// SPDX-License-Identifier: GPL-2.0-only
/*
* AppArmor security module
*
* This file contains AppArmor policy manipulation functions
*
* Copyright (C) 1998-2008 Novell/SUSE
* Copyright 2009-2010 Canonical Ltd.
*
* 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 <linux/cred.h>
#include <linux/rculist.h>
#include <linux/user_namespace.h>
#include "include/apparmor.h"
#include "include/capability.h"
#include "include/cred.h"
#include "include/file.h"
#include "include/ipc.h"
#include "include/match.h"
#include "include/path.h"
#include "include/policy.h"
#include "include/policy_ns.h"
#include "include/policy_unpack.h"
#include "include/resource.h"
int unprivileged_userns_apparmor_policy = 1;
int aa_unprivileged_unconfined_restricted;
const char *const aa_profile_mode_names[] = {
"enforce",
"complain",
"kill",
"unconfined",
"user",
};
static void aa_free_pdb(struct aa_policydb *pdb)
{
if (pdb) {
aa_put_dfa(pdb->dfa);
if (pdb->perms)
kvfree(pdb->perms);
aa_free_str_table(&pdb->trans);
kfree(pdb);
}
}
/**
* aa_pdb_free_kref - free aa_policydb by kref (called by aa_put_pdb)
* @kref: kref callback for freeing of a dfa (NOT NULL)
*/
void aa_pdb_free_kref(struct kref *kref)
{
struct aa_policydb *pdb = container_of(kref, struct aa_policydb, count);
aa_free_pdb(pdb);
}
struct aa_policydb *aa_alloc_pdb(gfp_t gfp)
{
struct aa_policydb *pdb = kzalloc(sizeof(struct aa_policydb), gfp);
if (!pdb)
return NULL;
kref_init(&pdb->count);
return pdb;
}
/**
* __add_profile - add a profiles to list and label tree
* @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 __add_profile(struct list_head *list, struct aa_profile *profile)
{
struct aa_label *l;
AA_BUG(!list);
AA_BUG(!profile);
AA_BUG(!profile->ns);
AA_BUG(!mutex_is_locked(&profile->ns->lock));
list_add_rcu(&profile->base.list, list);
/* get list reference */
aa_get_profile(profile);
l = aa_label_insert(&profile->ns->labels, &profile->label);
AA_BUG(l != &profile->label);
aa_put_label(l);
}
/**
* __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)
{
AA_BUG(!profile);
AA_BUG(!profile->ns);
AA_BUG(!mutex_is_locked(&profile->ns->lock));
list_del_rcu(&profile->base.list);
aa_put_profile(profile);
}
/**
* __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)
{
AA_BUG(!profile);
AA_BUG(!profile->ns);
AA_BUG(!mutex_is_locked(&profile->ns->lock));
/* release any children lists first */
__aa_profile_list_release(&profile->base.profiles);
/* released by free_profile */
aa_label_remove(&profile->label);
__aafs_profile_rmdir(profile);
__list_remove_profile(profile);
}
/**
* __aa_profile_list_release - remove all profiles on the list and put refs
* @head: list of profiles (NOT NULL)
*
* Requires: namespace lock be held
*/
void __aa_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);
}
/**
* aa_free_data - free a data blob
* @ptr: data to free
* @arg: unused
*/
static void aa_free_data(void *ptr, void *arg)
{
struct aa_data *data = ptr;
kvfree_sensitive(data->data, data->size);
kfree_sensitive(data->key);
kfree_sensitive(data);
}
static void free_attachment(struct aa_attachment *attach)
{
int i;
for (i = 0; i < attach->xattr_count; i++)
kfree_sensitive(attach->xattrs[i]);
kfree_sensitive(attach->xattrs);
aa_put_pdb(attach->xmatch);
}
static void free_ruleset(struct aa_ruleset *rules)
{
int i;
aa_put_pdb(rules->file);
aa_put_pdb(rules->policy);
aa_free_cap_rules(&rules->caps);
aa_free_rlimit_rules(&rules->rlimits);
for (i = 0; i < rules->secmark_count; i++)
kfree_sensitive(rules->secmark[i].label);
kfree_sensitive(rules->secmark);
kfree_sensitive(rules);
}
struct aa_ruleset *aa_alloc_ruleset(gfp_t gfp)
{
struct aa_ruleset *rules;
rules = kzalloc(sizeof(*rules), gfp);
if (rules)
INIT_LIST_HEAD(&rules->list);
return rules;
}
/**
* aa_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.
*/
void aa_free_profile(struct aa_profile *profile)
{
struct aa_ruleset *rule, *tmp;
struct rhashtable *rht;
AA_DEBUG("%s(%p)\n", __func__, profile);
if (!profile)
return;
/* free children profiles */
aa_policy_destroy(&profile->base);
aa_put_profile(rcu_access_pointer(profile->parent));
aa_put_ns(profile->ns);
kfree_sensitive(profile->rename);
kfree_sensitive(profile->disconnected);
free_attachment(&profile->attach);
/*
* at this point there are no tasks that can have a reference
* to rules
*/
list_for_each_entry_safe(rule, tmp, &profile->rules, list) {
list_del_init(&rule->list);
free_ruleset(rule);
}
kfree_sensitive(profile->dirname);
if (profile->data) {
rht = profile->data;
profile->data = NULL;
rhashtable_free_and_destroy(rht, aa_free_data, NULL);
kfree_sensitive(rht);
}
kfree_sensitive(profile->hash);
aa_put_loaddata(profile->rawdata);
aa_label_destroy(&profile->label);
kfree_sensitive(profile);
}
/**
* aa_alloc_profile - allocate, initialize and return a new profile
* @hname: name of the profile (NOT NULL)
* @proxy: proxy to use OR null if to allocate a new one
* @gfp: allocation type
*
* Returns: refcount profile or NULL on failure
*/
struct aa_profile *aa_alloc_profile(const char *hname, struct aa_proxy *proxy,
gfp_t gfp)
{
struct aa_profile *profile;
struct aa_ruleset *rules;
/* freed by free_profile - usually through aa_put_profile */
profile = kzalloc(struct_size(profile, label.vec, 2), gfp);
if (!profile)
return NULL;
if (!aa_policy_init(&profile->base, NULL, hname, gfp))
goto fail;
if (!aa_label_init(&profile->label, 1, gfp))
goto fail;
INIT_LIST_HEAD(&profile->rules);
/* allocate the first ruleset, but leave it empty */
rules = aa_alloc_ruleset(gfp);
if (!rules)
goto fail;
list_add(&rules->list, &profile->rules);
/* update being set needed by fs interface */
if (!proxy) {
proxy = aa_alloc_proxy(&profile->label, gfp);
if (!proxy)
goto fail;
} else
aa_get_proxy(proxy);
profile->label.proxy = proxy;
profile->label.hname = profile->base.hname;
profile->label.flags |= FLAG_PROFILE;
profile->label.vec[0] = profile;
/* refcount released by caller */
return profile;
fail:
aa_free_profile(profile);
return NULL;
}
/* TODO: profile accounting - setup in remove */
/**
* __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: rcu_read_lock 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);
}
/**
* __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: rcu_read_lock 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 __strn_find_child(head, name, strlen(name));
}
/**
* 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;
rcu_read_lock();
do {
profile = __find_child(&parent->base.profiles, name);
} while (profile && !aa_get_profile_not0(profile));
rcu_read_unlock();
/* 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: rcu_read_lock be held
*
* Returns: unrefcounted policy or NULL if not found
*/
static struct aa_policy *__lookup_parent(struct aa_ns *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;
}
/**
* __create_missing_ancestors - create place holders for missing ancestores
* @ns: namespace to lookup profile in (NOT NULL)
* @hname: hierarchical profile name to find parent of (NOT NULL)
* @gfp: type of allocation.
*
* Requires: ns mutex lock held
*
* Return: unrefcounted parent policy on success or %NULL if error creating
* place holder profiles.
*/
static struct aa_policy *__create_missing_ancestors(struct aa_ns *ns,
const char *hname,
gfp_t gfp)
{
struct aa_policy *policy;
struct aa_profile *parent, *profile = NULL;
char *split;
AA_BUG(!ns);
AA_BUG(!hname);
policy = &ns->base;
for (split = strstr(hname, "//"); split;) {
parent = profile;
profile = __strn_find_child(&policy->profiles, hname,
split - hname);
if (!profile) {
const char *name = kstrndup(hname, split - hname,
gfp);
if (!name)
return NULL;
profile = aa_alloc_null(parent, name, gfp);
kfree(name);
if (!profile)
return NULL;
if (!parent)
profile->ns = aa_get_ns(ns);
}
policy = &profile->base;
hname = split + 2;
split = strstr(hname, "//");
}
if (!profile)
return &ns->base;
return &profile->base;
}
/**
* __lookupn_profile - lookup the profile matching @hname
* @base: base list to start looking up profile name from (NOT NULL)
* @hname: hierarchical profile name (NOT NULL)
* @n: length of @hname
*
* Requires: rcu_read_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 *__lookupn_profile(struct aa_policy *base,
const char *hname, size_t n)
{
struct aa_profile *profile = NULL;
const char *split;
for (split = strnstr(hname, "//", n); split;
split = strnstr(hname, "//", n)) {
profile = __strn_find_child(&base->profiles, hname,
split - hname);
if (!profile)
return NULL;
base = &profile->base;
n -= split + 2 - hname;
hname = split + 2;
}
if (n)
return __strn_find_child(&base->profiles, hname, n);
return NULL;
}
static struct aa_profile *__lookup_profile(struct aa_policy *base,
const char *hname)
{
return __lookupn_profile(base, hname, strlen(hname));
}
/**
* aa_lookupn_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)
* @n: size of @hname
*
* Returns: refcounted profile or NULL if not found
*/
struct aa_profile *aa_lookupn_profile(struct aa_ns *ns, const char *hname,
size_t n)
{
struct aa_profile *profile;
rcu_read_lock();
do {
profile = __lookupn_profile(&ns->base, hname, n);
} while (profile && !aa_get_profile_not0(profile));
rcu_read_unlock();
/* the unconfined profile is not in the regular profile list */
if (!profile && strncmp(hname, "unconfined", n) == 0)
profile = aa_get_newest_profile(ns->unconfined);
/* refcount released by caller */
return profile;
}
struct aa_profile *aa_lookup_profile(struct aa_ns *ns, const char *hname)
{
return aa_lookupn_profile(ns, hname, strlen(hname));
}
struct aa_profile *aa_fqlookupn_profile(struct aa_label *base,
const char *fqname, size_t n)
{
struct aa_profile *profile;
struct aa_ns *ns;
const char *name, *ns_name;
size_t ns_len;
name = aa_splitn_fqname(fqname, n, &ns_name, &ns_len);
if (ns_name) {
ns = aa_lookupn_ns(labels_ns(base), ns_name, ns_len);
if (!ns)
return NULL;
} else
ns = aa_get_ns(labels_ns(base));
if (name)
profile = aa_lookupn_profile(ns, name, n - (name - fqname));
else if (ns)
/* default profile for ns, currently unconfined */
profile = aa_get_newest_profile(ns->unconfined);
else
profile = NULL;
aa_put_ns(ns);
return profile;
}
struct aa_profile *aa_alloc_null(struct aa_profile *parent, const char *name,
gfp_t gfp)
{
struct aa_profile *profile;
struct aa_ruleset *rules;
profile = aa_alloc_profile(name, NULL, gfp);
if (!profile)
return NULL;
/* TODO: ideally we should inherit abi from parent */
profile->label.flags |= FLAG_NULL;
rules = list_first_entry(&profile->rules, typeof(*rules), list);
rules->file = aa_get_pdb(nullpdb);
rules->policy = aa_get_pdb(nullpdb);
if (parent) {
profile->path_flags = parent->path_flags;
/* released on free_profile */
rcu_assign_pointer(profile->parent, aa_get_profile(parent));
profile->ns = aa_get_ns(parent->ns);
}
return profile;
}
/**
* aa_new_learning_profile - create or find a 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
* @base: name to base the null profile off of
* @gfp: type of allocation
*
* Find/Create a null- complain mode profile used in learning mode. The
* name of the profile is unique and follows the format of parent//null-XXX.
* where XXX is based on the @name or if that fails or is not supplied
* a unique number
*
* 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_learning_profile(struct aa_profile *parent, bool hat,
const char *base, gfp_t gfp)
{
struct aa_profile *p, *profile;
const char *bname;
char *name = NULL;
AA_BUG(!parent);
if (base) {
name = kmalloc(strlen(parent->base.hname) + 8 + strlen(base),
gfp);
if (name) {
sprintf(name, "%s//null-%s", parent->base.hname, base);
goto name;
}
/* fall through to try shorter uniq */
}
name = kmalloc(strlen(parent->base.hname) + 2 + 7 + 8, gfp);
if (!name)
return NULL;
sprintf(name, "%s//null-%x", parent->base.hname,
atomic_inc_return(&parent->ns->uniq_null));
name:
/* lookup to see if this is a dup creation */
bname = basename(name);
profile = aa_find_child(parent, bname);
if (profile)
goto out;
profile = aa_alloc_null(parent, name, gfp);
if (!profile)
goto fail;
profile->mode = APPARMOR_COMPLAIN;
if (hat)
profile->label.flags |= FLAG_HAT;
mutex_lock_nested(&profile->ns->lock, profile->ns->level);
p = __find_child(&parent->base.profiles, bname);
if (p) {
aa_free_profile(profile);
profile = aa_get_profile(p);
} else {
__add_profile(&parent->base.profiles, profile);
}
mutex_unlock(&profile->ns->lock);
/* refcount released by caller */
out:
kfree(name);
return profile;
fail:
kfree(name);
aa_free_profile(profile);
return NULL;
}
/**
* 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->label.flags & FLAG_IMMUTIBLE) {
*info = "cannot replace immutable profile";
return -EPERM;
} else if (noreplace) {
*info = "profile already exists";
return -EEXIST;
}
}
return 0;
}
/* audit callback for net specific fields */
static void audit_cb(struct audit_buffer *ab, void *va)
{
struct common_audit_data *sa = va;
struct apparmor_audit_data *ad = aad(sa);
if (ad->iface.ns) {
audit_log_format(ab, " ns=");
audit_log_untrustedstring(ab, ad->iface.ns);
}
}
/**
* audit_policy - Do auditing of policy changes
* @subj_label: label to check if it can manage policy
* @op: policy operation being performed
* @ns_name: name of namespace being manipulated
* @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(struct aa_label *subj_label, const char *op,
const char *ns_name, const char *name,
const char *info, int error)
{
DEFINE_AUDIT_DATA(ad, LSM_AUDIT_DATA_NONE, AA_CLASS_NONE, op);
ad.iface.ns = ns_name;
ad.name = name;
ad.info = info;
ad.error = error;
ad.subj_label = subj_label;
aa_audit_msg(AUDIT_APPARMOR_STATUS, &ad, audit_cb);
return error;
}
/* don't call out to other LSMs in the stack for apparmor policy admin
* permissions
*/
static int policy_ns_capable(const struct cred *subj_cred,
struct aa_label *label,
struct user_namespace *userns, int cap)
{
int err;
/* check for MAC_ADMIN cap in cred */
err = cap_capable(subj_cred, userns, cap, CAP_OPT_NONE);
if (!err)
err = aa_capable(subj_cred, label, cap, CAP_OPT_NONE);
return err;
}
/**
* aa_policy_view_capable - check if viewing policy in at @ns is allowed
* @subj_cred: cred of subject
* @label: label that is trying to view policy in ns
* @ns: namespace being viewed by @label (may be NULL if @label's ns)
*
* Returns: true if viewing policy is allowed
*
* If @ns is NULL then the namespace being viewed is assumed to be the
* tasks current namespace.
*/
bool aa_policy_view_capable(const struct cred *subj_cred,
struct aa_label *label, struct aa_ns *ns)
{
struct user_namespace *user_ns = subj_cred->user_ns;
struct aa_ns *view_ns = labels_view(label);
bool root_in_user_ns = uid_eq(current_euid(), make_kuid(user_ns, 0)) ||
in_egroup_p(make_kgid(user_ns, 0));
bool response = false;
if (!ns)
ns = view_ns;
if (root_in_user_ns && aa_ns_visible(view_ns, ns, true) &&
(user_ns == &init_user_ns ||
(unprivileged_userns_apparmor_policy != 0 &&
user_ns->level == view_ns->level)))
response = true;
return response;
}
bool aa_policy_admin_capable(const struct cred *subj_cred,
struct aa_label *label, struct aa_ns *ns)
{
struct user_namespace *user_ns = subj_cred->user_ns;
bool capable = policy_ns_capable(subj_cred, label, user_ns,
CAP_MAC_ADMIN) == 0;
AA_DEBUG("cap_mac_admin? %d\n", capable);
AA_DEBUG("policy locked? %d\n", aa_g_lock_policy);
return aa_policy_view_capable(subj_cred, label, ns) && capable &&
!aa_g_lock_policy;
}
bool aa_current_policy_view_capable(struct aa_ns *ns)
{
struct aa_label *label;
bool res;
label = __begin_current_label_crit_section();
res = aa_policy_view_capable(current_cred(), label, ns);
__end_current_label_crit_section(label);
return res;
}
bool aa_current_policy_admin_capable(struct aa_ns *ns)
{
struct aa_label *label;
bool res;
label = __begin_current_label_crit_section();
res = aa_policy_admin_capable(current_cred(), label, ns);
__end_current_label_crit_section(label);
return res;
}
/**
* aa_may_manage_policy - can the current task manage policy
* @subj_cred: subjects cred
* @label: label to check if it can manage policy
* @ns: namespace being managed by @label (may be NULL if @label's ns)
* @mask: contains the policy manipulation operation being done
*
* Returns: 0 if the task is allowed to manipulate policy else error
*/
int aa_may_manage_policy(const struct cred *subj_cred, struct aa_label *label,
struct aa_ns *ns, u32 mask)
{
const char *op;
if (mask & AA_MAY_REMOVE_POLICY)
op = OP_PROF_RM;
else if (mask & AA_MAY_REPLACE_POLICY)
op = OP_PROF_REPL;
else
op = OP_PROF_LOAD;
/* check if loading policy is locked out */
if (aa_g_lock_policy)
return audit_policy(label, op, NULL, NULL, "policy_locked",
-EACCES);
if (!aa_policy_admin_capable(subj_cred, label, ns))
return audit_policy(label, op, NULL, NULL, "not policy admin",
-EACCES);
/* TODO: add fine grained mediation of policy loads */
return 0;
}
static struct aa_profile *__list_lookup_parent(struct list_head *lh,
struct aa_profile *profile)
{
const char *base = basename(profile->base.hname);
long len = base - profile->base.hname;
struct aa_load_ent *ent;
/* parent won't have trailing // so remove from len */
if (len <= 2)
return NULL;
len -= 2;
list_for_each_entry(ent, lh, list) {
if (ent->new == profile)
continue;
if (strncmp(ent->new->base.hname, profile->base.hname, len) ==
0 && ent->new->base.hname[len] == 0)
return ent->new;
}
return NULL;
}
/**
* __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_profile *child, *tmp;
if (!list_empty(&old->base.profiles)) {
LIST_HEAD(lh);
list_splice_init_rcu(&old->base.profiles, &lh, synchronize_rcu);
list_for_each_entry_safe(child, tmp, &lh, base.list) {
struct aa_profile *p;
list_del_init(&child->base.list);
p = __find_child(&new->base.profiles, child->base.name);
if (p) {
/* @p replaces @child */
__replace_profile(child, p);
continue;
}
/* inherit @child and its children */
/* TODO: update hname of inherited children */
/* list refcount transferred to @new */
p = aa_deref_parent(child);
rcu_assign_pointer(child->parent, aa_get_profile(new));
list_add_rcu(&child->base.list, &new->base.profiles);
aa_put_profile(p);
}
}
if (!rcu_access_pointer(new->parent)) {
struct aa_profile *parent = aa_deref_parent(old);
rcu_assign_pointer(new->parent, aa_get_profile(parent));
}
aa_label_replace(&old->label, &new->label);
/* migrate dents must come after label replacement b/c update */
__aafs_profile_migrate_dents(old, new);
if (list_empty(&new->base.list)) {
/* new is not on a list already */
list_replace_rcu(&old->base.list, &new->base.list);
aa_get_profile(new);
aa_put_profile(old);
} else
__list_remove_profile(old);
}
/**
* __lookup_replace - lookup replacement information for a profile
* @ns: namespace the lookup occurs in
* @hname: name of profile to lookup
* @noreplace: true if not replacing an existing profile
* @p: Returns - profile to be replaced
* @info: Returns - info string on why lookup failed
*
* Returns: profile to replace (no ref) on success else ptr error
*/
static int __lookup_replace(struct aa_ns *ns, const char *hname,
bool noreplace, struct aa_profile **p,
const char **info)
{
*p = aa_get_profile(__lookup_profile(&ns->base, hname));
if (*p) {
int error = replacement_allowed(*p, noreplace, info);
if (error) {
*info = "profile can not be replaced";
return error;
}
}
return 0;
}
static void share_name(struct aa_profile *old, struct aa_profile *new)
{
aa_put_str(new->base.hname);
aa_get_str(old->base.hname);
new->base.hname = old->base.hname;
new->base.name = old->base.name;
new->label.hname = old->label.hname;
}
/* Update to newest version of parent after previous replacements
* Returns: unrefcount newest version of parent
*/
static struct aa_profile *update_to_newest_parent(struct aa_profile *new)
{
struct aa_profile *parent, *newest;
parent = rcu_dereference_protected(new->parent,
mutex_is_locked(&new->ns->lock));
newest = aa_get_newest_profile(parent);
/* parent replaced in this atomic set? */
if (newest != parent) {
aa_put_profile(parent);
rcu_assign_pointer(new->parent, newest);
} else
aa_put_profile(newest);
return newest;
}
/**
* aa_replace_profiles - replace profile(s) on the profile list
* @policy_ns: namespace load is occurring on
* @label: label that is attempting to load/replace policy
* @mask: permission mask
* @udata: serialized data stream (NOT NULL)
*
* unpack and replace a profile on the profile list and uses of that profile
* by any task creds via invalidating the old version of the profile, which
* tasks will notice to update their own cred. 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(struct aa_ns *policy_ns, struct aa_label *label,
u32 mask, struct aa_loaddata *udata)
{
const char *ns_name = NULL, *info = NULL;
struct aa_ns *ns = NULL;
struct aa_load_ent *ent, *tmp;
struct aa_loaddata *rawdata_ent;
const char *op;
ssize_t count, error;
LIST_HEAD(lh);
op = mask & AA_MAY_REPLACE_POLICY ? OP_PROF_REPL : OP_PROF_LOAD;
aa_get_loaddata(udata);
/* released below */
error = aa_unpack(udata, &lh, &ns_name);
if (error)
goto out;
/* ensure that profiles are all for the same ns
* TODO: update locking to remove this constaint. All profiles in
* the load set must succeed as a set or the load will
* fail. Sort ent list and take ns locks in hierarchy order
*/
count = 0;
list_for_each_entry(ent, &lh, list) {
if (ns_name) {
if (ent->ns_name &&
strcmp(ent->ns_name, ns_name) != 0) {
info = "policy load has mixed namespaces";
error = -EACCES;
goto fail;
}
} else if (ent->ns_name) {
if (count) {
info = "policy load has mixed namespaces";
error = -EACCES;
goto fail;
}
ns_name = ent->ns_name;
} else
count++;
}
if (ns_name) {
ns = aa_prepare_ns(policy_ns ? policy_ns : labels_ns(label),
ns_name);
if (IS_ERR(ns)) {
op = OP_PROF_LOAD;
info = "failed to prepare namespace";
error = PTR_ERR(ns);
ns = NULL;
ent = NULL;
goto fail;
}
} else
ns = aa_get_ns(policy_ns ? policy_ns : labels_ns(label));
mutex_lock_nested(&ns->lock, ns->level);
/* check for duplicate rawdata blobs: space and file dedup */
if (!list_empty(&ns->rawdata_list)) {
list_for_each_entry(rawdata_ent, &ns->rawdata_list, list) {
if (aa_rawdata_eq(rawdata_ent, udata)) {
struct aa_loaddata *tmp;
tmp = __aa_get_loaddata(rawdata_ent);
/* check we didn't fail the race */
if (tmp) {
aa_put_loaddata(udata);
udata = tmp;
break;
}
}
}
}
/* setup parent and ns info */
list_for_each_entry(ent, &lh, list) {
struct aa_policy *policy;
struct aa_profile *p;
if (aa_g_export_binary)
ent->new->rawdata = aa_get_loaddata(udata);
error = __lookup_replace(ns, ent->new->base.hname,
!(mask & AA_MAY_REPLACE_POLICY),
&ent->old, &info);
if (error)
goto fail_lock;
if (ent->new->rename) {
error = __lookup_replace(ns, ent->new->rename,
!(mask & AA_MAY_REPLACE_POLICY),
&ent->rename, &info);
if (error)
goto fail_lock;
}
/* released when @new is freed */
ent->new->ns = aa_get_ns(ns);
if (ent->old || ent->rename)
continue;
/* no ref on policy only use inside lock */
p = NULL;
policy = __lookup_parent(ns, ent->new->base.hname);
if (!policy) {
/* first check for parent in the load set */
p = __list_lookup_parent(&lh, ent->new);
if (!p) {
/*
* fill in missing parent with null
* profile that doesn't have
* permissions. This allows for
* individual profile loading where
* the child is loaded before the
* parent, and outside of the current
* atomic set. This unfortunately can
* happen with some userspaces. The
* null profile will be replaced once
* the parent is loaded.
*/
policy = __create_missing_ancestors(ns,
ent->new->base.hname,
GFP_KERNEL);
if (!policy) {
error = -ENOENT;
info = "parent does not exist";
goto fail_lock;
}
}
}
if (!p && policy != &ns->base)
/* released on profile replacement or free_profile */
p = (struct aa_profile *) policy;
rcu_assign_pointer(ent->new->parent, aa_get_profile(p));
}
/* create new fs entries for introspection if needed */
if (!udata->dents[AAFS_LOADDATA_DIR] && aa_g_export_binary) {
error = __aa_fs_create_rawdata(ns, udata);
if (error) {
info = "failed to create raw_data dir and files";
ent = NULL;
goto fail_lock;
}
}
list_for_each_entry(ent, &lh, list) {
if (!ent->old) {
struct dentry *parent;
if (rcu_access_pointer(ent->new->parent)) {
struct aa_profile *p;
p = aa_deref_parent(ent->new);
parent = prof_child_dir(p);
} else
parent = ns_subprofs_dir(ent->new->ns);
error = __aafs_profile_mkdir(ent->new, parent);
}
if (error) {
info = "failed to create";
goto fail_lock;
}
}
/* Done with checks that may fail - do actual replacement */
__aa_bump_ns_revision(ns);
if (aa_g_export_binary)
__aa_loaddata_update(udata, ns->revision);
list_for_each_entry_safe(ent, tmp, &lh, list) {
list_del_init(&ent->list);
op = (!ent->old && !ent->rename) ? OP_PROF_LOAD : OP_PROF_REPL;
if (ent->old && ent->old->rawdata == ent->new->rawdata &&
ent->new->rawdata) {
/* dedup actual profile replacement */
audit_policy(label, op, ns_name, ent->new->base.hname,
"same as current profile, skipping",
error);
/* break refcount cycle with proxy. */
aa_put_proxy(ent->new->label.proxy);
ent->new->label.proxy = NULL;
goto skip;
}
/*
* TODO: finer dedup based on profile range in data. Load set
* can differ but profile may remain unchanged
*/
audit_policy(label, op, ns_name, ent->new->base.hname, NULL,
error);
if (ent->old) {
share_name(ent->old, ent->new);
__replace_profile(ent->old, ent->new);
} else {
struct list_head *lh;
if (rcu_access_pointer(ent->new->parent)) {
struct aa_profile *parent;
parent = update_to_newest_parent(ent->new);
lh = &parent->base.profiles;
} else
lh = &ns->base.profiles;
__add_profile(lh, ent->new);
}
skip:
aa_load_ent_free(ent);
}
__aa_labelset_update_subtree(ns);
mutex_unlock(&ns->lock);
out:
aa_put_ns(ns);
aa_put_loaddata(udata);
kfree(ns_name);
if (error)
return error;
return udata->size;
fail_lock:
mutex_unlock(&ns->lock);
/* audit cause of failure */
op = (ent && !ent->old) ? OP_PROF_LOAD : OP_PROF_REPL;
fail:
audit_policy(label, op, ns_name, ent ? ent->new->base.hname : NULL,
info, error);
/* audit status that rest of profiles in the atomic set failed too */
info = "valid profile in failed atomic policy load";
list_for_each_entry(tmp, &lh, list) {
if (tmp == ent) {
info = "unchecked profile in failed atomic policy load";
/* skip entry that caused failure */
continue;
}
op = (!tmp->old) ? OP_PROF_LOAD : OP_PROF_REPL;
audit_policy(label, op, ns_name, tmp->new->base.hname, info,
error);
}
list_for_each_entry_safe(ent, tmp, &lh, list) {
list_del_init(&ent->list);
aa_load_ent_free(ent);
}
goto out;
}
/**
* aa_remove_profiles - remove profile(s) from the system
* @policy_ns: namespace the remove is being done from
* @subj: label attempting to remove policy
* @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 preconfinement values
*
* Returns: size of data consume else error code if fails
*/
ssize_t aa_remove_profiles(struct aa_ns *policy_ns, struct aa_label *subj,
char *fqname, size_t size)
{
struct aa_ns *ns = NULL;
struct aa_profile *profile = NULL;
const char *name = fqname, *info = NULL;
const char *ns_name = NULL;
ssize_t error = 0;
if (*fqname == 0) {
info = "no profile specified";
error = -ENOENT;
goto fail;
}
if (fqname[0] == ':') {
size_t ns_len;
name = aa_splitn_fqname(fqname, size, &ns_name, &ns_len);
/* released below */
ns = aa_lookupn_ns(policy_ns ? policy_ns : labels_ns(subj),
ns_name, ns_len);
if (!ns) {
info = "namespace does not exist";
error = -ENOENT;
goto fail;
}
} else
/* released below */
ns = aa_get_ns(policy_ns ? policy_ns : labels_ns(subj));
if (!name) {
/* remove namespace - can only happen if fqname[0] == ':' */
mutex_lock_nested(&ns->parent->lock, ns->parent->level);
__aa_bump_ns_revision(ns);
__aa_remove_ns(ns);
mutex_unlock(&ns->parent->lock);
} else {
/* remove profile */
mutex_lock_nested(&ns->lock, ns->level);
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;
__aa_bump_ns_revision(ns);
__remove_profile(profile);
__aa_labelset_update_subtree(ns);
mutex_unlock(&ns->lock);
}
/* don't fail removal if audit fails */
(void) audit_policy(subj, OP_PROF_RM, ns_name, name, info,
error);
aa_put_ns(ns);
aa_put_profile(profile);
return size;
fail_ns_lock:
mutex_unlock(&ns->lock);
aa_put_ns(ns);
fail:
(void) audit_policy(subj, OP_PROF_RM, ns_name, name, info,
error);
return error;
}
Codebase Browser
linux