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