linux/security/apparmor/policy.c
John Johansen d61c57fde8 apparmor: make export of raw binary profile to userspace optional
Embedded systems have limited space and don't need the introspection
or checkpoint restore capability provided by exporting the raw
profile binary data so make it so make it a config option.

This will reduce run time memory use and also speed up policy loads.

Signed-off-by: John Johansen <john.johansen@canonical.com>
2022-07-09 15:13:59 -07:00

1209 lines
33 KiB
C

// 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;
const char *const aa_profile_mode_names[] = {
"enforce",
"complain",
"kill",
"unconfined",
};
/**
* __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;
kfree_sensitive(data->data);
kfree_sensitive(data->key);
kfree_sensitive(data);
}
/**
* 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 rhashtable *rht;
int i;
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);
aa_free_file_rules(&profile->file);
aa_free_cap_rules(&profile->caps);
aa_free_rlimit_rules(&profile->rlimits);
for (i = 0; i < profile->xattr_count; i++)
kfree_sensitive(profile->xattrs[i]);
kfree_sensitive(profile->xattrs);
for (i = 0; i < profile->secmark_count; i++)
kfree_sensitive(profile->secmark[i].label);
kfree_sensitive(profile->secmark);
kfree_sensitive(profile->dirname);
aa_put_dfa(profile->xmatch);
aa_put_dfa(profile->policy.dfa);
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)
* @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;
/* 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;
/* 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;
}
/**
* __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;
}
/**
* aa_new_null_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_null_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_profile(name, NULL, gfp);
if (!profile)
goto fail;
profile->mode = APPARMOR_COMPLAIN;
profile->label.flags |= FLAG_NULL;
if (hat)
profile->label.flags |= FLAG_HAT;
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);
profile->file.dfa = aa_get_dfa(nulldfa);
profile->policy.dfa = aa_get_dfa(nulldfa);
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;
if (aad(sa)->iface.ns) {
audit_log_format(ab, " ns=");
audit_log_untrustedstring(ab, aad(sa)->iface.ns);
}
}
/**
* audit_policy - Do auditing of policy changes
* @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 *label, const char *op,
const char *ns_name, const char *name,
const char *info, int error)
{
DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_NONE, op);
aad(&sa)->iface.ns = ns_name;
aad(&sa)->name = name;
aad(&sa)->info = info;
aad(&sa)->error = error;
aad(&sa)->label = label;
aa_audit_msg(AUDIT_APPARMOR_STATUS, &sa, audit_cb);
return error;
}
/* don't call out to other LSMs in the stack for apparmor policy admin
* permissions
*/
static int policy_ns_capable(struct aa_label *label,
struct user_namespace *userns, int cap)
{
int err;
/* check for MAC_ADMIN cap in cred */
err = cap_capable(current_cred(), userns, cap, CAP_OPT_NONE);
if (!err)
err = aa_capable(label, cap, CAP_OPT_NONE);
return err;
}
/**
* aa_policy_view_capable - check if viewing policy in at @ns is allowed
* 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(struct aa_label *label, struct aa_ns *ns)
{
struct user_namespace *user_ns = current_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(struct aa_label *label, struct aa_ns *ns)
{
struct user_namespace *user_ns = current_user_ns();
bool capable = policy_ns_capable(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(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(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(label, ns);
__end_current_label_crit_section(label);
return res;
}
/**
* aa_may_manage_policy - can the current task manage policy
* @label: label to check if it can manage policy
* @op: the policy manipulation operation being done
*
* Returns: 0 if the task is allowed to manipulate policy else error
*/
int aa_may_manage_policy(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(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)
* @share_proxy: transfer @old->proxy to @new
*
* 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;
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 */
policy = __lookup_parent(ns, ent->new->base.hname);
if (!policy) {
struct aa_profile *p;
p = __list_lookup_parent(&lh, ent->new);
if (!p) {
error = -ENOENT;
info = "parent does not exist";
goto fail_lock;
}
rcu_assign_pointer(ent->new->parent, aa_get_profile(p));
} else if (policy != &ns->base) {
/* released on profile replacement or free_profile */
struct aa_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->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;
}