Minimal binding to libsodium

sodium.rs

use std::os::raw::{c_int, c_uchar, c_ulonglong};
use super::{HMAC, KEY, NONCE, XNONCE};

pub const KEY: usize = 32;
pub const HMAC: usize = 16;
pub const NONCE: usize = 12;
pub const XNONCE: usize = 24;

#[link(name = "sodium")]
extern "C" {
    fn crypto_aead_xchacha20poly1305_ietf_encrypt_detached(
        c: *mut c_uchar,
        mac: *mut c_uchar,
        maclen_p: *mut c_ulonglong,
        m: *const c_uchar,
        mlen: c_ulonglong,
        ad: *const c_uchar,
        adlen: c_ulonglong,
        nsec: *const c_uchar,
        npub: *const c_uchar,
        k: *const c_uchar
    ) -> c_int;
    fn crypto_aead_xchacha20poly1305_ietf_decrypt_detached(
        m: *mut c_uchar,
        nsec: *mut c_uchar,
        c: *const c_uchar,
        clen: c_ulonglong,
        mac: *const c_uchar,
        ad: *const c_uchar,
        adlen: c_ulonglong,
        npub: *const c_uchar,
        k: *const c_uchar
    ) -> c_int;
    fn crypto_aead_chacha20poly1305_ietf_encrypt_detached(
        c: *mut c_uchar,
        mac: *mut c_uchar,
        maclen_p: *mut c_ulonglong,
        m: *const c_uchar,
        mlen: c_ulonglong,
        ad: *const c_uchar,
        adlen: c_ulonglong,
        nsec: *const c_uchar,
        npub: *const c_uchar,
        k: *const c_uchar
    ) -> c_int;
    fn crypto_aead_chacha20poly1305_ietf_decrypt_detached(
        m: *mut c_uchar,
        nsec: *mut c_uchar,
        c: *const c_uchar,
        clen: c_ulonglong,
        mac: *const c_uchar,
        ad: *const c_uchar,
        adlen: c_ulonglong,
        npub: *const c_uchar,
        k: *const c_uchar
    ) -> c_int;
}

pub fn open(c: &mut [u8], ad: Option<&[u8]>, t: &[u8; HMAC], n: &[u8; NONCE], k: &[u8; KEY]) -> Result<(), ()> {
    let (ad_p, ad_len) = ad.map(|ad| (ad.as_ptr(), ad.len() as c_ulonglong)).unwrap_or((0 as *const _, 0));
    let ret = unsafe {
        crypto_aead_chacha20poly1305_ietf_decrypt_detached(
            c.as_mut_ptr(),
            0 as *mut _,
            c.as_ptr(),
            c.len() as c_ulonglong,
            t.as_ptr(),
            ad_p,
            ad_len,
            n.as_ptr(),
            k.as_ptr()
        )
    };
    if ret == 0 {
        Ok(())
    } else {
        Err(())
    }
}

pub fn seal(m: &mut [u8], ad: Option<&[u8]>, n: &[u8; NONCE], k: &[u8; KEY]) -> [u8; HMAC] {
    let (ad_p, ad_len) = ad.map(|ad| (ad.as_ptr(), ad.len() as c_ulonglong)).unwrap_or((0 as *const _, 0));
    let mut tag = [0u8; HMAC];
    let mut maclen = HMAC as c_ulonglong;
    unsafe {
        crypto_aead_chacha20poly1305_ietf_encrypt_detached(
            m.as_mut_ptr(),
            tag.as_mut_ptr(),
            &mut maclen,
            m.as_ptr(),
            m.len() as c_ulonglong,
            ad_p,
            ad_len,
            0 as *mut _,
            n.as_ptr(),
            k.as_ptr()
        );
    }
    tag
}

pub fn xopen(c: &mut [u8], ad: &[u8], t: &[u8; HMAC], n: &[u8; XNONCE], k: &[u8; KEY]) -> Result<(), ()> {
    let (ad_p, ad_len) = (ad.as_ptr(), ad.len() as c_ulonglong);
    let ret = unsafe {
        crypto_aead_xchacha20poly1305_ietf_decrypt_detached(
            c.as_mut_ptr(),
            0 as *mut _,
            c.as_ptr(),
            c.len() as c_ulonglong,
            t.as_ptr(),
            ad_p,
            ad_len,
            n.as_ptr(),
            k.as_ptr()
        )
    };
    if ret == 0 {
        Ok(())
    } else {
        Err(())
    }
}

pub fn xseal(m: &mut [u8], ad: &[u8], n: &[u8; XNONCE], k: &[u8; KEY]) -> [u8; HMAC] {
    let (ad_p, ad_len) = (ad.as_ptr(), ad.len() as c_ulonglong);
    let mut tag = [0u8; HMAC];
    let mut maclen = HMAC as c_ulonglong;
    unsafe {
        crypto_aead_xchacha20poly1305_ietf_encrypt_detached(
            m.as_mut_ptr(),
            tag.as_mut_ptr(),
            &mut maclen,
            m.as_ptr(),
            m.len() as c_ulonglong,
            ad_p,
            ad_len,
            0 as *mut _,
            n.as_ptr(),
            k.as_ptr()
        );
    }
    tag
}