apply changes from upstream to forked crate

jmwample · Jul 26, 2024 · 4ea0f59 · 4ea0f59
1 parent 7fc2968
commit 4ea0f59
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Showing 5 changed files with 22 additions and 6 deletions.
diff --git a/curve25519-elligator2/Cargo.toml b/curve25519-elligator2/Cargo.toml
@@ -77,3 +77,13 @@ digest = ["dep:digest", "elligator2"]
 
 [target.'cfg(all(not(curve25519_dalek_backend = "fiat"), not(curve25519_dalek_backend = "serial"), target_arch = "x86_64"))'.dependencies]
 curve25519-dalek-derive = { version = "0.1.1" }
+
+[lints.rust.unexpected_cfgs]
+level = "warn"
+check-cfg = [
+    'cfg(allow_unused_unsafe)',
+    'cfg(curve25519_dalek_backend, values("fiat", "serial", "simd"))',
+    'cfg(curve25519_dalek_diagnostics, values("build"))',
+    'cfg(curve25519_dalek_bits, values("32", "64"))',
+    'cfg(nightly)',
+]
diff --git a/curve25519-elligator2/src/backend/serial/u32/scalar.rs b/curve25519-elligator2/src/backend/serial/u32/scalar.rs
@@ -12,6 +12,7 @@
 
 use core::fmt::Debug;
 use core::ops::{Index, IndexMut};
+use subtle::{Choice, ConditionallySelectable};
 
 #[cfg(feature = "zeroize")]
 use zeroize::Zeroize;
@@ -196,10 +197,12 @@ impl Scalar29 {
         }
 
         // conditionally add l if the difference is negative
-        let underflow_mask = ((borrow >> 31) ^ 1).wrapping_sub(1);
         let mut carry: u32 = 0;
         for i in 0..9 {
-            carry = (carry >> 29) + difference[i] + (constants::L[i] & underflow_mask);
+            let underflow = Choice::from((borrow >> 31) as u8);
+
+            let addend = u32::conditional_select(&0, &constants::L[i], underflow);
+            carry = (carry >> 29) + difference[i] + addend;
             difference[i] = carry & mask;
         }
 

diff --git a/curve25519-elligator2/src/backend/serial/u64/scalar.rs b/curve25519-elligator2/src/backend/serial/u64/scalar.rs
@@ -13,6 +13,7 @@
 
 use core::fmt::Debug;
 use core::ops::{Index, IndexMut};
+use subtle::{Choice, ConditionallySelectable};
 
 #[cfg(feature = "zeroize")]
 use zeroize::Zeroize;
@@ -185,10 +186,12 @@ impl Scalar52 {
         }
 
         // conditionally add l if the difference is negative
-        let underflow_mask = ((borrow >> 63) ^ 1).wrapping_sub(1);
         let mut carry: u64 = 0;
         for i in 0..5 {
-            carry = (carry >> 52) + difference[i] + (constants::L[i] & underflow_mask);
+            let underflow = Choice::from((borrow >> 63) as u8);
+
+            let addend = u64::conditional_select(&0, &constants::L[i], underflow);
+            carry = (carry >> 52) + difference[i] + addend;
             difference[i] = carry & mask;
         }
 

diff --git a/curve25519-elligator2/src/backend/vector/ifma/edwards.rs b/curve25519-elligator2/src/backend/vector/ifma/edwards.rs
@@ -249,7 +249,7 @@ impl<'a> From<&'a edwards::EdwardsPoint> for NafLookupTable8<CachedPoint> {
     }
 }
 
-#[cfg(target_feature = "avx512ifma,avx512vl")]
+#[cfg(all(target_feature = "avx512ifma", target_feature = "avx512vl"))]
 #[cfg(test)]
 mod test {
     use super::*;

diff --git a/curve25519-elligator2/src/backend/vector/ifma/field.rs b/curve25519-elligator2/src/backend/vector/ifma/field.rs
@@ -629,7 +629,7 @@ impl<'a, 'b> Mul<&'b F51x4Reduced> for &'a F51x4Reduced {
     }
 }
 
-#[cfg(target_feature = "avx512ifma,avx512vl")]
+#[cfg(all(target_feature = "avx512ifma", target_feature = "avx512vl"))]
 #[cfg(test)]
 mod test {
     use super::*;