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Diffstat (limited to 'security/apparmor/policy.c')
| -rw-r--r-- | security/apparmor/policy.c | 1362 |
1 files changed, 1362 insertions, 0 deletions
diff --git a/security/apparmor/policy.c b/security/apparmor/policy.c new file mode 100644 index 0000000000..8a07793ce1 --- /dev/null +++ b/security/apparmor/policy.c @@ -0,0 +1,1362 @@ +// 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", + "user", +}; + + +/** + * __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); +} + +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_destroy_policydb(&attach->xmatch); +} + +static void free_ruleset(struct aa_ruleset *rules) +{ + int i; + + aa_destroy_policydb(&rules->file); + aa_destroy_policydb(&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.dfa = aa_get_dfa(nulldfa); + rules->file.perms = kcalloc(2, sizeof(struct aa_perms), GFP_KERNEL); + if (!rules->file.perms) + goto fail; + rules->file.size = 2; + rules->policy.dfa = aa_get_dfa(nulldfa); + rules->policy.perms = kcalloc(2, sizeof(struct aa_perms), GFP_KERNEL); + if (!rules->policy.perms) + goto fail; + rules->policy.size = 2; + + 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; + +fail: + aa_free_profile(profile); + + return NULL; +} + +/** + * 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; +} |