1 files changed, 9 insertions, 16 deletions
diff --git a/vendor/crypto-bigint/src/limb/rand.rs b/vendor/crypto-bigint/src/limb/rand.rs
index 0bc8af31a..43471682d 100644
--- a/vendor/crypto-bigint/src/limb/rand.rs
+++ b/vendor/crypto-bigint/src/limb/rand.rs
@@ -2,41 +2,34 @@
 
 use super::Limb;
 use crate::{Encoding, NonZero, Random, RandomMod};
-use rand_core::{CryptoRng, RngCore};
+use rand_core::CryptoRngCore;
 use subtle::ConstantTimeLess;
 
-#[cfg_attr(docsrs, doc(cfg(feature = "rand_core")))]
 impl Random for Limb {
     #[cfg(target_pointer_width = "32")]
-    fn random(mut rng: impl CryptoRng + RngCore) -> Self {
+    fn random(rng: &mut impl CryptoRngCore) -> Self {
         Self(rng.next_u32())
     }
 
     #[cfg(target_pointer_width = "64")]
-    fn random(mut rng: impl CryptoRng + RngCore) -> Self {
+    fn random(rng: &mut impl CryptoRngCore) -> Self {
         Self(rng.next_u64())
     }
 }
 
-#[cfg_attr(docsrs, doc(cfg(feature = "rand_core")))]
 impl RandomMod for Limb {
-    fn random_mod(mut rng: impl CryptoRng + RngCore, modulus: &NonZero<Self>) -> Self {
+    fn random_mod(rng: &mut impl CryptoRngCore, modulus: &NonZero<Self>) -> Self {
         let mut bytes = <Self as Encoding>::Repr::default();
 
-        // TODO(tarcieri): use `div_ceil` when available
-        // See: https://github.com/rust-lang/rust/issues/88581
-        let mut n_bytes = modulus.bits() / 8;
-
-        // Ensure the randomly generated value can always be larger than
-        // the modulus in order to ensure a uniform distribution
-        if n_bytes < Self::BYTE_SIZE {
-            n_bytes += 1;
-        }
+        let n_bits = modulus.bits();
+        let n_bytes = (n_bits + 7) / 8;
+        let mask = 0xff >> (8 * n_bytes - n_bits);
 
         loop {
             rng.fill_bytes(&mut bytes[..n_bytes]);
-            let n = Limb::from_le_bytes(bytes);
+            bytes[n_bytes - 1] &= mask;
 
+            let n = Limb::from_le_bytes(bytes);
             if n.ct_lt(modulus).into() {
                 return n;
             }