120 lines
2.6 KiB
C
120 lines
2.6 KiB
C
/*
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* Copyright (C) 2013 Intel Corporation
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*
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* Author:
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* Dmitry Kasatkin <dmitry.kasatkin@intel.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, version 2 of the License.
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*
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/err.h>
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#include <linux/ratelimit.h>
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#include <linux/key-type.h>
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#include <crypto/public_key.h>
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#include <keys/asymmetric-type.h>
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#include <keys/system_keyring.h>
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#include "integrity.h"
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/*
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* Request an asymmetric key.
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*/
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static struct key *request_asymmetric_key(struct key *keyring, uint32_t keyid)
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{
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struct key *key;
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char name[12];
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sprintf(name, "id:%08x", keyid);
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pr_debug("key search: \"%s\"\n", name);
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key = get_ima_blacklist_keyring();
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if (key) {
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key_ref_t kref;
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kref = keyring_search(make_key_ref(key, 1),
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&key_type_asymmetric, name);
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if (!IS_ERR(kref)) {
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pr_err("Key '%s' is in ima_blacklist_keyring\n", name);
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return ERR_PTR(-EKEYREJECTED);
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}
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}
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if (keyring) {
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/* search in specific keyring */
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key_ref_t kref;
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kref = keyring_search(make_key_ref(keyring, 1),
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&key_type_asymmetric, name);
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if (IS_ERR(kref))
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key = ERR_CAST(kref);
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else
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key = key_ref_to_ptr(kref);
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} else {
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key = request_key(&key_type_asymmetric, name, NULL);
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}
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if (IS_ERR(key)) {
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pr_err_ratelimited("Request for unknown key '%s' err %ld\n",
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name, PTR_ERR(key));
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switch (PTR_ERR(key)) {
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/* Hide some search errors */
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case -EACCES:
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case -ENOTDIR:
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case -EAGAIN:
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return ERR_PTR(-ENOKEY);
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default:
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return key;
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}
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}
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pr_debug("%s() = 0 [%x]\n", __func__, key_serial(key));
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return key;
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}
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int asymmetric_verify(struct key *keyring, const char *sig,
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int siglen, const char *data, int datalen)
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{
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struct public_key_signature pks;
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struct signature_v2_hdr *hdr = (struct signature_v2_hdr *)sig;
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struct key *key;
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int ret = -ENOMEM;
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if (siglen <= sizeof(*hdr))
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return -EBADMSG;
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siglen -= sizeof(*hdr);
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if (siglen != __be16_to_cpu(hdr->sig_size))
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return -EBADMSG;
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if (hdr->hash_algo >= PKEY_HASH__LAST)
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return -ENOPKG;
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key = request_asymmetric_key(keyring, __be32_to_cpu(hdr->keyid));
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if (IS_ERR(key))
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return PTR_ERR(key);
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memset(&pks, 0, sizeof(pks));
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pks.pkey_hash_algo = hdr->hash_algo;
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pks.digest = (u8 *)data;
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pks.digest_size = datalen;
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pks.nr_mpi = 1;
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pks.rsa.s = mpi_read_raw_data(hdr->sig, siglen);
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if (pks.rsa.s)
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ret = verify_signature(key, &pks);
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mpi_free(pks.rsa.s);
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key_put(key);
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pr_debug("%s() = %d\n", __func__, ret);
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return ret;
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}
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