wlan_rsn/key/
igtk.rs

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1// Copyright 2020 The Fuchsia Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5use crate::key::Tk;
6use crate::key_data::kde;
7use crate::Error;
8use mundane::bytes;
9use wlan_common::ie::rsn::cipher::Cipher;
10
11/// This IGTK provider does not support key rotations yet.
12#[derive(Debug)]
13pub struct IgtkProvider {
14    key: Box<[u8]>,
15    tk_bytes: usize,
16    cipher: Cipher,
17}
18
19// IEEE 802.11-2016 12.7.1.5 - The Authenticator shall select the IGTK
20// as a random value each time it is generated.
21fn generate_random_igtk(len: usize) -> Box<[u8]> {
22    let mut key = vec![0; len];
23    bytes::rand(&mut key[..]);
24    key.into_boxed_slice()
25}
26
27impl IgtkProvider {
28    pub fn new(cipher: Cipher) -> Result<IgtkProvider, anyhow::Error> {
29        let tk_bytes: usize =
30            cipher.tk_bytes().ok_or(Error::IgtkHierarchyUnsupportedCipherError)?.into();
31        Ok(IgtkProvider { key: generate_random_igtk(tk_bytes), cipher, tk_bytes })
32    }
33
34    pub fn cipher(&self) -> Cipher {
35        self.cipher
36    }
37
38    pub fn rotate_key(&mut self) {
39        self.key = generate_random_igtk(self.tk_bytes);
40    }
41
42    pub fn get_igtk(&self) -> Igtk {
43        Igtk { igtk: self.key.to_vec(), key_id: 0, ipn: [0u8; 6], cipher: self.cipher.clone() }
44    }
45}
46
47#[derive(Debug, Clone, PartialEq, Eq, Hash)]
48pub struct Igtk {
49    pub igtk: Vec<u8>,
50    pub key_id: u16,
51    pub ipn: [u8; 6],
52    pub cipher: Cipher,
53}
54
55impl Igtk {
56    pub fn from_kde(element: kde::Igtk, cipher: Cipher) -> Self {
57        Self { igtk: element.igtk, key_id: element.id, ipn: element.ipn, cipher }
58    }
59}
60
61impl Tk for Igtk {
62    fn tk(&self) -> &[u8] {
63        &self.igtk[..]
64    }
65}
66
67#[cfg(test)]
68mod tests {
69    use super::*;
70    use wlan_common::ie::rsn::suite_filter::DEFAULT_GROUP_MGMT_CIPHER;
71
72    #[test]
73    fn test_igtk_generation() {
74        let mut igtk_provider =
75            IgtkProvider::new(DEFAULT_GROUP_MGMT_CIPHER).expect("failed creating IgtkProvider");
76
77        let first_igtk = igtk_provider.get_igtk().tk().to_vec();
78        for _ in 0..3 {
79            igtk_provider.rotate_key();
80            if first_igtk != igtk_provider.get_igtk().tk().to_vec() {
81                return;
82            }
83        }
84        panic!("IGTK key rotation always generates the same key!");
85    }
86}
wlan_rsn/key/igtk.rs

wlan_rsn/key/
igtk.rs
