diff options
Diffstat (limited to 'security/apparmor/policy.c')
| -rw-r--r-- | security/apparmor/policy.c | 459 |
1 files changed, 357 insertions, 102 deletions
diff --git a/security/apparmor/policy.c b/security/apparmor/policy.c index af4f50fda9e3..50d5345ff5cb 100644 --- a/security/apparmor/policy.c +++ b/security/apparmor/policy.c @@ -88,15 +88,52 @@ #include "include/resource.h" int unprivileged_userns_apparmor_policy = 1; +int aa_unprivileged_unconfined_restricted; const char *const aa_profile_mode_names[] = { "enforce", "complain", "kill", "unconfined", + "user", }; +static void aa_free_pdb(struct aa_policydb *pdb) +{ + if (pdb) { + aa_put_dfa(pdb->dfa); + kvfree(pdb->perms); + aa_free_str_table(&pdb->trans); + kfree(pdb); + } +} + +/** + * aa_pdb_free_kref - free aa_policydb by kref (called by aa_put_pdb) + * @kref: kref callback for freeing of a dfa (NOT NULL) + */ +void aa_pdb_free_kref(struct kref *kref) +{ + struct aa_policydb *pdb = container_of(kref, struct aa_policydb, count); + + aa_free_pdb(pdb); +} + + +struct aa_policydb *aa_alloc_pdb(gfp_t gfp) +{ + struct aa_policydb *pdb = kzalloc(sizeof(struct aa_policydb), gfp); + + if (!pdb) + return NULL; + + kref_init(&pdb->count); + + return pdb; +} + + /** * __add_profile - add a profiles to list and label tree * @list: list to add it to (NOT NULL) @@ -187,9 +224,46 @@ static void aa_free_data(void *ptr, void *arg) { struct aa_data *data = ptr; - kzfree(data->data); - kzfree(data->key); - kzfree(data); + kvfree_sensitive(data->data, data->size); + kfree_sensitive(data->key); + kfree_sensitive(data); +} + +static void free_attachment(struct aa_attachment *attach) +{ + int i; + + for (i = 0; i < attach->xattr_count; i++) + kfree_sensitive(attach->xattrs[i]); + kfree_sensitive(attach->xattrs); + aa_put_pdb(attach->xmatch); +} + +static void free_ruleset(struct aa_ruleset *rules) +{ + int i; + + if (!rules) + return; + + aa_put_pdb(rules->file); + aa_put_pdb(rules->policy); + aa_free_cap_rules(&rules->caps); + aa_free_rlimit_rules(&rules->rlimits); + + for (i = 0; i < rules->secmark_count; i++) + kfree_sensitive(rules->secmark[i].label); + kfree_sensitive(rules->secmark); + kfree_sensitive(rules); +} + +struct aa_ruleset *aa_alloc_ruleset(gfp_t gfp) +{ + struct aa_ruleset *rules; + + rules = kzalloc(sizeof(*rules), gfp); + + return rules; } /** @@ -205,9 +279,8 @@ static void aa_free_data(void *ptr, void *arg) void aa_free_profile(struct aa_profile *profile) { struct rhashtable *rht; - int i; - AA_DEBUG("%s(%p)\n", __func__, profile); + AA_DEBUG(DEBUG_POLICY, "%s(%p)\n", __func__, profile); if (!profile) return; @@ -217,39 +290,38 @@ void aa_free_profile(struct aa_profile *profile) aa_put_profile(rcu_access_pointer(profile->parent)); aa_put_ns(profile->ns); - kzfree(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++) - kzfree(profile->xattrs[i]); - kzfree(profile->xattrs); - for (i = 0; i < profile->secmark_count; i++) - kzfree(profile->secmark[i].label); - kzfree(profile->secmark); - kzfree(profile->dirname); - aa_put_dfa(profile->xmatch); - aa_put_dfa(profile->policy.dfa); + 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 + */ + for (int i = 0; i < profile->n_rules; i++) + free_ruleset(profile->label.rules[i]); + + kfree_sensitive(profile->dirname); if (profile->data) { rht = profile->data; profile->data = NULL; rhashtable_free_and_destroy(rht, aa_free_data, NULL); - kzfree(rht); + kfree_sensitive(rht); } - kzfree(profile->hash); + kfree_sensitive(profile->hash); aa_put_loaddata(profile->rawdata); aa_label_destroy(&profile->label); - kzfree(profile); + 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 @@ -259,9 +331,11 @@ struct aa_profile *aa_alloc_profile(const char *hname, struct aa_proxy *proxy, { struct aa_profile *profile; - /* freed by free_profile - usually through aa_put_profile */ - profile = kzalloc(sizeof(*profile) + sizeof(struct aa_profile *) * 2, - gfp); + /* freed by free_profile - usually through aa_put_profile + * this adds space for a single ruleset in the rules section of the + * label + */ + profile = kzalloc(struct_size(profile, label.rules, 1), gfp); if (!profile) return NULL; @@ -270,6 +344,12 @@ struct aa_profile *aa_alloc_profile(const char *hname, struct aa_proxy *proxy, if (!aa_label_init(&profile->label, 1, gfp)) goto fail; + /* allocate the first ruleset, but leave it empty */ + profile->label.rules[0] = aa_alloc_ruleset(gfp); + if (!profile->label.rules[0]) + goto fail; + profile->n_rules = 1; + /* update being set needed by fs interface */ if (!proxy) { proxy = aa_alloc_proxy(&profile->label, gfp); @@ -283,6 +363,7 @@ struct aa_profile *aa_alloc_profile(const char *hname, struct aa_proxy *proxy, profile->label.flags |= FLAG_PROFILE; profile->label.vec[0] = profile; + profile->signal = SIGKILL; /* refcount released by caller */ return profile; @@ -292,6 +373,41 @@ fail: return NULL; } +static inline bool ANY_RULE_MEDIATES(struct aa_profile *profile, + unsigned char class) +{ + int i; + + for (i = 0; i < profile->n_rules; i++) { + if (RULE_MEDIATES(profile->label.rules[i], class)) + return true; + } + return false; +} + +/* set of rules that are mediated by unconfined */ +static int unconfined_mediates[] = { AA_CLASS_NS, AA_CLASS_IO_URING, 0 }; + +/* must be called after profile rulesets and start information is setup */ +void aa_compute_profile_mediates(struct aa_profile *profile) +{ + int c; + + if (profile_unconfined(profile)) { + int *pos; + + for (pos = unconfined_mediates; *pos; pos++) { + if (ANY_RULE_MEDIATES(profile, *pos)) + profile->label.mediates |= ((u64) 1) << AA_CLASS_NS; + } + return; + } + for (c = 0; c <= AA_CLASS_LAST; c++) { + if (ANY_RULE_MEDIATES(profile, c)) + profile->label.mediates |= ((u64) 1) << c; + } +} + /* TODO: profile accounting - setup in remove */ /** @@ -382,6 +498,55 @@ static struct aa_policy *__lookup_parent(struct aa_ns *ns, } /** + * __create_missing_ancestors - create place holders for missing ancestors + * @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) @@ -423,7 +588,7 @@ static struct aa_profile *__lookup_profile(struct aa_policy *base, } /** - * aa_lookup_profile - find a profile by its full or partial name + * 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 @@ -449,11 +614,6 @@ struct aa_profile *aa_lookupn_profile(struct aa_ns *ns, const char *hname, 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) { @@ -482,8 +642,39 @@ struct aa_profile *aa_fqlookupn_profile(struct aa_label *base, 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; + profile->attach.xmatch = aa_get_pdb(nullpdb); + rules = profile->label.rules[0]; + rules->file = aa_get_pdb(nullpdb); + rules->policy = aa_get_pdb(nullpdb); + aa_compute_profile_mediates(profile); + + if (parent) { + profile->path_flags = parent->path_flags; + /* override/inherit what is mediated from parent */ + profile->label.mediates = parent->label.mediates; + /* released on free_profile */ + rcu_assign_pointer(profile->parent, aa_get_profile(parent)); + profile->ns = aa_get_ns(parent->ns); + } + + return profile; +} + /** - * aa_new_null_profile - create or find a null-X learning profile + * aa_new_learning_profile - create or find a null-X learning profile * @parent: profile that caused this profile to be created (NOT NULL) * @hat: true if the null- learning profile is a hat * @base: name to base the null profile off of @@ -500,8 +691,8 @@ struct aa_profile *aa_fqlookupn_profile(struct aa_label *base, * * 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 *aa_new_learning_profile(struct aa_profile *parent, bool hat, + const char *base, gfp_t gfp) { struct aa_profile *p, *profile; const char *bname; @@ -532,21 +723,12 @@ name: if (profile) goto out; - profile = aa_alloc_profile(name, NULL, gfp); + profile = aa_alloc_null(parent, name, 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); @@ -597,16 +779,17 @@ static int replacement_allowed(struct aa_profile *profile, int noreplace, static void audit_cb(struct audit_buffer *ab, void *va) { struct common_audit_data *sa = va; + struct apparmor_audit_data *ad = aad(sa); - if (aad(sa)->iface.ns) { + if (ad->iface.ns) { audit_log_format(ab, " ns="); - audit_log_untrustedstring(ab, aad(sa)->iface.ns); + audit_log_untrustedstring(ab, ad->iface.ns); } } /** * audit_policy - Do auditing of policy changes - * @label: label to check if it can manage policy + * @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) @@ -615,35 +798,56 @@ static void audit_cb(struct audit_buffer *ab, void *va) * * Returns: the error to be returned after audit is done */ -static int audit_policy(struct aa_label *label, const char *op, +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(sa, LSM_AUDIT_DATA_NONE, op); + DEFINE_AUDIT_DATA(ad, LSM_AUDIT_DATA_NONE, AA_CLASS_NONE, op); - aad(&sa)->iface.ns = ns_name; - aad(&sa)->name = name; - aad(&sa)->info = info; - aad(&sa)->error = error; - aad(&sa)->label = label; + 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, &sa, audit_cb); + 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; +} + /** - * policy_view_capable - check if viewing policy in at @ns is allowed - * ns: namespace being viewed by current task (may be NULL) + * 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 policy_view_capable(struct aa_ns *ns) +bool aa_policy_view_capable(const struct cred *subj_cred, + struct aa_label *label, struct aa_ns *ns) { - struct user_namespace *user_ns = current_user_ns(); - struct aa_ns *view_ns = aa_get_current_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; @@ -655,30 +859,59 @@ bool policy_view_capable(struct aa_ns *ns) (unprivileged_userns_apparmor_policy != 0 && user_ns->level == view_ns->level))) response = true; - aa_put_ns(view_ns); return response; } -bool policy_admin_capable(struct aa_ns *ns) +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(DEBUG_POLICY, "cap_mac_admin? %d\n", capable); + AA_DEBUG(DEBUG_POLICY, "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 needput, res; + + label = __begin_current_label_crit_section(&needput); + res = aa_policy_view_capable(current_cred(), label, ns); + __end_current_label_crit_section(label, needput); + + return res; +} + +bool aa_current_policy_admin_capable(struct aa_ns *ns) { - struct user_namespace *user_ns = current_user_ns(); - bool capable = ns_capable(user_ns, CAP_MAC_ADMIN); + struct aa_label *label; + bool needput, res; - AA_DEBUG("cap_mac_admin? %d\n", capable); - AA_DEBUG("policy locked? %d\n", aa_g_lock_policy); + label = __begin_current_label_crit_section(&needput); + res = aa_policy_admin_capable(current_cred(), label, ns); + __end_current_label_crit_section(label, needput); - return policy_view_capable(ns) && capable && !aa_g_lock_policy; + 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 - * @op: the policy manipulation operation being done + * @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(struct aa_label *label, struct aa_ns *ns, u32 mask) +int aa_may_manage_policy(const struct cred *subj_cred, struct aa_label *label, + struct aa_ns *ns, u32 mask) { const char *op; @@ -694,7 +927,7 @@ int aa_may_manage_policy(struct aa_label *label, struct aa_ns *ns, u32 mask) return audit_policy(label, op, NULL, NULL, "policy_locked", -EACCES); - if (!policy_admin_capable(ns)) + if (!aa_policy_admin_capable(subj_cred, label, ns)) return audit_policy(label, op, NULL, NULL, "not policy admin", -EACCES); @@ -729,7 +962,6 @@ static struct aa_profile *__list_lookup_parent(struct list_head *lh, * __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. @@ -786,11 +1018,11 @@ 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 + * @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 */ @@ -873,7 +1105,7 @@ ssize_t aa_replace_profiles(struct aa_ns *policy_ns, struct aa_label *label, goto out; /* ensure that profiles are all for the same ns - * TODO: update locking to remove this constaint. All profiles in + * TODO: update locking to remove this constraint. 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 */ @@ -912,24 +1144,28 @@ ssize_t aa_replace_profiles(struct aa_ns *policy_ns, struct aa_label *label, mutex_lock_nested(&ns->lock, ns->level); /* check for duplicate rawdata blobs: space and file dedup */ - 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; + 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; - ent->new->rawdata = aa_get_loaddata(udata); + 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); @@ -951,25 +1187,42 @@ ssize_t aa_replace_profiles(struct aa_ns *policy_ns, struct aa_label *label, continue; /* no ref on policy only use inside lock */ + p = NULL; policy = __lookup_parent(ns, ent->new->base.hname); if (!policy) { - struct aa_profile *p; + /* first check for parent in the load set */ p = __list_lookup_parent(&lh, ent->new); if (!p) { - error = -ENOENT; - info = "parent does not exist"; - goto fail_lock; + /* + * 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; + } } - 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)); } + 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]) { + 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"; @@ -997,12 +1250,14 @@ ssize_t aa_replace_profiles(struct aa_ns *policy_ns, struct aa_label *label, /* Done with checks that may fail - do actual replacement */ __aa_bump_ns_revision(ns); - __aa_loaddata_update(udata, ns->revision); + 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) { + 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", @@ -1125,7 +1380,7 @@ ssize_t aa_remove_profiles(struct aa_ns *policy_ns, struct aa_label *subj, if (!name) { /* remove namespace - can only happen if fqname[0] == ':' */ - mutex_lock_nested(&ns->parent->lock, ns->level); + mutex_lock_nested(&ns->parent->lock, ns->parent->level); __aa_bump_ns_revision(ns); __aa_remove_ns(ns); mutex_unlock(&ns->parent->lock); |
