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