Branch data Line data Source code
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 : 0 : static void audit_cb(struct audit_buffer *ab, void *va)
34 : : {
35 : : struct common_audit_data *sa = va;
36 : :
37 : 0 : audit_log_format(ab, " rlimit=%s value=%lu",
38 : 0 : rlim_names[sa->aad->rlim.rlim], sa->aad->rlim.max);
39 : 0 : }
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 : 0 : 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 : 0 : struct apparmor_audit_data aad = {0,};
55 : :
56 : 0 : sa.type = LSM_AUDIT_DATA_NONE;
57 : 0 : sa.aad = &aad;
58 : 0 : aad.op = OP_SETRLIMIT,
59 : 0 : aad.rlim.rlim = resource;
60 : 0 : aad.rlim.max = value;
61 : 0 : aad.error = error;
62 : 0 : 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 : 0 : int aa_map_resource(int resource)
76 : : {
77 : 0 : 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 : 0 : 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 : 0 : 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 [ # # ][ # # ]: 0 : if (profile != task_profile ||
107 [ # # ]: 0 : (profile->rlimits.mask & (1 << resource) &&
108 : 0 : new_rlim->rlim_max > profile->rlimits.limits[resource].rlim_max))
109 : : error = -EACCES;
110 : :
111 : : aa_put_profile(task_profile);
112 : :
113 : 0 : 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 : 0 : 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 [ # # ]: 0 : if (old->rlimits.mask) {
131 [ # # ]: 0 : for (i = 0, mask = 1; i < RLIM_NLIMITS; i++, mask <<= 1) {
132 [ # # ]: 0 : if (old->rlimits.mask & mask) {
133 : 0 : rlim = current->signal->rlim + i;
134 : 0 : initrlim = init_task.signal->rlim + i;
135 : 0 : 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 [ # # ]: 0 : if (!new->rlimits.mask)
143 : 0 : return;
144 [ # # ]: 0 : for (i = 0, mask = 1; i < RLIM_NLIMITS; i++, mask <<= 1) {
145 [ # # ]: 0 : if (!(new->rlimits.mask & mask))
146 : 0 : continue;
147 : :
148 : 0 : rlim = current->signal->rlim + i;
149 : 0 : rlim->rlim_max = min(rlim->rlim_max,
150 : : new->rlimits.limits[i].rlim_max);
151 : : /* soft limit should not exceed hard limit */
152 : 0 : rlim->rlim_cur = min(rlim->rlim_cur, rlim->rlim_max);
153 : : }
154 : : }
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