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
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 */
52static 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 */
76int aa_map_resource(int resource)
77{
78	return rlim_map[resource];
79}
80
81static 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 */
104int 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 */
141void __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