1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * AppArmor security module 4 * 5 * This file contains AppArmor resource mediation and attachment 6 * 7 * Copyright (C) 1998-2008 Novell/SUSE 8 * Copyright 2009-2010 Canonical Ltd. 9 */ 10 11 #include <linux/audit.h> 12 #include <linux/security.h> 13 14 #include "include/audit.h" 15 #include "include/cred.h" 16 #include "include/resource.h" 17 #include "include/policy.h" 18 19 /* 20 * Table of rlimit names: we generate it from resource.h. 21 */ 22 #include "rlim_names.h" 23 24 struct aa_sfs_entry aa_sfs_entry_rlimit[] = { 25 AA_SFS_FILE_STRING("mask", AA_SFS_RLIMIT_MASK), 26 { } 27 }; 28 29 /* audit callback for resource specific fields */ 30 static void audit_cb(struct audit_buffer *ab, void *va) 31 { 32 struct common_audit_data *sa = va; 33 struct apparmor_audit_data *ad = aad(sa); 34 35 audit_log_format(ab, " rlimit=%s value=%lu", 36 rlim_names[ad->rlim.rlim], ad->rlim.max); 37 if (ad->peer) { 38 audit_log_format(ab, " peer="); 39 aa_label_xaudit(ab, labels_ns(ad->label), ad->peer, 40 FLAGS_NONE, GFP_ATOMIC); 41 } 42 } 43 44 /** 45 * audit_resource - audit setting resource limit 46 * @profile: profile being enforced (NOT NULL) 47 * @resource: rlimit being auditing 48 * @value: value being set 49 * @peer: aa_albel of the task being set 50 * @info: info being auditing 51 * @error: error value 52 * 53 * Returns: 0 or ad->error else other error code on failure 54 */ 55 static int audit_resource(struct aa_profile *profile, unsigned int resource, 56 unsigned long value, struct aa_label *peer, 57 const char *info, int error) 58 { 59 DEFINE_AUDIT_DATA(ad, LSM_AUDIT_DATA_NONE, AA_CLASS_RLIMITS, 60 OP_SETRLIMIT); 61 62 ad.rlim.rlim = resource; 63 ad.rlim.max = value; 64 ad.peer = peer; 65 ad.info = info; 66 ad.error = error; 67 68 return aa_audit(AUDIT_APPARMOR_AUTO, profile, &ad, audit_cb); 69 } 70 71 /** 72 * aa_map_resource - map compiled policy resource to internal # 73 * @resource: flattened policy resource number 74 * 75 * Returns: resource # for the current architecture. 76 * 77 * rlimit resource can vary based on architecture, map the compiled policy 78 * resource # to the internal representation for the architecture. 79 */ 80 int aa_map_resource(int resource) 81 { 82 return rlim_map[resource]; 83 } 84 85 static int profile_setrlimit(struct aa_profile *profile, unsigned int resource, 86 struct rlimit *new_rlim) 87 { 88 struct aa_ruleset *rules = list_first_entry(&profile->rules, 89 typeof(*rules), list); 90 int e = 0; 91 92 if (rules->rlimits.mask & (1 << resource) && new_rlim->rlim_max > 93 rules->rlimits.limits[resource].rlim_max) 94 e = -EACCES; 95 return audit_resource(profile, resource, new_rlim->rlim_max, NULL, NULL, 96 e); 97 } 98 99 /** 100 * aa_task_setrlimit - test permission to set an rlimit 101 * @label: label confining the task (NOT NULL) 102 * @task: task the resource is being set on 103 * @resource: the resource being set 104 * @new_rlim: the new resource limit (NOT NULL) 105 * 106 * Control raising the processes hard limit. 107 * 108 * Returns: 0 or error code if setting resource failed 109 */ 110 int aa_task_setrlimit(struct aa_label *label, struct task_struct *task, 111 unsigned int resource, struct rlimit *new_rlim) 112 { 113 struct aa_profile *profile; 114 struct aa_label *peer; 115 int error = 0; 116 117 rcu_read_lock(); 118 peer = aa_get_newest_cred_label(__task_cred(task)); 119 rcu_read_unlock(); 120 121 /* TODO: extend resource control to handle other (non current) 122 * profiles. AppArmor rules currently have the implicit assumption 123 * that the task is setting the resource of a task confined with 124 * the same profile or that the task setting the resource of another 125 * task has CAP_SYS_RESOURCE. 126 */ 127 128 if (label != peer && 129 aa_capable(label, CAP_SYS_RESOURCE, CAP_OPT_NOAUDIT) != 0) 130 error = fn_for_each(label, profile, 131 audit_resource(profile, resource, 132 new_rlim->rlim_max, peer, 133 "cap_sys_resource", -EACCES)); 134 else 135 error = fn_for_each_confined(label, profile, 136 profile_setrlimit(profile, resource, new_rlim)); 137 aa_put_label(peer); 138 139 return error; 140 } 141 142 /** 143 * __aa_transition_rlimits - apply new profile rlimits 144 * @old_l: old label on task (NOT NULL) 145 * @new_l: new label with rlimits to apply (NOT NULL) 146 */ 147 void __aa_transition_rlimits(struct aa_label *old_l, struct aa_label *new_l) 148 { 149 unsigned int mask = 0; 150 struct rlimit *rlim, *initrlim; 151 struct aa_profile *old, *new; 152 struct label_it i; 153 154 old = labels_profile(old_l); 155 new = labels_profile(new_l); 156 157 /* for any rlimits the profile controlled, reset the soft limit 158 * to the lesser of the tasks hard limit and the init tasks soft limit 159 */ 160 label_for_each_confined(i, old_l, old) { 161 struct aa_ruleset *rules = list_first_entry(&old->rules, 162 typeof(*rules), 163 list); 164 if (rules->rlimits.mask) { 165 int j; 166 167 for (j = 0, mask = 1; j < RLIM_NLIMITS; j++, 168 mask <<= 1) { 169 if (rules->rlimits.mask & mask) { 170 rlim = current->signal->rlim + j; 171 initrlim = init_task.signal->rlim + j; 172 rlim->rlim_cur = min(rlim->rlim_max, 173 initrlim->rlim_cur); 174 } 175 } 176 } 177 } 178 179 /* set any new hard limits as dictated by the new profile */ 180 label_for_each_confined(i, new_l, new) { 181 struct aa_ruleset *rules = list_first_entry(&new->rules, 182 typeof(*rules), 183 list); 184 int j; 185 186 if (!rules->rlimits.mask) 187 continue; 188 for (j = 0, mask = 1; j < RLIM_NLIMITS; j++, mask <<= 1) { 189 if (!(rules->rlimits.mask & mask)) 190 continue; 191 192 rlim = current->signal->rlim + j; 193 rlim->rlim_max = min(rlim->rlim_max, 194 rules->rlimits.limits[j].rlim_max); 195 /* soft limit should not exceed hard limit */ 196 rlim->rlim_cur = min(rlim->rlim_cur, rlim->rlim_max); 197 } 198 } 199 } 200