1 /*
2 * Copyright (c) 2009-2024 Apple Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
14 *
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23 * Please see the License for the specific language governing rights and
24 * limitations under the License.
25 *
26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27 */
28
29 /*-
30 * Copyright (C) 2003 WIDE Project.
31 * All rights reserved.
32 *
33 * Redistribution and use in source and binary forms, with or without
34 * modification, are permitted provided that the following conditions
35 * are met:
36 * 1. Redistributions of source code must retain the above copyright
37 * notice, this list of conditions and the following disclaimer.
38 * 2. Redistributions in binary form must reproduce the above copyright
39 * notice, this list of conditions and the following disclaimer in the
40 * documentation and/or other materials provided with the distribution.
41 * 3. Neither the name of the project nor the names of its contributors
42 * may be used to endorse or promote products derived from this software
43 * without specific prior written permission.
44 *
45 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
46 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
47 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
48 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
49 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
50 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
51 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
52 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
53 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
54 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
55 * SUCH DAMAGE.
56 */
57
58 /*-
59 * Copyright 1998 Niels Provos <[email protected]>
60 * All rights reserved.
61 *
62 * Theo de Raadt <[email protected]> came up with the idea of using
63 * such a mathematical system to generate more random (yet non-repeating)
64 * ids to solve the resolver/named problem. But Niels designed the
65 * actual system based on the constraints.
66 *
67 * Redistribution and use in source and binary forms, with or without
68 * modification, are permitted provided that the following conditions
69 * are met:
70 * 1. Redistributions of source code must retain the above copyright
71 * notice, this list of conditions and the following disclaimer.
72 * 2. Redistributions in binary form must reproduce the above copyright
73 * notice, this list of conditions and the following disclaimer in the
74 * documentation and/or other materials provided with the distribution.
75 * 3. All advertising materials mentioning features or use of this software
76 * must display the following acknowledgement:
77 * This product includes software developed by Niels Provos.
78 * 4. The name of the author may not be used to endorse or promote products
79 * derived from this software without specific prior written permission.
80 *
81 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
82 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
83 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
84 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
85 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
86 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
87 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
88 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
89 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
90 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
91 */
92
93 #include <sys/cdefs.h>
94
95 #include <sys/mcache.h>
96 #include <sys/types.h>
97 #include <sys/param.h>
98 #include <sys/kernel.h>
99 #include <libkern/libkern.h>
100 #include <dev/random/randomdev.h>
101
102 #include <netinet/ip6.h>
103 #include <netinet6/ip6_var.h>
104
105 uint32_t
ip6_randomid(uint64_t salt)106 ip6_randomid(uint64_t salt)
107 {
108 uint32_t new_id;
109 /*
110 * Mostly the salt value is heap or stack pointer value.
111 * To avoid any chance of leaking address apply macro that
112 * adds per-boot random number to it.
113 */
114 uint64_t salt_tmp = VM_KERNEL_ADDRPERM(salt);
115 VERIFY(salt_tmp != 0);
116
117 /*
118 * When the passed salt values are addresses, it is possible some bits
119 * to not change at all, for example some higher order bits may not change
120 * and some lower order bits may be all 0s given particular alignment and object
121 * sizes.
122 * Therefore we compute a XOR'd 16bit value by considering all the bits
123 * of the salt to increase the likelihood of it being different.
124 */
125 uint32_t new_id_salt = (uint32_t)(((salt_tmp >> 48) ^ (salt_tmp >> 32) ^
126 (salt_tmp >> 16) ^ salt_tmp) & 0xFF);
127
128 /* Avoid returning IP ID value of 0 */
129 do {
130 read_random(&new_id, sizeof(new_id));
131 } while (new_id == new_id_salt);
132
133 return new_id ^ new_id_salt;
134 }
135
136 uint32_t
ip6_randomflowlabel(void)137 ip6_randomflowlabel(void)
138 {
139 return RandomULong() & IPV6_FLOWLABEL_MASK;
140 }
141