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

diff --git a/crypto/bn/bn_gf2m.c b/crypto/bn/bn_gf2m.c
index 0bfb56971e3362eadbe248864dea15f30eefd6c6..e54a701166a5f65e6aa535d80a58a9bdf17e21ef 100644 (file)
--- a/crypto/bn/bn_gf2m.c
+++ b/crypto/bn/bn_gf2m.c
@@ -631,8 +631,11 @@ int BN_GF2m_mod_inv(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx)
                        }
                if (ubits==vbits)
                        {
-                       bn_correct_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_correct_top(b);