xref: /openbmc/linux/security/apparmor/procattr.c (revision 70342287)
1 /*
2  * AppArmor security module
3  *
4  * This file contains AppArmor /proc/<pid>/attr/ interface functions
5  *
6  * Copyright (C) 1998-2008 Novell/SUSE
7  * Copyright 2009-2010 Canonical Ltd.
8  *
9  * This program is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU General Public License as
11  * published by the Free Software Foundation, version 2 of the
12  * License.
13  */
14 
15 #include "include/apparmor.h"
16 #include "include/context.h"
17 #include "include/policy.h"
18 #include "include/domain.h"
19 #include "include/procattr.h"
20 
21 
22 /**
23  * aa_getprocattr - Return the profile information for @profile
24  * @profile: the profile to print profile info about  (NOT NULL)
25  * @string: Returns - string containing the profile info (NOT NULL)
26  *
27  * Returns: length of @string on success else error on failure
28  *
29  * Requires: profile != NULL
30  *
31  * Creates a string containing the namespace_name://profile_name for
32  * @profile.
33  *
34  * Returns: size of string placed in @string else error code on failure
35  */
36 int aa_getprocattr(struct aa_profile *profile, char **string)
37 {
38 	char *str;
39 	int len = 0, mode_len = 0, ns_len = 0, name_len;
40 	const char *mode_str = profile_mode_names[profile->mode];
41 	const char *ns_name = NULL;
42 	struct aa_namespace *ns = profile->ns;
43 	struct aa_namespace *current_ns = __aa_current_profile()->ns;
44 	char *s;
45 
46 	if (!aa_ns_visible(current_ns, ns))
47 		return -EACCES;
48 
49 	ns_name = aa_ns_name(current_ns, ns);
50 	ns_len = strlen(ns_name);
51 
52 	/* if the visible ns_name is > 0 increase size for : :// seperator */
53 	if (ns_len)
54 		ns_len += 4;
55 
56 	/* unconfined profiles don't have a mode string appended */
57 	if (!unconfined(profile))
58 		mode_len = strlen(mode_str) + 3;	/* + 3 for _() */
59 
60 	name_len = strlen(profile->base.hname);
61 	len = mode_len + ns_len + name_len + 1;	    /* + 1 for \n */
62 	s = str = kmalloc(len + 1, GFP_KERNEL);	    /* + 1 \0 */
63 	if (!str)
64 		return -ENOMEM;
65 
66 	if (ns_len) {
67 		/* skip over prefix current_ns->base.hname and separating // */
68 		sprintf(s, ":%s://", ns_name);
69 		s += ns_len;
70 	}
71 	if (unconfined(profile))
72 		/* mode string not being appended */
73 		sprintf(s, "%s\n", profile->base.hname);
74 	else
75 		sprintf(s, "%s (%s)\n", profile->base.hname, mode_str);
76 	*string = str;
77 
78 	/* NOTE: len does not include \0 of string, not saved as part of file */
79 	return len;
80 }
81 
82 /**
83  * split_token_from_name - separate a string of form  <token>^<name>
84  * @op: operation being checked
85  * @args: string to parse  (NOT NULL)
86  * @token: stores returned parsed token value  (NOT NULL)
87  *
88  * Returns: start position of name after token else NULL on failure
89  */
90 static char *split_token_from_name(int op, char *args, u64 * token)
91 {
92 	char *name;
93 
94 	*token = simple_strtoull(args, &name, 16);
95 	if ((name == args) || *name != '^') {
96 		AA_ERROR("%s: Invalid input '%s'", op_table[op], args);
97 		return ERR_PTR(-EINVAL);
98 	}
99 
100 	name++;			/* skip ^ */
101 	if (!*name)
102 		name = NULL;
103 	return name;
104 }
105 
106 /**
107  * aa_setprocattr_chagnehat - handle procattr interface to change_hat
108  * @args: args received from writing to /proc/<pid>/attr/current (NOT NULL)
109  * @size: size of the args
110  * @test: true if this is a test of change_hat permissions
111  *
112  * Returns: %0 or error code if change_hat fails
113  */
114 int aa_setprocattr_changehat(char *args, size_t size, int test)
115 {
116 	char *hat;
117 	u64 token;
118 	const char *hats[16];		/* current hard limit on # of names */
119 	int count = 0;
120 
121 	hat = split_token_from_name(OP_CHANGE_HAT, args, &token);
122 	if (IS_ERR(hat))
123 		return PTR_ERR(hat);
124 
125 	if (!hat && !token) {
126 		AA_ERROR("change_hat: Invalid input, NULL hat and NULL magic");
127 		return -EINVAL;
128 	}
129 
130 	if (hat) {
131 		/* set up hat name vector, args guaranteed null terminated
132 		 * at args[size] by setprocattr.
133 		 *
134 		 * If there are multiple hat names in the buffer each is
135 		 * separated by a \0.  Ie. userspace writes them pre tokenized
136 		 */
137 		char *end = args + size;
138 		for (count = 0; (hat < end) && count < 16; ++count) {
139 			char *next = hat + strlen(hat) + 1;
140 			hats[count] = hat;
141 			hat = next;
142 		}
143 	}
144 
145 	AA_DEBUG("%s: Magic 0x%llx Hat '%s'\n",
146 		 __func__, token, hat ? hat : NULL);
147 
148 	return aa_change_hat(hats, count, token, test);
149 }
150 
151 /**
152  * aa_setprocattr_changeprofile - handle procattr interface to changeprofile
153  * @fqname: args received from writting to /proc/<pid>/attr/current (NOT NULL)
154  * @onexec: true if change_profile should be delayed until exec
155  * @test: true if this is a test of change_profile permissions
156  *
157  * Returns: %0 or error code if change_profile fails
158  */
159 int aa_setprocattr_changeprofile(char *fqname, bool onexec, int test)
160 {
161 	char *name, *ns_name;
162 
163 	name = aa_split_fqname(fqname, &ns_name);
164 	return aa_change_profile(ns_name, name, onexec, test);
165 }
166 
167 int aa_setprocattr_permipc(char *fqname)
168 {
169 	/* TODO: add ipc permission querying */
170 	return -ENOTSUPP;
171 }
172