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