Revision fea20995976f4b2e8968f852a18e280487d42f0d authored by Paul Kocialkowski on 10 July 2017, 19:33:05 UTC, committed by Thierry Reding on 27 July 2017, 14:57:34 UTC
When there is no device to attach to the IOMMU domain, as may be the case when the device-tree does not contain the proper iommu node, it is best to keep going without IOMMU support rather than failing. This allows the driver to probe and function instead of taking down all of the tegra drm driver, leading to missing display support. Signed-off-by: Paul Kocialkowski <contact@paulk.fr> Fixes: 404bfb78daf3 ("gpu: host1x: Add IOMMU support") Reviewed-by: Mikko Perttunen <mperttunen@nvidia.com> Tested-by: Marcel Ziswiler <marcel.ziswiler@toradex.com> Signed-off-by: Thierry Reding <treding@nvidia.com> Link: https://patchwork.freedesktop.org/patch/msgid/20170710193305.5987-1-contact@paulk.fr
1 parent b9670ca
process_keys.c
/* Manage 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/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 "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 = 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,
};
/*
* Install the user and user session keyrings for the current process's UID.
*/
int install_user_keyrings(void)
{
struct user_struct *user;
const struct cred *cred;
struct key *uid_keyring, *session_keyring;
key_perm_t user_keyring_perm;
char buf[20];
int ret;
uid_t uid;
user_keyring_perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_ALL;
cred = current_cred();
user = cred->user;
uid = from_kuid(cred->user_ns, user->uid);
kenter("%p{%u}", user, uid);
if (user->uid_keyring && user->session_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", uid);
uid_keyring = find_keyring_by_name(buf, true);
if (IS_ERR(uid_keyring)) {
uid_keyring = keyring_alloc(buf, user->uid, INVALID_GID,
cred, user_keyring_perm,
KEY_ALLOC_IN_QUOTA,
NULL, 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", uid);
session_keyring = find_keyring_by_name(buf, true);
if (IS_ERR(session_keyring)) {
session_keyring =
keyring_alloc(buf, user->uid, INVALID_GID,
cred, user_keyring_perm,
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_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 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.
*
* 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;
rcu_assign_pointer(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 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);
}
}
/*
* Handle the fsgid changing.
*/
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);
}
}
/*
* Search the process keyrings attached to the supplied cred for the first
* matching key.
*
* 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_my_process_keyrings(struct keyring_search_context *ctx)
{
key_ref_t key_ref, ret, err;
/* 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 (ctx->cred->thread_keyring) {
key_ref = keyring_search_aux(
make_key_ref(ctx->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 (ctx->cred->process_keyring) {
key_ref = keyring_search_aux(
make_key_ref(ctx->cred->process_keyring, 1), ctx);
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 (ctx->cred->session_keyring) {
rcu_read_lock();
key_ref = keyring_search_aux(
make_key_ref(rcu_dereference(ctx->cred->session_keyring), 1),
ctx);
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 (ctx->cred->user->session_keyring) {
key_ref = keyring_search_aux(
make_key_ref(ctx->cred->user->session_keyring, 1),
ctx);
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;
}
}
/* 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.
*
* Return same as search_my_process_keyrings().
*/
key_ref_t search_process_keyrings(struct keyring_search_context *ctx)
{
struct request_key_auth *rka;
key_ref_t key_ref, ret = ERR_PTR(-EACCES), err;
might_sleep();
key_ref = search_my_process_keyrings(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;
/* defend against the auth key being revoked */
down_read(&cred->request_key_auth->sem);
if (key_validate(ctx->cred->request_key_auth) == 0) {
rka = ctx->cred->request_key_auth->payload.data[0];
ctx->cred = rka->cred;
key_ref = search_process_keyrings(ctx);
ctx->cred = cred;
up_read(&cred->request_key_auth->sem);
if (!IS_ERR(key_ref))
goto found;
ret = key_ref;
} else {
up_read(&cred->request_key_auth->sem);
}
}
/* 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,
key_perm_t 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,
};
struct request_key_auth *rka;
struct key *key;
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 = install_user_keyrings();
if (ret < 0)
goto error;
if (lflags & KEY_LOOKUP_CREATE)
ret = join_session_keyring(NULL);
else
ret = install_session_keyring(
ctx.cred->user->session_keyring);
if (ret < 0)
goto error;
goto reget_creds;
} else if (ctx.cred->session_keyring ==
ctx.cred->user->session_keyring &&
lflags & KEY_LOOKUP_CREATE) {
ret = join_session_keyring(NULL);
if (ret < 0)
goto error;
goto reget_creds;
}
rcu_read_lock();
key = rcu_dereference(ctx.cred->session_keyring);
__key_get(key);
rcu_read_unlock();
key_ref = make_key_ref(key, 1);
break;
case KEY_SPEC_USER_KEYRING:
if (!ctx.cred->user->uid_keyring) {
ret = install_user_keyrings();
if (ret < 0)
goto error;
}
key = ctx.cred->user->uid_keyring;
__key_get(key);
key_ref = make_key_ref(key, 1);
break;
case KEY_SPEC_USER_SESSION_KEYRING:
if (!ctx.cred->user->session_keyring) {
ret = install_user_keyrings();
if (ret < 0)
goto error;
}
key = ctx.cred->user->session_keyring;
__key_get(key);
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.type = key->type;
ctx.index_key.description = key->description;
ctx.index_key.desc_len = strlen(key->description);
ctx.match_data.raw_data = key;
kdebug("check possessed");
skey_ref = search_process_keyrings(&ctx);
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 (lflags & KEY_LOOKUP_FOR_UNLINK) {
ret = 0;
goto error;
}
if (!(lflags & KEY_LOOKUP_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 (!(lflags & KEY_LOOKUP_PARTIAL) &&
!test_bit(KEY_FLAG_INSTANTIATED, &key->flags))
goto invalid_key;
/* check the permissions */
ret = key_task_permission(key_ref, ctx.cred, perm);
if (ret < 0)
goto invalid_key;
key->last_used_at = current_kernel_time().tv_sec;
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;
}
/*
* 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;
}
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->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 install_user_keyrings();
}
late_initcall(init_root_keyring);
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