bn/bn_gf2m.c: make new BN_GF2m_mod_inv work with BN_DEBUG_RAND.

[openssl.git] / crypto / bn / bn_gf2m.c

diff --git a/crypto/bn/bn_gf2m.c b/crypto/bn/bn_gf2m.c
index d0e03f87daea4bbcc6d343ac9a3faff9911699da..e54a701166a5f65e6aa535d80a58a9bdf17e21ef 100644 (file)
--- a/crypto/bn/bn_gf2m.c
+++ b/crypto/bn/bn_gf2m.c
@@ -101,6 +101,7 @@
 /* Maximum number of iterations before BN_GF2m_mod_solve_quad_arr should fail. */
 #define MAX_ITERATIONS 50
 
+__fips_constseg
 static const BN_ULONG SQR_tb[16] =
   {     0,     1,     4,     5,    16,    17,    20,    21,
        64,    65,    68,    69,    80,    81,    84,    85 };
@@ -524,7 +525,7 @@ err:
  */
 int BN_GF2m_mod_inv(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx)
        {
-       BIGNUM *b, *c, *u, *v, *tmp;
+       BIGNUM *b, *c = NULL, *u = NULL, *v = NULL, *tmp;
        int ret = 0;
 
        bn_check_top(a);
@@ -630,11 +631,14 @@ int BN_GF2m_mod_inv(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx)
                        }
                if (ubits==vbits)
                        {
-                       bn_fix_top(u);
-                       ubits = BN_num_bits(u);
+                       BN_ULONG u;
+                       int utop = (ubits-1)/BN_BITS2;
+
+                       while ((u=udp[utop])==0 && utop) utop--;
+                       ubits = utop*BN_BITS2 + BN_num_bits_word(u);
                        }
                }
-       bn_fix_top(b);
+       bn_correct_top(b);
        }
 #endif
 
@@ -643,6 +647,11 @@ int BN_GF2m_mod_inv(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx)
        ret = 1;
 
 err:
+#ifdef BN_DEBUG /* BN_CTX_end would complain about the expanded form */
+        bn_correct_top(c);
+        bn_correct_top(u);
+        bn_correct_top(v);
+#endif
        BN_CTX_end(ctx);
        return ret;
        }