diff --git a/SOURCES/nettle-3.4.1-ecdsa-verify.patch b/SOURCES/nettle-3.4.1-ecdsa-verify.patch
new file mode 100644
index 0000000..c46f185
--- /dev/null
+++ b/SOURCES/nettle-3.4.1-ecdsa-verify.patch
@@ -0,0 +1,109 @@
+From 932ea29845da1ae350d9c056cb2cb0379a66d642 Mon Sep 17 00:00:00 2001
+From: Daiki Ueno <dueno@redhat.com>
+Date: Tue, 30 Mar 2021 09:22:47 +0200
+Subject: [PATCH] Port upstream hardening of EC scaler multiplication
+
+Some internal functions used in point multiplications are known to
+misbehave if the scaler is out-of-range. This performs canonical
+reduction on scalers, before point multiplication.
+
+Signed-off-by: Daiki Ueno <dueno@redhat.com>
+---
+ ecc-ecdsa-sign.c | 7 +++++--
+ ecc-ecdsa-verify.c | 14 ++++++++++++--
+ eddsa-hash.c | 9 +++++++--
+ 3 files changed, 24 insertions(+), 6 deletions(-)
+
+diff --git a/ecc-ecdsa-sign.c b/ecc-ecdsa-sign.c
+index 3b9e9cc1..45062528 100644
+--- a/ecc-ecdsa-sign.c
++++ b/ecc-ecdsa-sign.c
+@@ -62,6 +62,8 @@ ecc_ecdsa_sign (const struct ecc_curve *ecc,
+ mp_limb_t *rp, mp_limb_t *sp,
+ mp_limb_t *scratch)
+ {
++ mp_limb_t cy;
++
+ #define P scratch
+ #define kinv scratch /* Needs 5*ecc->p.size for computation */
+ #define hp (scratch + ecc->p.size) /* NOTE: ecc->p.size + 1 limbs! */
+@@ -91,8 +93,9 @@ ecc_ecdsa_sign (const struct ecc_curve *ecc,
+ ecc_modq_mul (ecc, tp, zp, rp);
+ ecc_modq_add (ecc, hp, hp, tp);
+ ecc_modq_mul (ecc, tp, hp, kinv);
+-
+- mpn_copyi (sp, tp, ecc->p.size);
++ /* Ensure canonical reduction. */
++ cy = mpn_sub_n (sp, tp, ecc->q.m, ecc->q.size);
++ cnd_copy (cy, sp, tp, ecc->q.size);
+ #undef P
+ #undef hp
+ #undef kinv
+diff --git a/ecc-ecdsa-verify.c b/ecc-ecdsa-verify.c
+index d7f5b684..6b8acb07 100644
+--- a/ecc-ecdsa-verify.c
++++ b/ecc-ecdsa-verify.c
+@@ -75,6 +75,8 @@ ecc_ecdsa_verify (const struct ecc_curve *ecc,
+ const mp_limb_t *rp, const mp_limb_t *sp,
+ mp_limb_t *scratch)
+ {
++ mp_limb_t cy;
++
+ /* Procedure, according to RFC 6090, "KT-I". q denotes the group
+ order.
+
+@@ -98,6 +100,7 @@ ecc_ecdsa_verify (const struct ecc_curve *ecc,
+ #define P1 (scratch + 4*ecc->p.size)
+ #define sinv (scratch)
+ #define hp (scratch + ecc->p.size)
++#define tp (scratch + 4*ecc->p.size)
+
+ if (! (ecdsa_in_range (ecc, rp)
+ && ecdsa_in_range (ecc, sp)))
+@@ -112,10 +115,16 @@ ecc_ecdsa_verify (const struct ecc_curve *ecc,
+
+ /* u1 = h / s, P1 = u1 * G */
+ ecc_hash (&ecc->q, hp, length, digest);
+- ecc_modq_mul (ecc, u1, hp, sinv);
++ ecc_modq_mul (ecc, tp, hp, sinv);
++ /* Ensure canonical reduction. */
++ cy = mpn_sub_n (u1, tp, ecc->q.m, ecc->q.size);
++ cnd_copy (cy, u1, tp, ecc->q.size);
+
+ /* u2 = r / s, P2 = u2 * Y */
+- ecc_modq_mul (ecc, u2, rp, sinv);
++ ecc_modq_mul (ecc, hp, rp, sinv);
++ /* Ensure canonical reduction. */
++ cy = mpn_sub_n (u2, hp, ecc->q.m, ecc->q.size);
++ cnd_copy (cy, u2, hp, ecc->q.size);
+
+ /* Total storage: 5*ecc->p.size + ecc->mul_itch */
+ ecc->mul (ecc, P2, u2, pp, u2 + ecc->p.size);
+@@ -154,4 +163,5 @@ ecc_ecdsa_verify (const struct ecc_curve *ecc,
+ #undef u2
+ #undef hp
+ #undef u1
++#undef tp
+ }
+diff --git a/eddsa-hash.c b/eddsa-hash.c
+index 4fb79f1b..53c6fc49 100644
+--- a/eddsa-hash.c
++++ b/eddsa-hash.c
+@@ -45,7 +45,12 @@ void
+ _eddsa_hash (const struct ecc_modulo *m,
+ mp_limb_t *rp, const uint8_t *digest)
+ {
++ mp_limb_t cy;
++
+ size_t nbytes = 1 + m->bit_size / 8;
+- mpn_set_base256_le (rp, 2*m->size, digest, 2*nbytes);
+- m->mod (m, rp);
++ mpn_set_base256_le (rp + m->size, 2*m->size, digest, 2*nbytes);
++ m->mod (m, rp + m->size);
++ /* Ensure canonical reduction. */
++ cy = mpn_sub_n (rp, rp + m->size, m->m, m->size);
++ cnd_copy (cy, rp, rp + m->size, m->size);
+ }
+--
+2.30.2
+
diff --git a/SPECS/nettle.spec b/SPECS/nettle.spec
index 814ab18..c3443f0 100644
--- a/SPECS/nettle.spec
+++ b/SPECS/nettle.spec
@@ -2,7 +2,7 @@
Name: nettle
Version: 3.4.1
-Release: 2%{?dist}
+Release: 4%{?dist}
Summary: A low-level cryptographic library
Group: Development/Libraries
@@ -13,6 +13,8 @@ Source0: %{name}-%{version}-hobbled.tar.xz
Patch0: nettle-3.3-remove-ecc-testsuite.patch
Patch1: nettle-3.4-annocheck.patch
Patch2: nettle-3.4.1-enable-intel-cet.patch
+# https://lists.lysator.liu.se/pipermail/nettle-bugs/2021/009458.html
+Patch3: nettle-3.4.1-ecdsa-verify.patch
BuildRequires: gcc
BuildRequires: gmp-devel, m4
@@ -54,6 +56,7 @@ sed 's/ecc-224.c//g' -i Makefile.in
%patch0 -p1
%patch1 -p1
%patch2 -p1
+%patch3 -p1
%build
autoreconf -ifv
@@ -126,6 +129,12 @@ fi
%changelog
+* Wed Apr 7 2021 Daiki Ueno <dueno@redhat.com> - 3.4.1-4
+- Fix patch application
+
+* Tue Mar 30 2021 Daiki Ueno <dueno@redhat.com> - 3.4.1-3
+- Port fixes for potential miscalculation in ecdsa_verify (#1942924)
+
* Fri May 15 2020 Anderson Sasaki <ansasaki@redhat.com> - 3.4.1-2
- Enable Intel CET support (#1737542)