Make BN_BLINDING internal

RSA is pretty bad. In my most optimistic moments I dream of a world that
stopped using it. That won't happen during my lifetime, unfortunately.
Blinding is one way of making it a little less leaky. Unfortunately this
side-channel leak mitigation leaked out of the library for no good reason.
Let's at least fix that aspect of it.

ok jsing

1 files changed, 22 insertions, 1 deletions

diff --git a/src/lib/libcrypto/bn/bn_local.h b/src/lib/libcrypto/bn/bn_local.h
index a8d40fbcc8..989770f2d6 100644
--- a/src/lib/libcrypto/bn/bn_local.h
+++ b/src/lib/libcrypto/bn/bn_local.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: bn_local.h,v 1.26 2023/07/09 18:27:22 tb Exp $ */
+/* $OpenBSD: bn_local.h,v 1.27 2023/07/28 10:05:16 tb Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -291,6 +291,27 @@ int	BN_mod_exp_recp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
 int     BN_div_recp(BIGNUM *dv, BIGNUM *rem, const BIGNUM *m,
     BN_RECP_CTX *recp, BN_CTX *ctx);
 
+/* BN_BLINDING flags */
+#define BN_BLINDING_NO_UPDATE   0x00000001
+#define BN_BLINDING_NO_RECREATE 0x00000002
+
+BN_BLINDING *BN_BLINDING_new(const BIGNUM *A, const BIGNUM *Ai, BIGNUM *mod);
+void BN_BLINDING_free(BN_BLINDING *b);
+int BN_BLINDING_update(BN_BLINDING *b, BN_CTX *ctx);
+int BN_BLINDING_convert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx);
+int BN_BLINDING_invert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx);
+int BN_BLINDING_convert_ex(BIGNUM *n, BIGNUM *r, BN_BLINDING *b, BN_CTX *);
+int BN_BLINDING_invert_ex(BIGNUM *n, const BIGNUM *r, BN_BLINDING *b, BN_CTX *);
+
+CRYPTO_THREADID *BN_BLINDING_thread_id(BN_BLINDING *);
+unsigned long BN_BLINDING_get_flags(const BN_BLINDING *);
+void BN_BLINDING_set_flags(BN_BLINDING *, unsigned long);
+BN_BLINDING *BN_BLINDING_create_param(BN_BLINDING *b,
+    const BIGNUM *e, BIGNUM *m, BN_CTX *ctx,
+    int (*bn_mod_exp)(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
+    const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx),
+    BN_MONT_CTX *m_ctx);
+
 /* Explicitly const time / non-const time versions for internal use */
 int BN_mod_exp_ct(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
     const BIGNUM *m, BN_CTX *ctx);