From f1b731dbc2530cab93fcfc5fcb18c9f3a100feeb Mon Sep 17 00:00:00 2001 From: Dmitry Kasatkin Date: Mon, 6 Oct 2014 15:21:05 +0100 Subject: [PATCH] KEYS: Restore partial ID matching functionality for asymmetric keys Bring back the functionality whereby an asymmetric key can be matched with a partial match on one of its IDs. Whilst we're at it, allow for the possibility of having an increased number of IDs. Reported-by: Dmitry Kasatkin Signed-off-by: Dmitry Kasatkin Signed-off-by: David Howells --- crypto/asymmetric_keys/asymmetric_keys.h | 3 - crypto/asymmetric_keys/asymmetric_type.c | 70 +++++++++++++++++++----- crypto/asymmetric_keys/pkcs7_trust.c | 9 ++- crypto/asymmetric_keys/x509_public_key.c | 18 ++++-- include/crypto/public_key.h | 3 +- include/keys/asymmetric-type.h | 3 + 6 files changed, 81 insertions(+), 25 deletions(-) diff --git a/crypto/asymmetric_keys/asymmetric_keys.h b/crypto/asymmetric_keys/asymmetric_keys.h index fd21ac28e0a0..f97330886d58 100644 --- a/crypto/asymmetric_keys/asymmetric_keys.h +++ b/crypto/asymmetric_keys/asymmetric_keys.h @@ -9,9 +9,6 @@ * 2 of the Licence, or (at your option) any later version. */ -extern bool asymmetric_match_key_ids(const struct asymmetric_key_ids *kids, - const struct asymmetric_key_id *match_id); - extern struct asymmetric_key_id *asymmetric_key_hex_to_key_id(const char *id); static inline diff --git a/crypto/asymmetric_keys/asymmetric_type.c b/crypto/asymmetric_keys/asymmetric_type.c index 29983cbb658d..052e944bb109 100644 --- a/crypto/asymmetric_keys/asymmetric_type.c +++ b/crypto/asymmetric_keys/asymmetric_type.c @@ -65,23 +65,44 @@ bool asymmetric_key_id_same(const struct asymmetric_key_id *kid1, } 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); + /** * 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 */ -bool asymmetric_match_key_ids(const struct asymmetric_key_ids *kids, - const struct asymmetric_key_id *match_id) +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; - if (asymmetric_key_id_same(kids->id[0], match_id)) - return true; - if (asymmetric_key_id_same(kids->id[1], match_id)) - return true; + for (i = 0; i < ARRAY_SIZE(kids->id); i++) + if (match(kids->id[i], match_id)) + return true; return false; } -EXPORT_SYMBOL_GPL(asymmetric_match_key_ids); /** * asymmetric_key_hex_to_key_id - Convert a hex string into a key ID. @@ -113,7 +134,7 @@ struct asymmetric_key_id *asymmetric_key_hex_to_key_id(const char *id) } /* - * Match asymmetric keys by 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) @@ -121,7 +142,21 @@ static bool asymmetric_key_cmp(const struct key *key, 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); + 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); } /* @@ -131,7 +166,8 @@ static bool asymmetric_key_cmp(const struct key *key, * There are some specifiers for matching key IDs rather than by the key * description: * - * "id:" - request a key by any available ID + * "id:" - find a key by partial match on any available ID + * "ex:" - 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. @@ -141,6 +177,8 @@ 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; @@ -148,6 +186,11 @@ static int asymmetric_key_match_preparse(struct key_match_data *match_data) 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; } @@ -157,7 +200,7 @@ static int asymmetric_key_match_preparse(struct key_match_data *match_data) return PTR_ERR(match_id); match_data->preparsed = match_id; - match_data->cmp = asymmetric_key_cmp; + match_data->cmp = cmp; match_data->lookup_type = KEYRING_SEARCH_LOOKUP_ITERATE; return 0; @@ -251,6 +294,7 @@ static void asymmetric_key_free_preparse(struct key_preparsed_payload *prep) { struct asymmetric_key_subtype *subtype = prep->type_data[0]; struct asymmetric_key_ids *kids = prep->type_data[1]; + int i; pr_devel("==>%s()\n", __func__); @@ -259,8 +303,8 @@ static void asymmetric_key_free_preparse(struct key_preparsed_payload *prep) module_put(subtype->owner); } if (kids) { - kfree(kids->id[0]); - kfree(kids->id[1]); + for (i = 0; i < ARRAY_SIZE(kids->id); i++) + kfree(kids->id[i]); kfree(kids); } kfree(prep->description); diff --git a/crypto/asymmetric_keys/pkcs7_trust.c b/crypto/asymmetric_keys/pkcs7_trust.c index ae47be6128c4..1d29376072da 100644 --- a/crypto/asymmetric_keys/pkcs7_trust.c +++ b/crypto/asymmetric_keys/pkcs7_trust.c @@ -54,7 +54,8 @@ static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7, /* Look to see if this certificate is present in the trusted * keys. */ - key = x509_request_asymmetric_key(trust_keyring, x509->id); + key = x509_request_asymmetric_key(trust_keyring, x509->id, + false); if (!IS_ERR(key)) { /* One of the X.509 certificates in the PKCS#7 message * is apparently the same as one we already trust. @@ -85,7 +86,8 @@ static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7, * trusted keys. */ if (last && last->authority) { - key = x509_request_asymmetric_key(trust_keyring, last->authority); + key = x509_request_asymmetric_key(trust_keyring, last->authority, + false); if (!IS_ERR(key)) { x509 = last; pr_devel("sinfo %u: Root cert %u signer is key %x\n", @@ -100,7 +102,8 @@ static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7, * the signed info directly. */ key = x509_request_asymmetric_key(trust_keyring, - sinfo->signing_cert_id); + sinfo->signing_cert_id, + false); if (!IS_ERR(key)) { pr_devel("sinfo %u: Direct signer is key %x\n", sinfo->index, key_serial(key)); diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c index 8bffb06b2683..6ef54495be87 100644 --- a/crypto/asymmetric_keys/x509_public_key.c +++ b/crypto/asymmetric_keys/x509_public_key.c @@ -53,13 +53,15 @@ __setup("ca_keys=", ca_keys_setup); * x509_request_asymmetric_key - Request a key by X.509 certificate params. * @keyring: The keys to search. * @kid: The key ID. + * @partial: Use partial match if true, exact if false. * * Find a key in the given keyring by subject name and key ID. These might, * for instance, be the issuer name and the authority key ID of an X.509 * certificate that needs to be verified. */ struct key *x509_request_asymmetric_key(struct key *keyring, - const struct asymmetric_key_id *kid) + const struct asymmetric_key_id *kid, + bool partial) { key_ref_t key; char *id, *p; @@ -69,8 +71,13 @@ struct key *x509_request_asymmetric_key(struct key *keyring, if (!id) return ERR_PTR(-ENOMEM); - *p++ = 'i'; - *p++ = 'd'; + if (partial) { + *p++ = 'i'; + *p++ = 'd'; + } else { + *p++ = 'e'; + *p++ = 'x'; + } *p++ = ':'; p = bin2hex(p, kid->data, kid->len); *p = 0; @@ -207,10 +214,11 @@ static int x509_validate_trust(struct x509_certificate *cert, if (!trust_keyring) return -EOPNOTSUPP; - if (ca_keyid && !asymmetric_key_id_same(cert->authority, ca_keyid)) + if (ca_keyid && !asymmetric_key_id_partial(cert->authority, ca_keyid)) return -EPERM; - key = x509_request_asymmetric_key(trust_keyring, cert->authority); + key = x509_request_asymmetric_key(trust_keyring, cert->authority, + false); if (!IS_ERR(key)) { if (!use_builtin_keys || test_bit(KEY_FLAG_BUILTIN, &key->flags)) diff --git a/include/crypto/public_key.h b/include/crypto/public_key.h index fa73a6fd536c..54add2069901 100644 --- a/include/crypto/public_key.h +++ b/include/crypto/public_key.h @@ -101,6 +101,7 @@ extern int verify_signature(const struct key *key, struct asymmetric_key_id; extern struct key *x509_request_asymmetric_key(struct key *keyring, - const struct asymmetric_key_id *kid); + const struct asymmetric_key_id *kid, + bool partial); #endif /* _LINUX_PUBLIC_KEY_H */ diff --git a/include/keys/asymmetric-type.h b/include/keys/asymmetric-type.h index 044ab0d3aa45..c0754abb2f56 100644 --- a/include/keys/asymmetric-type.h +++ b/include/keys/asymmetric-type.h @@ -51,6 +51,9 @@ struct asymmetric_key_ids { 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,