cregit-Linux how code gets into the kernel

Release 4.7 security/keys/user_defined.c

Directory: security/keys
/* user_defined.c: user defined key type
 *
 * Copyright (C) 2004 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 License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/seq_file.h>
#include <linux/err.h>
#include <keys/user-type.h>
#include <asm/uaccess.h>
#include "internal.h"

static int logon_vet_description(const char *desc);

/*
 * user defined keys take an arbitrary string as the description and an
 * arbitrary blob of data as the payload
 */

struct key_type key_type_user = {
	.name			= "user",
	.preparse		= user_preparse,
	.free_preparse		= user_free_preparse,
	.instantiate		= generic_key_instantiate,
	.update			= user_update,
	.revoke			= user_revoke,
	.destroy		= user_destroy,
	.describe		= user_describe,
	.read			= user_read,
};


EXPORT_SYMBOL_GPL(key_type_user);

/*
 * This key type is essentially the same as key_type_user, but it does
 * not define a .read op. This is suitable for storing username and
 * password pairs in the keyring that you do not want to be readable
 * from userspace.
 */

struct key_type key_type_logon = {
	.name			= "logon",
	.preparse		= user_preparse,
	.free_preparse		= user_free_preparse,
	.instantiate		= generic_key_instantiate,
	.update			= user_update,
	.revoke			= user_revoke,
	.destroy		= user_destroy,
	.describe		= user_describe,
	.vet_description	= logon_vet_description,
};

EXPORT_SYMBOL_GPL(key_type_logon);

/*
 * Preparse a user defined key payload
 */

int user_preparse(struct key_preparsed_payload *prep) { struct user_key_payload *upayload; size_t datalen = prep->datalen; if (datalen <= 0 || datalen > 32767 || !prep->data) return -EINVAL; upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL); if (!upayload) return -ENOMEM; /* attach the data */ prep->quotalen = datalen; prep->payload.data[0] = upayload; upayload->datalen = datalen; memcpy(upayload->data, prep->data, datalen); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
david howellsdavid howells105100.00%5100.00%
Total105100.00%5100.00%

EXPORT_SYMBOL_GPL(user_preparse); /* * Free a preparse of a user defined key payload */
void user_free_preparse(struct key_preparsed_payload *prep) { kfree(prep->payload.data[0]); }

Contributors

PersonTokensPropCommitsCommitProp
david howellsdavid howells22100.00%3100.00%
Total22100.00%3100.00%

EXPORT_SYMBOL_GPL(user_free_preparse); /* * update a user defined key * - the key's semaphore is write-locked */
int user_update(struct key *key, struct key_preparsed_payload *prep) { struct user_key_payload *zap = NULL; int ret; /* check the quota and attach the new data */ ret = key_payload_reserve(key, prep->datalen); if (ret < 0) return ret; /* attach the new data, displacing the old */ key->expiry = prep->expiry; if (!test_bit(KEY_FLAG_NEGATIVE, &key->flags)) zap = rcu_dereference_key(key); rcu_assign_keypointer(key, prep->payload.data[0]); prep->payload.data[0] = NULL; if (zap) kfree_rcu(zap, rcu); return ret; }

Contributors

PersonTokensPropCommitsCommitProp
david howellsdavid howells11298.25%787.50%
lai jiangshanlai jiangshan21.75%112.50%
Total114100.00%8100.00%

EXPORT_SYMBOL_GPL(user_update); /* * dispose of the links from a revoked keyring * - called with the key sem write-locked */
void user_revoke(struct key *key) { struct user_key_payload *upayload = key->payload.data[0]; /* clear the quota */ key_payload_reserve(key, 0); if (upayload) { rcu_assign_keypointer(key, NULL); kfree_rcu(upayload, rcu); } }

Contributors

PersonTokensPropCommitsCommitProp
david howellsdavid howells4994.23%250.00%
lai jiangshanlai jiangshan23.85%125.00%
mimi zoharmimi zohar11.92%125.00%
Total52100.00%4100.00%

EXPORT_SYMBOL(user_revoke); /* * dispose of the data dangling from the corpse of a user key */
void user_destroy(struct key *key) { struct user_key_payload *upayload = key->payload.data[0]; kfree(upayload); }

Contributors

PersonTokensPropCommitsCommitProp
david howellsdavid howells29100.00%3100.00%
Total29100.00%3100.00%

EXPORT_SYMBOL_GPL(user_destroy); /* * describe the user key */
void user_describe(const struct key *key, struct seq_file *m) { seq_puts(m, key->description); if (key_is_instantiated(key)) seq_printf(m, ": %u", key->datalen); }

Contributors

PersonTokensPropCommitsCommitProp
david howellsdavid howells43100.00%2100.00%
Total43100.00%2100.00%

EXPORT_SYMBOL_GPL(user_describe); /* * read the key data * - the key's semaphore is read-locked */
long user_read(const struct key *key, char __user *buffer, size_t buflen) { const struct user_key_payload *upayload; long ret; upayload = user_key_payload(key); ret = upayload->datalen; /* we can return the data as is */ if (buffer && buflen > 0) { if (buflen > upayload->datalen) buflen = upayload->datalen; if (copy_to_user(buffer, upayload->data, buflen) != 0) ret = -EFAULT; } return ret; }

Contributors

PersonTokensPropCommitsCommitProp
david howellsdavid howells89100.00%3100.00%
Total89100.00%3100.00%

EXPORT_SYMBOL_GPL(user_read); /* Vet the description for a "logon" key */
static int logon_vet_description(const char *desc) { char *p; /* require a "qualified" description string */ p = strchr(desc, ':'); if (!p) return -EINVAL; /* also reject description with ':' as first char */ if (p == desc) return -EINVAL; return 0; }

Contributors

PersonTokensPropCommitsCommitProp
jeff laytonjeff layton48100.00%1100.00%
Total48100.00%1100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
david howellsdavid howells57983.43%1173.33%
jeff laytonjeff layton10515.13%16.67%
michael halcrowmichael halcrow50.72%16.67%
lai jiangshanlai jiangshan40.58%16.67%
mimi zoharmimi zohar10.14%16.67%
Total694100.00%15100.00%
Directory: security/keys
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