diff options
Diffstat (limited to 'security/apparmor/resource.c')
| -rw-r--r-- | security/apparmor/resource.c | 206 |
1 files changed, 206 insertions, 0 deletions
diff --git a/security/apparmor/resource.c b/security/apparmor/resource.c new file mode 100644 index 0000000000..dcc94c3153 --- /dev/null +++ b/security/apparmor/resource.c @@ -0,0 +1,206 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * AppArmor security module + * + * This file contains AppArmor resource mediation and attachment + * + * Copyright (C) 1998-2008 Novell/SUSE + * Copyright 2009-2010 Canonical Ltd. + */ + +#include <linux/audit.h> +#include <linux/security.h> + +#include "include/audit.h" +#include "include/cred.h" +#include "include/resource.h" +#include "include/policy.h" + +/* + * Table of rlimit names: we generate it from resource.h. + */ +#include "rlim_names.h" + +struct aa_sfs_entry aa_sfs_entry_rlimit[] = { + AA_SFS_FILE_STRING("mask", AA_SFS_RLIMIT_MASK), + { } +}; + +/* audit callback for resource 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); + + audit_log_format(ab, " rlimit=%s value=%lu", + rlim_names[ad->rlim.rlim], ad->rlim.max); + if (ad->peer) { + audit_log_format(ab, " peer="); + aa_label_xaudit(ab, labels_ns(ad->subj_label), ad->peer, + FLAGS_NONE, GFP_ATOMIC); + } +} + +/** + * audit_resource - audit setting resource limit + * @subj_cred: cred setting the resource + * @profile: profile being enforced (NOT NULL) + * @resource: rlimit being auditing + * @value: value being set + * @peer: aa_albel of the task being set + * @info: info being auditing + * @error: error value + * + * Returns: 0 or ad->error else other error code on failure + */ +static int audit_resource(const struct cred *subj_cred, + struct aa_profile *profile, unsigned int resource, + unsigned long value, struct aa_label *peer, + const char *info, int error) +{ + DEFINE_AUDIT_DATA(ad, LSM_AUDIT_DATA_NONE, AA_CLASS_RLIMITS, + OP_SETRLIMIT); + + ad.subj_cred = subj_cred; + ad.rlim.rlim = resource; + ad.rlim.max = value; + ad.peer = peer; + ad.info = info; + ad.error = error; + + return aa_audit(AUDIT_APPARMOR_AUTO, profile, &ad, audit_cb); +} + +/** + * aa_map_resource - map compiled policy resource to internal # + * @resource: flattened policy resource number + * + * Returns: resource # for the current architecture. + * + * rlimit resource can vary based on architecture, map the compiled policy + * resource # to the internal representation for the architecture. + */ +int aa_map_resource(int resource) +{ + return rlim_map[resource]; +} + +static int profile_setrlimit(const struct cred *subj_cred, + struct aa_profile *profile, unsigned int resource, + struct rlimit *new_rlim) +{ + struct aa_ruleset *rules = list_first_entry(&profile->rules, + typeof(*rules), list); + int e = 0; + + if (rules->rlimits.mask & (1 << resource) && new_rlim->rlim_max > + rules->rlimits.limits[resource].rlim_max) + e = -EACCES; + return audit_resource(subj_cred, profile, resource, new_rlim->rlim_max, + NULL, NULL, e); +} + +/** + * aa_task_setrlimit - test permission to set an rlimit + * @subj_cred: cred setting the limit + * @label: label confining the task (NOT NULL) + * @task: task the resource is being set on + * @resource: the resource being set + * @new_rlim: the new resource limit (NOT NULL) + * + * Control raising the processes hard limit. + * + * Returns: 0 or error code if setting resource failed + */ +int aa_task_setrlimit(const struct cred *subj_cred, struct aa_label *label, + struct task_struct *task, + unsigned int resource, struct rlimit *new_rlim) +{ + struct aa_profile *profile; + struct aa_label *peer; + int error = 0; + + rcu_read_lock(); + peer = aa_get_newest_cred_label(__task_cred(task)); + rcu_read_unlock(); + + /* TODO: extend resource control to handle other (non current) + * profiles. AppArmor rules currently have the implicit assumption + * that the task is setting the resource of a task confined with + * the same profile or that the task setting the resource of another + * task has CAP_SYS_RESOURCE. + */ + + if (label != peer && + aa_capable(subj_cred, label, CAP_SYS_RESOURCE, CAP_OPT_NOAUDIT) != 0) + error = fn_for_each(label, profile, + audit_resource(subj_cred, profile, resource, + new_rlim->rlim_max, peer, + "cap_sys_resource", -EACCES)); + else + error = fn_for_each_confined(label, profile, + profile_setrlimit(subj_cred, profile, resource, + new_rlim)); + aa_put_label(peer); + + return error; +} + +/** + * __aa_transition_rlimits - apply new profile rlimits + * @old_l: old label on task (NOT NULL) + * @new_l: new label with rlimits to apply (NOT NULL) + */ +void __aa_transition_rlimits(struct aa_label *old_l, struct aa_label *new_l) +{ + unsigned int mask = 0; + struct rlimit *rlim, *initrlim; + struct aa_profile *old, *new; + struct label_it i; + + old = labels_profile(old_l); + new = labels_profile(new_l); + + /* for any rlimits the profile controlled, reset the soft limit + * to the lesser of the tasks hard limit and the init tasks soft limit + */ + label_for_each_confined(i, old_l, old) { + struct aa_ruleset *rules = list_first_entry(&old->rules, + typeof(*rules), + list); + if (rules->rlimits.mask) { + int j; + + for (j = 0, mask = 1; j < RLIM_NLIMITS; j++, + mask <<= 1) { + if (rules->rlimits.mask & mask) { + rlim = current->signal->rlim + j; + initrlim = init_task.signal->rlim + j; + rlim->rlim_cur = min(rlim->rlim_max, + initrlim->rlim_cur); + } + } + } + } + + /* set any new hard limits as dictated by the new profile */ + label_for_each_confined(i, new_l, new) { + struct aa_ruleset *rules = list_first_entry(&new->rules, + typeof(*rules), + list); + int j; + + if (!rules->rlimits.mask) + continue; + for (j = 0, mask = 1; j < RLIM_NLIMITS; j++, mask <<= 1) { + if (!(rules->rlimits.mask & mask)) + continue; + + rlim = current->signal->rlim + j; + rlim->rlim_max = min(rlim->rlim_max, + rules->rlimits.limits[j].rlim_max); + /* soft limit should not exceed hard limit */ + rlim->rlim_cur = min(rlim->rlim_cur, rlim->rlim_max); + } + } +} |