1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
|
Backport of:
From a63893791280d441c713293491da97c79c0950fe Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niels=20M=C3=B6ller?= <nisse@lysator.liu.se>
Date: Thu, 11 Mar 2021 19:37:41 +0100
Subject: [PATCH] New functions ecc_mod_mul_canonical and
ecc_mod_sqr_canonical.
* ecc-mod-arith.c (ecc_mod_mul_canonical, ecc_mod_sqr_canonical):
New functions.
* ecc-internal.h: Declare and document new functions.
* curve448-eh-to-x.c (curve448_eh_to_x): Use ecc_mod_sqr_canonical.
* curve25519-eh-to-x.c (curve25519_eh_to_x): Use ecc_mod_mul_canonical.
* ecc-eh-to-a.c (ecc_eh_to_a): Likewise.
* ecc-j-to-a.c (ecc_j_to_a): Likewise.
* ecc-mul-m.c (ecc_mul_m): Likewise.
(cherry picked from commit 2bf497ba4d6acc6f352bca015837fad33008565c)
Upstream-Status: Backport
https://sources.debian.org/data/main/n/nettle/3.4.1-1%2Bdeb10u1/debian/patches/CVE-2021-20305-1.patch
CVE: CVE-2021-20305 dep1
Signed-off-by: Armin Kuster <akuster@mvista.com>
---
ChangeLog | 11 +++++++++++
curve25519-eh-to-x.c | 6 +-----
curve448-eh-to-x.c | 5 +----
ecc-eh-to-a.c | 12 ++----------
ecc-internal.h | 15 +++++++++++++++
ecc-j-to-a.c | 15 +++------------
ecc-mod-arith.c | 24 ++++++++++++++++++++++++
ecc-mul-m.c | 6 ++----
8 files changed, 59 insertions(+), 35 deletions(-)
#diff --git a/ChangeLog b/ChangeLog
#index fd138d82..5cc5c188 100644
#--- a/ChangeLog
#+++ b/ChangeLog
#@@ -1,3 +1,14 @@
#+2021-03-11 Niels Möller <nisse@lysator.liu.se>
#+
#+ * ecc-mod-arith.c (ecc_mod_mul_canonical, ecc_mod_sqr_canonical):
#+ New functions.
#+ * ecc-internal.h: Declare and document new functions.
#+ * curve448-eh-to-x.c (curve448_eh_to_x): Use ecc_mod_sqr_canonical.
#+ * curve25519-eh-to-x.c (curve25519_eh_to_x): Use ecc_mod_mul_canonical.
#+ * ecc-eh-to-a.c (ecc_eh_to_a): Likewise.
#+ * ecc-j-to-a.c (ecc_j_to_a): Likewise.
#+ * ecc-mul-m.c (ecc_mul_m): Likewise.
#+
# 2021-02-17 Niels Möller <nisse@lysator.liu.se>
#
# * Released Nettle-3.7.1.
Index: nettle-3.5.1/curve25519-eh-to-x.c
===================================================================
--- nettle-3.5.1.orig/curve25519-eh-to-x.c
+++ nettle-3.5.1/curve25519-eh-to-x.c
@@ -53,7 +53,6 @@ curve25519_eh_to_x (mp_limb_t *xp, const
#define t2 (scratch + 2*ecc->p.size)
const struct ecc_curve *ecc = &_nettle_curve25519;
- mp_limb_t cy;
/* If u = U/W and v = V/W are the coordiantes of the point on the
Edwards curve we get the curve25519 x coordinate as
@@ -69,10 +68,7 @@ curve25519_eh_to_x (mp_limb_t *xp, const
ecc->p.invert (&ecc->p, t1, t0, t2 + ecc->p.size);
ecc_modp_add (ecc, t0, wp, vp);
- ecc_modp_mul (ecc, t2, t0, t1);
-
- cy = mpn_sub_n (xp, t2, ecc->p.m, ecc->p.size);
- cnd_copy (cy, xp, t2, ecc->p.size);
+ ecc_mod_mul_canonical (&ecc->p, xp, t0, t1, t2);
#undef vp
#undef wp
#undef t0
Index: nettle-3.5.1/ecc-eh-to-a.c
===================================================================
--- nettle-3.5.1.orig/ecc-eh-to-a.c
+++ nettle-3.5.1/ecc-eh-to-a.c
@@ -59,9 +59,7 @@ ecc_eh_to_a (const struct ecc_curve *ecc
/* Needs 2*size + scratch for the invert call. */
ecc->p.invert (&ecc->p, izp, zp, tp + ecc->p.size);
- ecc_modp_mul (ecc, tp, xp, izp);
- cy = mpn_sub_n (r, tp, ecc->p.m, ecc->p.size);
- cnd_copy (cy, r, tp, ecc->p.size);
+ ecc_mod_mul_canonical (&ecc->p, r, xp, izp, tp);
if (op)
{
@@ -81,7 +79,5 @@ ecc_eh_to_a (const struct ecc_curve *ecc
}
return;
}
- ecc_modp_mul (ecc, tp, yp, izp);
- cy = mpn_sub_n (r + ecc->p.size, tp, ecc->p.m, ecc->p.size);
- cnd_copy (cy, r + ecc->p.size, tp, ecc->p.size);
+ ecc_mod_mul_canonical (&ecc->p, r + ecc->p.size, yp, izp, tp);
}
Index: nettle-3.5.1/ecc-internal.h
===================================================================
--- nettle-3.5.1.orig/ecc-internal.h
+++ nettle-3.5.1/ecc-internal.h
@@ -49,6 +49,8 @@
#define ecc_mod_submul_1 _nettle_ecc_mod_submul_1
#define ecc_mod_mul _nettle_ecc_mod_mul
#define ecc_mod_sqr _nettle_ecc_mod_sqr
+#define ecc_mod_mul_canonical _nettle_ecc_mod_mul_canonical
+#define ecc_mod_sqr_canonical _nettle_ecc_mod_sqr_canonical
#define ecc_mod_random _nettle_ecc_mod_random
#define ecc_mod _nettle_ecc_mod
#define ecc_mod_inv _nettle_ecc_mod_inv
@@ -263,6 +265,19 @@ ecc_mod_sqr (const struct ecc_modulo *m,
#define ecc_modq_mul(ecc, r, a, b) \
ecc_mod_mul (&(ecc)->q, (r), (a), (b))
+/* These mul and sqr functions produce a canonical result, 0 <= R < M.
+ Requirements on input and output areas are similar to the above
+ functions, except that it is *not* allowed to pass rp = rp +
+ m->size.
+ */
+void
+ecc_mod_mul_canonical (const struct ecc_modulo *m, mp_limb_t *rp,
+ const mp_limb_t *ap, const mp_limb_t *bp, mp_limb_t *tp);
+
+void
+ecc_mod_sqr_canonical (const struct ecc_modulo *m, mp_limb_t *rp,
+ const mp_limb_t *ap, mp_limb_t *tp);
+
/* mod q operations. */
void
ecc_mod_random (const struct ecc_modulo *m, mp_limb_t *xp,
Index: nettle-3.5.1/ecc-j-to-a.c
===================================================================
--- nettle-3.5.1.orig/ecc-j-to-a.c
+++ nettle-3.5.1/ecc-j-to-a.c
@@ -51,8 +51,6 @@ ecc_j_to_a (const struct ecc_curve *ecc,
#define izBp (scratch + 3*ecc->p.size)
#define tp scratch
- mp_limb_t cy;
-
if (ecc->use_redc)
{
/* Set v = (r_z / B^2)^-1,
@@ -86,17 +84,14 @@ ecc_j_to_a (const struct ecc_curve *ecc,
ecc_modp_sqr (ecc, iz2p, izp);
}
- ecc_modp_mul (ecc, iz3p, iz2p, p);
- /* ecc_modp (and ecc_modp_mul) may return a value up to 2p - 1, so
- do a conditional subtraction. */
- cy = mpn_sub_n (r, iz3p, ecc->p.m, ecc->p.size);
- cnd_copy (cy, r, iz3p, ecc->p.size);
+ ecc_mod_mul_canonical (&ecc->p, r, iz2p, p, iz3p);
if (op)
{
/* Skip y coordinate */
if (op > 1)
{
+ mp_limb_t cy;
/* Also reduce the x coordinate mod ecc->q. It should
already be < 2*ecc->q, so one subtraction should
suffice. */
@@ -106,10 +101,7 @@ ecc_j_to_a (const struct ecc_curve *ecc,
return;
}
ecc_modp_mul (ecc, iz3p, iz2p, izp);
- ecc_modp_mul (ecc, tp, iz3p, p + ecc->p.size);
- /* And a similar subtraction. */
- cy = mpn_sub_n (r + ecc->p.size, tp, ecc->p.m, ecc->p.size);
- cnd_copy (cy, r + ecc->p.size, tp, ecc->p.size);
+ ecc_mod_mul_canonical (&ecc->p, r + ecc->p.size, iz3p, p + ecc->p.size, iz3p);
#undef izp
#undef up
Index: nettle-3.5.1/ecc-mod-arith.c
===================================================================
--- nettle-3.5.1.orig/ecc-mod-arith.c
+++ nettle-3.5.1/ecc-mod-arith.c
@@ -119,6 +119,30 @@ ecc_mod_mul (const struct ecc_modulo *m,
}
void
+ecc_mod_mul_canonical (const struct ecc_modulo *m, mp_limb_t *rp,
+ const mp_limb_t *ap, const mp_limb_t *bp, mp_limb_t *tp)
+{
+ mp_limb_t cy;
+ mpn_mul_n (tp + m->size, ap, bp, m->size);
+ m->reduce (m, tp + m->size);
+
+ cy = mpn_sub_n (rp, tp + m->size, m->m, m->size);
+ cnd_copy (cy, rp, tp + m->size, m->size);
+}
+
+void
+ecc_mod_sqr_canonical (const struct ecc_modulo *m, mp_limb_t *rp,
+ const mp_limb_t *ap, mp_limb_t *tp)
+{
+ mp_limb_t cy;
+ mpn_sqr (tp + m->size, ap, m->size);
+ m->reduce (m, tp + m->size);
+
+ cy = mpn_sub_n (rp, tp + m->size, m->m, m->size);
+ cnd_copy (cy, rp, tp + m->size, m->size);
+}
+
+void
ecc_mod_sqr (const struct ecc_modulo *m, mp_limb_t *rp,
const mp_limb_t *ap)
{
|
