![David Howells](/assets/img/avatar_default.png)
A previous patch added a ->match_preparse() method to the key type. This is allowed to override the function called by the iteration algorithm. Therefore, we can just set a default that simply checks for an exact match of the key description with the original criterion data and allow match_preparse to override it as needed. The key_type::match op is then redundant and can be removed, as can the user_match() function. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Vivek Goyal <vgoyal@redhat.com>
276 lines
6.9 KiB
C
276 lines
6.9 KiB
C
/* Request key authorisation token key definition.
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*
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* Copyright (C) 2005 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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* See Documentation/security/keys-request-key.txt
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*/
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/err.h>
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#include <linux/seq_file.h>
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#include <linux/slab.h>
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#include <asm/uaccess.h>
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#include "internal.h"
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#include <keys/user-type.h>
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static int request_key_auth_preparse(struct key_preparsed_payload *);
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static void request_key_auth_free_preparse(struct key_preparsed_payload *);
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static int request_key_auth_instantiate(struct key *,
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struct key_preparsed_payload *);
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static void request_key_auth_describe(const struct key *, struct seq_file *);
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static void request_key_auth_revoke(struct key *);
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static void request_key_auth_destroy(struct key *);
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static long request_key_auth_read(const struct key *, char __user *, size_t);
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/*
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* The request-key authorisation key type definition.
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*/
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struct key_type key_type_request_key_auth = {
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.name = ".request_key_auth",
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.def_datalen = sizeof(struct request_key_auth),
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.preparse = request_key_auth_preparse,
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.free_preparse = request_key_auth_free_preparse,
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.instantiate = request_key_auth_instantiate,
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.describe = request_key_auth_describe,
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.revoke = request_key_auth_revoke,
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.destroy = request_key_auth_destroy,
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.read = request_key_auth_read,
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};
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static int request_key_auth_preparse(struct key_preparsed_payload *prep)
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{
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return 0;
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}
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static void request_key_auth_free_preparse(struct key_preparsed_payload *prep)
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{
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}
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/*
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* Instantiate a request-key authorisation key.
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*/
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static int request_key_auth_instantiate(struct key *key,
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struct key_preparsed_payload *prep)
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{
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key->payload.data = (struct request_key_auth *)prep->data;
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return 0;
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}
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/*
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* Describe an authorisation token.
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*/
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static void request_key_auth_describe(const struct key *key,
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struct seq_file *m)
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{
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struct request_key_auth *rka = key->payload.data;
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seq_puts(m, "key:");
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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, " pid:%d ci:%zu", rka->pid, rka->callout_len);
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}
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/*
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* Read the callout_info data (retrieves the callout information).
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* - the key's semaphore is read-locked
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*/
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static long request_key_auth_read(const struct key *key,
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char __user *buffer, size_t buflen)
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{
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struct request_key_auth *rka = key->payload.data;
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size_t datalen;
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long ret;
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datalen = rka->callout_len;
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ret = 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 > datalen)
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buflen = datalen;
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if (copy_to_user(buffer, rka->callout_info, 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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/*
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* Handle revocation of an authorisation token key.
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*
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* Called with the key sem write-locked.
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*/
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static void request_key_auth_revoke(struct key *key)
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{
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struct request_key_auth *rka = key->payload.data;
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kenter("{%d}", key->serial);
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if (rka->cred) {
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put_cred(rka->cred);
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rka->cred = NULL;
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}
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}
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/*
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* Destroy an instantiation authorisation token key.
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*/
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static void request_key_auth_destroy(struct key *key)
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{
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struct request_key_auth *rka = key->payload.data;
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kenter("{%d}", key->serial);
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if (rka->cred) {
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put_cred(rka->cred);
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rka->cred = NULL;
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}
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key_put(rka->target_key);
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key_put(rka->dest_keyring);
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kfree(rka->callout_info);
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kfree(rka);
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}
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/*
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* Create an authorisation token for /sbin/request-key or whoever to gain
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* access to the caller's security data.
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*/
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struct key *request_key_auth_new(struct key *target, const void *callout_info,
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size_t callout_len, struct key *dest_keyring)
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{
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struct request_key_auth *rka, *irka;
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const struct cred *cred = current->cred;
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struct key *authkey = NULL;
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char desc[20];
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int ret;
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kenter("%d,", target->serial);
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/* allocate a auth record */
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rka = kmalloc(sizeof(*rka), GFP_KERNEL);
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if (!rka) {
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kleave(" = -ENOMEM");
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return ERR_PTR(-ENOMEM);
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}
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rka->callout_info = kmalloc(callout_len, GFP_KERNEL);
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if (!rka->callout_info) {
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kleave(" = -ENOMEM");
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kfree(rka);
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return ERR_PTR(-ENOMEM);
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}
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/* see if the calling process is already servicing the key request of
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* another process */
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if (cred->request_key_auth) {
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/* it is - use that instantiation context here too */
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down_read(&cred->request_key_auth->sem);
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/* if the auth key has been revoked, then the key we're
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* servicing is already instantiated */
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if (test_bit(KEY_FLAG_REVOKED, &cred->request_key_auth->flags))
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goto auth_key_revoked;
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irka = cred->request_key_auth->payload.data;
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rka->cred = get_cred(irka->cred);
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rka->pid = irka->pid;
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up_read(&cred->request_key_auth->sem);
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}
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else {
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/* it isn't - use this process as the context */
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rka->cred = get_cred(cred);
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rka->pid = current->pid;
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}
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rka->target_key = key_get(target);
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rka->dest_keyring = key_get(dest_keyring);
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memcpy(rka->callout_info, callout_info, callout_len);
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rka->callout_len = callout_len;
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/* allocate the auth key */
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sprintf(desc, "%x", target->serial);
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authkey = key_alloc(&key_type_request_key_auth, desc,
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cred->fsuid, cred->fsgid, cred,
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KEY_POS_VIEW | KEY_POS_READ | KEY_POS_SEARCH |
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KEY_USR_VIEW, KEY_ALLOC_NOT_IN_QUOTA);
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if (IS_ERR(authkey)) {
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ret = PTR_ERR(authkey);
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goto error_alloc;
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}
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/* construct the auth key */
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ret = key_instantiate_and_link(authkey, rka, 0, NULL, NULL);
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if (ret < 0)
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goto error_inst;
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kleave(" = {%d,%d}", authkey->serial, atomic_read(&authkey->usage));
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return authkey;
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auth_key_revoked:
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up_read(&cred->request_key_auth->sem);
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kfree(rka->callout_info);
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kfree(rka);
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kleave("= -EKEYREVOKED");
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return ERR_PTR(-EKEYREVOKED);
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error_inst:
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key_revoke(authkey);
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key_put(authkey);
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error_alloc:
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key_put(rka->target_key);
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key_put(rka->dest_keyring);
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kfree(rka->callout_info);
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kfree(rka);
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kleave("= %d", ret);
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return ERR_PTR(ret);
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}
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/*
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* Search the current process's keyrings for the authorisation key for
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* instantiation of a key.
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*/
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struct key *key_get_instantiation_authkey(key_serial_t target_id)
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{
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char description[16];
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struct keyring_search_context ctx = {
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.index_key.type = &key_type_request_key_auth,
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.index_key.description = description,
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.cred = current_cred(),
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.match_data.cmp = key_default_cmp,
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.match_data.raw_data = description,
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.match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT,
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};
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struct key *authkey;
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key_ref_t authkey_ref;
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sprintf(description, "%x", target_id);
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authkey_ref = search_process_keyrings(&ctx);
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if (IS_ERR(authkey_ref)) {
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authkey = ERR_CAST(authkey_ref);
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if (authkey == ERR_PTR(-EAGAIN))
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authkey = ERR_PTR(-ENOKEY);
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goto error;
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}
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authkey = key_ref_to_ptr(authkey_ref);
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if (test_bit(KEY_FLAG_REVOKED, &authkey->flags)) {
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key_put(authkey);
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authkey = ERR_PTR(-EKEYREVOKED);
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}
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error:
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return authkey;
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}
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