mirror of https://gitee.com/openkylin/linux.git
225 lines
4.9 KiB
C
225 lines
4.9 KiB
C
/* user_defined.c: user defined key type
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*
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* Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/seq_file.h>
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#include <linux/err.h>
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#include <keys/user-type.h>
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#include <asm/uaccess.h>
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#include "internal.h"
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static int logon_vet_description(const char *desc);
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/*
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* user defined keys take an arbitrary string as the description and an
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* arbitrary blob of data as the payload
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*/
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struct key_type key_type_user = {
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.name = "user",
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.preparse = user_preparse,
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.free_preparse = user_free_preparse,
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.instantiate = generic_key_instantiate,
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.update = user_update,
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.revoke = user_revoke,
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.destroy = user_destroy,
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.describe = user_describe,
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.read = user_read,
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};
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EXPORT_SYMBOL_GPL(key_type_user);
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/*
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* This key type is essentially the same as key_type_user, but it does
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* not define a .read op. This is suitable for storing username and
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* password pairs in the keyring that you do not want to be readable
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* from userspace.
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*/
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struct key_type key_type_logon = {
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.name = "logon",
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.preparse = user_preparse,
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.free_preparse = user_free_preparse,
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.instantiate = generic_key_instantiate,
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.update = user_update,
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.revoke = user_revoke,
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.destroy = user_destroy,
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.describe = user_describe,
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.vet_description = logon_vet_description,
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};
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EXPORT_SYMBOL_GPL(key_type_logon);
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/*
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* Preparse a user defined key payload
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*/
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int user_preparse(struct key_preparsed_payload *prep)
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{
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struct user_key_payload *upayload;
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size_t datalen = prep->datalen;
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if (datalen <= 0 || datalen > 32767 || !prep->data)
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return -EINVAL;
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upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL);
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if (!upayload)
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return -ENOMEM;
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/* attach the data */
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prep->quotalen = datalen;
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prep->payload.data[0] = upayload;
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upayload->datalen = datalen;
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memcpy(upayload->data, prep->data, datalen);
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return 0;
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}
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EXPORT_SYMBOL_GPL(user_preparse);
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/*
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* Free a preparse of a user defined key payload
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*/
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void user_free_preparse(struct key_preparsed_payload *prep)
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{
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kfree(prep->payload.data[0]);
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}
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EXPORT_SYMBOL_GPL(user_free_preparse);
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/*
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* update a user defined key
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* - the key's semaphore is write-locked
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*/
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int user_update(struct key *key, struct key_preparsed_payload *prep)
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{
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struct user_key_payload *upayload, *zap;
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size_t datalen = prep->datalen;
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int ret;
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ret = -EINVAL;
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if (datalen <= 0 || datalen > 32767 || !prep->data)
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goto error;
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/* construct a replacement payload */
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ret = -ENOMEM;
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upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL);
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if (!upayload)
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goto error;
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upayload->datalen = datalen;
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memcpy(upayload->data, prep->data, datalen);
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/* check the quota and attach the new data */
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zap = upayload;
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ret = key_payload_reserve(key, datalen);
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if (ret == 0) {
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/* attach the new data, displacing the old */
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if (!test_bit(KEY_FLAG_NEGATIVE, &key->flags))
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zap = key->payload.data[0];
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else
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zap = NULL;
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rcu_assign_keypointer(key, upayload);
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key->expiry = 0;
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}
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if (zap)
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kfree_rcu(zap, rcu);
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error:
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return ret;
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}
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EXPORT_SYMBOL_GPL(user_update);
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/*
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* dispose of the links from a revoked keyring
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* - called with the key sem write-locked
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*/
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void user_revoke(struct key *key)
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{
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struct user_key_payload *upayload = key->payload.data[0];
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/* clear the quota */
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key_payload_reserve(key, 0);
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if (upayload) {
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rcu_assign_keypointer(key, NULL);
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kfree_rcu(upayload, rcu);
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}
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}
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EXPORT_SYMBOL(user_revoke);
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/*
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* dispose of the data dangling from the corpse of a user key
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*/
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void user_destroy(struct key *key)
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{
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struct user_key_payload *upayload = key->payload.data[0];
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kfree(upayload);
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}
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EXPORT_SYMBOL_GPL(user_destroy);
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/*
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* describe the user key
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*/
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void user_describe(const struct key *key, struct seq_file *m)
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{
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seq_puts(m, key->description);
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if (key_is_instantiated(key))
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seq_printf(m, ": %u", key->datalen);
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}
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EXPORT_SYMBOL_GPL(user_describe);
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/*
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* read the key data
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* - the key's semaphore is read-locked
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*/
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long user_read(const struct key *key, char __user *buffer, size_t buflen)
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{
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const struct user_key_payload *upayload;
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long ret;
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upayload = user_key_payload(key);
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ret = upayload->datalen;
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/* we can return the data as is */
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if (buffer && buflen > 0) {
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if (buflen > upayload->datalen)
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buflen = upayload->datalen;
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if (copy_to_user(buffer, upayload->data, buflen) != 0)
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ret = -EFAULT;
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}
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return ret;
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}
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EXPORT_SYMBOL_GPL(user_read);
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/* Vet the description for a "logon" key */
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static int logon_vet_description(const char *desc)
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{
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char *p;
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/* require a "qualified" description string */
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p = strchr(desc, ':');
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if (!p)
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return -EINVAL;
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/* also reject description with ':' as first char */
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if (p == desc)
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return -EINVAL;
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return 0;
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}
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