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