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 */
audit_cb(struct audit_buffer * ab,void * va)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 */
audit_resource(struct aa_profile * profile,unsigned int resource,unsigned long value,int error)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 struct apparmor_audit_data aad = {0,};
54
55 COMMON_AUDIT_DATA_INIT(&sa, NONE);
56 sa.aad = &aad;
57 aad.op = OP_SETRLIMIT,
58 aad.rlim.rlim = resource;
59 aad.rlim.max = value;
60 aad.error = error;
61 return aa_audit(AUDIT_APPARMOR_AUTO, profile, GFP_KERNEL, &sa,
62 audit_cb);
63 }
64
65 /**
66 * aa_map_resouce - map compiled policy resource to internal #
67 * @resource: flattened policy resource number
68 *
69 * Returns: resource # for the current architecture.
70 *
71 * rlimit resource can vary based on architecture, map the compiled policy
72 * resource # to the internal representation for the architecture.
73 */
aa_map_resource(int resource)74 int aa_map_resource(int resource)
75 {
76 return rlim_map[resource];
77 }
78
79 /**
80 * aa_task_setrlimit - test permission to set an rlimit
81 * @profile - profile confining the task (NOT NULL)
82 * @task - task the resource is being set on
83 * @resource - the resource being set
84 * @new_rlim - the new resource limit (NOT NULL)
85 *
86 * Control raising the processes hard limit.
87 *
88 * Returns: 0 or error code if setting resource failed
89 */
aa_task_setrlimit(struct aa_profile * profile,struct task_struct * task,unsigned int resource,struct rlimit * new_rlim)90 int aa_task_setrlimit(struct aa_profile *profile, struct task_struct *task,
91 unsigned int resource, struct rlimit *new_rlim)
92 {
93 int error = 0;
94
95 /* TODO: extend resource control to handle other (non current)
96 * processes. AppArmor rules currently have the implicit assumption
97 * that the task is setting the resource of the current process
98 */
99 if ((task != current->group_leader) ||
100 (profile->rlimits.mask & (1 << resource) &&
101 new_rlim->rlim_max > profile->rlimits.limits[resource].rlim_max))
102 error = -EACCES;
103
104 return audit_resource(profile, resource, new_rlim->rlim_max, error);
105 }
106
107 /**
108 * __aa_transition_rlimits - apply new profile rlimits
109 * @old: old profile on task (NOT NULL)
110 * @new: new profile with rlimits to apply (NOT NULL)
111 */
__aa_transition_rlimits(struct aa_profile * old,struct aa_profile * new)112 void __aa_transition_rlimits(struct aa_profile *old, struct aa_profile *new)
113 {
114 unsigned int mask = 0;
115 struct rlimit *rlim, *initrlim;
116 int i;
117
118 /* for any rlimits the profile controlled reset the soft limit
119 * to the less of the tasks hard limit and the init tasks soft limit
120 */
121 if (old->rlimits.mask) {
122 for (i = 0, mask = 1; i < RLIM_NLIMITS; i++, mask <<= 1) {
123 if (old->rlimits.mask & mask) {
124 rlim = current->signal->rlim + i;
125 initrlim = init_task.signal->rlim + i;
126 rlim->rlim_cur = min(rlim->rlim_max,
127 initrlim->rlim_cur);
128 }
129 }
130 }
131
132 /* set any new hard limits as dictated by the new profile */
133 if (!new->rlimits.mask)
134 return;
135 for (i = 0, mask = 1; i < RLIM_NLIMITS; i++, mask <<= 1) {
136 if (!(new->rlimits.mask & mask))
137 continue;
138
139 rlim = current->signal->rlim + i;
140 rlim->rlim_max = min(rlim->rlim_max,
141 new->rlimits.limits[i].rlim_max);
142 /* soft limit should not exceed hard limit */
143 rlim->rlim_cur = min(rlim->rlim_cur, rlim->rlim_max);
144 }
145 }
146