// 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 = …; int aa_unprivileged_unconfined_restricted; const char *const aa_profile_mode_names[] = …; static void aa_free_pdb(struct aa_policydb *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 *aa_alloc_pdb(gfp_t gfp) { … } /** * __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) { … } /** * __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) { … } /** * __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_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) { … } /** * aa_free_data - free a data blob * @ptr: data to free * @arg: unused */ static void aa_free_data(void *ptr, void *arg) { … } static void free_attachment(struct aa_attachment *attach) { … } static void free_ruleset(struct aa_ruleset *rules) { … } struct aa_ruleset *aa_alloc_ruleset(gfp_t gfp) { … } /** * 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) { … } /** * 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) { … } /* 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) { … } /** * __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) { … } /** * 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) { … } /** * __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) { … } /** * __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) { … } /** * __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) { … } static struct aa_profile *__lookup_profile(struct aa_policy *base, const char *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 *aa_lookup_profile(struct aa_ns *ns, const char *hname) { … } struct aa_profile *aa_fqlookupn_profile(struct aa_label *base, const char *fqname, size_t n) { … } struct aa_profile *aa_alloc_null(struct aa_profile *parent, const char *name, gfp_t gfp) { … } /** * 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) { … } /** * 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) { … } /* audit callback for net specific fields */ static void audit_cb(struct audit_buffer *ab, void *va) { … } /** * 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) { … } /* 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) { … } /** * 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) { … } bool aa_policy_admin_capable(const struct cred *subj_cred, struct aa_label *label, struct aa_ns *ns) { … } bool aa_current_policy_view_capable(struct aa_ns *ns) { … } bool aa_current_policy_admin_capable(struct aa_ns *ns) { … } /** * 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) { … } static struct aa_profile *__list_lookup_parent(struct list_head *lh, struct aa_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) { … } /** * __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) { … } static void share_name(struct aa_profile *old, struct aa_profile *new) { … } /* 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) { … } /** * 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) { … } /** * 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) { … }
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