Previously, we used a little bit of generation to drive a lot of Rust macros. This works, but it's a little confusing to read and write. In addition, we used a lot of implementations with variable timings based on their input, which isn't great for crypto. This is the start of an attempt to just generate all of the relevant Rust code directly, and to use timing-channel resistant implementations for most of the routines.
136 lines
3.8 KiB
Rust
136 lines
3.8 KiB
Rust
pub fn addition(dest: &mut [u64], src: &[u64])
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{
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assert_eq!(dest.len(), src.len() + 1);
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let mut carry: u128 = 0;
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for i in 0..src.len() {
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let x128 = dest[i] as u128;
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let y128 = src[i] as u128;
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let z128 = x128 + y128 + carry;
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dest[i] = z128 as u64;
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carry = z128 >> 64;
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}
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dest[src.len()] = carry as u64;
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}
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pub fn unsafe_addition(dest: &mut [u64], src: &[u64], really_unsafe: bool)
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{
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assert_eq!(dest.len(), src.len());
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let mut carry: u128 = 0;
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for i in 0..src.len() {
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let x128 = dest[i] as u128;
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let y128 = src[i] as u128;
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let z128 = x128 + y128 + carry;
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dest[i] = z128 as u64;
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carry = z128 >> 64;
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}
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if !really_unsafe {
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assert_eq!(carry, 0, "Unsafe overflow in AddAssign");
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}
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}
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macro_rules! addition_impls
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{
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($base: ident, $bigger: ident) => {
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impl AddAssign<$base> for $base {
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fn add_assign(&mut self, rhs: $base) {
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unsafe_addition(&mut self.value, &rhs.value, false);
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}
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}
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impl<'a> AddAssign<&'a $base> for $base {
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fn add_assign(&mut self, rhs: &$base) {
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unsafe_addition(&mut self.value, &rhs.value, false);
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}
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}
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impl Add<$base> for $base {
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type Output = $bigger;
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fn add(self, rhs: $base) -> $bigger
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{
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let mut dest = $bigger::zero();
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&dest.value[0..rhs.value.len()].copy_from_slice(&self.value);
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addition(&mut dest.value, &rhs.value);
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dest
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}
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}
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impl<'a> Add<&'a $base> for $base {
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type Output = $bigger;
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fn add(self, rhs: &$base) -> $bigger
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{
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let mut dest = $bigger::zero();
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&dest.value[0..rhs.value.len()].copy_from_slice(&self.value);
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addition(&mut dest.value, &rhs.value);
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dest
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}
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}
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impl<'a> Add<$base> for &'a $base {
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type Output = $bigger;
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fn add(self, rhs: $base) -> $bigger
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{
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let mut dest = $bigger::zero();
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&dest.value[0..rhs.value.len()].copy_from_slice(&self.value);
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addition(&mut dest.value, &rhs.value);
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dest
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}
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}
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impl<'a,'b> Add<&'a $base> for &'b $base {
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type Output = $bigger;
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fn add(self, rhs: &$base) -> $bigger
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{
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let mut dest = $bigger::zero();
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&dest.value[0..rhs.value.len()].copy_from_slice(&self.value);
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addition(&mut dest.value, &rhs.value);
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dest
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}
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}
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}
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}
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#[cfg(test)]
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macro_rules! generate_add_tests {
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($name: ident, $lname: ident, $plus1: ident) => {
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#[test]
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fn $lname() {
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generate_add_tests!(body $name, $lname, $plus1);
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}
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};
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(ignore $name: ident, $lname: ident, $plus1: ident) => {
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#[test]
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#[ignore]
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fn $lname() {
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generate_add_tests!(body $name, $lname, $plus1);
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}
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};
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(body $name: ident, $lname: ident, $plus1: ident) => {
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let fname = build_test_path("add", stringify!($name));
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run_test(fname.to_string(), 3, |case| {
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let (neg0, abytes) = case.get("a").unwrap();
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let (neg1, bbytes) = case.get("b").unwrap();
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let (neg2, cbytes) = case.get("c").unwrap();
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assert!(!neg0 && !neg1 && !neg2);
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let a = $name::from_bytes(abytes);
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let b = $name::from_bytes(bbytes);
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let c = $plus1::from_bytes(cbytes);
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assert_eq!(c, &a + &b);
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if c.value[c.value.len()-1] == 0 {
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let mut aprime = a.clone();
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aprime += b;
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assert_eq!($name::from(c), aprime);
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}
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});
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};
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} |