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Diffstat (limited to 'crypto/asymmetric_keys/asymmetric_type.c')
| -rw-r--r-- | crypto/asymmetric_keys/asymmetric_type.c | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/crypto/asymmetric_keys/asymmetric_type.c b/crypto/asymmetric_keys/asymmetric_type.c new file mode 100644 index 000000000000..bfb0424026aa --- /dev/null +++ b/crypto/asymmetric_keys/asymmetric_type.c @@ -0,0 +1,156 @@ +/* Asymmetric public-key cryptography key type + * + * See Documentation/security/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 <keys/asymmetric-subtype.h> +#include <linux/seq_file.h> +#include <linux/module.h> +#include <linux/slab.h> +#include "asymmetric_keys.h" + +MODULE_LICENSE("GPL"); + +/* + * Match asymmetric keys on (part of) their name + * We have some shorthand methods for matching keys. We allow: + * + * "<desc>" - request a key by description + * "id:<id>" - request a key matching the ID + * "<subtype>:<id>" - request a key of a subtype + */ +static int asymmetric_key_match(const struct key *key, const void *description) +{ + const struct asymmetric_key_subtype *subtype = asymmetric_key_subtype(key); + const char *spec = description; + const char *id, *kid; + ptrdiff_t speclen; + size_t idlen, kidlen; + + if (!subtype || !spec || !*spec) + return 0; + + /* See if the full key description matches as is */ + if (key->description && strcmp(key->description, description) == 0) + return 1; + + /* All tests from here on break the criterion description into a + * specifier, a colon and then an identifier. + */ + id = strchr(spec, ':'); + if (!id) + return 0; + + speclen = id - spec; + id++; + + /* Anything after here requires a partial match on the ID string */ + kid = asymmetric_key_id(key); + if (!kid) + return 0; + + idlen = strlen(id); + kidlen = strlen(kid); + if (idlen > kidlen) + return 0; + + kid += kidlen - idlen; + if (strcasecmp(id, kid) != 0) + return 0; + + if (speclen == 2 && + memcmp(spec, "id", 2) == 0) + return 1; + + if (speclen == subtype->name_len && + memcmp(spec, subtype->name, speclen) == 0) + return 1; + + return 0; +} + +/* + * 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 char *kid = asymmetric_key_id(key); + size_t n; + + seq_puts(m, key->description); + + if (subtype) { + seq_puts(m, ": "); + subtype->describe(key, m); + + if (kid) { + seq_putc(m, ' '); + n = strlen(kid); + if (n <= 8) + seq_puts(m, kid); + else + seq_puts(m, kid + n - 8); + } + + seq_puts(m, " ["); + /* put something here to indicate the key's capabilities */ + seq_putc(m, ']'); + } +} + +/* + * Instantiate a asymmetric_key defined key. The key was preparsed, so we just + * have to transfer the data here. + */ +static int asymmetric_key_instantiate(struct key *key, struct key_preparsed_payload *prep) +{ + return -EOPNOTSUPP; +} + +/* + * 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); + if (subtype) { + subtype->destroy(key->payload.data); + module_put(subtype->owner); + key->type_data.p[0] = NULL; + } + kfree(key->type_data.p[1]); + key->type_data.p[1] = NULL; +} + +struct key_type key_type_asymmetric = { + .name = "asymmetric", + .instantiate = asymmetric_key_instantiate, + .match = asymmetric_key_match, + .destroy = asymmetric_key_destroy, + .describe = asymmetric_key_describe, +}; +EXPORT_SYMBOL_GPL(key_type_asymmetric); + +/* + * 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); |