Unverified Commit 17975801 authored by Steven Fackler's avatar Steven Fackler Committed by GitHub
Browse files

Merge pull request #1122 from russelltg/aes_wrap

Add AES_wrap_key and AES_unwrap_key functionality
parents ef86438a 1c3f5b5f
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+16 −0
Original line number Diff line number Diff line
@@ -25,4 +25,20 @@ extern "C" {
        ivec: *mut c_uchar,
        enc: c_int,
    );

    pub fn AES_wrap_key(
        key: *mut AES_KEY,
        iv: *const c_uchar,
        out: *mut c_uchar,
        in_: *const c_uchar,
        inlen: c_uint,
    ) -> c_int;

    pub fn AES_unwrap_key(
        key: *mut AES_KEY,
        iv: *const c_uchar,
        out: *mut c_uchar,
        in_: *const c_uchar,
        inlen: c_uint,
    ) -> c_int;
}
+125 −4
Original line number Diff line number Diff line
//! Low level AES IGE functionality
//! 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.
//! 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
@@ -22,6 +22,7 @@
//!
//! # Examples
//!
//! ## AES IGE
//! ```rust
//! use openssl::aes::{AesKey, aes_ige};
//! use openssl::symm::Mode;
@@ -35,9 +36,28 @@
//!  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;
use std::mem;
use libc::{c_int, c_uint};
use std::{mem, ptr};

use symm::Mode;

@@ -136,6 +156,81 @@ pub fn aes_ige(in_: &[u8], out: &mut [u8], key: &AesKey, iv: &mut [u8], mode: Mo
    }
}

/// 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 `in_`
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;
@@ -166,4 +261,30 @@ mod test {
        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[..]);
    }

}