1 files changed, 24 insertions, 6 deletions

diff --git a/src/crypto/fipsmodule/bn/mul.c b/src/crypto/fipsmodule/bn/mul.c
index 352b7e5f..4a0711d8 100644
--- a/src/crypto/fipsmodule/bn/mul.c
+++ b/src/crypto/fipsmodule/bn/mul.c
@@ -306,6 +306,24 @@ static BN_ULONG bn_abs_sub_part_words(BN_ULONG *r, const BN_ULONG *a,
   return borrow;
 }
 
+int bn_abs_sub_consttime(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
+                         BN_CTX *ctx) {
+  int cl = a->width < b->width ? a->width : b->width;
+  int dl = a->width - b->width;
+  int r_len = a->width < b->width ? b->width : a->width;
+  BN_CTX_start(ctx);
+  BIGNUM *tmp = BN_CTX_get(ctx);
+  int ok = tmp != NULL &&
+           bn_wexpand(r, r_len) &&
+           bn_wexpand(tmp, r_len);
+  if (ok) {
+    bn_abs_sub_part_words(r->d, a->d, b->d, cl, dl, tmp->d);
+    r->width = r_len;
+  }
+  BN_CTX_end(ctx);
+  return ok;
+}
+
 // Karatsuba recursive multiplication algorithm
 // (cf. Knuth, The Art of Computer Programming, Vol. 2)
 
@@ -523,9 +541,9 @@ static void bn_mul_part_recursive(BN_ULONG *r, const BN_ULONG *a,
   assert(c == 0);
 }
 
-// bn_mul_impl implements |BN_mul| and |bn_mul_fixed|. Note this function breaks
-// |BIGNUM| invariants and may return a negative zero. This is handled by the
-// callers.
+// bn_mul_impl implements |BN_mul| and |bn_mul_consttime|. Note this function
+// breaks |BIGNUM| invariants and may return a negative zero. This is handled by
+// the callers.
 static int bn_mul_impl(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
                        BN_CTX *ctx) {
   int al = a->width;
@@ -628,7 +646,7 @@ int BN_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx) {
   return 1;
 }
 
-int bn_mul_fixed(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx) {
+int bn_mul_consttime(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx) {
   // Prevent negative zeros.
   if (a->neg || b->neg) {
     OPENSSL_PUT_ERROR(BN, BN_R_NEGATIVE_NUMBER);
@@ -773,7 +791,7 @@ int BN_mul_word(BIGNUM *bn, BN_ULONG w) {
   return 1;
 }
 
-int bn_sqr_fixed(BIGNUM *r, const BIGNUM *a, BN_CTX *ctx) {
+int bn_sqr_consttime(BIGNUM *r, const BIGNUM *a, BN_CTX *ctx) {
   int al = a->width;
   if (al <= 0) {
     r->width = 0;
@@ -832,7 +850,7 @@ err:
 }
 
 int BN_sqr(BIGNUM *r, const BIGNUM *a, BN_CTX *ctx) {
-  if (!bn_sqr_fixed(r, a, ctx)) {
+  if (!bn_sqr_consttime(r, a, ctx)) {
     return 0;
   }