More optblocker usage

jedisct1 · Oct 23, 2024 · 1deb0b8 · 1deb0b8
1 parent b1f9c53
commit 1deb0b8
Showing 1 changed file with 3 additions and 4 deletions.
diff --git a/src/libsodium/crypto_core/ed25519/ref10/ed25519_ref10.c b/src/libsodium/crypto_core/ed25519/ref10/ed25519_ref10.c
@@ -321,6 +321,7 @@ slide_vartime(signed char *r, const unsigned char *a)
 }
 
 static volatile unsigned char optblocker_u8;
+static volatile uint64_t optblocker_u64;
 
 int
 ge25519_frombytes(ge25519_p3 *h, const unsigned char *s)
@@ -619,11 +620,9 @@ static unsigned char
 negative(signed char b)
 {
     /* 18446744073709551361..18446744073709551615: yes; 0..255: no */
-    uint64_t x = b;
+    const uint64_t x = (uint64_t) b;
 
-    x >>= 63; /* 1: yes; 0: no */
-
-    return x;
+    return ((x >> 61) ^ optblocker_u64) >> 2; /* 1: yes; 0: no */
 }
 
 static void