219 lines
5.1 KiB
C
219 lines
5.1 KiB
C
/*
|
|
* AppArmor security module
|
|
*
|
|
* This file contains AppArmor functions used to manipulate object security
|
|
* contexts.
|
|
*
|
|
* Copyright (C) 1998-2008 Novell/SUSE
|
|
* Copyright 2009-2010 Canonical Ltd.
|
|
*
|
|
* 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, version 2 of the
|
|
* License.
|
|
*
|
|
*
|
|
* AppArmor sets confinement on every task, via the the aa_task_cxt and
|
|
* the aa_task_cxt.label, both of which are required and are not allowed
|
|
* to be NULL. The aa_task_cxt is not reference counted and is unique
|
|
* to each cred (which is reference count). The label pointed to by
|
|
* the task_cxt is reference counted.
|
|
*
|
|
* TODO
|
|
* If a task uses change_hat it currently does not return to the old
|
|
* cred or task context but instead creates a new one. Ideally the task
|
|
* should return to the previous cred if it has not been modified.
|
|
*
|
|
*/
|
|
|
|
#include "include/context.h"
|
|
#include "include/policy.h"
|
|
|
|
/**
|
|
* aa_alloc_task_context - allocate a new task_cxt
|
|
* @flags: gfp flags for allocation
|
|
*
|
|
* Returns: allocated buffer or NULL on failure
|
|
*/
|
|
struct aa_task_cxt *aa_alloc_task_context(gfp_t flags)
|
|
{
|
|
return kzalloc(sizeof(struct aa_task_cxt), flags);
|
|
}
|
|
|
|
/**
|
|
* aa_free_task_context - free a task_cxt
|
|
* @cxt: task_cxt to free (MAYBE NULL)
|
|
*/
|
|
void aa_free_task_context(struct aa_task_cxt *cxt)
|
|
{
|
|
if (cxt) {
|
|
aa_put_label(cxt->label);
|
|
aa_put_label(cxt->previous);
|
|
aa_put_label(cxt->onexec);
|
|
|
|
kzfree(cxt);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* aa_dup_task_context - duplicate a task context, incrementing reference counts
|
|
* @new: a blank task context (NOT NULL)
|
|
* @old: the task context to copy (NOT NULL)
|
|
*/
|
|
void aa_dup_task_context(struct aa_task_cxt *new, const struct aa_task_cxt *old)
|
|
{
|
|
*new = *old;
|
|
aa_get_label(new->label);
|
|
aa_get_label(new->previous);
|
|
aa_get_label(new->onexec);
|
|
}
|
|
|
|
/**
|
|
* aa_get_task_label - Get another task's label
|
|
* @task: task to query (NOT NULL)
|
|
*
|
|
* Returns: counted reference to @task's label
|
|
*/
|
|
struct aa_label *aa_get_task_label(struct task_struct *task)
|
|
{
|
|
struct aa_label *p;
|
|
|
|
rcu_read_lock();
|
|
p = aa_get_newest_label(__aa_task_raw_label(task));
|
|
rcu_read_unlock();
|
|
|
|
return p;
|
|
}
|
|
|
|
/**
|
|
* aa_replace_current_label - replace the current tasks label
|
|
* @label: new label (NOT NULL)
|
|
*
|
|
* Returns: 0 or error on failure
|
|
*/
|
|
int aa_replace_current_label(struct aa_label *label)
|
|
{
|
|
struct aa_task_cxt *cxt = current_cxt();
|
|
struct cred *new;
|
|
BUG_ON(!label);
|
|
|
|
if (cxt->label == label)
|
|
return 0;
|
|
|
|
new = prepare_creds();
|
|
if (!new)
|
|
return -ENOMEM;
|
|
|
|
cxt = cred_cxt(new);
|
|
if (unconfined(label) || (labels_ns(cxt->label) != labels_ns(label)))
|
|
/* if switching to unconfined or a different label namespace
|
|
* clear out context state
|
|
*/
|
|
aa_clear_task_cxt_trans(cxt);
|
|
|
|
aa_get_label(label);
|
|
aa_put_label(cxt->label);
|
|
cxt->label = label;
|
|
|
|
commit_creds(new);
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* aa_set_current_onexec - set the tasks change_profile to happen onexec
|
|
* @label: system label to set at exec (MAYBE NULL to clear value)
|
|
*
|
|
* Returns: 0 or error on failure
|
|
*/
|
|
int aa_set_current_onexec(struct aa_label *label)
|
|
{
|
|
struct aa_task_cxt *cxt;
|
|
struct cred *new = prepare_creds();
|
|
if (!new)
|
|
return -ENOMEM;
|
|
|
|
cxt = cred_cxt(new);
|
|
aa_get_label(label);
|
|
aa_put_label(cxt->onexec);
|
|
cxt->onexec = label;
|
|
|
|
commit_creds(new);
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* aa_set_current_hat - set the current tasks hat
|
|
* @label: label to set as the current hat (NOT NULL)
|
|
* @token: token value that must be specified to change from the hat
|
|
*
|
|
* Do switch of tasks hat. If the task is currently in a hat
|
|
* validate the token to match.
|
|
*
|
|
* Returns: 0 or error on failure
|
|
*/
|
|
int aa_set_current_hat(struct aa_label *label, u64 token)
|
|
{
|
|
struct aa_task_cxt *cxt;
|
|
struct cred *new = prepare_creds();
|
|
if (!new)
|
|
return -ENOMEM;
|
|
BUG_ON(!label);
|
|
|
|
cxt = cred_cxt(new);
|
|
if (!cxt->previous) {
|
|
/* transfer refcount */
|
|
cxt->previous = cxt->label;
|
|
cxt->token = token;
|
|
} else if (cxt->token == token) {
|
|
aa_put_label(cxt->label);
|
|
} else {
|
|
/* previous_profile && cxt->token != token */
|
|
abort_creds(new);
|
|
return -EACCES;
|
|
}
|
|
cxt->label = aa_get_newest_label(label);
|
|
/* clear exec on switching context */
|
|
aa_put_label(cxt->onexec);
|
|
cxt->onexec = NULL;
|
|
|
|
commit_creds(new);
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* aa_restore_previous_label - exit from hat context restoring previous label
|
|
* @token: the token that must be matched to exit hat context
|
|
*
|
|
* Attempt to return out of a hat to the previous label. The token
|
|
* must match the stored token value.
|
|
*
|
|
* Returns: 0 or error of failure
|
|
*/
|
|
int aa_restore_previous_label(u64 token)
|
|
{
|
|
struct aa_task_cxt *cxt;
|
|
struct cred *new = prepare_creds();
|
|
if (!new)
|
|
return -ENOMEM;
|
|
|
|
cxt = cred_cxt(new);
|
|
if (cxt->token != token) {
|
|
abort_creds(new);
|
|
return -EACCES;
|
|
}
|
|
/* ignore restores when there is no saved label */
|
|
if (!cxt->previous) {
|
|
abort_creds(new);
|
|
return 0;
|
|
}
|
|
|
|
aa_put_label(cxt->label);
|
|
cxt->label = aa_get_newest_label(cxt->previous);
|
|
BUG_ON(!cxt->label);
|
|
/* clear exec && prev information when restoring to previous context */
|
|
aa_clear_task_cxt_trans(cxt);
|
|
|
|
commit_creds(new);
|
|
return 0;
|
|
}
|