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->subj_label), ad->peer, 40 FLAGS_NONE, GFP_ATOMIC); 41 } 42 } 43 44 /** 45 * audit_resource - audit setting resource limit 46 * @subj_cred: cred setting the resource 47 * @profile: profile being enforced (NOT NULL) 48 * @resource: rlimit being auditing 49 * @value: value being set 50 * @peer: aa_albel of the task being set 51 * @info: info being auditing 52 * @error: error value 53 * 54 * Returns: 0 or ad->error else other error code on failure 55 */ 56 static int audit_resource(const struct cred *subj_cred, 57 struct aa_profile *profile, unsigned int resource, 58 unsigned long value, struct aa_label *peer, 59 const char *info, int error) 60 { 61 DEFINE_AUDIT_DATA(ad, LSM_AUDIT_DATA_NONE, AA_CLASS_RLIMITS, 62 OP_SETRLIMIT); 63 64 ad.subj_cred = subj_cred; 65 ad.rlim.rlim = resource; 66 ad.rlim.max = value; 67 ad.peer = peer; 68 ad.info = info; 69 ad.error = error; 70 71 return aa_audit(AUDIT_APPARMOR_AUTO, profile, &ad, audit_cb); 72 } 73 74 /** 75 * aa_map_resource - map compiled policy resource to internal # 76 * @resource: flattened policy resource number 77 * 78 * Returns: resource # for the current architecture. 79 * 80 * rlimit resource can vary based on architecture, map the compiled policy 81 * resource # to the internal representation for the architecture. 82 */ 83 int aa_map_resource(int resource) 84 { 85 return rlim_map[resource]; 86 } 87 88 static int profile_setrlimit(const struct cred *subj_cred, 89 struct aa_profile *profile, unsigned int resource, 90 struct rlimit *new_rlim) 91 { 92 struct aa_ruleset *rules = list_first_entry(&profile->rules, 93 typeof(*rules), list); 94 int e = 0; 95 96 if (rules->rlimits.mask & (1 << resource) && new_rlim->rlim_max > 97 rules->rlimits.limits[resource].rlim_max) 98 e = -EACCES; 99 return audit_resource(subj_cred, profile, resource, new_rlim->rlim_max, 100 NULL, NULL, e); 101 } 102 103 /** 104 * aa_task_setrlimit - test permission to set an rlimit 105 * @subj_cred: cred setting the limit 106 * @label: label confining the task (NOT NULL) 107 * @task: task the resource is being set on 108 * @resource: the resource being set 109 * @new_rlim: the new resource limit (NOT NULL) 110 * 111 * Control raising the processes hard limit. 112 * 113 * Returns: 0 or error code if setting resource failed 114 */ 115 int aa_task_setrlimit(const struct cred *subj_cred, struct aa_label *label, 116 struct task_struct *task, 117 unsigned int resource, struct rlimit *new_rlim) 118 { 119 struct aa_profile *profile; 120 struct aa_label *peer; 121 int error = 0; 122 123 rcu_read_lock(); 124 peer = aa_get_newest_cred_label(__task_cred(task)); 125 rcu_read_unlock(); 126 127 /* TODO: extend resource control to handle other (non current) 128 * profiles. AppArmor rules currently have the implicit assumption 129 * that the task is setting the resource of a task confined with 130 * the same profile or that the task setting the resource of another 131 * task has CAP_SYS_RESOURCE. 132 */ 133 134 if (label != peer && 135 aa_capable(subj_cred, label, CAP_SYS_RESOURCE, CAP_OPT_NOAUDIT) != 0) 136 error = fn_for_each(label, profile, 137 audit_resource(subj_cred, profile, resource, 138 new_rlim->rlim_max, peer, 139 "cap_sys_resource", -EACCES)); 140 else 141 error = fn_for_each_confined(label, profile, 142 profile_setrlimit(subj_cred, profile, resource, 143 new_rlim)); 144 aa_put_label(peer); 145 146 return error; 147 } 148 149 /** 150 * __aa_transition_rlimits - apply new profile rlimits 151 * @old_l: old label on task (NOT NULL) 152 * @new_l: new label with rlimits to apply (NOT NULL) 153 */ 154 void __aa_transition_rlimits(struct aa_label *old_l, struct aa_label *new_l) 155 { 156 unsigned int mask = 0; 157 struct rlimit *rlim, *initrlim; 158 struct aa_profile *old, *new; 159 struct label_it i; 160 161 old = labels_profile(old_l); 162 new = labels_profile(new_l); 163 164 /* for any rlimits the profile controlled, reset the soft limit 165 * to the lesser of the tasks hard limit and the init tasks soft limit 166 */ 167 label_for_each_confined(i, old_l, old) { 168 struct aa_ruleset *rules = list_first_entry(&old->rules, 169 typeof(*rules), 170 list); 171 if (rules->rlimits.mask) { 172 int j; 173 174 for (j = 0, mask = 1; j < RLIM_NLIMITS; j++, 175 mask <<= 1) { 176 if (rules->rlimits.mask & mask) { 177 rlim = current->signal->rlim + j; 178 initrlim = init_task.signal->rlim + j; 179 rlim->rlim_cur = min(rlim->rlim_max, 180 initrlim->rlim_cur); 181 } 182 } 183 } 184 } 185 186 /* set any new hard limits as dictated by the new profile */ 187 label_for_each_confined(i, new_l, new) { 188 struct aa_ruleset *rules = list_first_entry(&new->rules, 189 typeof(*rules), 190 list); 191 int j; 192 193 if (!rules->rlimits.mask) 194 continue; 195 for (j = 0, mask = 1; j < RLIM_NLIMITS; j++, mask <<= 1) { 196 if (!(rules->rlimits.mask & mask)) 197 continue; 198 199 rlim = current->signal->rlim + j; 200 rlim->rlim_max = min(rlim->rlim_max, 201 rules->rlimits.limits[j].rlim_max); 202 /* soft limit should not exceed hard limit */ 203 rlim->rlim_cur = min(rlim->rlim_cur, rlim->rlim_max); 204 } 205 } 206 } 207