linuxdebug/security/keys/process_keys.c

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2024-07-16 15:50:57 +02:00
// SPDX-License-Identifier: GPL-2.0-or-later
/* Manage a process's keyrings
*
* Copyright (C) 2004-2005, 2008 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/sched/user.h>
#include <linux/keyctl.h>
#include <linux/fs.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/security.h>
#include <linux/user_namespace.h>
#include <linux/uaccess.h>
#include <linux/init_task.h>
#include <keys/request_key_auth-type.h>
#include "internal.h"
/* Session keyring create vs join semaphore */
static DEFINE_MUTEX(key_session_mutex);
/* The root user's tracking struct */
struct key_user root_key_user = {
.usage = REFCOUNT_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 = GLOBAL_ROOT_UID,
};
/*
* Get or create a user register keyring.
*/
static struct key *get_user_register(struct user_namespace *user_ns)
{
struct key *reg_keyring = READ_ONCE(user_ns->user_keyring_register);
if (reg_keyring)
return reg_keyring;
down_write(&user_ns->keyring_sem);
/* Make sure there's a register keyring. It gets owned by the
* user_namespace's owner.
*/
reg_keyring = user_ns->user_keyring_register;
if (!reg_keyring) {
reg_keyring = keyring_alloc(".user_reg",
user_ns->owner, INVALID_GID,
&init_cred,
KEY_POS_WRITE | KEY_POS_SEARCH |
KEY_USR_VIEW | KEY_USR_READ,
0,
NULL, NULL);
if (!IS_ERR(reg_keyring))
smp_store_release(&user_ns->user_keyring_register,
reg_keyring);
}
up_write(&user_ns->keyring_sem);
/* We don't return a ref since the keyring is pinned by the user_ns */
return reg_keyring;
}
/*
* Look up the user and user session keyrings for the current process's UID,
* creating them if they don't exist.
*/
int look_up_user_keyrings(struct key **_user_keyring,
struct key **_user_session_keyring)
{
const struct cred *cred = current_cred();
struct user_namespace *user_ns = current_user_ns();
struct key *reg_keyring, *uid_keyring, *session_keyring;
key_perm_t user_keyring_perm;
key_ref_t uid_keyring_r, session_keyring_r;
uid_t uid = from_kuid(user_ns, cred->user->uid);
char buf[20];
int ret;
user_keyring_perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_ALL;
kenter("%u", uid);
reg_keyring = get_user_register(user_ns);
if (IS_ERR(reg_keyring))
return PTR_ERR(reg_keyring);
down_write(&user_ns->keyring_sem);
ret = 0;
/* Get the user keyring. Note that 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.
*/
snprintf(buf, sizeof(buf), "_uid.%u", uid);
uid_keyring_r = keyring_search(make_key_ref(reg_keyring, true),
&key_type_keyring, buf, false);
kdebug("_uid %p", uid_keyring_r);
if (uid_keyring_r == ERR_PTR(-EAGAIN)) {
uid_keyring = keyring_alloc(buf, cred->user->uid, INVALID_GID,
cred, user_keyring_perm,
KEY_ALLOC_UID_KEYRING |
KEY_ALLOC_IN_QUOTA,
NULL, reg_keyring);
if (IS_ERR(uid_keyring)) {
ret = PTR_ERR(uid_keyring);
goto error;
}
} else if (IS_ERR(uid_keyring_r)) {
ret = PTR_ERR(uid_keyring_r);
goto error;
} else {
uid_keyring = key_ref_to_ptr(uid_keyring_r);
}
/* Get a default session keyring (which might also exist already) */
snprintf(buf, sizeof(buf), "_uid_ses.%u", uid);
session_keyring_r = keyring_search(make_key_ref(reg_keyring, true),
&key_type_keyring, buf, false);
kdebug("_uid_ses %p", session_keyring_r);
if (session_keyring_r == ERR_PTR(-EAGAIN)) {
session_keyring = keyring_alloc(buf, cred->user->uid, INVALID_GID,
cred, user_keyring_perm,
KEY_ALLOC_UID_KEYRING |
KEY_ALLOC_IN_QUOTA,
NULL, 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_session;
/* And only then link the user-session keyring to the
* register.
*/
ret = key_link(reg_keyring, session_keyring);
if (ret < 0)
goto error_release_session;
} else if (IS_ERR(session_keyring_r)) {
ret = PTR_ERR(session_keyring_r);
goto error_release;
} else {
session_keyring = key_ref_to_ptr(session_keyring_r);
}
up_write(&user_ns->keyring_sem);
if (_user_session_keyring)
*_user_session_keyring = session_keyring;
else
key_put(session_keyring);
if (_user_keyring)
*_user_keyring = uid_keyring;
else
key_put(uid_keyring);
kleave(" = 0");
return 0;
error_release_session:
key_put(session_keyring);
error_release:
key_put(uid_keyring);
error:
up_write(&user_ns->keyring_sem);
kleave(" = %d", ret);
return ret;
}
/*
* Get the user session keyring if it exists, but don't create it if it
* doesn't.
*/
struct key *get_user_session_keyring_rcu(const struct cred *cred)
{
struct key *reg_keyring = READ_ONCE(cred->user_ns->user_keyring_register);
key_ref_t session_keyring_r;
char buf[20];
struct keyring_search_context ctx = {
.index_key.type = &key_type_keyring,
.index_key.description = buf,
.cred = cred,
.match_data.cmp = key_default_cmp,
.match_data.raw_data = buf,
.match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT,
.flags = KEYRING_SEARCH_DO_STATE_CHECK,
};
if (!reg_keyring)
return NULL;
ctx.index_key.desc_len = snprintf(buf, sizeof(buf), "_uid_ses.%u",
from_kuid(cred->user_ns,
cred->user->uid));
session_keyring_r = keyring_search_rcu(make_key_ref(reg_keyring, true),
&ctx);
if (IS_ERR(session_keyring_r))
return NULL;
return key_ref_to_ptr(session_keyring_r);
}
/*
* Install a thread keyring to the given credentials struct if it didn't have
* one already. This is allowed to overrun the quota.
*
* Return: 0 if a thread keyring is now present; -errno on failure.
*/
int install_thread_keyring_to_cred(struct cred *new)
{
struct key *keyring;
if (new->thread_keyring)
return 0;
keyring = keyring_alloc("_tid", new->uid, new->gid, new,
KEY_POS_ALL | KEY_USR_VIEW,
KEY_ALLOC_QUOTA_OVERRUN,
NULL, NULL);
if (IS_ERR(keyring))
return PTR_ERR(keyring);
new->thread_keyring = keyring;
return 0;
}
/*
* Install a thread keyring to the current task if it didn't have one already.
*
* Return: 0 if a thread keyring is now present; -errno on failure.
*/
static int install_thread_keyring(void)
{
struct cred *new;
int ret;
new = prepare_creds();
if (!new)
return -ENOMEM;
ret = install_thread_keyring_to_cred(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
}
/*
* Install a process keyring to the given credentials struct if it didn't have
* one already. This is allowed to overrun the quota.
*
* Return: 0 if a process keyring is now present; -errno on failure.
*/
int install_process_keyring_to_cred(struct cred *new)
{
struct key *keyring;
if (new->process_keyring)
return 0;
keyring = keyring_alloc("_pid", new->uid, new->gid, new,
KEY_POS_ALL | KEY_USR_VIEW,
KEY_ALLOC_QUOTA_OVERRUN,
NULL, NULL);
if (IS_ERR(keyring))
return PTR_ERR(keyring);
new->process_keyring = keyring;
return 0;
}
/*
* Install a process keyring to the current task if it didn't have one already.
*
* Return: 0 if a process keyring is now present; -errno on failure.
*/
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;
}
return commit_creds(new);
}
/*
* Install the given keyring as the session keyring of the given credentials
* struct, replacing the existing one if any. If the given keyring is NULL,
* then install a new anonymous session keyring.
* @cred can not be in use by any task yet.
*
* Return: 0 on success; -errno on failure.
*/
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->session_keyring)
flags = KEY_ALLOC_IN_QUOTA;
keyring = keyring_alloc("_ses", cred->uid, cred->gid, cred,
KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ,
flags, NULL, NULL);
if (IS_ERR(keyring))
return PTR_ERR(keyring);
} else {
__key_get(keyring);
}
/* install the keyring */
old = cred->session_keyring;
cred->session_keyring = keyring;
if (old)
key_put(old);
return 0;
}
/*
* Install the given keyring as the session keyring of the current task,
* replacing the existing one if any. If the given keyring is NULL, then
* install a new anonymous session keyring.
*
* Return: 0 on success; -errno on failure.
*/
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, keyring);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
}
/*
* Handle the fsuid changing.
*/
void key_fsuid_changed(struct cred *new_cred)
{
/* update the ownership of the thread keyring */
if (new_cred->thread_keyring) {
down_write(&new_cred->thread_keyring->sem);
new_cred->thread_keyring->uid = new_cred->fsuid;
up_write(&new_cred->thread_keyring->sem);
}
}
/*
* Handle the fsgid changing.
*/
void key_fsgid_changed(struct cred *new_cred)
{
/* update the ownership of the thread keyring */
if (new_cred->thread_keyring) {
down_write(&new_cred->thread_keyring->sem);
new_cred->thread_keyring->gid = new_cred->fsgid;
up_write(&new_cred->thread_keyring->sem);
}
}
/*
* Search the process keyrings attached to the supplied cred for the first
* matching key under RCU conditions (the caller must be holding the RCU read
* lock).
*
* The search criteria are the type and the match function. The description is
* given to the match function as a parameter, but doesn't otherwise influence
* the search. Typically the match function will compare the description
* parameter to the key's description.
*
* This can only search keyrings that grant Search permission to the supplied
* credentials. Keyrings linked to searched keyrings will also be searched if
* they grant Search permission too. Keys can only be found if they grant
* Search permission to the credentials.
*
* Returns a pointer to the key with the key usage count incremented if
* successful, -EAGAIN if we didn't find any matching key or -ENOKEY if we only
* matched negative keys.
*
* In the case of a successful return, the possession attribute is set on the
* returned key reference.
*/
key_ref_t search_cred_keyrings_rcu(struct keyring_search_context *ctx)
{
struct key *user_session;
key_ref_t key_ref, ret, err;
const struct cred *cred = ctx->cred;
/* 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_rcu(
make_key_ref(cred->thread_keyring, 1), ctx);
if (!IS_ERR(key_ref))
goto found;
switch (PTR_ERR(key_ref)) {
case -EAGAIN: /* no key */
case -ENOKEY: /* negative key */
ret = key_ref;
break;
default:
err = key_ref;
break;
}
}
/* search the process keyring second */
if (cred->process_keyring) {
key_ref = keyring_search_rcu(
make_key_ref(cred->process_keyring, 1), ctx);
if (!IS_ERR(key_ref))
goto found;
switch (PTR_ERR(key_ref)) {
case -EAGAIN: /* no key */
if (ret)
break;
fallthrough;
case -ENOKEY: /* negative key */
ret = key_ref;
break;
default:
err = key_ref;
break;
}
}
/* search the session keyring */
if (cred->session_keyring) {
key_ref = keyring_search_rcu(
make_key_ref(cred->session_keyring, 1), ctx);
if (!IS_ERR(key_ref))
goto found;
switch (PTR_ERR(key_ref)) {
case -EAGAIN: /* no key */
if (ret)
break;
fallthrough;
case -ENOKEY: /* negative key */
ret = key_ref;
break;
default:
err = key_ref;
break;
}
}
/* or search the user-session keyring */
else if ((user_session = get_user_session_keyring_rcu(cred))) {
key_ref = keyring_search_rcu(make_key_ref(user_session, 1),
ctx);
key_put(user_session);
if (!IS_ERR(key_ref))
goto found;
switch (PTR_ERR(key_ref)) {
case -EAGAIN: /* no key */
if (ret)
break;
fallthrough;
case -ENOKEY: /* negative key */
ret = key_ref;
break;
default:
err = key_ref;
break;
}
}
/* no key - decide on the error we're going to go for */
key_ref = ret ? ret : err;
found:
return key_ref;
}
/*
* Search the process keyrings attached to the supplied cred for the first
* matching key in the manner of search_my_process_keyrings(), but also search
* the keys attached to the assumed authorisation key using its credentials if
* one is available.
*
* The caller must be holding the RCU read lock.
*
* Return same as search_cred_keyrings_rcu().
*/
key_ref_t search_process_keyrings_rcu(struct keyring_search_context *ctx)
{
struct request_key_auth *rka;
key_ref_t key_ref, ret = ERR_PTR(-EACCES), err;
key_ref = search_cred_keyrings_rcu(ctx);
if (!IS_ERR(key_ref))
goto found;
err = key_ref;
/* 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 (ctx->cred->request_key_auth &&
ctx->cred == current_cred() &&
ctx->index_key.type != &key_type_request_key_auth
) {
const struct cred *cred = ctx->cred;
if (key_validate(cred->request_key_auth) == 0) {
rka = ctx->cred->request_key_auth->payload.data[0];
//// was search_process_keyrings() [ie. recursive]
ctx->cred = rka->cred;
key_ref = search_cred_keyrings_rcu(ctx);
ctx->cred = cred;
if (!IS_ERR(key_ref))
goto found;
ret = key_ref;
}
}
/* no key - decide on the error we're going to go for */
if (err == ERR_PTR(-ENOKEY) || ret == ERR_PTR(-ENOKEY))
key_ref = ERR_PTR(-ENOKEY);
else if (err == ERR_PTR(-EACCES))
key_ref = ret;
else
key_ref = err;
found:
return key_ref;
}
/*
* See if the key we're looking at is the target key.
*/
bool lookup_user_key_possessed(const struct key *key,
const struct key_match_data *match_data)
{
return key == match_data->raw_data;
}
/*
* Look up a key ID given us by userspace with a given permissions mask to get
* the key it refers to.
*
* Flags can be passed to request that special keyrings be created if referred
* to directly, to permit partially constructed keys to be found and to skip
* validity and permission checks on the found key.
*
* Returns a pointer to the key with an incremented usage count if successful;
* -EINVAL if the key ID is invalid; -ENOKEY if the key ID does not correspond
* to a key or the best found key was a negative key; -EKEYREVOKED or
* -EKEYEXPIRED if the best found key was revoked or expired; -EACCES if the
* found key doesn't grant the requested permit or the LSM denied access to it;
* or -ENOMEM if a special keyring couldn't be created.
*
* In the case of a successful return, the possession attribute is set on the
* returned key reference.
*/
key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags,
enum key_need_perm need_perm)
{
struct keyring_search_context ctx = {
.match_data.cmp = lookup_user_key_possessed,
.match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT,
.flags = (KEYRING_SEARCH_NO_STATE_CHECK |
KEYRING_SEARCH_RECURSE),
};
struct request_key_auth *rka;
struct key *key, *user_session;
key_ref_t key_ref, skey_ref;
int ret;
try_again:
ctx.cred = get_current_cred();
key_ref = ERR_PTR(-ENOKEY);
switch (id) {
case KEY_SPEC_THREAD_KEYRING:
if (!ctx.cred->thread_keyring) {
if (!(lflags & KEY_LOOKUP_CREATE))
goto error;
ret = install_thread_keyring();
if (ret < 0) {
key_ref = ERR_PTR(ret);
goto error;
}
goto reget_creds;
}
key = ctx.cred->thread_keyring;
__key_get(key);
key_ref = make_key_ref(key, 1);
break;
case KEY_SPEC_PROCESS_KEYRING:
if (!ctx.cred->process_keyring) {
if (!(lflags & KEY_LOOKUP_CREATE))
goto error;
ret = install_process_keyring();
if (ret < 0) {
key_ref = ERR_PTR(ret);
goto error;
}
goto reget_creds;
}
key = ctx.cred->process_keyring;
__key_get(key);
key_ref = make_key_ref(key, 1);
break;
case KEY_SPEC_SESSION_KEYRING:
if (!ctx.cred->session_keyring) {
/* always install a session keyring upon access if one
* doesn't exist yet */
ret = look_up_user_keyrings(NULL, &user_session);
if (ret < 0)
goto error;
if (lflags & KEY_LOOKUP_CREATE)
ret = join_session_keyring(NULL);
else
ret = install_session_keyring(user_session);
key_put(user_session);
if (ret < 0)
goto error;
goto reget_creds;
} else if (test_bit(KEY_FLAG_UID_KEYRING,
&ctx.cred->session_keyring->flags) &&
lflags & KEY_LOOKUP_CREATE) {
ret = join_session_keyring(NULL);
if (ret < 0)
goto error;
goto reget_creds;
}
key = ctx.cred->session_keyring;
__key_get(key);
key_ref = make_key_ref(key, 1);
break;
case KEY_SPEC_USER_KEYRING:
ret = look_up_user_keyrings(&key, NULL);
if (ret < 0)
goto error;
key_ref = make_key_ref(key, 1);
break;
case KEY_SPEC_USER_SESSION_KEYRING:
ret = look_up_user_keyrings(NULL, &key);
if (ret < 0)
goto error;
key_ref = make_key_ref(key, 1);
break;
case KEY_SPEC_GROUP_KEYRING:
/* group keyrings are not yet supported */
key_ref = ERR_PTR(-EINVAL);
goto error;
case KEY_SPEC_REQKEY_AUTH_KEY:
key = ctx.cred->request_key_auth;
if (!key)
goto error;
__key_get(key);
key_ref = make_key_ref(key, 1);
break;
case KEY_SPEC_REQUESTOR_KEYRING:
if (!ctx.cred->request_key_auth)
goto error;
down_read(&ctx.cred->request_key_auth->sem);
if (test_bit(KEY_FLAG_REVOKED,
&ctx.cred->request_key_auth->flags)) {
key_ref = ERR_PTR(-EKEYREVOKED);
key = NULL;
} else {
rka = ctx.cred->request_key_auth->payload.data[0];
key = rka->dest_keyring;
__key_get(key);
}
up_read(&ctx.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 */
ctx.index_key = key->index_key;
ctx.match_data.raw_data = key;
kdebug("check possessed");
rcu_read_lock();
skey_ref = search_process_keyrings_rcu(&ctx);
rcu_read_unlock();
kdebug("possessed=%p", skey_ref);
if (!IS_ERR(skey_ref)) {
key_put(key);
key_ref = skey_ref;
}
break;
}
/* unlink does not use the nominated key in any way, so can skip all
* the permission checks as it is only concerned with the keyring */
if (need_perm != KEY_NEED_UNLINK) {
if (!(lflags & KEY_LOOKUP_PARTIAL)) {
ret = wait_for_key_construction(key, true);
switch (ret) {
case -ERESTARTSYS:
goto invalid_key;
default:
if (need_perm != KEY_AUTHTOKEN_OVERRIDE &&
need_perm != KEY_DEFER_PERM_CHECK)
goto invalid_key;
break;
case 0:
break;
}
} else if (need_perm != KEY_DEFER_PERM_CHECK) {
ret = key_validate(key);
if (ret < 0)
goto invalid_key;
}
ret = -EIO;
if (!(lflags & KEY_LOOKUP_PARTIAL) &&
key_read_state(key) == KEY_IS_UNINSTANTIATED)
goto invalid_key;
}
/* check the permissions */
ret = key_task_permission(key_ref, ctx.cred, need_perm);
if (ret < 0)
goto invalid_key;
key->last_used_at = ktime_get_real_seconds();
error:
put_cred(ctx.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(ctx.cred);
goto try_again;
}
EXPORT_SYMBOL(lookup_user_key);
/*
* Join the named keyring as the session keyring if possible else attempt to
* create a new one of that name and join that.
*
* If the name is NULL, an empty anonymous keyring will be installed as the
* session keyring.
*
* Named session keyrings are joined with a semaphore held to prevent the
* keyrings from going away whilst the attempt is made to going them and also
* to prevent a race in creating compatible session keyrings.
*/
long join_session_keyring(const char *name)
{
const struct cred *old;
struct cred *new;
struct key *keyring;
long ret, serial;
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->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_POS_ALL | KEY_USR_VIEW | KEY_USR_READ | KEY_USR_LINK,
KEY_ALLOC_IN_QUOTA, NULL, NULL);
if (IS_ERR(keyring)) {
ret = PTR_ERR(keyring);
goto error2;
}
} else if (IS_ERR(keyring)) {
ret = PTR_ERR(keyring);
goto error2;
} else if (keyring == new->session_keyring) {
ret = 0;
goto error3;
}
/* we've got a keyring - now to install it */
ret = install_session_keyring_to_cred(new, keyring);
if (ret < 0)
goto error3;
commit_creds(new);
mutex_unlock(&key_session_mutex);
ret = keyring->serial;
key_put(keyring);
okay:
return ret;
error3:
key_put(keyring);
error2:
mutex_unlock(&key_session_mutex);
error:
abort_creds(new);
return ret;
}
/*
* Replace a process's session keyring on behalf of one of its children when
* the target process is about to resume userspace execution.
*/
void key_change_session_keyring(struct callback_head *twork)
{
const struct cred *old = current_cred();
struct cred *new = container_of(twork, struct cred, rcu);
if (unlikely(current->flags & PF_EXITING)) {
put_cred(new);
return;
}
/* If get_ucounts fails more bits are needed in the refcount */
if (unlikely(!get_ucounts(old->ucounts))) {
WARN_ONCE(1, "In %s get_ucounts failed\n", __func__);
put_cred(new);
return;
}
new-> uid = old-> uid;
new-> euid = old-> euid;
new-> suid = old-> suid;
new->fsuid = old->fsuid;
new-> gid = old-> gid;
new-> egid = old-> egid;
new-> sgid = old-> sgid;
new->fsgid = old->fsgid;
new->user = get_uid(old->user);
new->ucounts = old->ucounts;
new->user_ns = get_user_ns(old->user_ns);
new->group_info = get_group_info(old->group_info);
new->securebits = old->securebits;
new->cap_inheritable = old->cap_inheritable;
new->cap_permitted = old->cap_permitted;
new->cap_effective = old->cap_effective;
new->cap_ambient = old->cap_ambient;
new->cap_bset = old->cap_bset;
new->jit_keyring = old->jit_keyring;
new->thread_keyring = key_get(old->thread_keyring);
new->process_keyring = key_get(old->process_keyring);
security_transfer_creds(new, old);
commit_creds(new);
}
/*
* Make sure that root's user and user-session keyrings exist.
*/
static int __init init_root_keyring(void)
{
return look_up_user_keyrings(NULL, NULL);
}
late_initcall(init_root_keyring);