android_kernel_samsung_msm8976/security/apparmor/policy.c
John Johansen 2e680dd61e apparmor: fix IRQ stack overflow during free_profile
BugLink: http://bugs.launchpad.net/bugs/1056078

Profile replacement can cause long chains of profiles to build up when
the profile being replaced is pinned. When the pinned profile is finally
freed, it puts the reference to its replacement, which may in turn nest
another call to free_profile on the stack. Because this may happen for
each profile in the replacedby chain this can result in a recusion that
causes the stack to overflow.

Break this nesting by directly walking the chain of replacedby profiles
(ie. use iteration instead of recursion to free the list). This results
in at most 2 levels of free_profile being called, while freeing a
replacedby chain.

Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
2012-10-25 02:12:50 +11:00

1215 lines
32 KiB
C

/*
* AppArmor security module
*
* This file contains AppArmor policy manipulation functions
*
* 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 policy is based around profiles, which contain the rules a
* task is confined by. Every task in the system has a profile attached
* to it determined either by matching "unconfined" tasks against the
* visible set of profiles or by following a profiles attachment rules.
*
* Each profile exists in a profile namespace which is a container of
* visible profiles. Each namespace contains a special "unconfined" profile,
* which doesn't enforce any confinement on a task beyond DAC.
*
* Namespace and profile names can be written together in either
* of two syntaxes.
* :namespace:profile - used by kernel interfaces for easy detection
* namespace://profile - used by policy
*
* Profile names can not start with : or @ or ^ and may not contain \0
*
* Reserved profile names
* unconfined - special automatically generated unconfined profile
* inherit - special name to indicate profile inheritance
* null-XXXX-YYYY - special automatically generated learning profiles
*
* Namespace names may not start with / or @ and may not contain \0 or :
* Reserved namespace names
* user-XXXX - user defined profiles
*
* a // in a profile or namespace name indicates a hierarchical name with the
* name before the // being the parent and the name after the child.
*
* Profile and namespace hierarchies serve two different but similar purposes.
* The namespace contains the set of visible profiles that are considered
* for attachment. The hierarchy of namespaces allows for virtualizing
* the namespace so that for example a chroot can have its own set of profiles
* which may define some local user namespaces.
* The profile hierarchy severs two distinct purposes,
* - it allows for sub profiles or hats, which allows an application to run
* subprograms under its own profile with different restriction than it
* self, and not have it use the system profile.
* eg. if a mail program starts an editor, the policy might make the
* restrictions tighter on the editor tighter than the mail program,
* and definitely different than general editor restrictions
* - it allows for binary hierarchy of profiles, so that execution history
* is preserved. This feature isn't exploited by AppArmor reference policy
* but is allowed. NOTE: this is currently suboptimal because profile
* aliasing is not currently implemented so that a profile for each
* level must be defined.
* eg. /bin/bash///bin/ls as a name would indicate /bin/ls was started
* from /bin/bash
*
* A profile or namespace name that can contain one or more // separators
* is referred to as an hname (hierarchical).
* eg. /bin/bash//bin/ls
*
* An fqname is a name that may contain both namespace and profile hnames.
* eg. :ns:/bin/bash//bin/ls
*
* NOTES:
* - locking of profile lists is currently fairly coarse. All profile
* lists within a namespace use the namespace lock.
* FIXME: move profile lists to using rcu_lists
*/
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include "include/apparmor.h"
#include "include/capability.h"
#include "include/context.h"
#include "include/file.h"
#include "include/ipc.h"
#include "include/match.h"
#include "include/path.h"
#include "include/policy.h"
#include "include/policy_unpack.h"
#include "include/resource.h"
#include "include/sid.h"
/* root profile namespace */
struct aa_namespace *root_ns;
const char *const profile_mode_names[] = {
"enforce",
"complain",
"kill",
};
/**
* hname_tail - find the last component of an hname
* @name: hname to find the base profile name component of (NOT NULL)
*
* Returns: the tail (base profile name) name component of an hname
*/
static const char *hname_tail(const char *hname)
{
char *split;
hname = strim((char *)hname);
for (split = strstr(hname, "//"); split; split = strstr(hname, "//"))
hname = split + 2;
return hname;
}
/**
* policy_init - initialize a policy structure
* @policy: policy to initialize (NOT NULL)
* @prefix: prefix name if any is required. (MAYBE NULL)
* @name: name of the policy, init will make a copy of it (NOT NULL)
*
* Note: this fn creates a copy of strings passed in
*
* Returns: true if policy init successful
*/
static bool policy_init(struct aa_policy *policy, const char *prefix,
const char *name)
{
/* freed by policy_free */
if (prefix) {
policy->hname = kmalloc(strlen(prefix) + strlen(name) + 3,
GFP_KERNEL);
if (policy->hname)
sprintf(policy->hname, "%s//%s", prefix, name);
} else
policy->hname = kstrdup(name, GFP_KERNEL);
if (!policy->hname)
return 0;
/* base.name is a substring of fqname */
policy->name = (char *)hname_tail(policy->hname);
INIT_LIST_HEAD(&policy->list);
INIT_LIST_HEAD(&policy->profiles);
kref_init(&policy->count);
return 1;
}
/**
* policy_destroy - free the elements referenced by @policy
* @policy: policy that is to have its elements freed (NOT NULL)
*/
static void policy_destroy(struct aa_policy *policy)
{
/* still contains profiles -- invalid */
if (!list_empty(&policy->profiles)) {
AA_ERROR("%s: internal error, "
"policy '%s' still contains profiles\n",
__func__, policy->name);
BUG();
}
if (!list_empty(&policy->list)) {
AA_ERROR("%s: internal error, policy '%s' still on list\n",
__func__, policy->name);
BUG();
}
/* don't free name as its a subset of hname */
kzfree(policy->hname);
}
/**
* __policy_find - find a policy by @name on a policy list
* @head: list to search (NOT NULL)
* @name: name to search for (NOT NULL)
*
* Requires: correct locks for the @head list be held
*
* Returns: unrefcounted policy that match @name or NULL if not found
*/
static struct aa_policy *__policy_find(struct list_head *head, const char *name)
{
struct aa_policy *policy;
list_for_each_entry(policy, head, list) {
if (!strcmp(policy->name, name))
return policy;
}
return NULL;
}
/**
* __policy_strn_find - find a policy that's name matches @len chars of @str
* @head: list to search (NOT NULL)
* @str: string to search for (NOT NULL)
* @len: length of match required
*
* Requires: correct locks for the @head list be held
*
* Returns: unrefcounted policy that match @str or NULL if not found
*
* if @len == strlen(@strlen) then this is equiv to __policy_find
* other wise it allows searching for policy by a partial match of name
*/
static struct aa_policy *__policy_strn_find(struct list_head *head,
const char *str, int len)
{
struct aa_policy *policy;
list_for_each_entry(policy, head, list) {
if (aa_strneq(policy->name, str, len))
return policy;
}
return NULL;
}
/*
* Routines for AppArmor namespaces
*/
static const char *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)
*
* Returns: true if @view is visible from @curr else false
*/
bool aa_ns_visible(struct aa_namespace *curr, struct aa_namespace *view)
{
if (curr == view)
return true;
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)
*
* Returns: name of @view visible from @curr
*/
const char *aa_ns_name(struct aa_namespace *curr, struct aa_namespace *view)
{
/* if view == curr then the namespace name isn't displayed */
if (curr == view)
return "";
if (aa_ns_visible(curr, view)) {
/* 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;
} else
return hidden_ns_name;
}
/**
* alloc_namespace - 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_namespace *alloc_namespace(const char *prefix,
const char *name)
{
struct aa_namespace *ns;
ns = kzalloc(sizeof(*ns), GFP_KERNEL);
AA_DEBUG("%s(%p)\n", __func__, ns);
if (!ns)
return NULL;
if (!policy_init(&ns->base, prefix, name))
goto fail_ns;
INIT_LIST_HEAD(&ns->sub_ns);
rwlock_init(&ns->lock);
/* released by free_namespace */
ns->unconfined = aa_alloc_profile("unconfined");
if (!ns->unconfined)
goto fail_unconfined;
ns->unconfined->sid = aa_alloc_sid();
ns->unconfined->flags = PFLAG_UNCONFINED | PFLAG_IX_ON_NAME_ERROR |
PFLAG_IMMUTABLE;
/*
* released by free_namespace, however __remove_namespace breaks
* the cyclic references (ns->unconfined, and unconfined->ns) and
* replaces with refs to parent namespace unconfined
*/
ns->unconfined->ns = aa_get_namespace(ns);
return ns;
fail_unconfined:
kzfree(ns->base.hname);
fail_ns:
kzfree(ns);
return NULL;
}
/**
* free_namespace - 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,
*/
static void free_namespace(struct aa_namespace *ns)
{
if (!ns)
return;
policy_destroy(&ns->base);
aa_put_namespace(ns->parent);
if (ns->unconfined && ns->unconfined->ns == ns)
ns->unconfined->ns = NULL;
aa_put_profile(ns->unconfined);
kzfree(ns);
}
/**
* aa_free_namespace_kref - free aa_namespace by kref (see aa_put_namespace)
* @kr: kref callback for freeing of a namespace (NOT NULL)
*/
void aa_free_namespace_kref(struct kref *kref)
{
free_namespace(container_of(kref, struct aa_namespace, base.count));
}
/**
* __aa_find_namespace - find a namespace on a list by @name
* @head: list to search for namespace on (NOT NULL)
* @name: name of namespace to look for (NOT NULL)
*
* Returns: unrefcounted namespace
*
* Requires: ns lock be held
*/
static struct aa_namespace *__aa_find_namespace(struct list_head *head,
const char *name)
{
return (struct aa_namespace *)__policy_find(head, name);
}
/**
* aa_find_namespace - 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_namespace *aa_find_namespace(struct aa_namespace *root,
const char *name)
{
struct aa_namespace *ns = NULL;
read_lock(&root->lock);
ns = aa_get_namespace(__aa_find_namespace(&root->sub_ns, name));
read_unlock(&root->lock);
return ns;
}
/**
* aa_prepare_namespace - find an existing or create a new namespace of @name
* @name: the namespace to find or add (MAYBE NULL)
*
* Returns: refcounted namespace or NULL if failed to create one
*/
static struct aa_namespace *aa_prepare_namespace(const char *name)
{
struct aa_namespace *ns, *root;
root = aa_current_profile()->ns;
write_lock(&root->lock);
/* if name isn't specified the profile is loaded to the current ns */
if (!name) {
/* released by caller */
ns = aa_get_namespace(root);
goto out;
}
/* try and find the specified ns and if it doesn't exist create it */
/* released by caller */
ns = aa_get_namespace(__aa_find_namespace(&root->sub_ns, name));
if (!ns) {
/* namespace not found */
struct aa_namespace *new_ns;
write_unlock(&root->lock);
new_ns = alloc_namespace(root->base.hname, name);
if (!new_ns)
return NULL;
write_lock(&root->lock);
/* test for race when new_ns was allocated */
ns = __aa_find_namespace(&root->sub_ns, name);
if (!ns) {
/* add parent ref */
new_ns->parent = aa_get_namespace(root);
list_add(&new_ns->base.list, &root->sub_ns);
/* add list ref */
ns = aa_get_namespace(new_ns);
} else {
/* raced so free the new one */
free_namespace(new_ns);
/* get reference on namespace */
aa_get_namespace(ns);
}
}
out:
write_unlock(&root->lock);
/* return ref */
return ns;
}
/**
* __list_add_profile - add a profile to a list
* @list: list to add it to (NOT NULL)
* @profile: the profile to add (NOT NULL)
*
* refcount @profile, should be put by __list_remove_profile
*
* Requires: namespace lock be held, or list not be shared
*/
static void __list_add_profile(struct list_head *list,
struct aa_profile *profile)
{
list_add(&profile->base.list, list);
/* get list reference */
aa_get_profile(profile);
}
/**
* __list_remove_profile - remove a profile from the list it is on
* @profile: the profile to remove (NOT NULL)
*
* remove a profile from the list, warning generally removal should
* be done with __replace_profile as most profile removals are
* replacements to the unconfined profile.
*
* put @profile list refcount
*
* Requires: namespace lock be held, or list not have been live
*/
static void __list_remove_profile(struct aa_profile *profile)
{
list_del_init(&profile->base.list);
if (!(profile->flags & PFLAG_NO_LIST_REF))
/* release list reference */
aa_put_profile(profile);
}
/**
* __replace_profile - replace @old with @new on a list
* @old: profile to be replaced (NOT NULL)
* @new: profile to replace @old with (NOT NULL)
*
* Will duplicate and refcount elements that @new inherits from @old
* and will inherit @old children.
*
* refcount @new for list, put @old list refcount
*
* Requires: namespace list lock be held, or list not be shared
*/
static void __replace_profile(struct aa_profile *old, struct aa_profile *new)
{
struct aa_policy *policy;
struct aa_profile *child, *tmp;
if (old->parent)
policy = &old->parent->base;
else
policy = &old->ns->base;
/* released when @new is freed */
new->parent = aa_get_profile(old->parent);
new->ns = aa_get_namespace(old->ns);
new->sid = old->sid;
__list_add_profile(&policy->profiles, new);
/* inherit children */
list_for_each_entry_safe(child, tmp, &old->base.profiles, base.list) {
aa_put_profile(child->parent);
child->parent = aa_get_profile(new);
/* list refcount transferred to @new*/
list_move(&child->base.list, &new->base.profiles);
}
/* released by free_profile */
old->replacedby = aa_get_profile(new);
__list_remove_profile(old);
}
static void __profile_list_release(struct list_head *head);
/**
* __remove_profile - remove old profile, and children
* @profile: profile to be replaced (NOT NULL)
*
* Requires: namespace list lock be held, or list not be shared
*/
static void __remove_profile(struct aa_profile *profile)
{
/* release any children lists first */
__profile_list_release(&profile->base.profiles);
/* released by free_profile */
profile->replacedby = aa_get_profile(profile->ns->unconfined);
__list_remove_profile(profile);
}
/**
* __profile_list_release - remove all profiles on the list and put refs
* @head: list of profiles (NOT NULL)
*
* Requires: namespace lock be held
*/
static void __profile_list_release(struct list_head *head)
{
struct aa_profile *profile, *tmp;
list_for_each_entry_safe(profile, tmp, head, base.list)
__remove_profile(profile);
}
static void __ns_list_release(struct list_head *head);
/**
* destroy_namespace - remove everything contained by @ns
* @ns: namespace to have it contents removed (NOT NULL)
*/
static void destroy_namespace(struct aa_namespace *ns)
{
if (!ns)
return;
write_lock(&ns->lock);
/* release all profiles in this namespace */
__profile_list_release(&ns->base.profiles);
/* release all sub namespaces */
__ns_list_release(&ns->sub_ns);
write_unlock(&ns->lock);
}
/**
* __remove_namespace - 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.
*/
static void __remove_namespace(struct aa_namespace *ns)
{
struct aa_profile *unconfined = ns->unconfined;
/* remove ns from namespace list */
list_del_init(&ns->base.list);
/*
* break the ns, unconfined profile cyclic reference and forward
* all new unconfined profiles requests to the parent namespace
* This will result in all confined tasks that have a profile
* being removed, inheriting the parent->unconfined profile.
*/
if (ns->parent)
ns->unconfined = aa_get_profile(ns->parent->unconfined);
destroy_namespace(ns);
/* release original ns->unconfined ref */
aa_put_profile(unconfined);
/* release ns->base.list ref, from removal above */
aa_put_namespace(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_namespace *ns, *tmp;
list_for_each_entry_safe(ns, tmp, head, base.list)
__remove_namespace(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_namespace(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_namespace *ns = root_ns;
root_ns = NULL;
destroy_namespace(ns);
aa_put_namespace(ns);
}
/**
* aa_alloc_profile - allocate, initialize and return a new profile
* @hname: name of the profile (NOT NULL)
*
* Returns: refcount profile or NULL on failure
*/
struct aa_profile *aa_alloc_profile(const char *hname)
{
struct aa_profile *profile;
/* freed by free_profile - usually through aa_put_profile */
profile = kzalloc(sizeof(*profile), GFP_KERNEL);
if (!profile)
return NULL;
if (!policy_init(&profile->base, NULL, hname)) {
kzfree(profile);
return NULL;
}
/* refcount released by caller */
return profile;
}
/**
* aa_new_null_profile - create a new null-X learning profile
* @parent: profile that caused this profile to be created (NOT NULL)
* @hat: true if the null- learning profile is a hat
*
* Create a null- complain mode profile used in learning mode. The name of
* the profile is unique and follows the format of parent//null-sid.
*
* null profiles are added to the profile list but the list does not
* hold a count on them so that they are automatically released when
* not in use.
*
* Returns: new refcounted profile else NULL on failure
*/
struct aa_profile *aa_new_null_profile(struct aa_profile *parent, int hat)
{
struct aa_profile *profile = NULL;
char *name;
u32 sid = aa_alloc_sid();
/* freed below */
name = kmalloc(strlen(parent->base.hname) + 2 + 7 + 8, GFP_KERNEL);
if (!name)
goto fail;
sprintf(name, "%s//null-%x", parent->base.hname, sid);
profile = aa_alloc_profile(name);
kfree(name);
if (!profile)
goto fail;
profile->sid = sid;
profile->mode = APPARMOR_COMPLAIN;
profile->flags = PFLAG_NULL;
if (hat)
profile->flags |= PFLAG_HAT;
/* released on free_profile */
profile->parent = aa_get_profile(parent);
profile->ns = aa_get_namespace(parent->ns);
write_lock(&profile->ns->lock);
__list_add_profile(&parent->base.profiles, profile);
write_unlock(&profile->ns->lock);
/* refcount released by caller */
return profile;
fail:
aa_free_sid(sid);
return NULL;
}
/**
* free_profile - free a profile
* @profile: the profile to free (MAYBE NULL)
*
* Free a profile, its hats and null_profile. All references to the profile,
* its hats and null_profile must have been put.
*
* If the profile was referenced from a task context, free_profile() will
* be called from an rcu callback routine, so we must not sleep here.
*/
static void free_profile(struct aa_profile *profile)
{
struct aa_profile *p;
AA_DEBUG("%s(%p)\n", __func__, profile);
if (!profile)
return;
if (!list_empty(&profile->base.list)) {
AA_ERROR("%s: internal error, "
"profile '%s' still on ns list\n",
__func__, profile->base.name);
BUG();
}
/* free children profiles */
policy_destroy(&profile->base);
aa_put_profile(profile->parent);
aa_put_namespace(profile->ns);
kzfree(profile->rename);
aa_free_file_rules(&profile->file);
aa_free_cap_rules(&profile->caps);
aa_free_rlimit_rules(&profile->rlimits);
aa_free_sid(profile->sid);
aa_put_dfa(profile->xmatch);
aa_put_dfa(profile->policy.dfa);
/* put the profile reference for replacedby, but not via
* put_profile(kref_put).
* replacedby can form a long chain that can result in cascading
* frees that blows the stack because kref_put makes a nested fn
* call (it looks like recursion, with free_profile calling
* free_profile) for each profile in the chain lp#1056078.
*/
for (p = profile->replacedby; p; ) {
if (atomic_dec_and_test(&p->base.count.refcount)) {
/* no more refs on p, grab its replacedby */
struct aa_profile *next = p->replacedby;
/* break the chain */
p->replacedby = NULL;
/* now free p, chain is broken */
free_profile(p);
/* follow up with next profile in the chain */
p = next;
} else
break;
}
kzfree(profile);
}
/**
* aa_free_profile_kref - free aa_profile by kref (called by aa_put_profile)
* @kr: kref callback for freeing of a profile (NOT NULL)
*/
void aa_free_profile_kref(struct kref *kref)
{
struct aa_profile *p = container_of(kref, struct aa_profile,
base.count);
free_profile(p);
}
/* TODO: profile accounting - setup in remove */
/**
* __find_child - find a profile on @head list with a name matching @name
* @head: list to search (NOT NULL)
* @name: name of profile (NOT NULL)
*
* Requires: ns lock protecting list be held
*
* Returns: unrefcounted profile ptr, or NULL if not found
*/
static struct aa_profile *__find_child(struct list_head *head, const char *name)
{
return (struct aa_profile *)__policy_find(head, name);
}
/**
* __strn_find_child - find a profile on @head list using substring of @name
* @head: list to search (NOT NULL)
* @name: name of profile (NOT NULL)
* @len: length of @name substring to match
*
* Requires: ns lock protecting list be held
*
* Returns: unrefcounted profile ptr, or NULL if not found
*/
static struct aa_profile *__strn_find_child(struct list_head *head,
const char *name, int len)
{
return (struct aa_profile *)__policy_strn_find(head, name, len);
}
/**
* aa_find_child - find a profile by @name in @parent
* @parent: profile to search (NOT NULL)
* @name: profile name to search for (NOT NULL)
*
* Returns: a refcounted profile or NULL if not found
*/
struct aa_profile *aa_find_child(struct aa_profile *parent, const char *name)
{
struct aa_profile *profile;
read_lock(&parent->ns->lock);
profile = aa_get_profile(__find_child(&parent->base.profiles, name));
read_unlock(&parent->ns->lock);
/* refcount released by caller */
return profile;
}
/**
* __lookup_parent - lookup the parent of a profile of name @hname
* @ns: namespace to lookup profile in (NOT NULL)
* @hname: hierarchical profile name to find parent of (NOT NULL)
*
* Lookups up the parent of a fully qualified profile name, the profile
* that matches hname does not need to exist, in general this
* is used to load a new profile.
*
* Requires: ns->lock be held
*
* Returns: unrefcounted policy or NULL if not found
*/
static struct aa_policy *__lookup_parent(struct aa_namespace *ns,
const char *hname)
{
struct aa_policy *policy;
struct aa_profile *profile = NULL;
char *split;
policy = &ns->base;
for (split = strstr(hname, "//"); split;) {
profile = __strn_find_child(&policy->profiles, hname,
split - hname);
if (!profile)
return NULL;
policy = &profile->base;
hname = split + 2;
split = strstr(hname, "//");
}
if (!profile)
return &ns->base;
return &profile->base;
}
/**
* __lookup_profile - lookup the profile matching @hname
* @base: base list to start looking up profile name from (NOT NULL)
* @hname: hierarchical profile name (NOT NULL)
*
* Requires: ns->lock be held
*
* Returns: unrefcounted profile pointer or NULL if not found
*
* Do a relative name lookup, recursing through profile tree.
*/
static struct aa_profile *__lookup_profile(struct aa_policy *base,
const char *hname)
{
struct aa_profile *profile = NULL;
char *split;
for (split = strstr(hname, "//"); split;) {
profile = __strn_find_child(&base->profiles, hname,
split - hname);
if (!profile)
return NULL;
base = &profile->base;
hname = split + 2;
split = strstr(hname, "//");
}
profile = __find_child(&base->profiles, hname);
return profile;
}
/**
* aa_lookup_profile - find a profile by its full or partial name
* @ns: the namespace to start from (NOT NULL)
* @hname: name to do lookup on. Does not contain namespace prefix (NOT NULL)
*
* Returns: refcounted profile or NULL if not found
*/
struct aa_profile *aa_lookup_profile(struct aa_namespace *ns, const char *hname)
{
struct aa_profile *profile;
read_lock(&ns->lock);
profile = aa_get_profile(__lookup_profile(&ns->base, hname));
read_unlock(&ns->lock);
/* the unconfined profile is not in the regular profile list */
if (!profile && strcmp(hname, "unconfined") == 0)
profile = aa_get_profile(ns->unconfined);
/* refcount released by caller */
return profile;
}
/**
* replacement_allowed - test to see if replacement is allowed
* @profile: profile to test if it can be replaced (MAYBE NULL)
* @noreplace: true if replacement shouldn't be allowed but addition is okay
* @info: Returns - info about why replacement failed (NOT NULL)
*
* Returns: %0 if replacement allowed else error code
*/
static int replacement_allowed(struct aa_profile *profile, int noreplace,
const char **info)
{
if (profile) {
if (profile->flags & PFLAG_IMMUTABLE) {
*info = "cannot replace immutible profile";
return -EPERM;
} else if (noreplace) {
*info = "profile already exists";
return -EEXIST;
}
}
return 0;
}
/**
* __add_new_profile - simple wrapper around __list_add_profile
* @ns: namespace that profile is being added to (NOT NULL)
* @policy: the policy container to add the profile to (NOT NULL)
* @profile: profile to add (NOT NULL)
*
* add a profile to a list and do other required basic allocations
*/
static void __add_new_profile(struct aa_namespace *ns, struct aa_policy *policy,
struct aa_profile *profile)
{
if (policy != &ns->base)
/* released on profile replacement or free_profile */
profile->parent = aa_get_profile((struct aa_profile *) policy);
__list_add_profile(&policy->profiles, profile);
/* released on free_profile */
profile->sid = aa_alloc_sid();
profile->ns = aa_get_namespace(ns);
}
/**
* aa_audit_policy - Do auditing of policy changes
* @op: policy operation being performed
* @gfp: memory allocation flags
* @name: name of profile being manipulated (NOT NULL)
* @info: any extra information to be audited (MAYBE NULL)
* @error: error code
*
* Returns: the error to be returned after audit is done
*/
static int audit_policy(int op, gfp_t gfp, const char *name, const char *info,
int error)
{
struct common_audit_data sa;
struct apparmor_audit_data aad = {0,};
sa.type = LSM_AUDIT_DATA_NONE;
sa.aad = &aad;
aad.op = op;
aad.name = name;
aad.info = info;
aad.error = error;
return aa_audit(AUDIT_APPARMOR_STATUS, __aa_current_profile(), gfp,
&sa, NULL);
}
/**
* aa_may_manage_policy - can the current task manage policy
* @op: the policy manipulation operation being done
*
* Returns: true if the task is allowed to manipulate policy
*/
bool aa_may_manage_policy(int op)
{
/* check if loading policy is locked out */
if (aa_g_lock_policy) {
audit_policy(op, GFP_KERNEL, NULL, "policy_locked", -EACCES);
return 0;
}
if (!capable(CAP_MAC_ADMIN)) {
audit_policy(op, GFP_KERNEL, NULL, "not policy admin", -EACCES);
return 0;
}
return 1;
}
/**
* aa_replace_profiles - replace profile(s) on the profile list
* @udata: serialized data stream (NOT NULL)
* @size: size of the serialized data stream
* @noreplace: true if only doing addition, no replacement allowed
*
* unpack and replace a profile on the profile list and uses of that profile
* by any aa_task_cxt. If the profile does not exist on the profile list
* it is added.
*
* Returns: size of data consumed else error code on failure.
*/
ssize_t aa_replace_profiles(void *udata, size_t size, bool noreplace)
{
struct aa_policy *policy;
struct aa_profile *old_profile = NULL, *new_profile = NULL;
struct aa_profile *rename_profile = NULL;
struct aa_namespace *ns = NULL;
const char *ns_name, *name = NULL, *info = NULL;
int op = OP_PROF_REPL;
ssize_t error;
/* released below */
new_profile = aa_unpack(udata, size, &ns_name);
if (IS_ERR(new_profile)) {
error = PTR_ERR(new_profile);
new_profile = NULL;
goto fail;
}
/* released below */
ns = aa_prepare_namespace(ns_name);
if (!ns) {
info = "failed to prepare namespace";
error = -ENOMEM;
name = ns_name;
goto fail;
}
name = new_profile->base.hname;
write_lock(&ns->lock);
/* no ref on policy only use inside lock */
policy = __lookup_parent(ns, new_profile->base.hname);
if (!policy) {
info = "parent does not exist";
error = -ENOENT;
goto audit;
}
old_profile = __find_child(&policy->profiles, new_profile->base.name);
/* released below */
aa_get_profile(old_profile);
if (new_profile->rename) {
rename_profile = __lookup_profile(&ns->base,
new_profile->rename);
/* released below */
aa_get_profile(rename_profile);
if (!rename_profile) {
info = "profile to rename does not exist";
name = new_profile->rename;
error = -ENOENT;
goto audit;
}
}
error = replacement_allowed(old_profile, noreplace, &info);
if (error)
goto audit;
error = replacement_allowed(rename_profile, noreplace, &info);
if (error)
goto audit;
audit:
if (!old_profile && !rename_profile)
op = OP_PROF_LOAD;
error = audit_policy(op, GFP_ATOMIC, name, info, error);
if (!error) {
if (rename_profile)
__replace_profile(rename_profile, new_profile);
if (old_profile) {
/* when there are both rename and old profiles
* inherit old profiles sid
*/
if (rename_profile)
aa_free_sid(new_profile->sid);
__replace_profile(old_profile, new_profile);
}
if (!(old_profile || rename_profile))
__add_new_profile(ns, policy, new_profile);
}
write_unlock(&ns->lock);
out:
aa_put_namespace(ns);
aa_put_profile(rename_profile);
aa_put_profile(old_profile);
aa_put_profile(new_profile);
if (error)
return error;
return size;
fail:
error = audit_policy(op, GFP_KERNEL, name, info, error);
goto out;
}
/**
* aa_remove_profiles - remove profile(s) from the system
* @fqname: name of the profile or namespace to remove (NOT NULL)
* @size: size of the name
*
* Remove a profile or sub namespace from the current namespace, so that
* they can not be found anymore and mark them as replaced by unconfined
*
* NOTE: removing confinement does not restore rlimits to preconfinemnet values
*
* Returns: size of data consume else error code if fails
*/
ssize_t aa_remove_profiles(char *fqname, size_t size)
{
struct aa_namespace *root, *ns = NULL;
struct aa_profile *profile = NULL;
const char *name = fqname, *info = NULL;
ssize_t error = 0;
if (*fqname == 0) {
info = "no profile specified";
error = -ENOENT;
goto fail;
}
root = aa_current_profile()->ns;
if (fqname[0] == ':') {
char *ns_name;
name = aa_split_fqname(fqname, &ns_name);
if (ns_name) {
/* released below */
ns = aa_find_namespace(root, ns_name);
if (!ns) {
info = "namespace does not exist";
error = -ENOENT;
goto fail;
}
}
} else
/* released below */
ns = aa_get_namespace(root);
if (!name) {
/* remove namespace - can only happen if fqname[0] == ':' */
write_lock(&ns->parent->lock);
__remove_namespace(ns);
write_unlock(&ns->parent->lock);
} else {
/* remove profile */
write_lock(&ns->lock);
profile = aa_get_profile(__lookup_profile(&ns->base, name));
if (!profile) {
error = -ENOENT;
info = "profile does not exist";
goto fail_ns_lock;
}
name = profile->base.hname;
__remove_profile(profile);
write_unlock(&ns->lock);
}
/* don't fail removal if audit fails */
(void) audit_policy(OP_PROF_RM, GFP_KERNEL, name, info, error);
aa_put_namespace(ns);
aa_put_profile(profile);
return size;
fail_ns_lock:
write_unlock(&ns->lock);
aa_put_namespace(ns);
fail:
(void) audit_policy(OP_PROF_RM, GFP_KERNEL, name, info, error);
return error;
}