/*
* Preparse the match criterion. If we don't set lookup_type and cmp,
* the default will be an exact match on the key description.
*
* There are some specifiers for matching key IDs rather than by the key
* description:
*
* "id:<id>" - find a key by partial match on any available ID
* "ex:<id>" - find a key by exact match on any available ID
*
* These have to be searched by iteration rather than by direct lookup because
* the key is hashed according to its description.
*/
static int asymmetric_key_match_preparse(struct key_match_data *match_data)
{
struct asymmetric_key_id *match_id;
const char *spec = match_data->raw_data;
const char *id;
bool (*cmp)(const struct key *, const struct key_match_data *) =
asymmetric_key_cmp;
if (!spec || !*spec)
return -EINVAL;
if (spec[0] == 'i' &&
spec[1] == 'd' &&
spec[2] == ':') {
id = spec + 3;
cmp = asymmetric_key_cmp_partial;
} else if (spec[0] == 'e' &&
spec[1] == 'x' &&
spec[2] == ':') {
id = spec + 3;
} else {
goto default_match;
}
match_id = asymmetric_key_hex_to_key_id(id);
if (IS_ERR(match_id))
return PTR_ERR(match_id);
match_data->preparsed = match_id;
match_data->cmp = cmp;
match_data->lookup_type = KEYRING_SEARCH_LOOKUP_ITERATE;
return 0;
default_match:
return 0;
}
/*
* Free the preparsed the match criterion.
*/
static void asymmetric_key_match_free(struct key_match_data *match_data)
{
kfree(match_data->preparsed);
}
/*
* Describe the asymmetric key
*/
static void asymmetric_key_describe(const struct key *key, struct seq_file *m)
{
const struct asymmetric_key_subtype *subtype = asymmetric_key_subtype(key);
const struct asymmetric_key_ids *kids = asymmetric_key_ids(key);
const struct asymmetric_key_id *kid;
const unsigned char *p;
int n;
seq_puts(m, key->description);
if (subtype) {
seq_puts(m, ": ");
subtype->describe(key, m);
if (kids && kids->id[1]) {
kid = kids->id[1];
seq_putc(m, ' ');
n = kid->len;
p = kid->data;
if (n > 4) {
p += n - 4;
n = 4;
}
seq_printf(m, "%*phN", n, p);
}
seq_puts(m, " [");
/* put something here to indicate the key's capabilities */
seq_putc(m, ']');
}
}
/*
* Preparse a asymmetric payload to get format the contents appropriately for the
* internal payload to cut down on the number of scans of the data performed.
*
* We also generate a proposed description from the contents of the key that
* can be used to name the key if the user doesn't want to provide one.
*/
static int asymmetric_key_preparse(struct key_preparsed_payload *prep)
{
struct asymmetric_key_parser *parser;
int ret;
pr_devel("==>%s()\n", __func__);
if (prep->datalen == 0)
return -EINVAL;
down_read(&asymmetric_key_parsers_sem);
ret = -EBADMSG;
list_for_each_entry(parser, &asymmetric_key_parsers, link) {
pr_debug("Trying parser '%s'\n", parser->name);
ret = parser->parse(prep);
if (ret != -EBADMSG) {
pr_debug("Parser recognised the format (ret %d)\n",
ret);
break;
}
}
up_read(&asymmetric_key_parsers_sem);
pr_devel("<==%s() = %d\n", __func__, ret);
return ret;
}
/*
* Clean up the key ID list
*/
static void asymmetric_key_free_kids(struct asymmetric_key_ids *kids)
{
int i;
if (kids) {
for (i = 0; i < ARRAY_SIZE(kids->id); i++)
kfree(kids->id[i]);
kfree(kids);
}
}
/*
* Clean up the preparse data
*/
static void asymmetric_key_free_preparse(struct key_preparsed_payload *prep)
{
struct asymmetric_key_subtype *subtype = prep->payload.data[asym_subtype];
struct asymmetric_key_ids *kids = prep->payload.data[asym_key_ids];
pr_devel("==>%s()\n", __func__);
if (subtype) {
subtype->destroy(prep->payload.data[asym_crypto],
prep->payload.data[asym_auth]);
module_put(subtype->owner);
}
asymmetric_key_free_kids(kids);
kfree(prep->description);
}
/*
* dispose of the data dangling from the corpse of a asymmetric key
*/
static void asymmetric_key_destroy(struct key *key)
{
struct asymmetric_key_subtype *subtype = asymmetric_key_subtype(key);
struct asymmetric_key_ids *kids = key->payload.data[asym_key_ids];
void *data = key->payload.data[asym_crypto];
void *auth = key->payload.data[asym_auth];
key->payload.data[asym_crypto] = NULL;
key->payload.data[asym_subtype] = NULL;
key->payload.data[asym_key_ids] = NULL;
key->payload.data[asym_auth] = NULL;
if (subtype) {
subtype->destroy(data, auth);
module_put(subtype->owner);
}
asymmetric_key_free_kids(kids);
}
static struct key_restriction *asymmetric_restriction_alloc(
key_restrict_link_func_t check,
struct key *key)
{
struct key_restriction *keyres =
kzalloc(sizeof(struct key_restriction), GFP_KERNEL);
if (!keyres)
return ERR_PTR(-ENOMEM);
keyres->check = check;
keyres->key = key;
keyres->keytype = &key_type_asymmetric;
return keyres;
}
/*
* look up keyring restrict functions for asymmetric keys
*/
static struct key_restriction *asymmetric_lookup_restriction(
const char *restriction)
{
char *restrict_method;
char *parse_buf;
char *next;
struct key_restriction *ret = ERR_PTR(-EINVAL);
if (strcmp("builtin_trusted", restriction) == 0)
return asymmetric_restriction_alloc(
restrict_link_by_builtin_trusted, NULL);
if (strcmp("builtin_and_secondary_trusted", restriction) == 0)
return asymmetric_restriction_alloc(
restrict_link_by_builtin_and_secondary_trusted, NULL);
parse_buf = kstrndup(restriction, PAGE_SIZE, GFP_KERNEL);
if (!parse_buf)
return ERR_PTR(-ENOMEM);
next = parse_buf;
restrict_method = strsep(&next, ":");
if ((strcmp(restrict_method, "key_or_keyring") == 0) && next) {
char *key_text;
key_serial_t serial;
struct key *key;
key_restrict_link_func_t link_fn =
restrict_link_by_key_or_keyring;
bool allow_null_key = false;
key_text = strsep(&next, ":");
if (next) {
if (strcmp(next, "chain") != 0)
goto out;
link_fn = restrict_link_by_key_or_keyring_chain;
allow_null_key = true;
}
if (kstrtos32(key_text, 0, &serial) < 0)
goto out;
if ((serial == 0) && allow_null_key) {
key = NULL;
} else {
key = key_lookup(serial);
if (IS_ERR(key)) {
ret = ERR_CAST(key);
goto out;
}
}
ret = asymmetric_restriction_alloc(link_fn, key);
if (IS_ERR(ret))
key_put(key);
}
out:
kfree(parse_buf);
return ret;
}
int asymmetric_key_eds_op(struct kernel_pkey_params *params,
const void *in, void *out)
{
const struct asymmetric_key_subtype *subtype;
struct key *key = params->key;
int ret;
pr_devel("==>%s()\n", __func__);
if (key->type != &key_type_asymmetric)
return -EINVAL;
subtype = asymmetric_key_subtype(key);
if (!subtype ||
!key->payload.data[0])
return -EINVAL;
if (!subtype->eds_op)
return -ENOTSUPP;
ret = subtype->eds_op(params, in, out);
pr_devel("<==%s() = %d\n", __func__, ret);
return ret;
}
static int asymmetric_key_verify_signature(struct kernel_pkey_params *params,
const void *in, const void *in2)
{
struct public_key_signature sig = {
.s_size = params->in2_len,
.digest_size = params->in_len,
.encoding = params->encoding,
.hash_algo = params->hash_algo,
.digest = (void *)in,
.s = (void *)in2,
};
return verify_signature(params->key, &sig);
}
struct key_type key_type_asymmetric = {
.name = "asymmetric",
.preparse = asymmetric_key_preparse,
.free_preparse = asymmetric_key_free_preparse,
.instantiate = generic_key_instantiate,
.match_preparse = asymmetric_key_match_preparse,
.match_free = asymmetric_key_match_free,
.destroy = asymmetric_key_destroy,
.describe = asymmetric_key_describe,
.lookup_restriction = asymmetric_lookup_restriction,
.asym_query = query_asymmetric_key,
.asym_eds_op = asymmetric_key_eds_op,
.asym_verify_signature = asymmetric_key_verify_signature,
};
EXPORT_SYMBOL_GPL(key_type_asymmetric);
/**
* register_asymmetric_key_parser - Register a asymmetric key blob parser
* @parser: The parser to register
*/
int register_asymmetric_key_parser(struct asymmetric_key_parser *parser)
{
struct asymmetric_key_parser *cursor;
int ret;
down_write(&asymmetric_key_parsers_sem);
list_for_each_entry(cursor, &asymmetric_key_parsers, link) {
if (strcmp(cursor->name, parser->name) == 0) {
pr_err("Asymmetric key parser '%s' already registered\n",
parser->name);
ret = -EEXIST;
goto out;
}
}
list_add_tail(&parser->link, &asymmetric_key_parsers);
pr_notice("Asymmetric key parser '%s' registered\n", parser->name);
ret = 0;
out:
up_write(&asymmetric_key_parsers_sem);
return ret;
}
EXPORT_SYMBOL_GPL(register_asymmetric_key_parser);
/**
* unregister_asymmetric_key_parser - Unregister a asymmetric key blob parser
* @parser: The parser to unregister
*/
void unregister_asymmetric_key_parser(struct asymmetric_key_parser *parser)
{
down_write(&asymmetric_key_parsers_sem);
list_del(&parser->link);
up_write(&asymmetric_key_parsers_sem);
pr_notice("Asymmetric key parser '%s' unregistered\n", parser->name);
}
EXPORT_SYMBOL_GPL(unregister_asymmetric_key_parser);
/*
* Module stuff
*/
static int __init asymmetric_key_init(void)
{
return register_key_type(&key_type_asymmetric);
}
static void __exit asymmetric_key_cleanup(void)
{
unregister_key_type(&key_type_asymmetric);
}
module_init(asymmetric_key_init);
module_exit(asymmetric_key_cleanup);
#endif /* !__UBOOT__ */

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lib/crypto/public_key.c Normal file
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// SPDX-License-Identifier: GPL-2.0-or-later
/* In-software asymmetric public-key crypto subtype
*
* See Documentation/crypto/asymmetric-keys.txt
*
* Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#define pr_fmt(fmt) "PKEY: "fmt
#ifdef __UBOOT__
#include <linux/compat.h>
#else
#include <linux/module.h>
#include <linux/export.h>
#endif
#include <linux/kernel.h>
#ifndef __UBOOT__
#include <linux/slab.h>
#include <linux/seq_file.h>
#include <linux/scatterlist.h>
#include <keys/asymmetric-subtype.h>
#endif
#include <crypto/public_key.h>
#ifndef __UBOOT__
#include <crypto/akcipher.h>
#endif
MODULE_DESCRIPTION("In-software asymmetric public-key subtype");
MODULE_AUTHOR("Red Hat, Inc.");
MODULE_LICENSE("GPL");
#ifndef __UBOOT__
/*
* Provide a part of a description of the key for /proc/keys.
*/
static void public_key_describe(const struct key *asymmetric_key,
struct seq_file *m)
{
struct public_key *key = asymmetric_key->payload.data[asym_crypto];
if (key)
seq_printf(m, "%s.%s", key->id_type, key->pkey_algo);
}
#endif
/*
* Destroy a public key algorithm key.
*/
void public_key_free(struct public_key *key)
{
if (key) {
kfree(key->key);
kfree(key->params);
kfree(key);
}
}
EXPORT_SYMBOL_GPL(public_key_free);
#ifdef __UBOOT__
/*
* from <linux>/crypto/asymmetric_keys/signature.c
*
* Destroy a public key signature.
*/
void public_key_signature_free(struct public_key_signature *sig)
{
int i;
if (sig) {
for (i = 0; i < ARRAY_SIZE(sig->auth_ids); i++)
free(sig->auth_ids[i]);
free(sig->s);
free(sig->digest);
free(sig);
}
}
EXPORT_SYMBOL_GPL(public_key_signature_free);
#else
/*
* Destroy a public key algorithm key.
*/
static void public_key_destroy(void *payload0, void *payload3)
{
public_key_free(payload0);
public_key_signature_free(payload3);
}
/*
* Determine the crypto algorithm name.
*/
static
int software_key_determine_akcipher(const char *encoding,
const char *hash_algo,
const struct public_key *pkey,
char alg_name[CRYPTO_MAX_ALG_NAME])
{
int n;
if (strcmp(encoding, "pkcs1") == 0) {
/* The data wangled by the RSA algorithm is typically padded
* and encoded in some manner, such as EMSA-PKCS1-1_5 [RFC3447
* sec 8.2].
*/
if (!hash_algo)
n = snprintf(alg_name, CRYPTO_MAX_ALG_NAME,
"pkcs1pad(%s)",
pkey->pkey_algo);
else
n = snprintf(alg_name, CRYPTO_MAX_ALG_NAME,
"pkcs1pad(%s,%s)",
pkey->pkey_algo, hash_algo);
return n >= CRYPTO_MAX_ALG_NAME ? -EINVAL : 0;
}
if (strcmp(encoding, "raw") == 0) {
strcpy(alg_name, pkey->pkey_algo);
return 0;
}
return -ENOPKG;
}
static u8 *pkey_pack_u32(u8 *dst, u32 val)
{
memcpy(dst, &val, sizeof(val));
return dst + sizeof(val);
}
/*
* Query information about a key.
*/
static int software_key_query(const struct kernel_pkey_params *params,
struct kernel_pkey_query *info)
{
struct crypto_akcipher *tfm;
struct public_key *pkey = params->key->payload.data[asym_crypto];
char alg_name[CRYPTO_MAX_ALG_NAME];
u8 *key, *ptr;
int ret, len;
ret = software_key_determine_akcipher(params->encoding,
params->hash_algo,
pkey, alg_name);
if (ret < 0)
return ret;
tfm = crypto_alloc_akcipher(alg_name, 0, 0);
if (IS_ERR(tfm))
return PTR_ERR(tfm);
key = kmalloc(pkey->keylen + sizeof(u32) * 2 + pkey->paramlen,
GFP_KERNEL);
if (!key)
goto error_free_tfm;
memcpy(key, pkey->key, pkey->keylen);
ptr = key + pkey->keylen;
ptr = pkey_pack_u32(ptr, pkey->algo);
ptr = pkey_pack_u32(ptr, pkey->paramlen);
memcpy(ptr, pkey->params, pkey->paramlen);
if (pkey->key_is_private)
ret = crypto_akcipher_set_priv_key(tfm, key, pkey->keylen);
else
ret = crypto_akcipher_set_pub_key(tfm, key, pkey->keylen);
if (ret < 0)
goto error_free_key;
len = crypto_akcipher_maxsize(tfm);
info->key_size = len * 8;
info->max_data_size = len;
info->max_sig_size = len;
info->max_enc_size = len;
info->max_dec_size = len;
info->supported_ops = (KEYCTL_SUPPORTS_ENCRYPT |
KEYCTL_SUPPORTS_VERIFY);
if (pkey->key_is_private)
info->supported_ops |= (KEYCTL_SUPPORTS_DECRYPT |
KEYCTL_SUPPORTS_SIGN);
ret = 0;
error_free_key:
kfree(key);
error_free_tfm:
crypto_free_akcipher(tfm);
pr_devel("<==%s() = %d\n", __func__, ret);
return ret;
}
/*
* Do encryption, decryption and signing ops.
*/
static int software_key_eds_op(struct kernel_pkey_params *params,
const void *in, void *out)
{
const struct public_key *pkey = params->key->payload.data[asym_crypto];
struct akcipher_request *req;
struct crypto_akcipher *tfm;
struct crypto_wait cwait;
struct scatterlist in_sg, out_sg;
char alg_name[CRYPTO_MAX_ALG_NAME];
char *key, *ptr;
int ret;
pr_devel("==>%s()\n", __func__);
ret = software_key_determine_akcipher(params->encoding,
params->hash_algo,
pkey, alg_name);
if (ret < 0)
return ret;
tfm = crypto_alloc_akcipher(alg_name, 0, 0);
if (IS_ERR(tfm))
return PTR_ERR(tfm);
req = akcipher_request_alloc(tfm, GFP_KERNEL);
if (!req)
goto error_free_tfm;
key = kmalloc(pkey->keylen + sizeof(u32) * 2 + pkey->paramlen,
GFP_KERNEL);
if (!key)
goto error_free_req;
memcpy(key, pkey->key, pkey->keylen);
ptr = key + pkey->keylen;
ptr = pkey_pack_u32(ptr, pkey->algo);
ptr = pkey_pack_u32(ptr, pkey->paramlen);
memcpy(ptr, pkey->params, pkey->paramlen);
if (pkey->key_is_private)
ret = crypto_akcipher_set_priv_key(tfm, key, pkey->keylen);
else
ret = crypto_akcipher_set_pub_key(tfm, key, pkey->keylen);
if (ret)
goto error_free_key;
sg_init_one(&in_sg, in, params->in_len);
sg_init_one(&out_sg, out, params->out_len);
akcipher_request_set_crypt(req, &in_sg, &out_sg, params->in_len,
params->out_len);
crypto_init_wait(&cwait);
akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
CRYPTO_TFM_REQ_MAY_SLEEP,
crypto_req_done, &cwait);
/* Perform the encryption calculation. */
switch (params->op) {
case kernel_pkey_encrypt:
ret = crypto_akcipher_encrypt(req);
break;
case kernel_pkey_decrypt:
ret = crypto_akcipher_decrypt(req);
break;
case kernel_pkey_sign:
ret = crypto_akcipher_sign(req);
break;
default:
BUG();
}
ret = crypto_wait_req(ret, &cwait);
if (ret == 0)
ret = req->dst_len;
error_free_key:
kfree(key);
error_free_req:
akcipher_request_free(req);
error_free_tfm:
crypto_free_akcipher(tfm);
pr_devel("<==%s() = %d\n", __func__, ret);
return ret;
}
/*
* Verify a signature using a public key.
*/
int public_key_verify_signature(const struct public_key *pkey,
const struct public_key_signature *sig)
{
struct crypto_wait cwait;
struct crypto_akcipher *tfm;
struct akcipher_request *req;
struct scatterlist src_sg[2];
char alg_name[CRYPTO_MAX_ALG_NAME];
char *key, *ptr;
int ret;
pr_devel("==>%s()\n", __func__);
BUG_ON(!pkey);
BUG_ON(!sig);
BUG_ON(!sig->s);
ret = software_key_determine_akcipher(sig->encoding,
sig->hash_algo,
pkey, alg_name);
if (ret < 0)
return ret;
tfm = crypto_alloc_akcipher(alg_name, 0, 0);
if (IS_ERR(tfm))
return PTR_ERR(tfm);
ret = -ENOMEM;
req = akcipher_request_alloc(tfm, GFP_KERNEL);
if (!req)
goto error_free_tfm;
key = kmalloc(pkey->keylen + sizeof(u32) * 2 + pkey->paramlen,
GFP_KERNEL);
if (!key)
goto error_free_req;
memcpy(key, pkey->key, pkey->keylen);
ptr = key + pkey->keylen;
ptr = pkey_pack_u32(ptr, pkey->algo);
ptr = pkey_pack_u32(ptr, pkey->paramlen);
memcpy(ptr, pkey->params, pkey->paramlen);
if (pkey->key_is_private)
ret = crypto_akcipher_set_priv_key(tfm, key, pkey->keylen);
else
ret = crypto_akcipher_set_pub_key(tfm, key, pkey->keylen);
if (ret)
goto error_free_key;
sg_init_table(src_sg, 2);
sg_set_buf(&src_sg[0], sig->s, sig->s_size);
sg_set_buf(&src_sg[1], sig->digest, sig->digest_size);
akcipher_request_set_crypt(req, src_sg, NULL, sig->s_size,
sig->digest_size);
crypto_init_wait(&cwait);
akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
CRYPTO_TFM_REQ_MAY_SLEEP,
crypto_req_done, &cwait);
ret = crypto_wait_req(crypto_akcipher_verify(req), &cwait);
error_free_key:
kfree(key);
error_free_req:
akcipher_request_free(req);
error_free_tfm:
crypto_free_akcipher(tfm);
pr_devel("<==%s() = %d\n", __func__, ret);
if (WARN_ON_ONCE(ret > 0))
ret = -EINVAL;
return ret;
}
EXPORT_SYMBOL_GPL(public_key_verify_signature);
static int public_key_verify_signature_2(const struct key *key,
const struct public_key_signature *sig)
{
const struct public_key *pk = key->payload.data[asym_crypto];
return public_key_verify_signature(pk, sig);
}
/*
* Public key algorithm asymmetric key subtype
*/
struct asymmetric_key_subtype public_key_subtype = {
.owner = THIS_MODULE,
.name = "public_key",
.name_len = sizeof("public_key") - 1,
.describe = public_key_describe,
.destroy = public_key_destroy,
.query = software_key_query,
.eds_op = software_key_eds_op,
.verify_signature = public_key_verify_signature_2,
};
EXPORT_SYMBOL_GPL(public_key_subtype);
#endif /* !__UBOOT__ */