Revision b02faed15d86f846b0f23f47b92e0782baa873ed authored by Mark Rutland on 03 October 2017, 17:25:46 UTC, committed by Catalin Marinas on 04 October 2017, 16:37:33 UTC
AddressSanitizer instrumentation can significantly bloat the stack, and with GCC 7 this can result in stack overflows at boot time in some configurations. We can avoid this by doubling our stack size when KASAN is in use, as is already done on x86 (and has been since KASAN was introduced). Regardless of other patches to decrease KASAN's stack utilization, kernels built with KASAN will always require more stack space than those built without, and we should take this into account. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
1 parent 37f6b42
policy_ns.c
/*
* AppArmor security module
*
* This file contains AppArmor policy manipulation functions
*
* Copyright (C) 1998-2008 Novell/SUSE
* Copyright 2009-2017 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 policy namespaces, allow for different sets of policies
* to be loaded for tasks within the namespace.
*/
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/string.h>
#include "include/apparmor.h"
#include "include/context.h"
#include "include/policy_ns.h"
#include "include/label.h"
#include "include/policy.h"
/* root profile namespace */
struct aa_ns *root_ns;
const char *aa_hidden_ns_name = "---";
/**
* aa_ns_visible - test if @view is visible from @curr
* @curr: namespace to treat as the parent (NOT NULL)
* @view: namespace to test if visible from @curr (NOT NULL)
* @subns: whether view of a subns is allowed
*
* Returns: true if @view is visible from @curr else false
*/
bool aa_ns_visible(struct aa_ns *curr, struct aa_ns *view, bool subns)
{
if (curr == view)
return true;
if (!subns)
return false;
for ( ; view; view = view->parent) {
if (view->parent == curr)
return true;
}
return false;
}
/**
* aa_na_name - Find the ns name to display for @view from @curr
* @curr - current namespace (NOT NULL)
* @view - namespace attempting to view (NOT NULL)
* @subns - are subns visible
*
* Returns: name of @view visible from @curr
*/
const char *aa_ns_name(struct aa_ns *curr, struct aa_ns *view, bool subns)
{
/* if view == curr then the namespace name isn't displayed */
if (curr == view)
return "";
if (aa_ns_visible(curr, view, subns)) {
/* at this point if a ns is visible it is in a view ns
* thus the curr ns.hname is a prefix of its name.
* Only output the virtualized portion of the name
* Add + 2 to skip over // separating curr hname prefix
* from the visible tail of the views hname
*/
return view->base.hname + strlen(curr->base.hname) + 2;
}
return aa_hidden_ns_name;
}
/**
* alloc_ns - allocate, initialize and return a new namespace
* @prefix: parent namespace name (MAYBE NULL)
* @name: a preallocated name (NOT NULL)
*
* Returns: refcounted namespace or NULL on failure.
*/
static struct aa_ns *alloc_ns(const char *prefix, const char *name)
{
struct aa_ns *ns;
ns = kzalloc(sizeof(*ns), GFP_KERNEL);
AA_DEBUG("%s(%p)\n", __func__, ns);
if (!ns)
return NULL;
if (!aa_policy_init(&ns->base, prefix, name, GFP_KERNEL))
goto fail_ns;
INIT_LIST_HEAD(&ns->sub_ns);
INIT_LIST_HEAD(&ns->rawdata_list);
mutex_init(&ns->lock);
init_waitqueue_head(&ns->wait);
/* released by aa_free_ns() */
ns->unconfined = aa_alloc_profile("unconfined", NULL, GFP_KERNEL);
if (!ns->unconfined)
goto fail_unconfined;
ns->unconfined->label.flags |= FLAG_IX_ON_NAME_ERROR |
FLAG_IMMUTIBLE | FLAG_NS_COUNT | FLAG_UNCONFINED;
ns->unconfined->mode = APPARMOR_UNCONFINED;
ns->unconfined->file.dfa = aa_get_dfa(nulldfa);
ns->unconfined->policy.dfa = aa_get_dfa(nulldfa);
/* ns and ns->unconfined share ns->unconfined refcount */
ns->unconfined->ns = ns;
atomic_set(&ns->uniq_null, 0);
aa_labelset_init(&ns->labels);
return ns;
fail_unconfined:
kzfree(ns->base.hname);
fail_ns:
kzfree(ns);
return NULL;
}
/**
* aa_free_ns - free a profile namespace
* @ns: the namespace to free (MAYBE NULL)
*
* Requires: All references to the namespace must have been put, if the
* namespace was referenced by a profile confining a task,
*/
void aa_free_ns(struct aa_ns *ns)
{
if (!ns)
return;
aa_policy_destroy(&ns->base);
aa_labelset_destroy(&ns->labels);
aa_put_ns(ns->parent);
ns->unconfined->ns = NULL;
aa_free_profile(ns->unconfined);
kzfree(ns);
}
/**
* aa_findn_ns - look up a profile namespace on the namespace list
* @root: namespace to search in (NOT NULL)
* @name: name of namespace to find (NOT NULL)
* @n: length of @name
*
* Returns: a refcounted namespace on the list, or NULL if no namespace
* called @name exists.
*
* refcount released by caller
*/
struct aa_ns *aa_findn_ns(struct aa_ns *root, const char *name, size_t n)
{
struct aa_ns *ns = NULL;
rcu_read_lock();
ns = aa_get_ns(__aa_findn_ns(&root->sub_ns, name, n));
rcu_read_unlock();
return ns;
}
/**
* aa_find_ns - look up a profile namespace on the namespace list
* @root: namespace to search in (NOT NULL)
* @name: name of namespace to find (NOT NULL)
*
* Returns: a refcounted namespace on the list, or NULL if no namespace
* called @name exists.
*
* refcount released by caller
*/
struct aa_ns *aa_find_ns(struct aa_ns *root, const char *name)
{
return aa_findn_ns(root, name, strlen(name));
}
/**
* __aa_lookupn_ns - lookup the namespace matching @hname
* @base: base list to start looking up profile name from (NOT NULL)
* @hname: hierarchical ns name (NOT NULL)
* @n: length of @hname
*
* Requires: rcu_read_lock be held
*
* Returns: unrefcounted ns pointer or NULL if not found
*
* Do a relative name lookup, recursing through profile tree.
*/
struct aa_ns *__aa_lookupn_ns(struct aa_ns *view, const char *hname, size_t n)
{
struct aa_ns *ns = view;
const char *split;
for (split = strnstr(hname, "//", n); split;
split = strnstr(hname, "//", n)) {
ns = __aa_findn_ns(&ns->sub_ns, hname, split - hname);
if (!ns)
return NULL;
n -= split + 2 - hname;
hname = split + 2;
}
if (n)
return __aa_findn_ns(&ns->sub_ns, hname, n);
return NULL;
}
/**
* aa_lookupn_ns - look up a policy namespace relative to @view
* @view: namespace to search in (NOT NULL)
* @name: name of namespace to find (NOT NULL)
* @n: length of @name
*
* Returns: a refcounted namespace on the list, or NULL if no namespace
* called @name exists.
*
* refcount released by caller
*/
struct aa_ns *aa_lookupn_ns(struct aa_ns *view, const char *name, size_t n)
{
struct aa_ns *ns = NULL;
rcu_read_lock();
ns = aa_get_ns(__aa_lookupn_ns(view, name, n));
rcu_read_unlock();
return ns;
}
static struct aa_ns *__aa_create_ns(struct aa_ns *parent, const char *name,
struct dentry *dir)
{
struct aa_ns *ns;
int error;
AA_BUG(!parent);
AA_BUG(!name);
AA_BUG(!mutex_is_locked(&parent->lock));
ns = alloc_ns(parent->base.hname, name);
if (!ns)
return NULL;
mutex_lock(&ns->lock);
error = __aafs_ns_mkdir(ns, ns_subns_dir(parent), name, dir);
if (error) {
AA_ERROR("Failed to create interface for ns %s\n",
ns->base.name);
mutex_unlock(&ns->lock);
aa_free_ns(ns);
return ERR_PTR(error);
}
ns->parent = aa_get_ns(parent);
ns->level = parent->level + 1;
list_add_rcu(&ns->base.list, &parent->sub_ns);
/* add list ref */
aa_get_ns(ns);
mutex_unlock(&ns->lock);
return ns;
}
/**
* aa_create_ns - create an ns, fail if it already exists
* @parent: the parent of the namespace being created
* @name: the name of the namespace
* @dir: if not null the dir to put the ns entries in
*
* Returns: the a refcounted ns that has been add or an ERR_PTR
*/
struct aa_ns *__aa_find_or_create_ns(struct aa_ns *parent, const char *name,
struct dentry *dir)
{
struct aa_ns *ns;
AA_BUG(!mutex_is_locked(&parent->lock));
/* try and find the specified ns */
/* released by caller */
ns = aa_get_ns(__aa_find_ns(&parent->sub_ns, name));
if (!ns)
ns = __aa_create_ns(parent, name, dir);
else
ns = ERR_PTR(-EEXIST);
/* return ref */
return ns;
}
/**
* aa_prepare_ns - find an existing or create a new namespace of @name
* @parent: ns to treat as parent
* @name: the namespace to find or add (NOT NULL)
*
* Returns: refcounted namespace or PTR_ERR if failed to create one
*/
struct aa_ns *aa_prepare_ns(struct aa_ns *parent, const char *name)
{
struct aa_ns *ns;
mutex_lock(&parent->lock);
/* try and find the specified ns and if it doesn't exist create it */
/* released by caller */
ns = aa_get_ns(__aa_find_ns(&parent->sub_ns, name));
if (!ns)
ns = __aa_create_ns(parent, name, NULL);
mutex_unlock(&parent->lock);
/* return ref */
return ns;
}
static void __ns_list_release(struct list_head *head);
/**
* destroy_ns - remove everything contained by @ns
* @ns: namespace to have it contents removed (NOT NULL)
*/
static void destroy_ns(struct aa_ns *ns)
{
if (!ns)
return;
mutex_lock(&ns->lock);
/* release all profiles in this namespace */
__aa_profile_list_release(&ns->base.profiles);
/* release all sub namespaces */
__ns_list_release(&ns->sub_ns);
if (ns->parent) {
unsigned long flags;
write_lock_irqsave(&ns->labels.lock, flags);
__aa_proxy_redirect(ns_unconfined(ns),
ns_unconfined(ns->parent));
write_unlock_irqrestore(&ns->labels.lock, flags);
}
__aafs_ns_rmdir(ns);
mutex_unlock(&ns->lock);
}
/**
* __aa_remove_ns - remove a namespace and all its children
* @ns: namespace to be removed (NOT NULL)
*
* Requires: ns->parent->lock be held and ns removed from parent.
*/
void __aa_remove_ns(struct aa_ns *ns)
{
/* remove ns from namespace list */
list_del_rcu(&ns->base.list);
destroy_ns(ns);
aa_put_ns(ns);
}
/**
* __ns_list_release - remove all profile namespaces on the list put refs
* @head: list of profile namespaces (NOT NULL)
*
* Requires: namespace lock be held
*/
static void __ns_list_release(struct list_head *head)
{
struct aa_ns *ns, *tmp;
list_for_each_entry_safe(ns, tmp, head, base.list)
__aa_remove_ns(ns);
}
/**
* aa_alloc_root_ns - allocate the root profile namespace
*
* Returns: %0 on success else error
*
*/
int __init aa_alloc_root_ns(void)
{
/* released by aa_free_root_ns - used as list ref*/
root_ns = alloc_ns(NULL, "root");
if (!root_ns)
return -ENOMEM;
return 0;
}
/**
* aa_free_root_ns - free the root profile namespace
*/
void __init aa_free_root_ns(void)
{
struct aa_ns *ns = root_ns;
root_ns = NULL;
destroy_ns(ns);
aa_put_ns(ns);
}
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