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 17 #include "include/audit.h" 18 #include "include/context.h" 19 #include "include/resource.h" 20 #include "include/policy.h" 21 22 /* 23 * Table of rlimit names: we generate it from resource.h. 24 */ 25 #include "rlim_names.h" 26 27 struct aa_fs_entry aa_fs_entry_rlimit[] = { 28 AA_FS_FILE_STRING("mask", AA_FS_RLIMIT_MASK), 29 { } 30 }; 31 32 /* audit callback for resource specific fields */ 33 static void audit_cb(struct audit_buffer *ab, void *va) 34 { 35 struct common_audit_data *sa = va; 36 37 audit_log_format(ab, " rlimit=%s value=%lu", 38 rlim_names[sa->aad->rlim.rlim], sa->aad->rlim.max); 39 } 40 41 /** 42 * audit_resource - audit setting resource limit 43 * @profile: profile being enforced (NOT NULL) 44 * @resoure: rlimit being auditing 45 * @value: value being set 46 * @error: error value 47 * 48 * Returns: 0 or sa->error else other error code on failure 49 */ 50 static int audit_resource(struct aa_profile *profile, unsigned int resource, 51 unsigned long value, int error) 52 { 53 struct common_audit_data sa; 54 struct apparmor_audit_data aad = {0,}; 55 56 sa.type = LSM_AUDIT_DATA_NONE; 57 sa.aad = &aad; 58 aad.op = OP_SETRLIMIT, 59 aad.rlim.rlim = resource; 60 aad.rlim.max = value; 61 aad.error = error; 62 return aa_audit(AUDIT_APPARMOR_AUTO, profile, GFP_KERNEL, &sa, 63 audit_cb); 64 } 65 66 /** 67 * aa_map_resouce - map compiled policy resource to internal # 68 * @resource: flattened policy resource number 69 * 70 * Returns: resource # for the current architecture. 71 * 72 * rlimit resource can vary based on architecture, map the compiled policy 73 * resource # to the internal representation for the architecture. 74 */ 75 int aa_map_resource(int resource) 76 { 77 return rlim_map[resource]; 78 } 79 80 /** 81 * aa_task_setrlimit - test permission to set an rlimit 82 * @profile - profile confining the task (NOT NULL) 83 * @task - task the resource is being set on 84 * @resource - the resource being set 85 * @new_rlim - the new resource limit (NOT NULL) 86 * 87 * Control raising the processes hard limit. 88 * 89 * Returns: 0 or error code if setting resource failed 90 */ 91 int aa_task_setrlimit(struct aa_profile *profile, struct task_struct *task, 92 unsigned int resource, struct rlimit *new_rlim) 93 { 94 struct aa_profile *task_profile; 95 int error = 0; 96 97 rcu_read_lock(); 98 task_profile = aa_get_profile(aa_cred_profile(__task_cred(task))); 99 rcu_read_unlock(); 100 101 /* TODO: extend resource control to handle other (non current) 102 * profiles. AppArmor rules currently have the implicit assumption 103 * that the task is setting the resource of a task confined with 104 * the same profile. 105 */ 106 if (profile != task_profile || 107 (profile->rlimits.mask & (1 << resource) && 108 new_rlim->rlim_max > profile->rlimits.limits[resource].rlim_max)) 109 error = -EACCES; 110 111 aa_put_profile(task_profile); 112 113 return audit_resource(profile, resource, new_rlim->rlim_max, error); 114 } 115 116 /** 117 * __aa_transition_rlimits - apply new profile rlimits 118 * @old: old profile on task (NOT NULL) 119 * @new: new profile with rlimits to apply (NOT NULL) 120 */ 121 void __aa_transition_rlimits(struct aa_profile *old, struct aa_profile *new) 122 { 123 unsigned int mask = 0; 124 struct rlimit *rlim, *initrlim; 125 int i; 126 127 /* for any rlimits the profile controlled reset the soft limit 128 * to the less of the tasks hard limit and the init tasks soft limit 129 */ 130 if (old->rlimits.mask) { 131 for (i = 0, mask = 1; i < RLIM_NLIMITS; i++, mask <<= 1) { 132 if (old->rlimits.mask & mask) { 133 rlim = current->signal->rlim + i; 134 initrlim = init_task.signal->rlim + i; 135 rlim->rlim_cur = min(rlim->rlim_max, 136 initrlim->rlim_cur); 137 } 138 } 139 } 140 141 /* set any new hard limits as dictated by the new profile */ 142 if (!new->rlimits.mask) 143 return; 144 for (i = 0, mask = 1; i < RLIM_NLIMITS; i++, mask <<= 1) { 145 if (!(new->rlimits.mask & mask)) 146 continue; 147 148 rlim = current->signal->rlim + i; 149 rlim->rlim_max = min(rlim->rlim_max, 150 new->rlimits.limits[i].rlim_max); 151 /* soft limit should not exceed hard limit */ 152 rlim->rlim_cur = min(rlim->rlim_cur, rlim->rlim_max); 153 } 154 } 155