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![James Morris](/assets/img/avatar_default.png)
Conflicts: security/keys/keyring.c Resolved conflict with whitespace fix in find_keyring_by_name() Signed-off-by: James Morris <jmorris@namei.org>
587 lines
14 KiB
C
587 lines
14 KiB
C
/* Request a key from userspace
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*
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* Copyright (C) 2004-2007 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/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/kmod.h>
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#include <linux/err.h>
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#include <linux/keyctl.h>
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#include <linux/slab.h>
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#include "internal.h"
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#define key_negative_timeout 60 /* default timeout on a negative key's existence */
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/*
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* wait_on_bit() sleep function for uninterruptible waiting
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*/
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static int key_wait_bit(void *flags)
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{
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schedule();
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return 0;
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}
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/*
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* wait_on_bit() sleep function for interruptible waiting
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*/
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static int key_wait_bit_intr(void *flags)
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{
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schedule();
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return signal_pending(current) ? -ERESTARTSYS : 0;
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}
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/*
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* call to complete the construction of a key
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*/
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void complete_request_key(struct key_construction *cons, int error)
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{
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kenter("{%d,%d},%d", cons->key->serial, cons->authkey->serial, error);
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if (error < 0)
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key_negate_and_link(cons->key, key_negative_timeout, NULL,
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cons->authkey);
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else
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key_revoke(cons->authkey);
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key_put(cons->key);
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key_put(cons->authkey);
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kfree(cons);
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}
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EXPORT_SYMBOL(complete_request_key);
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/*
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* request userspace finish the construction of a key
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* - execute "/sbin/request-key <op> <key> <uid> <gid> <keyring> <keyring> <keyring>"
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*/
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static int call_sbin_request_key(struct key_construction *cons,
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const char *op,
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void *aux)
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{
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const struct cred *cred = current_cred();
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key_serial_t prkey, sskey;
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struct key *key = cons->key, *authkey = cons->authkey, *keyring,
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*session;
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char *argv[9], *envp[3], uid_str[12], gid_str[12];
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char key_str[12], keyring_str[3][12];
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char desc[20];
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int ret, i;
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kenter("{%d},{%d},%s", key->serial, authkey->serial, op);
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ret = install_user_keyrings();
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if (ret < 0)
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goto error_alloc;
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/* allocate a new session keyring */
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sprintf(desc, "_req.%u", key->serial);
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cred = get_current_cred();
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keyring = keyring_alloc(desc, cred->fsuid, cred->fsgid, cred,
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KEY_ALLOC_QUOTA_OVERRUN, NULL);
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put_cred(cred);
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if (IS_ERR(keyring)) {
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ret = PTR_ERR(keyring);
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goto error_alloc;
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}
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/* attach the auth key to the session keyring */
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ret = key_link(keyring, authkey);
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if (ret < 0)
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goto error_link;
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/* record the UID and GID */
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sprintf(uid_str, "%d", cred->fsuid);
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sprintf(gid_str, "%d", cred->fsgid);
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/* we say which key is under construction */
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sprintf(key_str, "%d", key->serial);
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/* we specify the process's default keyrings */
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sprintf(keyring_str[0], "%d",
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cred->thread_keyring ? cred->thread_keyring->serial : 0);
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prkey = 0;
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if (cred->tgcred->process_keyring)
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prkey = cred->tgcred->process_keyring->serial;
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rcu_read_lock();
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session = rcu_dereference(cred->tgcred->session_keyring);
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if (!session)
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session = cred->user->session_keyring;
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sskey = session->serial;
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rcu_read_unlock();
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sprintf(keyring_str[2], "%d", sskey);
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/* set up a minimal environment */
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i = 0;
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envp[i++] = "HOME=/";
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envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
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envp[i] = NULL;
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/* set up the argument list */
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i = 0;
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argv[i++] = "/sbin/request-key";
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argv[i++] = (char *) op;
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argv[i++] = key_str;
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argv[i++] = uid_str;
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argv[i++] = gid_str;
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argv[i++] = keyring_str[0];
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argv[i++] = keyring_str[1];
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argv[i++] = keyring_str[2];
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argv[i] = NULL;
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/* do it */
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ret = call_usermodehelper_keys(argv[0], argv, envp, keyring,
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UMH_WAIT_PROC);
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kdebug("usermode -> 0x%x", ret);
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if (ret >= 0) {
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/* ret is the exit/wait code */
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if (test_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags) ||
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key_validate(key) < 0)
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ret = -ENOKEY;
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else
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/* ignore any errors from userspace if the key was
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* instantiated */
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ret = 0;
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}
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error_link:
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key_put(keyring);
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error_alloc:
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complete_request_key(cons, ret);
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kleave(" = %d", ret);
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return ret;
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}
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/*
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* call out to userspace for key construction
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* - we ignore program failure and go on key status instead
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*/
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static int construct_key(struct key *key, const void *callout_info,
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size_t callout_len, void *aux,
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struct key *dest_keyring)
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{
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struct key_construction *cons;
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request_key_actor_t actor;
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struct key *authkey;
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int ret;
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kenter("%d,%p,%zu,%p", key->serial, callout_info, callout_len, aux);
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cons = kmalloc(sizeof(*cons), GFP_KERNEL);
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if (!cons)
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return -ENOMEM;
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/* allocate an authorisation key */
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authkey = request_key_auth_new(key, callout_info, callout_len,
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dest_keyring);
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if (IS_ERR(authkey)) {
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kfree(cons);
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ret = PTR_ERR(authkey);
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authkey = NULL;
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} else {
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cons->authkey = key_get(authkey);
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cons->key = key_get(key);
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/* make the call */
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actor = call_sbin_request_key;
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if (key->type->request_key)
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actor = key->type->request_key;
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ret = actor(cons, "create", aux);
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/* check that the actor called complete_request_key() prior to
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* returning an error */
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WARN_ON(ret < 0 &&
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!test_bit(KEY_FLAG_REVOKED, &authkey->flags));
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key_put(authkey);
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}
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kleave(" = %d", ret);
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return ret;
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}
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/*
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* get the appropriate destination keyring for the request
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* - we return whatever keyring we select with an extra reference upon it which
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* the caller must release
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*/
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static void construct_get_dest_keyring(struct key **_dest_keyring)
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{
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struct request_key_auth *rka;
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const struct cred *cred = current_cred();
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struct key *dest_keyring = *_dest_keyring, *authkey;
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kenter("%p", dest_keyring);
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/* find the appropriate keyring */
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if (dest_keyring) {
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/* the caller supplied one */
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key_get(dest_keyring);
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} else {
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/* use a default keyring; falling through the cases until we
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* find one that we actually have */
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switch (cred->jit_keyring) {
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case KEY_REQKEY_DEFL_DEFAULT:
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case KEY_REQKEY_DEFL_REQUESTOR_KEYRING:
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if (cred->request_key_auth) {
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authkey = cred->request_key_auth;
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down_read(&authkey->sem);
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rka = authkey->payload.data;
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if (!test_bit(KEY_FLAG_REVOKED,
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&authkey->flags))
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dest_keyring =
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key_get(rka->dest_keyring);
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up_read(&authkey->sem);
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if (dest_keyring)
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break;
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}
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case KEY_REQKEY_DEFL_THREAD_KEYRING:
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dest_keyring = key_get(cred->thread_keyring);
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if (dest_keyring)
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break;
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case KEY_REQKEY_DEFL_PROCESS_KEYRING:
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dest_keyring = key_get(cred->tgcred->process_keyring);
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if (dest_keyring)
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break;
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case KEY_REQKEY_DEFL_SESSION_KEYRING:
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rcu_read_lock();
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dest_keyring = key_get(
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rcu_dereference(cred->tgcred->session_keyring));
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rcu_read_unlock();
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if (dest_keyring)
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break;
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case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
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dest_keyring =
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key_get(cred->user->session_keyring);
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break;
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case KEY_REQKEY_DEFL_USER_KEYRING:
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dest_keyring = key_get(cred->user->uid_keyring);
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break;
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case KEY_REQKEY_DEFL_GROUP_KEYRING:
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default:
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BUG();
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}
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}
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*_dest_keyring = dest_keyring;
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kleave(" [dk %d]", key_serial(dest_keyring));
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return;
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}
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/*
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* allocate a new key in under-construction state and attempt to link it in to
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* the requested place
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* - may return a key that's already under construction instead
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*/
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static int construct_alloc_key(struct key_type *type,
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const char *description,
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struct key *dest_keyring,
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unsigned long flags,
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struct key_user *user,
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struct key **_key)
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{
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const struct cred *cred = current_cred();
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struct key *key;
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key_ref_t key_ref;
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int ret;
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kenter("%s,%s,,,", type->name, description);
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mutex_lock(&user->cons_lock);
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key = key_alloc(type, description, cred->fsuid, cred->fsgid, cred,
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KEY_POS_ALL, flags);
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if (IS_ERR(key))
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goto alloc_failed;
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set_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags);
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if (dest_keyring)
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down_write(&dest_keyring->sem);
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/* attach the key to the destination keyring under lock, but we do need
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* to do another check just in case someone beat us to it whilst we
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* waited for locks */
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mutex_lock(&key_construction_mutex);
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key_ref = search_process_keyrings(type, description, type->match, cred);
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if (!IS_ERR(key_ref))
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goto key_already_present;
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if (dest_keyring)
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__key_link(dest_keyring, key);
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mutex_unlock(&key_construction_mutex);
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if (dest_keyring)
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up_write(&dest_keyring->sem);
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mutex_unlock(&user->cons_lock);
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*_key = key;
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kleave(" = 0 [%d]", key_serial(key));
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return 0;
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/* the key is now present - we tell the caller that we found it by
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* returning -EINPROGRESS */
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key_already_present:
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mutex_unlock(&key_construction_mutex);
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ret = 0;
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if (dest_keyring) {
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ret = __key_link(dest_keyring, key_ref_to_ptr(key_ref));
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up_write(&dest_keyring->sem);
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}
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mutex_unlock(&user->cons_lock);
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key_put(key);
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if (ret < 0) {
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key_ref_put(key_ref);
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*_key = NULL;
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kleave(" = %d [link]", ret);
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return ret;
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}
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*_key = key = key_ref_to_ptr(key_ref);
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kleave(" = -EINPROGRESS [%d]", key_serial(key));
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return -EINPROGRESS;
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alloc_failed:
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mutex_unlock(&user->cons_lock);
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*_key = NULL;
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kleave(" = %ld", PTR_ERR(key));
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return PTR_ERR(key);
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}
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/*
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* commence key construction
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*/
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static struct key *construct_key_and_link(struct key_type *type,
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const char *description,
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const char *callout_info,
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size_t callout_len,
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void *aux,
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struct key *dest_keyring,
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unsigned long flags)
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{
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struct key_user *user;
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struct key *key;
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int ret;
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kenter("");
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user = key_user_lookup(current_fsuid(), current_user_ns());
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if (!user)
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return ERR_PTR(-ENOMEM);
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construct_get_dest_keyring(&dest_keyring);
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ret = construct_alloc_key(type, description, dest_keyring, flags, user,
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&key);
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key_user_put(user);
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if (ret == 0) {
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ret = construct_key(key, callout_info, callout_len, aux,
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dest_keyring);
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if (ret < 0) {
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kdebug("cons failed");
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goto construction_failed;
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}
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} else if (ret == -EINPROGRESS) {
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ret = 0;
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} else {
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key = ERR_PTR(ret);
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}
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key_put(dest_keyring);
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kleave(" = key %d", key_serial(key));
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return key;
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construction_failed:
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key_negate_and_link(key, key_negative_timeout, NULL, NULL);
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key_put(key);
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key_put(dest_keyring);
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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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* request a key
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* - search the process's keyrings
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* - check the list of keys being created or updated
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* - call out to userspace for a key if supplementary info was provided
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* - cache the key in an appropriate keyring
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*/
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struct key *request_key_and_link(struct key_type *type,
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const char *description,
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const void *callout_info,
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size_t callout_len,
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void *aux,
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struct key *dest_keyring,
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unsigned long flags)
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{
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const struct cred *cred = current_cred();
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struct key *key;
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key_ref_t key_ref;
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int ret;
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kenter("%s,%s,%p,%zu,%p,%p,%lx",
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type->name, description, callout_info, callout_len, aux,
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dest_keyring, flags);
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/* search all the process keyrings for a key */
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key_ref = search_process_keyrings(type, description, type->match,
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cred);
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if (!IS_ERR(key_ref)) {
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key = key_ref_to_ptr(key_ref);
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if (dest_keyring) {
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construct_get_dest_keyring(&dest_keyring);
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ret = key_link(dest_keyring, key);
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key_put(dest_keyring);
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if (ret < 0) {
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key_put(key);
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key = ERR_PTR(ret);
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goto error;
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}
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}
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} else if (PTR_ERR(key_ref) != -EAGAIN) {
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key = ERR_CAST(key_ref);
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} else {
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/* the search failed, but the keyrings were searchable, so we
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* should consult userspace if we can */
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key = ERR_PTR(-ENOKEY);
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if (!callout_info)
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goto error;
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key = construct_key_and_link(type, description, callout_info,
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callout_len, aux, dest_keyring,
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flags);
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}
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error:
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kleave(" = %p", key);
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return key;
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}
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/*
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* wait for construction of a key to complete
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*/
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int wait_for_key_construction(struct key *key, bool intr)
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{
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int ret;
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ret = wait_on_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT,
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intr ? key_wait_bit_intr : key_wait_bit,
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intr ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE);
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if (ret < 0)
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return ret;
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return key_validate(key);
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}
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EXPORT_SYMBOL(wait_for_key_construction);
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/*
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* request a key
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* - search the process's keyrings
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* - check the list of keys being created or updated
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* - call out to userspace for a key if supplementary info was provided
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* - waits uninterruptible for creation to complete
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*/
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struct key *request_key(struct key_type *type,
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const char *description,
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const char *callout_info)
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{
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struct key *key;
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size_t callout_len = 0;
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int ret;
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if (callout_info)
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callout_len = strlen(callout_info);
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key = request_key_and_link(type, description, callout_info, callout_len,
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NULL, NULL, KEY_ALLOC_IN_QUOTA);
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if (!IS_ERR(key)) {
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ret = wait_for_key_construction(key, false);
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if (ret < 0) {
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key_put(key);
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return ERR_PTR(ret);
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}
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}
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return key;
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}
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EXPORT_SYMBOL(request_key);
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/*
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* request a key with auxiliary data for the upcaller
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* - search the process's keyrings
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* - check the list of keys being created or updated
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* - call out to userspace for a key if supplementary info was provided
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* - waits uninterruptible for creation to complete
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*/
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struct key *request_key_with_auxdata(struct key_type *type,
|
|
const char *description,
|
|
const void *callout_info,
|
|
size_t callout_len,
|
|
void *aux)
|
|
{
|
|
struct key *key;
|
|
int ret;
|
|
|
|
key = request_key_and_link(type, description, callout_info, callout_len,
|
|
aux, NULL, KEY_ALLOC_IN_QUOTA);
|
|
if (!IS_ERR(key)) {
|
|
ret = wait_for_key_construction(key, false);
|
|
if (ret < 0) {
|
|
key_put(key);
|
|
return ERR_PTR(ret);
|
|
}
|
|
}
|
|
return key;
|
|
}
|
|
EXPORT_SYMBOL(request_key_with_auxdata);
|
|
|
|
/*
|
|
* request a key (allow async construction)
|
|
* - search the process's keyrings
|
|
* - check the list of keys being created or updated
|
|
* - call out to userspace for a key if supplementary info was provided
|
|
*/
|
|
struct key *request_key_async(struct key_type *type,
|
|
const char *description,
|
|
const void *callout_info,
|
|
size_t callout_len)
|
|
{
|
|
return request_key_and_link(type, description, callout_info,
|
|
callout_len, NULL, NULL,
|
|
KEY_ALLOC_IN_QUOTA);
|
|
}
|
|
EXPORT_SYMBOL(request_key_async);
|
|
|
|
/*
|
|
* request a key with auxiliary data for the upcaller (allow async construction)
|
|
* - search the process's keyrings
|
|
* - check the list of keys being created or updated
|
|
* - call out to userspace for a key if supplementary info was provided
|
|
*/
|
|
struct key *request_key_async_with_auxdata(struct key_type *type,
|
|
const char *description,
|
|
const void *callout_info,
|
|
size_t callout_len,
|
|
void *aux)
|
|
{
|
|
return request_key_and_link(type, description, callout_info,
|
|
callout_len, aux, NULL, KEY_ALLOC_IN_QUOTA);
|
|
}
|
|
EXPORT_SYMBOL(request_key_async_with_auxdata);
|