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141 lines · 3.6 KiB

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 label information for @label
21 * @label: the label to print label info about (NOT NULL)
22 * @string: Returns - string containing the label info (NOT NULL)
23 * @newline: indicates that a newline should be added
24 *
25 * Requires: label != NULL && string != NULL
26 *
27 * Creates a string containing the label information for @label.
28 *
29 * Returns: size of string placed in @string else error code on failure
30 */
31int aa_getprocattr(struct aa_label *label, char **string, bool newline)
32{
33 struct aa_ns *ns = labels_ns(label);
34 struct aa_ns *current_ns = aa_get_current_ns();
35 int len;
36
37 if (!aa_ns_visible(current_ns, ns, true)) {
38 aa_put_ns(current_ns);
39 return -EACCES;
40 }
41
42 len = aa_label_snxprint(NULL, 0, current_ns, label,
43 FLAG_SHOW_MODE | FLAG_VIEW_SUBNS |
44 FLAG_HIDDEN_UNCONFINED);
45 AA_BUG(len < 0);
46
47 *string = kmalloc(len + 2, GFP_KERNEL);
48 if (!*string) {
49 aa_put_ns(current_ns);
50 return -ENOMEM;
51 }
52
53 len = aa_label_snxprint(*string, len + 2, current_ns, label,
54 FLAG_SHOW_MODE | FLAG_VIEW_SUBNS |
55 FLAG_HIDDEN_UNCONFINED);
56 if (len < 0) {
57 kfree(*string);
58 *string = NULL;
59 aa_put_ns(current_ns);
60 return len;
61 }
62
63 if (newline)
64 (*string)[len++] = '\n';
65 (*string)[len] = 0;
66
67 aa_put_ns(current_ns);
68 return len;
69}
70
71/**
72 * split_token_from_name - separate a string of form <token>^<name>
73 * @op: operation being checked
74 * @args: string to parse (NOT NULL)
75 * @token: stores returned parsed token value (NOT NULL)
76 *
77 * Returns: start position of name after token else NULL on failure
78 */
79static char *split_token_from_name(const char *op, char *args, u64 *token)
80{
81 char *name;
82
83 *token = simple_strtoull(args, &name, 16);
84 if ((name == args) || *name != '^') {
85 AA_ERROR("%s: Invalid input '%s'", op, args);
86 return ERR_PTR(-EINVAL);
87 }
88
89 name++; /* skip ^ */
90 if (!*name)
91 name = NULL;
92 return name;
93}
94
95/**
96 * aa_setprocattr_changehat - handle procattr interface to change_hat
97 * @args: args received from writing to /proc/<pid>/attr/current (NOT NULL)
98 * @size: size of the args
99 * @flags: set of flags governing behavior
100 *
101 * Returns: %0 or error code if change_hat fails
102 */
103int aa_setprocattr_changehat(char *args, size_t size, int flags)
104{
105 char *hat;
106 u64 token;
107 const char *hats[16]; /* current hard limit on # of names */
108 int count = 0;
109
110 hat = split_token_from_name(OP_CHANGE_HAT, args, &token);
111 if (IS_ERR(hat))
112 return PTR_ERR(hat);
113
114 if (!hat && !token) {
115 AA_ERROR("change_hat: Invalid input, NULL hat and NULL magic");
116 return -EINVAL;
117 }
118
119 if (hat) {
120 /* set up hat name vector, args guaranteed null terminated
121 * at args[size] by setprocattr.
122 *
123 * If there are multiple hat names in the buffer each is
124 * separated by a \0. Ie. userspace writes them pre tokenized
125 */
126 char *end = args + size;
127 for (count = 0; (hat < end) && count < 16; ++count) {
128 char *next = hat + strlen(hat) + 1;
129 hats[count] = hat;
130 AA_DEBUG(DEBUG_DOMAIN,
131 "%s: (pid %d) Magic 0x%llx count %d hat '%s'\n"
132 , __func__, current->pid, token, count, hat);
133 hat = next;
134 }
135 } else
136 AA_DEBUG(DEBUG_DOMAIN,
137 "%s: (pid %d) Magic 0x%llx count %d Hat '%s'\n",
138 __func__, current->pid, token, count, "<NULL>");
139
140 return aa_change_hat(hats, count, token, flags);
141}