smb 0.2.0

A Pure Rust SMB Client implementation
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168

#[cfg(any(feature = "encrypt_aes128ccm", feature = "encrypt_aes256ccm"))]
use aes::cipher::{generic_array::GenericArray, BlockCipher, BlockEncrypt, BlockSizeUser};
#[cfg(feature = "encrypt_aes128ccm")]
use aes::Aes128;
#[cfg(feature = "encrypt_aes256ccm")]
use aes::Aes256;
#[cfg(any(feature = "encrypt_aes128ccm", feature = "encrypt_aes256ccm"))]
use ccm::{
    aead::AeadMutInPlace,
    consts::{U11, U16},
    Ccm, KeyInit, KeySizeUser,
};
use std::fmt::Debug;

use crate::packets::smb2::*;

use super::CryptoError;

pub struct EncryptionResult {
    pub signature: u128,
}

pub trait EncryptingAlgo: Debug + Send {
    /// Algo-specific encryption function.
    fn encrypt(
        &mut self,
        payload: &mut [u8],
        header_data: &[u8],
        nonce: &EncryptionNonce,
    ) -> Result<EncryptionResult, CryptoError>;

    /// Algo-specific decryption function.
    fn decrypt(
        &mut self,
        payload: &mut [u8],
        header_data: &[u8],
        nonce: &EncryptionNonce,
        signature: u128,
    ) -> Result<(), CryptoError>;

    /// Returns the size of the nonce required by the encryption algorithm.
    fn nonce_size(&self) -> usize;

    /// Returns the nonce to be used for encryption/decryption (trimmed to the required size),
    /// as the rest of the nonce is expected to be zero.
    fn trim_nonce<'a>(&self, nonce: &'a EncryptionNonce) -> &'a [u8] {
        // Sanity: the rest of the nonce is expected to be zero.
        debug_assert!(nonce[self.nonce_size()..].iter().all(|&x| x == 0));
        &nonce[..self.nonce_size()]
    }

    /// Clone the algo into a boxed trait object.
    ///
    /// This method is added to allow cloning the trait object, and allow cloning it's users,
    /// to enable multi-threaded access to the same encryption algorithm:
    /// Some of the algorithms are only mutable, and can't be shared between threads.
    fn clone_box(&self) -> Box<dyn EncryptingAlgo>;
}

pub const ENCRYPTING_ALGOS: &[EncryptionCipher] = &[
    #[cfg(feature = "encrypt_aes128ccm")]
    EncryptionCipher::Aes128Ccm,
    #[cfg(feature = "encrypt_aes256ccm")]
    EncryptionCipher::Aes256Ccm,
];

pub fn make_encrypting_algo(
    encrypting_algorithm: EncryptionCipher,
    encrypting_key: &[u8],
) -> Result<Box<dyn EncryptingAlgo>, CryptoError> {
    if !ENCRYPTING_ALGOS.contains(&encrypting_algorithm) {
        return Err(CryptoError::UnsupportedAlgorithm);
    }
    match encrypting_algorithm {
        #[cfg(feature = "encrypt_aes128ccm")]
        EncryptionCipher::Aes128Ccm => Ok(CcmEncryptor::<Aes128>::build(encrypting_key.into())?),
        #[cfg(feature = "encrypt_aes256ccm")]
        EncryptionCipher::Aes256Ccm => Ok(CcmEncryptor::<Aes256>::build(encrypting_key.into())?),
        _ => Err(CryptoError::UnsupportedAlgorithm),
    }
}

#[cfg(any(feature = "encrypt_aes128ccm", feature = "encrypt_aes256ccm"))]
#[derive(Clone)]
pub struct CcmEncryptor<C>
where
    C: BlockCipher + BlockSizeUser<BlockSize = U16> + BlockEncrypt,
{
    cipher: Ccm<C, U16, U11>,
}

#[cfg(any(feature = "encrypt_aes128ccm", feature = "encrypt_aes256ccm"))]
impl<C> CcmEncryptor<C>
where
    C: BlockCipher
        + BlockSizeUser<BlockSize = U16>
        + BlockEncrypt
        + KeyInit
        + Send
        + Clone
        + 'static,
{
    fn build(
        encrypting_key: &GenericArray<u8, <C as KeySizeUser>::KeySize>,
    ) -> Result<Box<dyn EncryptingAlgo>, CryptoError> {
        Ok(Box::new(Self {
            cipher: Ccm::<C, U16, U11>::new_from_slice(encrypting_key)?,
        }))
    }
}

#[cfg(any(feature = "encrypt_aes128ccm", feature = "encrypt_aes256ccm"))]
impl<C> EncryptingAlgo for CcmEncryptor<C>
where
    C: BlockCipher + BlockSizeUser<BlockSize = U16> + BlockEncrypt + Send + Clone + 'static,
{
    fn encrypt(
        &mut self,
        payload: &mut [u8],
        header_data: &[u8],
        nonce: &EncryptionNonce,
    ) -> Result<EncryptionResult, CryptoError> {
        let nonce = GenericArray::from_slice(self.trim_nonce(nonce));
        let signature = self
            .cipher
            .encrypt_in_place_detached(nonce, header_data, payload)?;

        Ok(EncryptionResult {
            signature: u128::from_le_bytes(signature.into()),
        })
    }

    fn decrypt(
        &mut self,
        payload: &mut [u8],
        header_data: &[u8],
        nonce: &EncryptionNonce,
        signature: u128,
    ) -> Result<(), CryptoError> {
        let nonce = GenericArray::from_slice(self.trim_nonce(nonce));
        self.cipher.decrypt_in_place_detached(
            nonce,
            header_data,
            payload,
            &signature.to_le_bytes().into(),
        )?;

        Ok(())
    }

    fn nonce_size(&self) -> usize {
        11
    }

    fn clone_box(&self) -> Box<dyn EncryptingAlgo> {
        Box::new(self.clone())
    }
}

#[cfg(any(feature = "encrypt_aes128ccm", feature = "encrypt_aes256ccm"))]
impl<C> Debug for CcmEncryptor<C>
where
    C: BlockCipher + BlockSizeUser<BlockSize = U16> + BlockEncrypt,
{
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "Ccm128Encrypter")
    }
}