Imported from linux kernel v5.0.
Signed-off-by: AKASHI Takahiro takahiro.akashi@linaro.org --- include/crypto/public_key.h | 89 +++++ include/keys/asymmetric-type.h | 92 +++++ lib/crypto/Kconfig | 19 + lib/crypto/Makefile | 10 + lib/crypto/asymmetric_type.c | 655 +++++++++++++++++++++++++++++++++ lib/crypto/public_key.c | 344 +++++++++++++++++ 6 files changed, 1209 insertions(+) create mode 100644 include/crypto/public_key.h create mode 100644 include/keys/asymmetric-type.h create mode 100644 lib/crypto/Kconfig create mode 100644 lib/crypto/Makefile create mode 100644 lib/crypto/asymmetric_type.c create mode 100644 lib/crypto/public_key.c
diff --git a/include/crypto/public_key.h b/include/crypto/public_key.h new file mode 100644 index 000000000000..91b1f2615294 --- /dev/null +++ b/include/crypto/public_key.h @@ -0,0 +1,89 @@ +/* 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) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#ifndef _LINUX_PUBLIC_KEY_H +#define _LINUX_PUBLIC_KEY_H + +#ifndef __UBOOT__ +#include <linux/keyctl.h> +#endif +#include <linux/types.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; + 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 */ diff --git a/include/keys/asymmetric-type.h b/include/keys/asymmetric-type.h new file mode 100644 index 000000000000..ac34780cd6a4 --- /dev/null +++ b/include/keys/asymmetric-type.h @@ -0,0 +1,92 @@ +/* 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) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#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 */ diff --git a/lib/crypto/Kconfig b/lib/crypto/Kconfig new file mode 100644 index 000000000000..b8e8288d2f80 --- /dev/null +++ b/lib/crypto/Kconfig @@ -0,0 +1,19 @@ +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 diff --git a/lib/crypto/Makefile b/lib/crypto/Makefile new file mode 100644 index 000000000000..a284de9e0411 --- /dev/null +++ b/lib/crypto/Makefile @@ -0,0 +1,10 @@ +# 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 diff --git a/lib/crypto/asymmetric_type.c b/lib/crypto/asymmetric_type.c new file mode 100644 index 000000000000..905e8b490133 --- /dev/null +++ b/lib/crypto/asymmetric_type.c @@ -0,0 +1,655 @@ +/* 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) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ +#include <crypto/public_key.h> +#include <linux/compat.h> +#include <linux/ctype.h> +#include <linux/string.h> +#include <keys/asymmetric-type.h> + +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); + 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__ */ diff --git a/lib/crypto/public_key.c b/lib/crypto/public_key.c new file mode 100644 index 000000000000..c48f777b06b4 --- /dev/null +++ b/lib/crypto/public_key.c @@ -0,0 +1,344 @@ +/* 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) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#define pr_fmt(fmt) "PKEY: "fmt +#include <linux/compat.h> +#include <linux/kernel.h> +#include <crypto/public_key.h> + +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); + } +} +EXPORT_SYMBOL_GPL(public_key_free); + +/* + * 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); + +#ifndef __UBOOT__ +/* + * 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; +} + +/* + * 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]; + 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); + + if (pkey->key_is_private) + ret = crypto_akcipher_set_priv_key(tfm, + pkey->key, pkey->keylen); + else + ret = crypto_akcipher_set_pub_key(tfm, + pkey->key, pkey->keylen); + if (ret < 0) + goto error_free_tfm; + + 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_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]; + 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; + + if (pkey->key_is_private) + ret = crypto_akcipher_set_priv_key(tfm, + pkey->key, pkey->keylen); + else + ret = crypto_akcipher_set_pub_key(tfm, + pkey->key, pkey->keylen); + if (ret) + goto error_free_req; + + 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_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 sig_sg, digest_sg; + char alg_name[CRYPTO_MAX_ALG_NAME]; + void *output; + unsigned int outlen; + 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; + + if (pkey->key_is_private) + ret = crypto_akcipher_set_priv_key(tfm, + pkey->key, pkey->keylen); + else + ret = crypto_akcipher_set_pub_key(tfm, + pkey->key, pkey->keylen); + if (ret) + goto error_free_req; + + ret = -ENOMEM; + outlen = crypto_akcipher_maxsize(tfm); + output = kmalloc(outlen, GFP_KERNEL); + if (!output) + goto error_free_req; + + sg_init_one(&sig_sg, sig->s, sig->s_size); + sg_init_one(&digest_sg, output, outlen); + akcipher_request_set_crypt(req, &sig_sg, &digest_sg, sig->s_size, + outlen); + 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 verification calculation. This doesn't actually do the + * verification, but rather calculates the hash expected by the + * signature and returns that to us. + */ + ret = crypto_wait_req(crypto_akcipher_verify(req), &cwait); + if (ret) + goto out_free_output; + + /* Do the actual verification step. */ + if (req->dst_len != sig->digest_size || + memcmp(sig->digest, output, sig->digest_size) != 0) + ret = -EKEYREJECTED; + +out_free_output: + kfree(output); +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__ */