      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
    169
    170
    171
    172
    173
    174
    175
    176
    177
    178
    179
    180
    181
    182
    183
    184
    185
    186
    187
    188
    189
    190
    191
    192
    193
    194
    195
    196
    197
    198
    199
    200
    201
    202
    203
    204
    205
    206
    207
    208
    209
    210
    211
    212
    213
    214
    215
    216
    217
    218
    219
    220
    221
    222
    223
    224
    225
    226
    227
    228
    229
    230
    231
    232
    233
    234
    235
    236
    237
    238
    239
    240
    241
    242
    243
    244
    245
    246
    247
    248
    249
    250
    251
    252
    253
    254
    255
    256
    257
    258
    259
    260
    261
    262
    263
    264
    265
    266
    267
    268
    269
    270
    271
    272
    273
    274
    275
    276
    277
    278
    279
    280
    281
    282
    283
    284
    285
    286
    287
    288
    289
    290
    291
    292
    293

    //! Low level AES IGE and key wrapping functionality
    //!
    //! AES ECB, CBC, XTS, CTR, CFB, GCM and other conventional symmetric encryption
    //! modes are found in [`symm`].  This is the implementation of AES IGE and key wrapping
    //!
    //! Advanced Encryption Standard (AES) provides symmetric key cipher that
    //! the same key is used to encrypt and decrypt data.  This implementation
    //! uses 128, 192, or 256 bit keys.  This module provides functions to
    //! create a new key with [`new_encrypt`] and perform an encryption/decryption
    //! using that key with [`aes_ige`].
    //!
    //! [`new_encrypt`]: struct.AesKey.html#method.new_encrypt
    //! [`aes_ige`]: fn.aes_ige.html
    //!
    //! The [`symm`] module should be used in preference to this module in most cases.
    //! The IGE block cypher is a non-traditional cipher mode.  More traditional AES
    //! encryption methods are found in the [`Crypter`] and [`Cipher`] structs.
    //!
    //! [`symm`]: ../symm/index.html
    //! [`Crypter`]: ../symm/struct.Crypter.html
    //! [`Cipher`]: ../symm/struct.Cipher.html
    //!
    //! # Examples
    //!
    //! ## AES IGE
    //! ```rust
    //! use openssl::aes::{AesKey, aes_ige};
    //! use openssl::symm::Mode;
    //!
    //! let key = b"\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0A\x0B\x0C\x0D\x0E\x0F";
    //! let plaintext = b"\x12\x34\x56\x78\x90\x12\x34\x56\x12\x34\x56\x78\x90\x12\x34\x56";
    //! let mut iv = *b"\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0A\x0B\x0C\x0D\x0E\x0F\
    //!                 \x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1A\x1B\x1C\x1D\x1E\x1F";
    //!
    //!  let key = AesKey::new_encrypt(key).unwrap();
    //!  let mut output = [0u8; 16];
    //!  aes_ige(plaintext, &mut output, &key, &mut iv, Mode::Encrypt);
    //!  assert_eq!(output, *b"\xa6\xad\x97\x4d\x5c\xea\x1d\x36\xd2\xf3\x67\x98\x09\x07\xed\x32");
    //! ```
    //!
    //! ## Key wrapping
    //! ```rust
    //! use openssl::aes::{AesKey, unwrap_key, wrap_key};
    //!
    //! let kek = b"\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0A\x0B\x0C\x0D\x0E\x0F";
    //! let key_to_wrap = b"\x00\x11\x22\x33\x44\x55\x66\x77\x88\x99\xAA\xBB\xCC\xDD\xEE\xFF";
    //!
    //! let enc_key = AesKey::new_encrypt(kek).unwrap();
    //! let mut ciphertext = [0u8; 24];
    //! wrap_key(&enc_key, None, &mut ciphertext, &key_to_wrap[..]).unwrap();
    //! let dec_key = AesKey::new_decrypt(kek).unwrap();
    //! let mut orig_key = [0u8; 16];
    //! unwrap_key(&dec_key, None, &mut orig_key, &ciphertext[..]).unwrap();
    //!
    //! assert_eq!(&orig_key[..], &key_to_wrap[..]);
    //! ```
    //!
    use ffi;
    use libc::{c_int, c_uint};
    use std::{mem, ptr};

    use symm::Mode;

    /// Provides Error handling for parsing keys.
    #[derive(Debug)]
    pub struct KeyError(());

    /// The key used to encrypt or decrypt cipher blocks.
    pub struct AesKey(ffi::AES_KEY);

    impl AesKey {
        /// Prepares a key for encryption.
        ///
        /// # Failure
        ///
        /// Returns an error if the key is not 128, 192, or 256 bits.
        #[allow(deprecated)] // https://github.com/rust-lang/rust/issues/63566
        pub fn new_encrypt(key: &[u8]) -> Result<AesKey, KeyError> {
            unsafe {
                assert!(key.len() <= c_int::max_value() as usize / 8);

                let mut aes_key = mem::uninitialized();
                let r = ffi::AES_set_encrypt_key(
                    key.as_ptr() as *const _,
                    key.len() as c_int * 8,
                    &mut aes_key,
                );
                if r == 0 {
                    Ok(AesKey(aes_key))
                } else {
                    Err(KeyError(()))
                }
            }
        }

        /// Prepares a key for decryption.
        ///
        /// # Failure
        ///
        /// Returns an error if the key is not 128, 192, or 256 bits.
        #[allow(deprecated)] // https://github.com/rust-lang/rust/issues/63566
        pub fn new_decrypt(key: &[u8]) -> Result<AesKey, KeyError> {
            unsafe {
                assert!(key.len() <= c_int::max_value() as usize / 8);

                let mut aes_key = mem::uninitialized();
                let r = ffi::AES_set_decrypt_key(
                    key.as_ptr() as *const _,
                    key.len() as c_int * 8,
                    &mut aes_key,
                );

                if r == 0 {
                    Ok(AesKey(aes_key))
                } else {
                    Err(KeyError(()))
                }
            }
        }
    }

    /// Performs AES IGE encryption or decryption
    ///
    /// AES IGE (Infinite Garble Extension) is a form of AES block cipher utilized in
    /// OpenSSL.  Infinite Garble referes to propogating forward errors.  IGE, like other
    /// block ciphers implemented for AES requires an initalization vector.  The IGE mode
    /// allows a stream of blocks to be encrypted or decrypted without having the entire
    /// plaintext available.  For more information, visit [AES IGE Encryption].
    ///
    /// This block cipher uses 16 byte blocks.  The rust implmentation will panic
    /// if the input or output does not meet this 16-byte boundry.  Attention must
    /// be made in this low level implementation to pad the value to the 128-bit boundry.
    ///
    /// [AES IGE Encryption]: http://www.links.org/files/openssl-ige.pdf
    ///
    /// # Panics
    ///
    /// Panics if `in_` is not the same length as `out`, if that length is not a multiple of 16, or if
    /// `iv` is not at least 32 bytes.
    pub fn aes_ige(in_: &[u8], out: &mut [u8], key: &AesKey, iv: &mut [u8], mode: Mode) {
        unsafe {
            assert!(in_.len() == out.len());
            assert!(in_.len() % ffi::AES_BLOCK_SIZE as usize == 0);
            assert!(iv.len() >= ffi::AES_BLOCK_SIZE as usize * 2);

            let mode = match mode {
                Mode::Encrypt => ffi::AES_ENCRYPT,
                Mode::Decrypt => ffi::AES_DECRYPT,
            };
            ffi::AES_ige_encrypt(
                in_.as_ptr() as *const _,
                out.as_mut_ptr() as *mut _,
                in_.len(),
                &key.0,
                iv.as_mut_ptr() as *mut _,
                mode,
            );
        }
    }

    /// Wrap a key, according to [RFC 3394](https://tools.ietf.org/html/rfc3394)
    ///
    /// * `key`: The key-encrypting-key to use. Must be a encrypting key
    /// * `iv`: The IV to use. You must use the same IV for both wrapping and unwrapping
    /// * `out`: The output buffer to store the ciphertext
    /// * `in_`: The input buffer, storing the key to be wrapped
    ///
    /// Returns the number of bytes written into `out`
    ///
    /// # Panics
    ///
    /// Panics if either `out` or `in_` do not have sizes that are a multiple of 8, or if
    /// `out` is not 8 bytes longer than `in_`
    pub fn wrap_key(
        key: &AesKey,
        iv: Option<[u8; 8]>,
        out: &mut [u8],
        in_: &[u8],
    ) -> Result<usize, KeyError> {
        unsafe {
            assert!(out.len() >= in_.len() + 8); // Ciphertext is 64 bits longer (see 2.2.1)

            let written = ffi::AES_wrap_key(
                &key.0 as *const _ as *mut _, // this is safe, the implementation only uses the key as a const pointer.
                iv.as_ref()
                    .map_or(ptr::null(), |iv| iv.as_ptr() as *const _),
                out.as_ptr() as *mut _,
                in_.as_ptr() as *const _,
                in_.len() as c_uint,
            );
            if written <= 0 {
                Err(KeyError(()))
            } else {
                Ok(written as usize)
            }
        }
    }

    /// Unwrap a key, according to [RFC 3394](https://tools.ietf.org/html/rfc3394)
    ///
    /// * `key`: The key-encrypting-key to decrypt the wrapped key. Must be a decrypting key
    /// * `iv`: The same IV used for wrapping the key
    /// * `out`: The buffer to write the unwrapped key to
    /// * `in_`: The input ciphertext
    ///
    /// Returns the number of bytes written into `out`
    ///
    /// # Panics
    ///
    /// Panics if either `out` or `in_` do not have sizes that are a multiple of 8, or
    /// if `in_` is not 8 bytes longer than `out`
    pub fn unwrap_key(
        key: &AesKey,
        iv: Option<[u8; 8]>,
        out: &mut [u8],
        in_: &[u8],
    ) -> Result<usize, KeyError> {
        unsafe {
            assert!(out.len() + 8 <= in_.len());

            let written = ffi::AES_unwrap_key(
                &key.0 as *const _ as *mut _, // this is safe, the implementation only uses the key as a const pointer.
                iv.as_ref()
                    .map_or(ptr::null(), |iv| iv.as_ptr() as *const _),
                out.as_ptr() as *mut _,
                in_.as_ptr() as *const _,
                in_.len() as c_uint,
            );

            if written <= 0 {
                Err(KeyError(()))
            } else {
                Ok(written as usize)
            }
        }
    }

    #[cfg(test)]
    mod test {
        use hex::FromHex;

        use super::*;
        use symm::Mode;

        // From https://www.mgp25.com/AESIGE/
        #[test]
        fn ige_vector_1() {
            let raw_key = "000102030405060708090A0B0C0D0E0F";
            let raw_iv = "000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F";
            let raw_pt = "0000000000000000000000000000000000000000000000000000000000000000";
            let raw_ct = "1A8519A6557BE652E9DA8E43DA4EF4453CF456B4CA488AA383C79C98B34797CB";

            let key = AesKey::new_encrypt(&Vec::from_hex(raw_key).unwrap()).unwrap();
            let mut iv = Vec::from_hex(raw_iv).unwrap();
            let pt = Vec::from_hex(raw_pt).unwrap();
            let ct = Vec::from_hex(raw_ct).unwrap();

            let mut ct_actual = vec![0; ct.len()];
            aes_ige(&pt, &mut ct_actual, &key, &mut iv, Mode::Encrypt);
            assert_eq!(ct_actual, ct);

            let key = AesKey::new_decrypt(&Vec::from_hex(raw_key).unwrap()).unwrap();
            let mut iv = Vec::from_hex(raw_iv).unwrap();
            let mut pt_actual = vec![0; pt.len()];
            aes_ige(&ct, &mut pt_actual, &key, &mut iv, Mode::Decrypt);
            assert_eq!(pt_actual, pt);
        }

        // from the RFC https://tools.ietf.org/html/rfc3394#section-2.2.3
        #[test]
        fn test_wrap_unwrap() {
            let raw_key = Vec::from_hex("000102030405060708090A0B0C0D0E0F").unwrap();
            let key_data = Vec::from_hex("00112233445566778899AABBCCDDEEFF").unwrap();
            let expected_ciphertext =
                Vec::from_hex("1FA68B0A8112B447AEF34BD8FB5A7B829D3E862371D2CFE5").unwrap();

            let enc_key = AesKey::new_encrypt(&raw_key).unwrap();
            let mut wrapped = [0; 24];
            assert_eq!(
                wrap_key(&enc_key, None, &mut wrapped, &key_data).unwrap(),
                24
            );
            assert_eq!(&wrapped[..], &expected_ciphertext[..]);

            let dec_key = AesKey::new_decrypt(&raw_key).unwrap();
            let mut unwrapped = [0; 16];
            assert_eq!(
                unwrap_key(&dec_key, None, &mut unwrapped, &wrapped).unwrap(),
                16
            );
            assert_eq!(&unwrapped[..], &key_data[..]);
        }
    }