mpi: Add functions to manipulate the sign.

* src/gcrypt.h.in (gcry_mpi_is_neg): New.
(gcry_mpi_neg, gcry_mpi_abs): New.
* mpi/mpiutil.c (_gcry_mpi_is_neg): New.
(_gcry_mpi_neg, _gcry_mpi_abs): New.
* src/visibility.c, src/visibility.h: Add wrappers.
* src/libgcrypt.def, src/libgcrypt.vers: Export them.
* src/mpi.h (mpi_is_neg): New.  Rename old macro to mpi_has_sign.
* mpi/mpi-mod.c (_gcry_mpi_mod_barrett): Use mpi_has_sign.
* mpi/mpi-mpow.c (calc_barrett): Ditto.
* cipher/primegen.c (_gcry_derive_x931_prime): Ditto
* cipher/rsa.c (secret): Ditto.

14 files changed, 112 insertions, 8 deletions

diff --git a/NEWS b/NEWS
index ee737f97..e4fe1eb0 100644
--- a/NEWS
+++ b/NEWS
@@ -46,6 +46,9 @@ Noteworthy changes in version 1.6.0 (unreleased)
  GCRY_RNG_TYPE_STANDARD          NEW.
  GCRY_RNG_TYPE_FIPS              NEW.
  GCRY_RNG_TYPE_SYSTEM            NEW.
+ gcry_mpi_is_neg                 NEW.
+ gcry_mpi_neg                    NEW.
+ gcry_mpi_abs                    NEW.
  gcry_mpi_snatch                 NEW.
  gcry_mpi_point_t                NEW.
  gcry_mpi_point_new              NEW.
@@ -65,6 +68,7 @@ Noteworthy changes in version 1.6.0 (unreleased)
  gcry_mpi_ec_dup                 NEW.
  gcry_mpi_ec_add                 NEW.
  gcry_mpi_ec_mul                 NEW.
+ gcry_mpi_ec_curve_point         NEW.
  GCRYMPI_FLAG_IMMUTABLE          NEW.
  GCRYMPI_FLAG_CONST              NEW.
  GCRYMPI_CONST_ONE               NEW.
diff --git a/cipher/primegen.c b/cipher/primegen.c
index d0cf20c1..3610ae7e 100644
--- a/cipher/primegen.c
+++ b/cipher/primegen.c
@@ -1351,7 +1351,7 @@ _gcry_derive_x931_prime (const gcry_mpi_t xp,
     mpi_sub (r1, r1, tmp);
 
     /* Fixup a negative value.  */
-    if (mpi_is_neg (r1))
+    if (mpi_has_sign (r1))
       mpi_add (r1, r1, p1p2);
 
     /* yp0 = xp + (r1 - xp mod p1*p2)  */
diff --git a/cipher/rsa.c b/cipher/rsa.c
index bb22d059..8d17129c 100644
--- a/cipher/rsa.c
+++ b/cipher/rsa.c
@@ -722,7 +722,7 @@ secret (gcry_mpi_t output, gcry_mpi_t input, RSA_secret_key *skey )
       mpi_powm( m2, input, h, skey->q );
       /* h = u * ( m2 - m1 ) mod q */
       mpi_sub( h, m2, m1 );
-      if ( mpi_is_neg( h ) )
+      if ( mpi_has_sign ( h ) )
         mpi_add ( h, h, skey->q );
       mpi_mulm( h, skey->u, h, skey->q );
       /* m = m2 + h * p */
diff --git a/doc/gcrypt.texi b/doc/gcrypt.texi
index 4c8cdb15..ba9bb02a 100644
--- a/doc/gcrypt.texi
+++ b/doc/gcrypt.texi
@@ -2424,7 +2424,7 @@ For the EdDSA algorithm (cf. Ed25515) the required input parameters are:
 @example
 (data
   (flags eddsa)
-  (hash-algo sha-512)
+  (hash-algo sha512)
   (value @var{message}))
 @end example
 
@@ -3763,6 +3763,17 @@ Set @var{u} into @var{w} and release @var{u}.  If @var{w} is
 @code{NULL} only @var{u} will be released.
 @end deftypefun
 
+@deftypefun void gcry_mpi_neg (@w{gcry_mpi_t @var{w}}, @w{gcry_mpi_t @var{u}})
+
+Set the sign of @var{w} to the negative of @var{u}.
+@end deftypefun
+
+@deftypefun void gcry_mpi_abs (@w{gcry_mpi_t @var{w}})
+
+Clear the sign of @var{w}.
+@end deftypefun
+
+
 @node MPI formats
 @section MPI formats
 
@@ -3949,6 +3960,11 @@ integer @var{v} returning 0 for equality, a positive value for @var{u} >
 @var{v} and a negative for @var{u} < @var{v}.
 @end deftypefun
 
+@deftypefun int gcry_mpi_is_neg (@w{const gcry_mpi_t @var{a}})
+
+Return 1 if @var{a} is less than zero; return 0 if zero or positive.
+@end deftypefun
+
 
 @node Bit manipulations
 @section Bit manipulations
diff --git a/mpi/ec.c b/mpi/ec.c
index 54fa0286..478416fa 100644
--- a/mpi/ec.c
+++ b/mpi/ec.c
@@ -1025,7 +1025,7 @@ _gcry_mpi_ec_mul_point (mpi_point_t result,
   k  = mpi_copy (scalar);
   yy = mpi_copy (point->y);
 
-  if ( mpi_is_neg (k) )
+  if ( mpi_has_sign (k) )
     {
       k->sign = 0;
       ec_invm (yy, yy, ctx);
diff --git a/mpi/mpi-mod.c b/mpi/mpi-mod.c
index 7ebfe6dc..795826e7 100644
--- a/mpi/mpi-mod.c
+++ b/mpi/mpi-mod.c
@@ -157,7 +157,7 @@ _gcry_mpi_mod_barrett (gcry_mpi_t r, gcry_mpi_t x, mpi_barrett_t ctx)
     r2->nlimbs = k+1;
   mpi_sub ( r, r1, r2 );
 
-  if ( mpi_is_neg( r ) )
+  if ( mpi_has_sign ( r ) )
     {
       if (!ctx->r3)
         {
diff --git a/mpi/mpi-mpow.c b/mpi/mpi-mpow.c
index ca5b3f18..ec677fe9 100644
--- a/mpi/mpi-mpow.c
+++ b/mpi/mpi-mpow.c
@@ -204,7 +204,7 @@ calc_barrett( gcry_mpi_t r, gcry_mpi_t x, gcry_mpi_t m, gcry_mpi_t y, int k, gcr
 	r2->nlimbs = k+1;
     mpi_sub( r, r1, r2 );
 
-    if( mpi_is_neg( r ) ) {
+    if( mpi_has_sign (r) ) {
 	gcry_mpi_t tmp;
 
 	tmp = mpi_alloc( k + 2 );
diff --git a/mpi/mpiutil.c b/mpi/mpiutil.c
index a65d2361..433dda6b 100644
--- a/mpi/mpiutil.c
+++ b/mpi/mpiutil.c
@@ -324,6 +324,45 @@ gcry_mpi_copy( gcry_mpi_t a )
 }
 
 
+/* Return true if A is negative.  */
+int
+_gcry_mpi_is_neg (gcry_mpi_t a)
+{
+  if (a->sign && _gcry_mpi_cmp_ui (a, 0))
+    return 1;
+  else
+    return 0;
+}
+
+
+/* W = - U */
+void
+_gcry_mpi_neg (gcry_mpi_t w, gcry_mpi_t u)
+{
+  if (mpi_is_immutable (w))
+    {
+      mpi_immutable_failed ();
+      return;
+    }
+
+  w->sign = !u->sign;
+}
+
+
+/* W = [W] */
+void
+_gcry_mpi_abs (gcry_mpi_t w)
+{
+  if (mpi_is_immutable (w))
+    {
+      mpi_immutable_failed ();
+      return;
+    }
+
+  w->sign = 0;
+}
+
+
 /****************
  * This function allocates an MPI which is optimized to hold
  * a value as large as the one given in the argument and allocates it
diff --git a/src/gcrypt.h.in b/src/gcrypt.h.in
index 06d66639..71c50abf 100644
--- a/src/gcrypt.h.in
+++ b/src/gcrypt.h.in
@@ -508,6 +508,15 @@ gcry_mpi_t gcry_mpi_set_ui (gcry_mpi_t w, unsigned long u);
 /* Swap the values of A and B. */
 void gcry_mpi_swap (gcry_mpi_t a, gcry_mpi_t b);
 
+/* Return 1 if A is negative; 0 if zero or positive.  */
+int gcry_mpi_is_neg (gcry_mpi_t a);
+
+/* W = - U */
+void gcry_mpi_neg (gcry_mpi_t w, gcry_mpi_t u);
+
+/* W = [W] */
+void gcry_mpi_abs (gcry_mpi_t w);
+
 /* Compare the big integer number U and V returning 0 for equality, a
    positive value for U > V and a negative for U < V. */
 int gcry_mpi_cmp (const gcry_mpi_t u, const gcry_mpi_t v);
@@ -661,6 +670,8 @@ void gcry_mpi_ec_add (gcry_mpi_point_t w,
 void gcry_mpi_ec_mul (gcry_mpi_point_t w, gcry_mpi_t n, gcry_mpi_point_t u,
                       gcry_ctx_t ctx);
 
+/* Return true if POINT is on the curve described by CTX.  */
+int gcry_mpi_ec_curve_point (gcry_mpi_point_t w, gcry_ctx_t ctx);
 
 /* Return the number of bits required to represent A. */
 unsigned int gcry_mpi_get_nbits (gcry_mpi_t a);
@@ -728,8 +739,11 @@ gcry_mpi_t _gcry_mpi_get_const (int no);
 #define mpi_snatch( w, u)      gcry_mpi_snatch( (w), (u) )
 #define mpi_set( w, u)         gcry_mpi_set( (w), (u) )
 #define mpi_set_ui( w, u)      gcry_mpi_set_ui( (w), (u) )
+#define mpi_abs( w )           gcry_mpi_abs( (w) )
+#define mpi_neg( w, u)         gcry_mpi_neg( (w), (u) )
 #define mpi_cmp( u, v )        gcry_mpi_cmp( (u), (v) )
 #define mpi_cmp_ui( u, v )     gcry_mpi_cmp_ui( (u), (v) )
+#define mpi_is_neg( a )        gcry_mpi_is_new ((a))
 
 #define mpi_add_ui(w,u,v)      gcry_mpi_add_ui((w),(u),(v))
 #define mpi_add(w,u,v)         gcry_mpi_add ((w),(u),(v))
diff --git a/src/libgcrypt.def b/src/libgcrypt.def
index f275ae91..9539d39a 100644
--- a/src/libgcrypt.def
+++ b/src/libgcrypt.def
@@ -239,5 +239,11 @@ EXPORTS
 
       gcry_sexp_nth_buffer      @214
 
+      gcry_mpi_ec_curve_point   @215
+
+      gcry_mpi_is_neg           @216
+      gcry_mpi_neg              @217
+      gcry_mpi_abs              @218
+
 
 ;; end of file with public symbols for Windows.
diff --git a/src/libgcrypt.vers b/src/libgcrypt.vers
index 473ee68d..9bb7ae2c 100644
--- a/src/libgcrypt.vers
+++ b/src/libgcrypt.vers
@@ -77,6 +77,7 @@ GCRYPT_1.6 {
     gcry_sexp_sprint; gcry_sexp_sscan; gcry_sexp_vlist;
     gcry_sexp_nth_string;
 
+    gcry_mpi_is_neg; gcry_mpi_neg; gcry_mpi_abs;
     gcry_mpi_add; gcry_mpi_add_ui; gcry_mpi_addm; gcry_mpi_aprint;
     gcry_mpi_clear_bit; gcry_mpi_clear_flag; gcry_mpi_clear_highbit;
     gcry_mpi_cmp; gcry_mpi_cmp_ui; gcry_mpi_copy; gcry_mpi_div;
@@ -96,7 +97,7 @@ GCRYPT_1.6 {
     gcry_mpi_ec_get_mpi; gcry_mpi_ec_get_point;
     gcry_mpi_ec_set_mpi; gcry_mpi_ec_set_point;
     gcry_mpi_ec_get_affine;
-    gcry_mpi_ec_dup; gcry_mpi_ec_add; gcry_mpi_ec_mul;
+    gcry_mpi_ec_dup; gcry_mpi_ec_add; gcry_mpi_ec_mul; gcry_mpi_ec_curve_point;
 
     _gcry_mpi_get_const;
 
diff --git a/src/mpi.h b/src/mpi.h
index 0114dba7..09ba7170 100644
--- a/src/mpi.h
+++ b/src/mpi.h
@@ -78,7 +78,7 @@ struct gcry_mpi
 #define MPI_NULL NULL
 
 #define mpi_get_nlimbs(a)     ((a)->nlimbs)
-#define mpi_is_neg(a)	      ((a)->sign)
+#define mpi_has_sign(a)	      ((a)->sign)
 
 /*-- mpiutil.c --*/
 
@@ -134,6 +134,9 @@ void _gcry_mpi_m_check( gcry_mpi_t a );
 void _gcry_mpi_swap( gcry_mpi_t a, gcry_mpi_t b);
 gcry_mpi_t _gcry_mpi_new (unsigned int nbits);
 gcry_mpi_t _gcry_mpi_snew (unsigned int nbits);
+int _gcry_mpi_is_neg (gcry_mpi_t a);
+void _gcry_mpi_neg (gcry_mpi_t w, gcry_mpi_t u);
+void _gcry_mpi_abs (gcry_mpi_t w);
 
 /* Constants used to return constant MPIs.  See _gcry_mpi_init if you
    want to add more constants. */
diff --git a/src/visibility.c b/src/visibility.c
index bb51d58e..0e244117 100644
--- a/src/visibility.c
+++ b/src/visibility.c
@@ -293,6 +293,24 @@ gcry_mpi_swap (gcry_mpi_t a, gcry_mpi_t b)
 }
 
 int
+gcry_mpi_is_neg (gcry_mpi_t a)
+{
+  return _gcry_mpi_is_neg (a);
+}
+
+void
+gcry_mpi_neg (gcry_mpi_t w, gcry_mpi_t u)
+{
+  _gcry_mpi_neg (w, u);
+}
+
+void
+gcry_mpi_abs (gcry_mpi_t w)
+{
+  _gcry_mpi_abs (w);
+}
+
+int
 gcry_mpi_cmp (const gcry_mpi_t u, const gcry_mpi_t v)
 {
   return _gcry_mpi_cmp (u, v);
diff --git a/src/visibility.h b/src/visibility.h
index 54da016f..a6cb3dcf 100644
--- a/src/visibility.h
+++ b/src/visibility.h
@@ -536,6 +536,7 @@ MARK_VISIBLE (gcry_sexp_sprint)
 MARK_VISIBLE (gcry_sexp_sscan)
 MARK_VISIBLE (gcry_sexp_vlist)
 
+MARK_VISIBLEX(gcry_mpi_abs)
 MARK_VISIBLE (gcry_mpi_add)
 MARK_VISIBLE (gcry_mpi_add_ui)
 MARK_VISIBLE (gcry_mpi_addm)
@@ -561,12 +562,14 @@ MARK_VISIBLE (gcry_mpi_gcd)
 MARK_VISIBLE (gcry_mpi_get_flag)
 MARK_VISIBLE (gcry_mpi_get_nbits)
 MARK_VISIBLE (gcry_mpi_get_opaque)
+MARK_VISIBLEX(gcry_mpi_is_neg)
 MARK_VISIBLE (gcry_mpi_invm)
 MARK_VISIBLE (gcry_mpi_mod)
 MARK_VISIBLE (gcry_mpi_mul)
 MARK_VISIBLE (gcry_mpi_mul_2exp)
 MARK_VISIBLE (gcry_mpi_mul_ui)
 MARK_VISIBLE (gcry_mpi_mulm)
+MARK_VISIBLEX(gcry_mpi_neg)
 MARK_VISIBLE (gcry_mpi_new)
 MARK_VISIBLE (gcry_mpi_point_get)
 MARK_VISIBLE (gcry_mpi_point_new)