xref: /linux/security/apparmor/procattr.c (revision e5c86679d5e864947a52fb31e45a425dea3e7fa9)
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/policy_ns.h"
19 #include "include/domain.h"
20 #include "include/procattr.h"
21 
22 
23 /**
24  * aa_getprocattr - Return the profile information for @profile
25  * @profile: the profile to print profile info about  (NOT NULL)
26  * @string: Returns - string containing the profile info (NOT NULL)
27  *
28  * Returns: length of @string on success else error on failure
29  *
30  * Requires: profile != NULL
31  *
32  * Creates a string containing the namespace_name://profile_name for
33  * @profile.
34  *
35  * Returns: size of string placed in @string else error code on failure
36  */
37 int aa_getprocattr(struct aa_profile *profile, char **string)
38 {
39 	char *str;
40 	int len = 0, mode_len = 0, ns_len = 0, name_len;
41 	const char *mode_str = aa_profile_mode_names[profile->mode];
42 	const char *ns_name = NULL;
43 	struct aa_ns *ns = profile->ns;
44 	struct aa_ns *current_ns = __aa_current_profile()->ns;
45 	char *s;
46 
47 	if (!aa_ns_visible(current_ns, ns, true))
48 		return -EACCES;
49 
50 	ns_name = aa_ns_name(current_ns, ns, true);
51 	ns_len = strlen(ns_name);
52 
53 	/* if the visible ns_name is > 0 increase size for : :// seperator */
54 	if (ns_len)
55 		ns_len += 4;
56 
57 	/* unconfined profiles don't have a mode string appended */
58 	if (!unconfined(profile))
59 		mode_len = strlen(mode_str) + 3;	/* + 3 for _() */
60 
61 	name_len = strlen(profile->base.hname);
62 	len = mode_len + ns_len + name_len + 1;	    /* + 1 for \n */
63 	s = str = kmalloc(len + 1, GFP_KERNEL);	    /* + 1 \0 */
64 	if (!str)
65 		return -ENOMEM;
66 
67 	if (ns_len) {
68 		/* skip over prefix current_ns->base.hname and separating // */
69 		sprintf(s, ":%s://", ns_name);
70 		s += ns_len;
71 	}
72 	if (unconfined(profile))
73 		/* mode string not being appended */
74 		sprintf(s, "%s\n", profile->base.hname);
75 	else
76 		sprintf(s, "%s (%s)\n", profile->base.hname, mode_str);
77 	*string = str;
78 
79 	/* NOTE: len does not include \0 of string, not saved as part of file */
80 	return len;
81 }
82 
83 /**
84  * split_token_from_name - separate a string of form  <token>^<name>
85  * @op: operation being checked
86  * @args: string to parse  (NOT NULL)
87  * @token: stores returned parsed token value  (NOT NULL)
88  *
89  * Returns: start position of name after token else NULL on failure
90  */
91 static char *split_token_from_name(const char *op, char *args, u64 *token)
92 {
93 	char *name;
94 
95 	*token = simple_strtoull(args, &name, 16);
96 	if ((name == args) || *name != '^') {
97 		AA_ERROR("%s: Invalid input '%s'", op, args);
98 		return ERR_PTR(-EINVAL);
99 	}
100 
101 	name++;			/* skip ^ */
102 	if (!*name)
103 		name = NULL;
104 	return name;
105 }
106 
107 /**
108  * aa_setprocattr_chagnehat - handle procattr interface to change_hat
109  * @args: args received from writing to /proc/<pid>/attr/current (NOT NULL)
110  * @size: size of the args
111  * @test: true if this is a test of change_hat permissions
112  *
113  * Returns: %0 or error code if change_hat fails
114  */
115 int aa_setprocattr_changehat(char *args, size_t size, int test)
116 {
117 	char *hat;
118 	u64 token;
119 	const char *hats[16];		/* current hard limit on # of names */
120 	int count = 0;
121 
122 	hat = split_token_from_name(OP_CHANGE_HAT, args, &token);
123 	if (IS_ERR(hat))
124 		return PTR_ERR(hat);
125 
126 	if (!hat && !token) {
127 		AA_ERROR("change_hat: Invalid input, NULL hat and NULL magic");
128 		return -EINVAL;
129 	}
130 
131 	if (hat) {
132 		/* set up hat name vector, args guaranteed null terminated
133 		 * at args[size] by setprocattr.
134 		 *
135 		 * If there are multiple hat names in the buffer each is
136 		 * separated by a \0.  Ie. userspace writes them pre tokenized
137 		 */
138 		char *end = args + size;
139 		for (count = 0; (hat < end) && count < 16; ++count) {
140 			char *next = hat + strlen(hat) + 1;
141 			hats[count] = hat;
142 			AA_DEBUG("%s: (pid %d) Magic 0x%llx count %d hat '%s'\n"
143 				 , __func__, current->pid, token, count, hat);
144 			hat = next;
145 		}
146 	} else
147 		AA_DEBUG("%s: (pid %d) Magic 0x%llx count %d Hat '%s'\n",
148 			 __func__, current->pid, token, count, "<NULL>");
149 
150 	return aa_change_hat(hats, count, token, test);
151 }
152