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