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
24 struct 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 */
audit_cb(struct audit_buffer * ab,void * va)30 static void audit_cb(struct audit_buffer *ab, void *va)
31 {
32 struct common_audit_data *sa = va;
33
34 audit_log_format(ab, " rlimit=%s value=%lu",
35 rlim_names[aad(sa)->rlim.rlim], aad(sa)->rlim.max);
36 if (aad(sa)->peer) {
37 audit_log_format(ab, " peer=");
38 aa_label_xaudit(ab, labels_ns(aad(sa)->label), aad(sa)->peer,
39 FLAGS_NONE, GFP_ATOMIC);
40 }
41 }
42
43 /**
44 * audit_resource - audit setting resource limit
45 * @profile: profile being enforced (NOT NULL)
46 * @resource: rlimit being auditing
47 * @value: value being set
48 * @error: error value
49 *
50 * Returns: 0 or sa->error else other error code on failure
51 */
audit_resource(struct aa_profile * profile,unsigned int resource,unsigned long value,struct aa_label * peer,const char * info,int error)52 static int audit_resource(struct aa_profile *profile, unsigned int resource,
53 unsigned long value, struct aa_label *peer,
54 const char *info, int error)
55 {
56 DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_NONE, OP_SETRLIMIT);
57
58 aad(&sa)->rlim.rlim = resource;
59 aad(&sa)->rlim.max = value;
60 aad(&sa)->peer = peer;
61 aad(&sa)->info = info;
62 aad(&sa)->error = error;
63
64 return aa_audit(AUDIT_APPARMOR_AUTO, profile, &sa, audit_cb);
65 }
66
67 /**
68 * aa_map_resouce - map compiled policy resource to internal #
69 * @resource: flattened policy resource number
70 *
71 * Returns: resource # for the current architecture.
72 *
73 * rlimit resource can vary based on architecture, map the compiled policy
74 * resource # to the internal representation for the architecture.
75 */
aa_map_resource(int resource)76 int aa_map_resource(int resource)
77 {
78 return rlim_map[resource];
79 }
80
profile_setrlimit(struct aa_profile * profile,unsigned int resource,struct rlimit * new_rlim)81 static int profile_setrlimit(struct aa_profile *profile, unsigned int resource,
82 struct rlimit *new_rlim)
83 {
84 int e = 0;
85
86 if (profile->rlimits.mask & (1 << resource) && new_rlim->rlim_max >
87 profile->rlimits.limits[resource].rlim_max)
88 e = -EACCES;
89 return audit_resource(profile, resource, new_rlim->rlim_max, NULL, NULL,
90 e);
91 }
92
93 /**
94 * aa_task_setrlimit - test permission to set an rlimit
95 * @label - label confining the task (NOT NULL)
96 * @task - task the resource is being set on
97 * @resource - the resource being set
98 * @new_rlim - the new resource limit (NOT NULL)
99 *
100 * Control raising the processes hard limit.
101 *
102 * Returns: 0 or error code if setting resource failed
103 */
aa_task_setrlimit(struct aa_label * label,struct task_struct * task,unsigned int resource,struct rlimit * new_rlim)104 int aa_task_setrlimit(struct aa_label *label, struct task_struct *task,
105 unsigned int resource, struct rlimit *new_rlim)
106 {
107 struct aa_profile *profile;
108 struct aa_label *peer;
109 int error = 0;
110
111 rcu_read_lock();
112 peer = aa_get_newest_cred_label(__task_cred(task));
113 rcu_read_unlock();
114
115 /* TODO: extend resource control to handle other (non current)
116 * profiles. AppArmor rules currently have the implicit assumption
117 * that the task is setting the resource of a task confined with
118 * the same profile or that the task setting the resource of another
119 * task has CAP_SYS_RESOURCE.
120 */
121
122 if (label != peer &&
123 aa_capable(label, CAP_SYS_RESOURCE, CAP_OPT_NOAUDIT) != 0)
124 error = fn_for_each(label, profile,
125 audit_resource(profile, resource,
126 new_rlim->rlim_max, peer,
127 "cap_sys_resource", -EACCES));
128 else
129 error = fn_for_each_confined(label, profile,
130 profile_setrlimit(profile, resource, new_rlim));
131 aa_put_label(peer);
132
133 return error;
134 }
135
136 /**
137 * __aa_transition_rlimits - apply new profile rlimits
138 * @old_l: old label on task (NOT NULL)
139 * @new_l: new label with rlimits to apply (NOT NULL)
140 */
__aa_transition_rlimits(struct aa_label * old_l,struct aa_label * new_l)141 void __aa_transition_rlimits(struct aa_label *old_l, struct aa_label *new_l)
142 {
143 unsigned int mask = 0;
144 struct rlimit *rlim, *initrlim;
145 struct aa_profile *old, *new;
146 struct label_it i;
147
148 old = labels_profile(old_l);
149 new = labels_profile(new_l);
150
151 /* for any rlimits the profile controlled, reset the soft limit
152 * to the lesser of the tasks hard limit and the init tasks soft limit
153 */
154 label_for_each_confined(i, old_l, old) {
155 if (old->rlimits.mask) {
156 int j;
157
158 for (j = 0, mask = 1; j < RLIM_NLIMITS; j++,
159 mask <<= 1) {
160 if (old->rlimits.mask & mask) {
161 rlim = current->signal->rlim + j;
162 initrlim = init_task.signal->rlim + j;
163 rlim->rlim_cur = min(rlim->rlim_max,
164 initrlim->rlim_cur);
165 }
166 }
167 }
168 }
169
170 /* set any new hard limits as dictated by the new profile */
171 label_for_each_confined(i, new_l, new) {
172 int j;
173
174 if (!new->rlimits.mask)
175 continue;
176 for (j = 0, mask = 1; j < RLIM_NLIMITS; j++, mask <<= 1) {
177 if (!(new->rlimits.mask & mask))
178 continue;
179
180 rlim = current->signal->rlim + j;
181 rlim->rlim_max = min(rlim->rlim_max,
182 new->rlimits.limits[j].rlim_max);
183 /* soft limit should not exceed hard limit */
184 rlim->rlim_cur = min(rlim->rlim_cur, rlim->rlim_max);
185 }
186 }
187 }
188