From: Niels Möller <nisse@lysator.liu.se>
Date: Tue, 3 Nov 2020 19:26:34 +0000 (+0100)
Subject: Stricter requirements for in-place ecc_add_func.
X-Git-Tag: nettle_3.7rc1~52^2~15
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4031de2dc0405d6d0218b8c410f92e9f5583b247;p=thirdparty%2Fnettle.git

Stricter requirements for in-place ecc_add_func.
---

diff --git a/ChangeLog b/ChangeLog
index f44401fb..025403c9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
 2020-11-03  Niels Möller  <nisse@lysator.liu.se>
 
+	* ecc-internal.h (ecc_add_func): Document in-place operation.
+	* ecc-mul-a-eh.c (ecc_mul_a_eh): Fix call to ecc->add_hhh accordingly.
+	* testsuite/ecc-add-test.c (test_main): Likewise.
+
 	* ecc-add-eh.c (ecc_add_eh): Reduce scratch need.
 	* ecc-add-th.c (ecc_add_th): Analogous changes.
 	* ecc-internal.h (ECC_ADD_EH_ITCH, ECC_ADD_TH_ITCH): Now 4*size.
diff --git a/ecc-internal.h b/ecc-internal.h
index 0afd7c6b..6dba06d1 100644
--- a/ecc-internal.h
+++ b/ecc-internal.h
@@ -129,6 +129,7 @@ typedef int ecc_mod_sqrt_func (const struct ecc_modulo *m,
 			       const mp_limb_t *up, const mp_limb_t *vp,
 			       mp_limb_t *scratch);
 
+/* Allows in-place operation with r == p, but not r == q */
 typedef void ecc_add_func (const struct ecc_curve *ecc,
 			   mp_limb_t *r,
 			   const mp_limb_t *p, const mp_limb_t *q,
diff --git a/ecc-mul-a-eh.c b/ecc-mul-a-eh.c
index d7765ebf..b0aa2697 100644
--- a/ecc-mul-a-eh.c
+++ b/ecc-mul-a-eh.c
@@ -167,7 +167,7 @@ ecc_mul_a_eh (const struct ecc_curve *ecc,
 
       bits &= TABLE_MASK;
       sec_tabselect (tp, 3*ecc->p.size, table, TABLE_SIZE, bits);
-      ecc->add_hhh (ecc, r, tp, r, scratch_out);
+      ecc->add_hhh (ecc, r, r, tp, scratch_out);
     }
 #undef table
 #undef tp
diff --git a/testsuite/ecc-add-test.c b/testsuite/ecc-add-test.c
index d3b0bd92..6f58a3bb 100644
--- a/testsuite/ecc-add-test.c
+++ b/testsuite/ecc-add-test.c
@@ -35,7 +35,7 @@ test_main (void)
 	  ecc->add_hh (ecc, p, z, z, scratch);
 	  test_ecc_mul_h (i, 0, p);
 
-	  ecc->add_hhh (ecc, p, g, p, scratch);
+	  ecc->add_hhh (ecc, p, p, g, scratch);
 	  test_ecc_mul_h (i, 1, p);
 
 	  ecc->add_hh (ecc, p, z, g, scratch);