1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * AppArmor security module
4 *
5 * This file contains AppArmor /proc/<pid>/attr/ interface functions
6 *
7 * Copyright (C) 1998-2008 Novell/SUSE
8 * Copyright 2009-2010 Canonical Ltd.
9 */
10
11#include "include/apparmor.h"
12#include "include/cred.h"
13#include "include/policy.h"
14#include "include/policy_ns.h"
15#include "include/domain.h"
16#include "include/procattr.h"
17
18
19/**
20 * aa_getprocattr - Return the profile information for @profile
21 * @profile: the profile to print profile info about  (NOT NULL)
22 * @string: Returns - string containing the profile info (NOT NULL)
23 *
24 * Returns: length of @string on success else error on failure
25 *
26 * Requires: profile != NULL
27 *
28 * Creates a string containing the namespace_name://profile_name for
29 * @profile.
30 *
31 * Returns: size of string placed in @string else error code on failure
32 */
33int aa_getprocattr(struct aa_label *label, char **string)
34{
35	struct aa_ns *ns = labels_ns(label);
36	struct aa_ns *current_ns = aa_get_current_ns();
37	int len;
38
39	if (!aa_ns_visible(current_ns, ns, true)) {
40		aa_put_ns(current_ns);
41		return -EACCES;
42	}
43
44	len = aa_label_snxprint(NULL, 0, current_ns, label,
45				FLAG_SHOW_MODE | FLAG_VIEW_SUBNS |
46				FLAG_HIDDEN_UNCONFINED);
47	AA_BUG(len < 0);
48
49	*string = kmalloc(len + 2, GFP_KERNEL);
50	if (!*string) {
51		aa_put_ns(current_ns);
52		return -ENOMEM;
53	}
54
55	len = aa_label_snxprint(*string, len + 2, current_ns, label,
56				FLAG_SHOW_MODE | FLAG_VIEW_SUBNS |
57				FLAG_HIDDEN_UNCONFINED);
58	if (len < 0) {
59		aa_put_ns(current_ns);
60		return len;
61	}
62
63	(*string)[len] = '\n';
64	(*string)[len + 1] = 0;
65
66	aa_put_ns(current_ns);
67	return len + 1;
68}
69
70/**
71 * split_token_from_name - separate a string of form  <token>^<name>
72 * @op: operation being checked
73 * @args: string to parse  (NOT NULL)
74 * @token: stores returned parsed token value  (NOT NULL)
75 *
76 * Returns: start position of name after token else NULL on failure
77 */
78static char *split_token_from_name(const char *op, char *args, u64 *token)
79{
80	char *name;
81
82	*token = simple_strtoull(args, &name, 16);
83	if ((name == args) || *name != '^') {
84		AA_ERROR("%s: Invalid input '%s'", op, args);
85		return ERR_PTR(-EINVAL);
86	}
87
88	name++;			/* skip ^ */
89	if (!*name)
90		name = NULL;
91	return name;
92}
93
94/**
95 * aa_setprocattr_chagnehat - handle procattr interface to change_hat
96 * @args: args received from writing to /proc/<pid>/attr/current (NOT NULL)
97 * @size: size of the args
98 * @flags: set of flags governing behavior
99 *
100 * Returns: %0 or error code if change_hat fails
101 */
102int aa_setprocattr_changehat(char *args, size_t size, int flags)
103{
104	char *hat;
105	u64 token;
106	const char *hats[16];		/* current hard limit on # of names */
107	int count = 0;
108
109	hat = split_token_from_name(OP_CHANGE_HAT, args, &token);
110	if (IS_ERR(hat))
111		return PTR_ERR(hat);
112
113	if (!hat && !token) {
114		AA_ERROR("change_hat: Invalid input, NULL hat and NULL magic");
115		return -EINVAL;
116	}
117
118	if (hat) {
119		/* set up hat name vector, args guaranteed null terminated
120		 * at args[size] by setprocattr.
121		 *
122		 * If there are multiple hat names in the buffer each is
123		 * separated by a \0.  Ie. userspace writes them pre tokenized
124		 */
125		char *end = args + size;
126		for (count = 0; (hat < end) && count < 16; ++count) {
127			char *next = hat + strlen(hat) + 1;
128			hats[count] = hat;
129			AA_DEBUG("%s: (pid %d) Magic 0x%llx count %d hat '%s'\n"
130				 , __func__, current->pid, token, count, hat);
131			hat = next;
132		}
133	} else
134		AA_DEBUG("%s: (pid %d) Magic 0x%llx count %d Hat '%s'\n",
135			 __func__, current->pid, token, count, "<NULL>");
136
137	return aa_change_hat(hats, count, token, flags);
138}
139