projects/linux·blob master · refs

206 lines · 5.7 KiB

1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * AppArmor security module
4 *
5 * This file contains AppArmor resource mediation and attachment
6 *
7 * Copyright (C) 1998-2008 Novell/SUSE
8 * Copyright 2009-2010 Canonical Ltd.
9 */
10
11#include <linux/audit.h>
12#include <linux/security.h>
13
14#include "include/audit.h"
15#include "include/cred.h"
16#include "include/resource.h"
17#include "include/policy.h"
18
19/*
20 * Table of rlimit names: we generate it from resource.h.
21 */
22#include "rlim_names.h"
23
24struct aa_sfs_entry aa_sfs_entry_rlimit[] = {
25 AA_SFS_FILE_STRING("mask", AA_SFS_RLIMIT_MASK),
26 { }
27};
28
29/* audit callback for resource specific fields */
30static void audit_cb(struct audit_buffer *ab, void *va)
31{
32 struct common_audit_data *sa = va;
33 struct apparmor_audit_data *ad = aad(sa);
34
35 audit_log_format(ab, " rlimit=%s value=%lu",
36 rlim_names[ad->rlim.rlim], ad->rlim.max);
37 if (ad->peer) {
38 audit_log_format(ab, " peer=");
39 aa_label_xaudit(ab, labels_ns(ad->subj_label), ad->peer,
40 FLAGS_NONE, GFP_ATOMIC);
41 }
42}
43
44/**
45 * audit_resource - audit setting resource limit
46 * @subj_cred: cred setting the resource
47 * @profile: profile being enforced (NOT NULL)
48 * @resource: rlimit being auditing
49 * @value: value being set
50 * @peer: aa_albel of the task being set
51 * @info: info being auditing
52 * @error: error value
53 *
54 * Returns: 0 or ad->error else other error code on failure
55 */
56static int audit_resource(const struct cred *subj_cred,
57 struct aa_profile *profile, unsigned int resource,
58 unsigned long value, struct aa_label *peer,
59 const char *info, int error)
60{
61 DEFINE_AUDIT_DATA(ad, LSM_AUDIT_DATA_NONE, AA_CLASS_RLIMITS,
62 OP_SETRLIMIT);
63
64 ad.subj_cred = subj_cred;
65 ad.rlim.rlim = resource;
66 ad.rlim.max = value;
67 ad.peer = peer;
68 ad.info = info;
69 ad.error = error;
70
71 return aa_audit(AUDIT_APPARMOR_AUTO, profile, &ad, audit_cb);
72}
73
74/**
75 * aa_map_resource - map compiled policy resource to internal #
76 * @resource: flattened policy resource number
77 *
78 * Returns: resource # for the current architecture.
79 *
80 * rlimit resource can vary based on architecture, map the compiled policy
81 * resource # to the internal representation for the architecture.
82 */
83int aa_map_resource(int resource)
84{
85 return rlim_map[resource];
86}
87
88static int profile_setrlimit(const struct cred *subj_cred,
89 struct aa_profile *profile, unsigned int resource,
90 struct rlimit *new_rlim)
91{
92 struct aa_ruleset *rules = profile->label.rules[0];
93 int e = 0;
94
95 if (rules->rlimits.mask & (1 << resource) && new_rlim->rlim_max >
96 rules->rlimits.limits[resource].rlim_max)
97 e = -EACCES;
98 return audit_resource(subj_cred, profile, resource, new_rlim->rlim_max,
99 NULL, NULL, e);
100}
101
102/**
103 * aa_task_setrlimit - test permission to set an rlimit
104 * @subj_cred: cred setting the limit
105 * @label: label confining the task (NOT NULL)
106 * @task: task the resource is being set on
107 * @resource: the resource being set
108 * @new_rlim: the new resource limit (NOT NULL)
109 *
110 * Control raising the processes hard limit.
111 *
112 * Returns: 0 or error code if setting resource failed
113 */
114int aa_task_setrlimit(const struct cred *subj_cred, struct aa_label *label,
115 struct task_struct *task,
116 unsigned int resource, struct rlimit *new_rlim)
117{
118 struct aa_profile *profile;
119 struct aa_label *peer;
120 int error = 0;
121
122 rcu_read_lock();
123 peer = aa_get_newest_cred_label(__task_cred(task));
124 rcu_read_unlock();
125
126 /* TODO: extend resource control to handle other (non current)
127 * profiles. AppArmor rules currently have the implicit assumption
128 * that the task is setting the resource of a task confined with
129 * the same profile or that the task setting the resource of another
130 * task has CAP_SYS_RESOURCE.
131 */
132
133 if (label != peer &&
134 aa_capable(subj_cred, label, CAP_SYS_RESOURCE, CAP_OPT_NOAUDIT) != 0)
135 error = fn_for_each(label, profile,
136 audit_resource(subj_cred, profile, resource,
137 new_rlim->rlim_max, peer,
138 "cap_sys_resource", -EACCES));
139 else
140 error = fn_for_each_confined(label, profile,
141 profile_setrlimit(subj_cred, profile, resource,
142 new_rlim));
143 aa_put_label(peer);
144
145 return error;
146}
147
148/**
149 * __aa_transition_rlimits - apply new profile rlimits
150 * @old_l: old label on task (NOT NULL)
151 * @new_l: new label with rlimits to apply (NOT NULL)
152 */
153void __aa_transition_rlimits(struct aa_label *old_l, struct aa_label *new_l)
154{
155 unsigned int mask = 0;
156 struct rlimit *rlim, *initrlim;
157 struct aa_profile *old, *new;
158 struct label_it i;
159
160 old = labels_profile(old_l);
161 new = labels_profile(new_l);
162
163 /* for any rlimits the profile controlled, reset the soft limit
164 * to the lesser of the tasks hard limit and the init tasks soft limit
165 */
166 label_for_each_confined(i, old_l, old) {
167 struct aa_ruleset *rules = old->label.rules[0];
168 if (rules->rlimits.mask) {
169 int j;
170
171 for (j = 0, mask = 1; j < RLIM_NLIMITS; j++,
172 mask <<= 1) {
173 if (rules->rlimits.mask & mask) {
174 rlim = current->signal->rlim + j;
175 initrlim = init_task.signal->rlim + j;
176 rlim->rlim_cur = min(rlim->rlim_max,
177 initrlim->rlim_cur);
178 }
179 }
180 }
181 }
182
183 /* set any new hard limits as dictated by the new profile */
184 label_for_each_confined(i, new_l, new) {
185 struct aa_ruleset *rules = new->label.rules[0];
186 int j;
187
188 if (!rules->rlimits.mask)
189 continue;
190 for (j = 0, mask = 1; j < RLIM_NLIMITS; j++, mask <<= 1) {
191 if (!(rules->rlimits.mask & mask))
192 continue;
193
194 rlim = current->signal->rlim + j;
195 rlim->rlim_max = min(rlim->rlim_max,
196 rules->rlimits.limits[j].rlim_max);
197 /* soft limit should not exceed hard limit */
198 rlim->rlim_cur = min(rlim->rlim_cur, rlim->rlim_max);
199 if (j == RLIMIT_CPU &&
200 rlim->rlim_cur != RLIM_INFINITY &&
201 IS_ENABLED(CONFIG_POSIX_TIMERS))
202 (void) update_rlimit_cpu(current->group_leader,
203 rlim->rlim_cur);
204 }
205 }
206}