1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
360 lines
9.1 KiB
C
360 lines
9.1 KiB
C
/* request_key.c: request a key from userspace
|
|
*
|
|
* 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/sched.h>
|
|
#include <linux/kmod.h>
|
|
#include <linux/err.h>
|
|
#include "internal.h"
|
|
|
|
struct key_construction {
|
|
struct list_head link; /* link in construction queue */
|
|
struct key *key; /* key being constructed */
|
|
};
|
|
|
|
/* when waiting for someone else's keys, you get added to this */
|
|
DECLARE_WAIT_QUEUE_HEAD(request_key_conswq);
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* request userspace finish the construction of a key
|
|
* - execute "/sbin/request-key <op> <key> <uid> <gid> <keyring> <keyring> <keyring> <info>"
|
|
* - if callout_info is an empty string, it'll be rendered as a "-" instead
|
|
*/
|
|
static int call_request_key(struct key *key,
|
|
const char *op,
|
|
const char *callout_info)
|
|
{
|
|
struct task_struct *tsk = current;
|
|
unsigned long flags;
|
|
key_serial_t prkey, sskey;
|
|
char *argv[10], *envp[3], uid_str[12], gid_str[12];
|
|
char key_str[12], keyring_str[3][12];
|
|
int i;
|
|
|
|
/* record the UID and GID */
|
|
sprintf(uid_str, "%d", current->fsuid);
|
|
sprintf(gid_str, "%d", current->fsgid);
|
|
|
|
/* we say which key is under construction */
|
|
sprintf(key_str, "%d", key->serial);
|
|
|
|
/* we specify the process's default keyrings */
|
|
sprintf(keyring_str[0], "%d",
|
|
tsk->thread_keyring ? tsk->thread_keyring->serial : 0);
|
|
|
|
prkey = 0;
|
|
if (tsk->signal->process_keyring)
|
|
prkey = tsk->signal->process_keyring->serial;
|
|
|
|
sskey = 0;
|
|
spin_lock_irqsave(&tsk->sighand->siglock, flags);
|
|
if (tsk->signal->session_keyring)
|
|
sskey = tsk->signal->session_keyring->serial;
|
|
spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
|
|
|
|
|
|
if (!sskey)
|
|
sskey = tsk->user->session_keyring->serial;
|
|
|
|
sprintf(keyring_str[1], "%d", prkey);
|
|
sprintf(keyring_str[2], "%d", sskey);
|
|
|
|
/* set up a minimal environment */
|
|
i = 0;
|
|
envp[i++] = "HOME=/";
|
|
envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
|
|
envp[i] = NULL;
|
|
|
|
/* set up the argument list */
|
|
i = 0;
|
|
argv[i++] = "/sbin/request-key";
|
|
argv[i++] = (char *) op;
|
|
argv[i++] = key_str;
|
|
argv[i++] = uid_str;
|
|
argv[i++] = gid_str;
|
|
argv[i++] = keyring_str[0];
|
|
argv[i++] = keyring_str[1];
|
|
argv[i++] = keyring_str[2];
|
|
argv[i++] = callout_info[0] ? (char *) callout_info : "-";
|
|
argv[i] = NULL;
|
|
|
|
/* do it */
|
|
return call_usermodehelper(argv[0], argv, envp, 1);
|
|
|
|
} /* end call_request_key() */
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* call out to userspace for the key
|
|
* - called with the construction sem held, but the sem is dropped here
|
|
* - we ignore program failure and go on key status instead
|
|
*/
|
|
static struct key *__request_key_construction(struct key_type *type,
|
|
const char *description,
|
|
const char *callout_info)
|
|
{
|
|
struct key_construction cons;
|
|
struct timespec now;
|
|
struct key *key;
|
|
int ret, negative;
|
|
|
|
/* create a key and add it to the queue */
|
|
key = key_alloc(type, description,
|
|
current->fsuid, current->fsgid, KEY_USR_ALL, 0);
|
|
if (IS_ERR(key))
|
|
goto alloc_failed;
|
|
|
|
write_lock(&key->lock);
|
|
key->flags |= KEY_FLAG_USER_CONSTRUCT;
|
|
write_unlock(&key->lock);
|
|
|
|
cons.key = key;
|
|
list_add_tail(&cons.link, &key->user->consq);
|
|
|
|
/* we drop the construction sem here on behalf of the caller */
|
|
up_write(&key_construction_sem);
|
|
|
|
/* make the call */
|
|
ret = call_request_key(key, "create", callout_info);
|
|
if (ret < 0)
|
|
goto request_failed;
|
|
|
|
/* if the key wasn't instantiated, then we want to give an error */
|
|
ret = -ENOKEY;
|
|
if (!(key->flags & KEY_FLAG_INSTANTIATED))
|
|
goto request_failed;
|
|
|
|
down_write(&key_construction_sem);
|
|
list_del(&cons.link);
|
|
up_write(&key_construction_sem);
|
|
|
|
/* also give an error if the key was negatively instantiated */
|
|
check_not_negative:
|
|
if (key->flags & KEY_FLAG_NEGATIVE) {
|
|
key_put(key);
|
|
key = ERR_PTR(-ENOKEY);
|
|
}
|
|
|
|
out:
|
|
return key;
|
|
|
|
request_failed:
|
|
/* it wasn't instantiated
|
|
* - remove from construction queue
|
|
* - mark the key as dead
|
|
*/
|
|
negative = 0;
|
|
down_write(&key_construction_sem);
|
|
|
|
list_del(&cons.link);
|
|
|
|
write_lock(&key->lock);
|
|
key->flags &= ~KEY_FLAG_USER_CONSTRUCT;
|
|
|
|
/* check it didn't get instantiated between the check and the down */
|
|
if (!(key->flags & KEY_FLAG_INSTANTIATED)) {
|
|
key->flags |= KEY_FLAG_INSTANTIATED | KEY_FLAG_NEGATIVE;
|
|
negative = 1;
|
|
}
|
|
|
|
write_unlock(&key->lock);
|
|
up_write(&key_construction_sem);
|
|
|
|
if (!negative)
|
|
goto check_not_negative; /* surprisingly, the key got
|
|
* instantiated */
|
|
|
|
/* set the timeout and store in the session keyring if we can */
|
|
now = current_kernel_time();
|
|
key->expiry = now.tv_sec + key_negative_timeout;
|
|
|
|
if (current->signal->session_keyring) {
|
|
unsigned long flags;
|
|
struct key *keyring;
|
|
|
|
spin_lock_irqsave(¤t->sighand->siglock, flags);
|
|
keyring = current->signal->session_keyring;
|
|
atomic_inc(&keyring->usage);
|
|
spin_unlock_irqrestore(¤t->sighand->siglock, flags);
|
|
|
|
key_link(keyring, key);
|
|
key_put(keyring);
|
|
}
|
|
|
|
key_put(key);
|
|
|
|
/* notify anyone who was waiting */
|
|
wake_up_all(&request_key_conswq);
|
|
|
|
key = ERR_PTR(ret);
|
|
goto out;
|
|
|
|
alloc_failed:
|
|
up_write(&key_construction_sem);
|
|
goto out;
|
|
|
|
} /* end __request_key_construction() */
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* call out to userspace to request the key
|
|
* - we check the construction queue first to see if an appropriate key is
|
|
* already being constructed by userspace
|
|
*/
|
|
static struct key *request_key_construction(struct key_type *type,
|
|
const char *description,
|
|
struct key_user *user,
|
|
const char *callout_info)
|
|
{
|
|
struct key_construction *pcons;
|
|
struct key *key, *ckey;
|
|
|
|
DECLARE_WAITQUEUE(myself, current);
|
|
|
|
/* see if there's such a key under construction already */
|
|
down_write(&key_construction_sem);
|
|
|
|
list_for_each_entry(pcons, &user->consq, link) {
|
|
ckey = pcons->key;
|
|
|
|
if (ckey->type != type)
|
|
continue;
|
|
|
|
if (type->match(ckey, description))
|
|
goto found_key_under_construction;
|
|
}
|
|
|
|
/* see about getting userspace to construct the key */
|
|
key = __request_key_construction(type, description, callout_info);
|
|
error:
|
|
return key;
|
|
|
|
/* someone else has the same key under construction
|
|
* - we want to keep an eye on their key
|
|
*/
|
|
found_key_under_construction:
|
|
atomic_inc(&ckey->usage);
|
|
up_write(&key_construction_sem);
|
|
|
|
/* wait for the key to be completed one way or another */
|
|
add_wait_queue(&request_key_conswq, &myself);
|
|
|
|
for (;;) {
|
|
set_current_state(TASK_UNINTERRUPTIBLE);
|
|
if (!(ckey->flags & KEY_FLAG_USER_CONSTRUCT))
|
|
break;
|
|
schedule();
|
|
}
|
|
|
|
set_current_state(TASK_RUNNING);
|
|
remove_wait_queue(&request_key_conswq, &myself);
|
|
|
|
/* we'll need to search this process's keyrings to see if the key is
|
|
* now there since we can't automatically assume it's also available
|
|
* there */
|
|
key_put(ckey);
|
|
ckey = NULL;
|
|
|
|
key = NULL; /* request a retry */
|
|
goto error;
|
|
|
|
} /* end request_key_construction() */
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* request a key
|
|
* - search the process's keyrings
|
|
* - check the list of keys being created or updated
|
|
* - call out to userspace for a key if requested (supplementary info can be
|
|
* passed)
|
|
*/
|
|
struct key *request_key(struct key_type *type,
|
|
const char *description,
|
|
const char *callout_info)
|
|
{
|
|
struct key_user *user;
|
|
struct key *key;
|
|
|
|
/* search all the process keyrings for a key */
|
|
key = search_process_keyrings_aux(type, description, type->match);
|
|
|
|
if (PTR_ERR(key) == -EAGAIN) {
|
|
/* the search failed, but the keyrings were searchable, so we
|
|
* should consult userspace if we can */
|
|
key = ERR_PTR(-ENOKEY);
|
|
if (!callout_info)
|
|
goto error;
|
|
|
|
/* - get hold of the user's construction queue */
|
|
user = key_user_lookup(current->fsuid);
|
|
if (!user) {
|
|
key = ERR_PTR(-ENOMEM);
|
|
goto error;
|
|
}
|
|
|
|
for (;;) {
|
|
/* ask userspace (returns NULL if it waited on a key
|
|
* being constructed) */
|
|
key = request_key_construction(type, description,
|
|
user, callout_info);
|
|
if (key)
|
|
break;
|
|
|
|
/* someone else made the key we want, so we need to
|
|
* search again as it might now be available to us */
|
|
key = search_process_keyrings_aux(type, description,
|
|
type->match);
|
|
if (PTR_ERR(key) != -EAGAIN)
|
|
break;
|
|
}
|
|
|
|
key_user_put(user);
|
|
}
|
|
|
|
error:
|
|
return key;
|
|
|
|
} /* end request_key() */
|
|
|
|
EXPORT_SYMBOL(request_key);
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* validate a key
|
|
*/
|
|
int key_validate(struct key *key)
|
|
{
|
|
struct timespec now;
|
|
int ret = 0;
|
|
|
|
if (key) {
|
|
/* check it's still accessible */
|
|
ret = -EKEYREVOKED;
|
|
if (key->flags & (KEY_FLAG_REVOKED | KEY_FLAG_DEAD))
|
|
goto error;
|
|
|
|
/* check it hasn't expired */
|
|
ret = 0;
|
|
if (key->expiry) {
|
|
now = current_kernel_time();
|
|
if (now.tv_sec >= key->expiry)
|
|
ret = -EKEYEXPIRED;
|
|
}
|
|
}
|
|
|
|
error:
|
|
return ret;
|
|
|
|
} /* end key_validate() */
|
|
|
|
EXPORT_SYMBOL(key_validate);
|