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 */
31 int 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 aa_put_ns(current_ns);
58 return len;
59 }
60
61 if (newline)
62 (*string)[len++] = '\n';
63 (*string)[len] = 0;
64
65 aa_put_ns(current_ns);
66 return len;
67 }
68
69 /**
70 * split_token_from_name - separate a string of form <token>^<name>
71 * @op: operation being checked
72 * @args: string to parse (NOT NULL)
73 * @token: stores returned parsed token value (NOT NULL)
74 *
75 * Returns: start position of name after token else NULL on failure
76 */
77 static char *split_token_from_name(const char *op, char *args, u64 *token)
78 {
79 char *name;
80
81 *token = simple_strtoull(args, &name, 16);
82 if ((name == args) || *name != '^') {
83 AA_ERROR("%s: Invalid input '%s'", op, args);
84 return ERR_PTR(-EINVAL);
85 }
86
87 name++; /* skip ^ */
88 if (!*name)
89 name = NULL;
90 return name;
91 }
92
93 /**
94 * aa_setprocattr_changehat - handle procattr interface to change_hat
95 * @args: args received from writing to /proc/<pid>/attr/current (NOT NULL)
96 * @size: size of the args
97 * @flags: set of flags governing behavior
98 *
99 * Returns: %0 or error code if change_hat fails
100 */
101 int aa_setprocattr_changehat(char *args, size_t size, int flags)
102 {
103 char *hat;
104 u64 token;
105 const char *hats[16]; /* current hard limit on # of names */
106 int count = 0;
107
108 hat = split_token_from_name(OP_CHANGE_HAT, args, &token);
109 if (IS_ERR(hat))
110 return PTR_ERR(hat);
111
112 if (!hat && !token) {
113 AA_ERROR("change_hat: Invalid input, NULL hat and NULL magic");
114 return -EINVAL;
115 }
116
117 if (hat) {
118 /* set up hat name vector, args guaranteed null terminated
119 * at args[size] by setprocattr.
120 *
121 * If there are multiple hat names in the buffer each is
122 * separated by a \0. Ie. userspace writes them pre tokenized
123 */
124 char *end = args + size;
125 for (count = 0; (hat < end) && count < 16; ++count) {
126 char *next = hat + strlen(hat) + 1;
127 hats[count] = hat;
128 AA_DEBUG("%s: (pid %d) Magic 0x%llx count %d hat '%s'\n"
129 , __func__, current->pid, token, count, hat);
130 hat = next;
131 }
132 } else
133 AA_DEBUG("%s: (pid %d) Magic 0x%llx count %d Hat '%s'\n",
134 __func__, current->pid, token, count, "<NULL>");
135
136 return aa_change_hat(hats, count, token, flags);
137 }
138
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