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Diffstat (limited to 'kernel/security/apparmor/policy.c')
| -rw-r--r-- | kernel/security/apparmor/policy.c | 1301 |
1 files changed, 1301 insertions, 0 deletions
diff --git a/kernel/security/apparmor/policy.c b/kernel/security/apparmor/policy.c new file mode 100644 index 000000000..705c2879d --- /dev/null +++ b/kernel/security/apparmor/policy.c @@ -0,0 +1,1301 @@ +/* + * 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" + + +/* root profile namespace */ +struct aa_namespace *root_ns; + +const char *const aa_profile_mode_names[] = { + "enforce", + "complain", + "kill", + "unconfined", +}; + +/** + * 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); + + 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 (on_list_rcu(&policy->profiles)) { + AA_ERROR("%s: internal error, " + "policy '%s' still contains profiles\n", + __func__, policy->name); + BUG(); + } + if (on_list_rcu(&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: rcu_read_lock 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_rcu(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: rcu_read_lock 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_rcu(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); + mutex_init(&ns->lock); + + /* released by free_namespace */ + ns->unconfined = aa_alloc_profile("unconfined"); + if (!ns->unconfined) + goto fail_unconfined; + + ns->unconfined->flags = PFLAG_IX_ON_NAME_ERROR | + PFLAG_IMMUTABLE | PFLAG_NS_COUNT; + ns->unconfined->mode = APPARMOR_UNCONFINED; + + /* ns and ns->unconfined share ns->unconfined refcount */ + ns->unconfined->ns = ns; + + atomic_set(&ns->uniq_null, 0); + + 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); + + ns->unconfined->ns = NULL; + aa_free_profile(ns->unconfined); + kzfree(ns); +} + +/** + * __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: rcu_read_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; + + rcu_read_lock(); + ns = aa_get_namespace(__aa_find_namespace(&root->sub_ns, name)); + rcu_read_unlock(); + + 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; + + mutex_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) { + ns = alloc_namespace(root->base.hname, name); + if (!ns) + goto out; + if (__aa_fs_namespace_mkdir(ns, ns_subns_dir(root), name)) { + AA_ERROR("Failed to create interface for ns %s\n", + ns->base.name); + free_namespace(ns); + ns = NULL; + goto out; + } + ns->parent = aa_get_namespace(root); + list_add_rcu(&ns->base.list, &root->sub_ns); + /* add list ref */ + aa_get_namespace(ns); + } +out: + mutex_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_rcu(&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_rcu(&profile->base.list); + aa_put_profile(profile); +} + +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 */ + __aa_update_replacedby(profile, profile->ns->unconfined); + __aa_fs_profile_rmdir(profile); + __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; + + mutex_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); + + if (ns->parent) + __aa_update_replacedby(ns->unconfined, ns->parent->unconfined); + __aa_fs_namespace_rmdir(ns); + mutex_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) +{ + /* remove ns from namespace list */ + list_del_rcu(&ns->base.list); + destroy_namespace(ns); + 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); +} + + +static void free_replacedby(struct aa_replacedby *r) +{ + if (r) { + /* r->profile will not be updated any more as r is dead */ + aa_put_profile(rcu_dereference_protected(r->profile, true)); + kzfree(r); + } +} + + +void aa_free_replacedby_kref(struct kref *kref) +{ + struct aa_replacedby *r = container_of(kref, struct aa_replacedby, + count); + free_replacedby(r); +} + +/** + * 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_DEBUG("%s(%p)\n", __func__, profile); + + if (!profile) + return; + + /* free children profiles */ + policy_destroy(&profile->base); + aa_put_profile(rcu_access_pointer(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); + + kzfree(profile->dirname); + aa_put_dfa(profile->xmatch); + aa_put_dfa(profile->policy.dfa); + aa_put_replacedby(profile->replacedby); + + kzfree(profile->hash); + kzfree(profile); +} + +/** + * aa_free_profile_rcu - free aa_profile by rcu (called by aa_free_profile_kref) + * @head: rcu_head callback for freeing of a profile (NOT NULL) + */ +static void aa_free_profile_rcu(struct rcu_head *head) +{ + struct aa_profile *p = container_of(head, struct aa_profile, rcu); + if (p->flags & PFLAG_NS_COUNT) + free_namespace(p->ns); + else + aa_free_profile(p); +} + +/** + * 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, count); + call_rcu(&p->rcu, aa_free_profile_rcu); +} + +/** + * 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; + + profile->replacedby = kzalloc(sizeof(struct aa_replacedby), GFP_KERNEL); + if (!profile->replacedby) + goto fail; + kref_init(&profile->replacedby->count); + + if (!policy_init(&profile->base, NULL, hname)) + goto fail; + kref_init(&profile->count); + + /* refcount released by caller */ + return profile; + +fail: + kzfree(profile->replacedby); + kzfree(profile); + + return NULL; +} + +/** + * 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-<uniq>. + * + * 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; + int uniq = atomic_inc_return(&parent->ns->uniq_null); + + /* 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, uniq); + + profile = aa_alloc_profile(name); + kfree(name); + if (!profile) + goto fail; + + profile->mode = APPARMOR_COMPLAIN; + profile->flags = PFLAG_NULL; + if (hat) + profile->flags |= PFLAG_HAT; + + /* released on free_profile */ + rcu_assign_pointer(profile->parent, aa_get_profile(parent)); + profile->ns = aa_get_namespace(parent->ns); + + mutex_lock(&profile->ns->lock); + __list_add_profile(&parent->base.profiles, profile); + mutex_unlock(&profile->ns->lock); + + /* refcount released by caller */ + return profile; + +fail: + return NULL; +} + +/* 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: 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 (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: 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); +} + +/** + * 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(); + profile = aa_get_profile(__find_child(&parent->base.profiles, name)); + 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_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: 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 *__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; + + rcu_read_lock(); + do { + profile = __lookup_profile(&ns->base, hname); + } while (profile && !aa_get_profile_not0(profile)); + rcu_read_unlock(); + + /* the unconfined profile is not in the regular profile list */ + if (!profile && strcmp(hname, "unconfined") == 0) + profile = aa_get_newest_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; +} + +/** + * 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; +} + +static struct aa_profile *__list_lookup_parent(struct list_head *lh, + struct aa_profile *profile) +{ + const char *base = hname_tail(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_replacedby: transfer @old->replacedby 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, + bool share_replacedby) +{ + 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, share_replacedby); + 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_update_replacedby(old, new); + if (share_replacedby) { + aa_put_replacedby(new->replacedby); + new->replacedby = aa_get_replacedby(old->replacedby); + } else if (!rcu_access_pointer(new->replacedby->profile)) + /* aafs interface uses replacedby */ + rcu_assign_pointer(new->replacedby->profile, + aa_get_profile(new)); + __aa_fs_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_namespace *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; +} + +/** + * 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) +{ + const char *ns_name, *name = NULL, *info = NULL; + struct aa_namespace *ns = NULL; + struct aa_load_ent *ent, *tmp; + int op = OP_PROF_REPL; + ssize_t error; + LIST_HEAD(lh); + + /* released below */ + error = aa_unpack(udata, size, &lh, &ns_name); + if (error) + goto out; + + /* released below */ + ns = aa_prepare_namespace(ns_name); + if (!ns) { + info = "failed to prepare namespace"; + error = -ENOMEM; + name = ns_name; + goto fail; + } + + mutex_lock(&ns->lock); + /* setup parent and ns info */ + list_for_each_entry(ent, &lh, list) { + struct aa_policy *policy; + + name = ent->new->base.hname; + error = __lookup_replace(ns, ent->new->base.hname, noreplace, + &ent->old, &info); + if (error) + goto fail_lock; + + if (ent->new->rename) { + error = __lookup_replace(ns, ent->new->rename, + noreplace, &ent->rename, + &info); + if (error) + goto fail_lock; + } + + /* released when @new is freed */ + ent->new->ns = aa_get_namespace(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"; + name = ent->new->base.hname; + 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 */ + list_for_each_entry(ent, &lh, list) { + if (ent->old) { + /* inherit old interface files */ + + /* if (ent->rename) + TODO: support rename */ + /* } else if (ent->rename) { + TODO: support rename */ + } else { + 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 = __aa_fs_profile_mkdir(ent->new, parent); + } + + if (error) { + info = "failed to create "; + goto fail_lock; + } + } + + /* Done with checks that may fail - do actual replacement */ + 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; + + audit_policy(op, GFP_ATOMIC, ent->new->base.name, NULL, error); + + if (ent->old) { + __replace_profile(ent->old, ent->new, 1); + if (ent->rename) { + /* aafs interface uses replacedby */ + struct aa_replacedby *r = ent->new->replacedby; + rcu_assign_pointer(r->profile, + aa_get_profile(ent->new)); + __replace_profile(ent->rename, ent->new, 0); + } + } else if (ent->rename) { + /* aafs interface uses replacedby */ + rcu_assign_pointer(ent->new->replacedby->profile, + aa_get_profile(ent->new)); + __replace_profile(ent->rename, ent->new, 0); + } else if (ent->new->parent) { + struct aa_profile *parent, *newest; + parent = aa_deref_parent(ent->new); + newest = aa_get_newest_profile(parent); + + /* parent replaced in this atomic set? */ + if (newest != parent) { + aa_get_profile(newest); + aa_put_profile(parent); + rcu_assign_pointer(ent->new->parent, newest); + } else + aa_put_profile(newest); + /* aafs interface uses replacedby */ + rcu_assign_pointer(ent->new->replacedby->profile, + aa_get_profile(ent->new)); + __list_add_profile(&parent->base.profiles, ent->new); + } else { + /* aafs interface uses replacedby */ + rcu_assign_pointer(ent->new->replacedby->profile, + aa_get_profile(ent->new)); + __list_add_profile(&ns->base.profiles, ent->new); + } + aa_load_ent_free(ent); + } + mutex_unlock(&ns->lock); + +out: + aa_put_namespace(ns); + + if (error) + return error; + return size; + +fail_lock: + mutex_unlock(&ns->lock); +fail: + error = audit_policy(op, GFP_KERNEL, name, 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 + * @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); + /* 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] == ':' */ + mutex_lock(&ns->parent->lock); + __remove_namespace(ns); + mutex_unlock(&ns->parent->lock); + } else { + /* remove profile */ + mutex_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); + mutex_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: + mutex_unlock(&ns->lock); + aa_put_namespace(ns); + +fail: + (void) audit_policy(OP_PROF_RM, GFP_KERNEL, name, info, error); + return error; +} |