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/resource.h" 19 #include "include/policy.h" 20 21 /* 22 * Table of rlimit names: we generate it from resource.h. 23 */ 24 #include "rlim_names.h" 25 26 struct aa_fs_entry aa_fs_entry_rlimit[] = { 27 AA_FS_FILE_STRING("mask", AA_FS_RLIMIT_MASK), 28 { } 29 }; 30 31 /* audit callback for resource specific fields */ 32 static void audit_cb(struct audit_buffer *ab, void *va) 33 { 34 struct common_audit_data *sa = va; 35 36 audit_log_format(ab, " rlimit=%s value=%lu", 37 rlim_names[sa->aad.rlim.rlim], sa->aad.rlim.max); 38 } 39 40 /** 41 * audit_resource - audit setting resource limit 42 * @profile: profile being enforced (NOT NULL) 43 * @resoure: rlimit being auditing 44 * @value: value being set 45 * @error: error value 46 * 47 * Returns: 0 or sa->error else other error code on failure 48 */ 49 static int audit_resource(struct aa_profile *profile, unsigned int resource, 50 unsigned long value, int error) 51 { 52 struct common_audit_data sa; 53 54 COMMON_AUDIT_DATA_INIT(&sa, NONE); 55 sa.aad.op = OP_SETRLIMIT, 56 sa.aad.rlim.rlim = resource; 57 sa.aad.rlim.max = value; 58 sa.aad.error = error; 59 return aa_audit(AUDIT_APPARMOR_AUTO, profile, GFP_KERNEL, &sa, 60 audit_cb); 61 } 62 63 /** 64 * aa_map_resouce - map compiled policy resource to internal # 65 * @resource: flattened policy resource number 66 * 67 * Returns: resource # for the current architecture. 68 * 69 * rlimit resource can vary based on architecture, map the compiled policy 70 * resource # to the internal representation for the architecture. 71 */ 72 int aa_map_resource(int resource) 73 { 74 return rlim_map[resource]; 75 } 76 77 /** 78 * aa_task_setrlimit - test permission to set an rlimit 79 * @profile - profile confining the task (NOT NULL) 80 * @task - task the resource is being set on 81 * @resource - the resource being set 82 * @new_rlim - the new resource limit (NOT NULL) 83 * 84 * Control raising the processes hard limit. 85 * 86 * Returns: 0 or error code if setting resource failed 87 */ 88 int aa_task_setrlimit(struct aa_profile *profile, struct task_struct *task, 89 unsigned int resource, struct rlimit *new_rlim) 90 { 91 int error = 0; 92 93 /* TODO: extend resource control to handle other (non current) 94 * processes. AppArmor rules currently have the implicit assumption 95 * that the task is setting the resource of the current process 96 */ 97 if ((task != current->group_leader) || 98 (profile->rlimits.mask & (1 << resource) && 99 new_rlim->rlim_max > profile->rlimits.limits[resource].rlim_max)) 100 error = -EACCES; 101 102 return audit_resource(profile, resource, new_rlim->rlim_max, error); 103 } 104 105 /** 106 * __aa_transition_rlimits - apply new profile rlimits 107 * @old: old profile on task (NOT NULL) 108 * @new: new profile with rlimits to apply (NOT NULL) 109 */ 110 void __aa_transition_rlimits(struct aa_profile *old, struct aa_profile *new) 111 { 112 unsigned int mask = 0; 113 struct rlimit *rlim, *initrlim; 114 int i; 115 116 /* for any rlimits the profile controlled reset the soft limit 117 * to the less of the tasks hard limit and the init tasks soft limit 118 */ 119 if (old->rlimits.mask) { 120 for (i = 0, mask = 1; i < RLIM_NLIMITS; i++, mask <<= 1) { 121 if (old->rlimits.mask & mask) { 122 rlim = current->signal->rlim + i; 123 initrlim = init_task.signal->rlim + i; 124 rlim->rlim_cur = min(rlim->rlim_max, 125 initrlim->rlim_cur); 126 } 127 } 128 } 129 130 /* set any new hard limits as dictated by the new profile */ 131 if (!new->rlimits.mask) 132 return; 133 for (i = 0, mask = 1; i < RLIM_NLIMITS; i++, mask <<= 1) { 134 if (!(new->rlimits.mask & mask)) 135 continue; 136 137 rlim = current->signal->rlim + i; 138 rlim->rlim_max = min(rlim->rlim_max, 139 new->rlimits.limits[i].rlim_max); 140 /* soft limit should not exceed hard limit */ 141 rlim->rlim_cur = min(rlim->rlim_cur, rlim->rlim_max); 142 } 143 } 144