mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-23 12:43:55 +08:00
a6f76f23d2
Make execve() take advantage of copy-on-write credentials, allowing it to set up the credentials in advance, and then commit the whole lot after the point of no return. This patch and the preceding patches have been tested with the LTP SELinux testsuite. This patch makes several logical sets of alteration: (1) execve(). The credential bits from struct linux_binprm are, for the most part, replaced with a single credentials pointer (bprm->cred). This means that all the creds can be calculated in advance and then applied at the point of no return with no possibility of failure. I would like to replace bprm->cap_effective with: cap_isclear(bprm->cap_effective) but this seems impossible due to special behaviour for processes of pid 1 (they always retain their parent's capability masks where normally they'd be changed - see cap_bprm_set_creds()). The following sequence of events now happens: (a) At the start of do_execve, the current task's cred_exec_mutex is locked to prevent PTRACE_ATTACH from obsoleting the calculation of creds that we make. (a) prepare_exec_creds() is then called to make a copy of the current task's credentials and prepare it. This copy is then assigned to bprm->cred. This renders security_bprm_alloc() and security_bprm_free() unnecessary, and so they've been removed. (b) The determination of unsafe execution is now performed immediately after (a) rather than later on in the code. The result is stored in bprm->unsafe for future reference. (c) prepare_binprm() is called, possibly multiple times. (i) This applies the result of set[ug]id binaries to the new creds attached to bprm->cred. Personality bit clearance is recorded, but now deferred on the basis that the exec procedure may yet fail. (ii) This then calls the new security_bprm_set_creds(). This should calculate the new LSM and capability credentials into *bprm->cred. This folds together security_bprm_set() and parts of security_bprm_apply_creds() (these two have been removed). Anything that might fail must be done at this point. (iii) bprm->cred_prepared is set to 1. bprm->cred_prepared is 0 on the first pass of the security calculations, and 1 on all subsequent passes. This allows SELinux in (ii) to base its calculations only on the initial script and not on the interpreter. (d) flush_old_exec() is called to commit the task to execution. This performs the following steps with regard to credentials: (i) Clear pdeath_signal and set dumpable on certain circumstances that may not be covered by commit_creds(). (ii) Clear any bits in current->personality that were deferred from (c.i). (e) install_exec_creds() [compute_creds() as was] is called to install the new credentials. This performs the following steps with regard to credentials: (i) Calls security_bprm_committing_creds() to apply any security requirements, such as flushing unauthorised files in SELinux, that must be done before the credentials are changed. This is made up of bits of security_bprm_apply_creds() and security_bprm_post_apply_creds(), both of which have been removed. This function is not allowed to fail; anything that might fail must have been done in (c.ii). (ii) Calls commit_creds() to apply the new credentials in a single assignment (more or less). Possibly pdeath_signal and dumpable should be part of struct creds. (iii) Unlocks the task's cred_replace_mutex, thus allowing PTRACE_ATTACH to take place. (iv) Clears The bprm->cred pointer as the credentials it was holding are now immutable. (v) Calls security_bprm_committed_creds() to apply any security alterations that must be done after the creds have been changed. SELinux uses this to flush signals and signal handlers. (f) If an error occurs before (d.i), bprm_free() will call abort_creds() to destroy the proposed new credentials and will then unlock cred_replace_mutex. No changes to the credentials will have been made. (2) LSM interface. A number of functions have been changed, added or removed: (*) security_bprm_alloc(), ->bprm_alloc_security() (*) security_bprm_free(), ->bprm_free_security() Removed in favour of preparing new credentials and modifying those. (*) security_bprm_apply_creds(), ->bprm_apply_creds() (*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds() Removed; split between security_bprm_set_creds(), security_bprm_committing_creds() and security_bprm_committed_creds(). (*) security_bprm_set(), ->bprm_set_security() Removed; folded into security_bprm_set_creds(). (*) security_bprm_set_creds(), ->bprm_set_creds() New. The new credentials in bprm->creds should be checked and set up as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the second and subsequent calls. (*) security_bprm_committing_creds(), ->bprm_committing_creds() (*) security_bprm_committed_creds(), ->bprm_committed_creds() New. Apply the security effects of the new credentials. This includes closing unauthorised files in SELinux. This function may not fail. When the former is called, the creds haven't yet been applied to the process; when the latter is called, they have. The former may access bprm->cred, the latter may not. (3) SELinux. SELinux has a number of changes, in addition to those to support the LSM interface changes mentioned above: (a) The bprm_security_struct struct has been removed in favour of using the credentials-under-construction approach. (c) flush_unauthorized_files() now takes a cred pointer and passes it on to inode_has_perm(), file_has_perm() and dentry_open(). Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: James Morris <jmorris@namei.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
761 lines
17 KiB
C
761 lines
17 KiB
C
/* Management of a process's keyrings
|
|
*
|
|
* Copyright (C) 2004-2005, 2008 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/sched.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/keyctl.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/err.h>
|
|
#include <linux/mutex.h>
|
|
#include <asm/uaccess.h>
|
|
#include "internal.h"
|
|
|
|
/* session keyring create vs join semaphore */
|
|
static DEFINE_MUTEX(key_session_mutex);
|
|
|
|
/* user keyring creation semaphore */
|
|
static DEFINE_MUTEX(key_user_keyring_mutex);
|
|
|
|
/* the root user's tracking struct */
|
|
struct key_user root_key_user = {
|
|
.usage = ATOMIC_INIT(3),
|
|
.cons_lock = __MUTEX_INITIALIZER(root_key_user.cons_lock),
|
|
.lock = __SPIN_LOCK_UNLOCKED(root_key_user.lock),
|
|
.nkeys = ATOMIC_INIT(2),
|
|
.nikeys = ATOMIC_INIT(2),
|
|
.uid = 0,
|
|
};
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* install user and user session keyrings for a particular UID
|
|
*/
|
|
int install_user_keyrings(void)
|
|
{
|
|
struct user_struct *user;
|
|
const struct cred *cred;
|
|
struct key *uid_keyring, *session_keyring;
|
|
char buf[20];
|
|
int ret;
|
|
|
|
cred = current_cred();
|
|
user = cred->user;
|
|
|
|
kenter("%p{%u}", user, user->uid);
|
|
|
|
if (user->uid_keyring) {
|
|
kleave(" = 0 [exist]");
|
|
return 0;
|
|
}
|
|
|
|
mutex_lock(&key_user_keyring_mutex);
|
|
ret = 0;
|
|
|
|
if (!user->uid_keyring) {
|
|
/* get the UID-specific keyring
|
|
* - there may be one in existence already as it may have been
|
|
* pinned by a session, but the user_struct pointing to it
|
|
* may have been destroyed by setuid */
|
|
sprintf(buf, "_uid.%u", user->uid);
|
|
|
|
uid_keyring = find_keyring_by_name(buf, true);
|
|
if (IS_ERR(uid_keyring)) {
|
|
uid_keyring = keyring_alloc(buf, user->uid, (gid_t) -1,
|
|
cred, KEY_ALLOC_IN_QUOTA,
|
|
NULL);
|
|
if (IS_ERR(uid_keyring)) {
|
|
ret = PTR_ERR(uid_keyring);
|
|
goto error;
|
|
}
|
|
}
|
|
|
|
/* get a default session keyring (which might also exist
|
|
* already) */
|
|
sprintf(buf, "_uid_ses.%u", user->uid);
|
|
|
|
session_keyring = find_keyring_by_name(buf, true);
|
|
if (IS_ERR(session_keyring)) {
|
|
session_keyring =
|
|
keyring_alloc(buf, user->uid, (gid_t) -1,
|
|
cred, KEY_ALLOC_IN_QUOTA, NULL);
|
|
if (IS_ERR(session_keyring)) {
|
|
ret = PTR_ERR(session_keyring);
|
|
goto error_release;
|
|
}
|
|
|
|
/* we install a link from the user session keyring to
|
|
* the user keyring */
|
|
ret = key_link(session_keyring, uid_keyring);
|
|
if (ret < 0)
|
|
goto error_release_both;
|
|
}
|
|
|
|
/* install the keyrings */
|
|
user->uid_keyring = uid_keyring;
|
|
user->session_keyring = session_keyring;
|
|
}
|
|
|
|
mutex_unlock(&key_user_keyring_mutex);
|
|
kleave(" = 0");
|
|
return 0;
|
|
|
|
error_release_both:
|
|
key_put(session_keyring);
|
|
error_release:
|
|
key_put(uid_keyring);
|
|
error:
|
|
mutex_unlock(&key_user_keyring_mutex);
|
|
kleave(" = %d", ret);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* install a fresh thread keyring directly to new credentials
|
|
*/
|
|
int install_thread_keyring_to_cred(struct cred *new)
|
|
{
|
|
struct key *keyring;
|
|
|
|
keyring = keyring_alloc("_tid", new->uid, new->gid, new,
|
|
KEY_ALLOC_QUOTA_OVERRUN, NULL);
|
|
if (IS_ERR(keyring))
|
|
return PTR_ERR(keyring);
|
|
|
|
new->thread_keyring = keyring;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* install a fresh thread keyring, discarding the old one
|
|
*/
|
|
static int install_thread_keyring(void)
|
|
{
|
|
struct cred *new;
|
|
int ret;
|
|
|
|
new = prepare_creds();
|
|
if (!new)
|
|
return -ENOMEM;
|
|
|
|
BUG_ON(new->thread_keyring);
|
|
|
|
ret = install_thread_keyring_to_cred(new);
|
|
if (ret < 0) {
|
|
abort_creds(new);
|
|
return ret;
|
|
}
|
|
|
|
return commit_creds(new);
|
|
}
|
|
|
|
/*
|
|
* install a process keyring directly to a credentials struct
|
|
* - returns -EEXIST if there was already a process keyring, 0 if one installed,
|
|
* and other -ve on any other error
|
|
*/
|
|
int install_process_keyring_to_cred(struct cred *new)
|
|
{
|
|
struct key *keyring;
|
|
int ret;
|
|
|
|
if (new->tgcred->process_keyring)
|
|
return -EEXIST;
|
|
|
|
keyring = keyring_alloc("_pid", new->uid, new->gid,
|
|
new, KEY_ALLOC_QUOTA_OVERRUN, NULL);
|
|
if (IS_ERR(keyring))
|
|
return PTR_ERR(keyring);
|
|
|
|
spin_lock_irq(&new->tgcred->lock);
|
|
if (!new->tgcred->process_keyring) {
|
|
new->tgcred->process_keyring = keyring;
|
|
keyring = NULL;
|
|
ret = 0;
|
|
} else {
|
|
ret = -EEXIST;
|
|
}
|
|
spin_unlock_irq(&new->tgcred->lock);
|
|
key_put(keyring);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* make sure a process keyring is installed
|
|
* - we
|
|
*/
|
|
static int install_process_keyring(void)
|
|
{
|
|
struct cred *new;
|
|
int ret;
|
|
|
|
new = prepare_creds();
|
|
if (!new)
|
|
return -ENOMEM;
|
|
|
|
ret = install_process_keyring_to_cred(new);
|
|
if (ret < 0) {
|
|
abort_creds(new);
|
|
return ret != -EEXIST ?: 0;
|
|
}
|
|
|
|
return commit_creds(new);
|
|
}
|
|
|
|
/*
|
|
* install a session keyring directly to a credentials struct
|
|
*/
|
|
static int install_session_keyring_to_cred(struct cred *cred,
|
|
struct key *keyring)
|
|
{
|
|
unsigned long flags;
|
|
struct key *old;
|
|
|
|
might_sleep();
|
|
|
|
/* create an empty session keyring */
|
|
if (!keyring) {
|
|
flags = KEY_ALLOC_QUOTA_OVERRUN;
|
|
if (cred->tgcred->session_keyring)
|
|
flags = KEY_ALLOC_IN_QUOTA;
|
|
|
|
keyring = keyring_alloc("_ses", cred->uid, cred->gid,
|
|
cred, flags, NULL);
|
|
if (IS_ERR(keyring))
|
|
return PTR_ERR(keyring);
|
|
} else {
|
|
atomic_inc(&keyring->usage);
|
|
}
|
|
|
|
/* install the keyring */
|
|
spin_lock_irq(&cred->tgcred->lock);
|
|
old = cred->tgcred->session_keyring;
|
|
rcu_assign_pointer(cred->tgcred->session_keyring, keyring);
|
|
spin_unlock_irq(&cred->tgcred->lock);
|
|
|
|
/* we're using RCU on the pointer, but there's no point synchronising
|
|
* on it if it didn't previously point to anything */
|
|
if (old) {
|
|
synchronize_rcu();
|
|
key_put(old);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* install a session keyring, discarding the old one
|
|
* - if a keyring is not supplied, an empty one is invented
|
|
*/
|
|
static int install_session_keyring(struct key *keyring)
|
|
{
|
|
struct cred *new;
|
|
int ret;
|
|
|
|
new = prepare_creds();
|
|
if (!new)
|
|
return -ENOMEM;
|
|
|
|
ret = install_session_keyring_to_cred(new, NULL);
|
|
if (ret < 0) {
|
|
abort_creds(new);
|
|
return ret;
|
|
}
|
|
|
|
return commit_creds(new);
|
|
}
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* the filesystem user ID changed
|
|
*/
|
|
void key_fsuid_changed(struct task_struct *tsk)
|
|
{
|
|
/* update the ownership of the thread keyring */
|
|
BUG_ON(!tsk->cred);
|
|
if (tsk->cred->thread_keyring) {
|
|
down_write(&tsk->cred->thread_keyring->sem);
|
|
tsk->cred->thread_keyring->uid = tsk->cred->fsuid;
|
|
up_write(&tsk->cred->thread_keyring->sem);
|
|
}
|
|
|
|
} /* end key_fsuid_changed() */
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* the filesystem group ID changed
|
|
*/
|
|
void key_fsgid_changed(struct task_struct *tsk)
|
|
{
|
|
/* update the ownership of the thread keyring */
|
|
BUG_ON(!tsk->cred);
|
|
if (tsk->cred->thread_keyring) {
|
|
down_write(&tsk->cred->thread_keyring->sem);
|
|
tsk->cred->thread_keyring->gid = tsk->cred->fsgid;
|
|
up_write(&tsk->cred->thread_keyring->sem);
|
|
}
|
|
|
|
} /* end key_fsgid_changed() */
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* search the process keyrings for the first matching key
|
|
* - we use the supplied match function to see if the description (or other
|
|
* feature of interest) matches
|
|
* - we return -EAGAIN if we didn't find any matching key
|
|
* - we return -ENOKEY if we found only negative matching keys
|
|
*/
|
|
key_ref_t search_process_keyrings(struct key_type *type,
|
|
const void *description,
|
|
key_match_func_t match,
|
|
const struct cred *cred)
|
|
{
|
|
struct request_key_auth *rka;
|
|
key_ref_t key_ref, ret, err;
|
|
|
|
might_sleep();
|
|
|
|
/* we want to return -EAGAIN or -ENOKEY if any of the keyrings were
|
|
* searchable, but we failed to find a key or we found a negative key;
|
|
* otherwise we want to return a sample error (probably -EACCES) if
|
|
* none of the keyrings were searchable
|
|
*
|
|
* in terms of priority: success > -ENOKEY > -EAGAIN > other error
|
|
*/
|
|
key_ref = NULL;
|
|
ret = NULL;
|
|
err = ERR_PTR(-EAGAIN);
|
|
|
|
/* search the thread keyring first */
|
|
if (cred->thread_keyring) {
|
|
key_ref = keyring_search_aux(
|
|
make_key_ref(cred->thread_keyring, 1),
|
|
cred, type, description, match);
|
|
if (!IS_ERR(key_ref))
|
|
goto found;
|
|
|
|
switch (PTR_ERR(key_ref)) {
|
|
case -EAGAIN: /* no key */
|
|
if (ret)
|
|
break;
|
|
case -ENOKEY: /* negative key */
|
|
ret = key_ref;
|
|
break;
|
|
default:
|
|
err = key_ref;
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* search the process keyring second */
|
|
if (cred->tgcred->process_keyring) {
|
|
key_ref = keyring_search_aux(
|
|
make_key_ref(cred->tgcred->process_keyring, 1),
|
|
cred, type, description, match);
|
|
if (!IS_ERR(key_ref))
|
|
goto found;
|
|
|
|
switch (PTR_ERR(key_ref)) {
|
|
case -EAGAIN: /* no key */
|
|
if (ret)
|
|
break;
|
|
case -ENOKEY: /* negative key */
|
|
ret = key_ref;
|
|
break;
|
|
default:
|
|
err = key_ref;
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* search the session keyring */
|
|
if (cred->tgcred->session_keyring) {
|
|
rcu_read_lock();
|
|
key_ref = keyring_search_aux(
|
|
make_key_ref(rcu_dereference(
|
|
cred->tgcred->session_keyring),
|
|
1),
|
|
cred, type, description, match);
|
|
rcu_read_unlock();
|
|
|
|
if (!IS_ERR(key_ref))
|
|
goto found;
|
|
|
|
switch (PTR_ERR(key_ref)) {
|
|
case -EAGAIN: /* no key */
|
|
if (ret)
|
|
break;
|
|
case -ENOKEY: /* negative key */
|
|
ret = key_ref;
|
|
break;
|
|
default:
|
|
err = key_ref;
|
|
break;
|
|
}
|
|
}
|
|
/* or search the user-session keyring */
|
|
else if (cred->user->session_keyring) {
|
|
key_ref = keyring_search_aux(
|
|
make_key_ref(cred->user->session_keyring, 1),
|
|
cred, type, description, match);
|
|
if (!IS_ERR(key_ref))
|
|
goto found;
|
|
|
|
switch (PTR_ERR(key_ref)) {
|
|
case -EAGAIN: /* no key */
|
|
if (ret)
|
|
break;
|
|
case -ENOKEY: /* negative key */
|
|
ret = key_ref;
|
|
break;
|
|
default:
|
|
err = key_ref;
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* if this process has an instantiation authorisation key, then we also
|
|
* search the keyrings of the process mentioned there
|
|
* - we don't permit access to request_key auth keys via this method
|
|
*/
|
|
if (cred->request_key_auth &&
|
|
cred == current_cred() &&
|
|
type != &key_type_request_key_auth
|
|
) {
|
|
/* defend against the auth key being revoked */
|
|
down_read(&cred->request_key_auth->sem);
|
|
|
|
if (key_validate(cred->request_key_auth) == 0) {
|
|
rka = cred->request_key_auth->payload.data;
|
|
|
|
key_ref = search_process_keyrings(type, description,
|
|
match, rka->cred);
|
|
|
|
up_read(&cred->request_key_auth->sem);
|
|
|
|
if (!IS_ERR(key_ref))
|
|
goto found;
|
|
|
|
switch (PTR_ERR(key_ref)) {
|
|
case -EAGAIN: /* no key */
|
|
if (ret)
|
|
break;
|
|
case -ENOKEY: /* negative key */
|
|
ret = key_ref;
|
|
break;
|
|
default:
|
|
err = key_ref;
|
|
break;
|
|
}
|
|
} else {
|
|
up_read(&cred->request_key_auth->sem);
|
|
}
|
|
}
|
|
|
|
/* no key - decide on the error we're going to go for */
|
|
key_ref = ret ? ret : err;
|
|
|
|
found:
|
|
return key_ref;
|
|
|
|
} /* end search_process_keyrings() */
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* see if the key we're looking at is the target key
|
|
*/
|
|
static int lookup_user_key_possessed(const struct key *key, const void *target)
|
|
{
|
|
return key == target;
|
|
|
|
} /* end lookup_user_key_possessed() */
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* lookup a key given a key ID from userspace with a given permissions mask
|
|
* - don't create special keyrings unless so requested
|
|
* - partially constructed keys aren't found unless requested
|
|
*/
|
|
key_ref_t lookup_user_key(key_serial_t id, int create, int partial,
|
|
key_perm_t perm)
|
|
{
|
|
struct request_key_auth *rka;
|
|
const struct cred *cred;
|
|
struct key *key;
|
|
key_ref_t key_ref, skey_ref;
|
|
int ret;
|
|
|
|
try_again:
|
|
cred = get_current_cred();
|
|
key_ref = ERR_PTR(-ENOKEY);
|
|
|
|
switch (id) {
|
|
case KEY_SPEC_THREAD_KEYRING:
|
|
if (!cred->thread_keyring) {
|
|
if (!create)
|
|
goto error;
|
|
|
|
ret = install_thread_keyring();
|
|
if (ret < 0) {
|
|
key = ERR_PTR(ret);
|
|
goto error;
|
|
}
|
|
goto reget_creds;
|
|
}
|
|
|
|
key = cred->thread_keyring;
|
|
atomic_inc(&key->usage);
|
|
key_ref = make_key_ref(key, 1);
|
|
break;
|
|
|
|
case KEY_SPEC_PROCESS_KEYRING:
|
|
if (!cred->tgcred->process_keyring) {
|
|
if (!create)
|
|
goto error;
|
|
|
|
ret = install_process_keyring();
|
|
if (ret < 0) {
|
|
key = ERR_PTR(ret);
|
|
goto error;
|
|
}
|
|
goto reget_creds;
|
|
}
|
|
|
|
key = cred->tgcred->process_keyring;
|
|
atomic_inc(&key->usage);
|
|
key_ref = make_key_ref(key, 1);
|
|
break;
|
|
|
|
case KEY_SPEC_SESSION_KEYRING:
|
|
if (!cred->tgcred->session_keyring) {
|
|
/* always install a session keyring upon access if one
|
|
* doesn't exist yet */
|
|
ret = install_user_keyrings();
|
|
if (ret < 0)
|
|
goto error;
|
|
ret = install_session_keyring(
|
|
cred->user->session_keyring);
|
|
|
|
if (ret < 0)
|
|
goto error;
|
|
goto reget_creds;
|
|
}
|
|
|
|
rcu_read_lock();
|
|
key = rcu_dereference(cred->tgcred->session_keyring);
|
|
atomic_inc(&key->usage);
|
|
rcu_read_unlock();
|
|
key_ref = make_key_ref(key, 1);
|
|
break;
|
|
|
|
case KEY_SPEC_USER_KEYRING:
|
|
if (!cred->user->uid_keyring) {
|
|
ret = install_user_keyrings();
|
|
if (ret < 0)
|
|
goto error;
|
|
}
|
|
|
|
key = cred->user->uid_keyring;
|
|
atomic_inc(&key->usage);
|
|
key_ref = make_key_ref(key, 1);
|
|
break;
|
|
|
|
case KEY_SPEC_USER_SESSION_KEYRING:
|
|
if (!cred->user->session_keyring) {
|
|
ret = install_user_keyrings();
|
|
if (ret < 0)
|
|
goto error;
|
|
}
|
|
|
|
key = cred->user->session_keyring;
|
|
atomic_inc(&key->usage);
|
|
key_ref = make_key_ref(key, 1);
|
|
break;
|
|
|
|
case KEY_SPEC_GROUP_KEYRING:
|
|
/* group keyrings are not yet supported */
|
|
key = ERR_PTR(-EINVAL);
|
|
goto error;
|
|
|
|
case KEY_SPEC_REQKEY_AUTH_KEY:
|
|
key = cred->request_key_auth;
|
|
if (!key)
|
|
goto error;
|
|
|
|
atomic_inc(&key->usage);
|
|
key_ref = make_key_ref(key, 1);
|
|
break;
|
|
|
|
case KEY_SPEC_REQUESTOR_KEYRING:
|
|
if (!cred->request_key_auth)
|
|
goto error;
|
|
|
|
down_read(&cred->request_key_auth->sem);
|
|
if (cred->request_key_auth->flags & KEY_FLAG_REVOKED) {
|
|
key_ref = ERR_PTR(-EKEYREVOKED);
|
|
key = NULL;
|
|
} else {
|
|
rka = cred->request_key_auth->payload.data;
|
|
key = rka->dest_keyring;
|
|
atomic_inc(&key->usage);
|
|
}
|
|
up_read(&cred->request_key_auth->sem);
|
|
if (!key)
|
|
goto error;
|
|
key_ref = make_key_ref(key, 1);
|
|
break;
|
|
|
|
default:
|
|
key_ref = ERR_PTR(-EINVAL);
|
|
if (id < 1)
|
|
goto error;
|
|
|
|
key = key_lookup(id);
|
|
if (IS_ERR(key)) {
|
|
key_ref = ERR_CAST(key);
|
|
goto error;
|
|
}
|
|
|
|
key_ref = make_key_ref(key, 0);
|
|
|
|
/* check to see if we possess the key */
|
|
skey_ref = search_process_keyrings(key->type, key,
|
|
lookup_user_key_possessed,
|
|
cred);
|
|
|
|
if (!IS_ERR(skey_ref)) {
|
|
key_put(key);
|
|
key_ref = skey_ref;
|
|
}
|
|
|
|
break;
|
|
}
|
|
|
|
if (!partial) {
|
|
ret = wait_for_key_construction(key, true);
|
|
switch (ret) {
|
|
case -ERESTARTSYS:
|
|
goto invalid_key;
|
|
default:
|
|
if (perm)
|
|
goto invalid_key;
|
|
case 0:
|
|
break;
|
|
}
|
|
} else if (perm) {
|
|
ret = key_validate(key);
|
|
if (ret < 0)
|
|
goto invalid_key;
|
|
}
|
|
|
|
ret = -EIO;
|
|
if (!partial && !test_bit(KEY_FLAG_INSTANTIATED, &key->flags))
|
|
goto invalid_key;
|
|
|
|
/* check the permissions */
|
|
ret = key_task_permission(key_ref, cred, perm);
|
|
if (ret < 0)
|
|
goto invalid_key;
|
|
|
|
error:
|
|
put_cred(cred);
|
|
return key_ref;
|
|
|
|
invalid_key:
|
|
key_ref_put(key_ref);
|
|
key_ref = ERR_PTR(ret);
|
|
goto error;
|
|
|
|
/* if we attempted to install a keyring, then it may have caused new
|
|
* creds to be installed */
|
|
reget_creds:
|
|
put_cred(cred);
|
|
goto try_again;
|
|
|
|
} /* end lookup_user_key() */
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* join the named keyring as the session keyring if possible, or attempt to
|
|
* create a new one of that name if not
|
|
* - if the name is NULL, an empty anonymous keyring is installed instead
|
|
* - named session keyring joining is done with a semaphore held
|
|
*/
|
|
long join_session_keyring(const char *name)
|
|
{
|
|
const struct cred *old;
|
|
struct cred *new;
|
|
struct key *keyring;
|
|
long ret, serial;
|
|
|
|
/* only permit this if there's a single thread in the thread group -
|
|
* this avoids us having to adjust the creds on all threads and risking
|
|
* ENOMEM */
|
|
if (!is_single_threaded(current))
|
|
return -EMLINK;
|
|
|
|
new = prepare_creds();
|
|
if (!new)
|
|
return -ENOMEM;
|
|
old = current_cred();
|
|
|
|
/* if no name is provided, install an anonymous keyring */
|
|
if (!name) {
|
|
ret = install_session_keyring_to_cred(new, NULL);
|
|
if (ret < 0)
|
|
goto error;
|
|
|
|
serial = new->tgcred->session_keyring->serial;
|
|
ret = commit_creds(new);
|
|
if (ret == 0)
|
|
ret = serial;
|
|
goto okay;
|
|
}
|
|
|
|
/* allow the user to join or create a named keyring */
|
|
mutex_lock(&key_session_mutex);
|
|
|
|
/* look for an existing keyring of this name */
|
|
keyring = find_keyring_by_name(name, false);
|
|
if (PTR_ERR(keyring) == -ENOKEY) {
|
|
/* not found - try and create a new one */
|
|
keyring = keyring_alloc(name, old->uid, old->gid, old,
|
|
KEY_ALLOC_IN_QUOTA, NULL);
|
|
if (IS_ERR(keyring)) {
|
|
ret = PTR_ERR(keyring);
|
|
goto error2;
|
|
}
|
|
} else if (IS_ERR(keyring)) {
|
|
ret = PTR_ERR(keyring);
|
|
goto error2;
|
|
}
|
|
|
|
/* we've got a keyring - now to install it */
|
|
ret = install_session_keyring_to_cred(new, keyring);
|
|
if (ret < 0)
|
|
goto error2;
|
|
|
|
commit_creds(new);
|
|
mutex_unlock(&key_session_mutex);
|
|
|
|
ret = keyring->serial;
|
|
key_put(keyring);
|
|
okay:
|
|
return ret;
|
|
|
|
error2:
|
|
mutex_unlock(&key_session_mutex);
|
|
error:
|
|
abort_creds(new);
|
|
return ret;
|
|
}
|