[openssl] OpenSSL_1_1_0-stable update

nic.tuv at gmail.com nic.tuv at gmail.com
Wed Feb 20 18:06:57 UTC 2019


The branch OpenSSL_1_1_0-stable has been updated
       via  b7fc0784c4cfe81db8728f814925c6f98dd948d1 (commit)
       via  09c11fe59b3d45d35e61d95d0f3a5a371f96a19d (commit)
      from  68be523db761867cde2c5476cf43f8766c593b2a (commit)


- Log -----------------------------------------------------------------
commit b7fc0784c4cfe81db8728f814925c6f98dd948d1
Author: Nicola Tuveri <nic.tuv at gmail.com>
Date:   Mon Feb 18 03:46:54 2019 +0200

    [test] unit test for field_inv function pointer in EC_METHOD
    
    This is a rewrite of commit 8f58ede09572dcc6a7e6c01280dd348240199568 for
    the 1.1.0-stable branch.
    
    Co-authored-by: Billy Brumley <bbrumley at gmail.com>
    
    Reviewed-by: Matt Caswell <matt at openssl.org>
    (Merged from https://github.com/openssl/openssl/pull/8263)

commit 09c11fe59b3d45d35e61d95d0f3a5a371f96a19d
Author: Billy Brumley <bbrumley at gmail.com>
Date:   Sat Feb 2 10:53:29 2019 +0200

    SCA hardening for mod. field inversion in EC_GROUP
    
    This commit adds a dedicated function in `EC_METHOD` to access a modular
    field inversion implementation suitable for the specifics of the
    implemented curve, featuring SCA countermeasures.
    
    The new pointer is defined as:
    `int (*field_inv)(const EC_GROUP*, BIGNUM *r, const BIGNUM *a, BN_CTX*)`
    and computes the multiplicative inverse of `a` in the underlying field,
    storing the result in `r`.
    
    Three implementations are included, each including specific SCA
    countermeasures:
      - `ec_GFp_simple_field_inv()`, featuring SCA hardening through
        blinding.
      - `ec_GFp_mont_field_inv()`, featuring SCA hardening through Fermat's
        Little Theorem (FLT) inversion.
      - `ec_GF2m_simple_field_inv()`, that uses `BN_GF2m_mod_inv()` which
        already features SCA hardening through blinding.
    
    From a security point of view, this also helps addressing a leakage
    previously affecting conversions from projective to affine coordinates.
    
    This commit also adds a new error reason code (i.e.,
    `EC_R_CANNOT_INVERT`) to improve consistency between the three
    implementations as all of them could fail for the same reason but
    through different code paths resulting in inconsistent error stack
    states.
    
    Co-authored-by: Nicola Tuveri <nic.tuv at gmail.com>
    
    (cherry picked from commit e0033efc30b0f00476bba8f0fa5512be5dc8a3f1)
    
    Reviewed-by: Matt Caswell <matt at openssl.org>
    Reviewed-by: Nicola Tuveri <nic.tuv at gmail.com>
    (Merged from https://github.com/openssl/openssl/pull/8263)

-----------------------------------------------------------------------

Summary of changes:
 CHANGES                            |   6 +
 crypto/ec/ec2_smpl.c               | 140 ++++++++++++-----------
 crypto/ec/ec_err.c                 |   6 +-
 crypto/ec/ec_lcl.h                 |  13 ++-
 crypto/ec/ecp_mont.c               |  51 ++++++++-
 crypto/ec/ecp_nist.c               |   3 +-
 crypto/ec/ecp_nistp224.c           |   3 +-
 crypto/ec/ecp_nistp256.c           |   3 +-
 crypto/ec/ecp_nistp521.c           |   3 +-
 crypto/ec/ecp_nistz256.c           |   3 +-
 crypto/ec/ecp_smpl.c               |  51 ++++++++-
 include/openssl/ec.h               |   6 +-
 test/build.info                    |   9 ++
 test/ec_internal_test.c            | 220 +++++++++++++++++++++++++++++++++++++
 test/recipes/03-test_internal_ec.t |  19 ++++
 15 files changed, 462 insertions(+), 74 deletions(-)
 create mode 100644 test/ec_internal_test.c
 create mode 100644 test/recipes/03-test_internal_ec.t

diff --git a/CHANGES b/CHANGES
index d634252..d0b6fd7 100644
--- a/CHANGES
+++ b/CHANGES
@@ -9,6 +9,12 @@
 
  Changes between 1.1.0j and 1.1.0k [xx XXX xxxx]
 
+  *) Added SCA hardening for modular field inversion in EC_GROUP through
+     a new dedicated field_inv() pointer in EC_METHOD.
+     This also addresses a leakage affecting conversions from projective
+     to affine coordinates.
+     [Billy Bob Brumley, Nicola Tuveri]
+
   *) Fix a use after free bug in d2i_X509_PUBKEY when overwriting a
      re-used X509_PUBKEY object if the second PUBKEY is malformed.
      [Bernd Edlinger]
diff --git a/crypto/ec/ec2_smpl.c b/crypto/ec/ec2_smpl.c
index cdacce6..6cb6d1b 100644
--- a/crypto/ec/ec2_smpl.c
+++ b/crypto/ec/ec2_smpl.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 2002-2019 The OpenSSL Project Authors. All Rights Reserved.
  *
  * Licensed under the OpenSSL license (the "License").  You may not use
  * this file except in compliance with the License.  You can obtain a copy
@@ -29,67 +29,6 @@
 
 #ifndef OPENSSL_NO_EC2M
 
-const EC_METHOD *EC_GF2m_simple_method(void)
-{
-    static const EC_METHOD ret = {
-        EC_FLAGS_DEFAULT_OCT,
-        NID_X9_62_characteristic_two_field,
-        ec_GF2m_simple_group_init,
-        ec_GF2m_simple_group_finish,
-        ec_GF2m_simple_group_clear_finish,
-        ec_GF2m_simple_group_copy,
-        ec_GF2m_simple_group_set_curve,
-        ec_GF2m_simple_group_get_curve,
-        ec_GF2m_simple_group_get_degree,
-        ec_group_simple_order_bits,
-        ec_GF2m_simple_group_check_discriminant,
-        ec_GF2m_simple_point_init,
-        ec_GF2m_simple_point_finish,
-        ec_GF2m_simple_point_clear_finish,
-        ec_GF2m_simple_point_copy,
-        ec_GF2m_simple_point_set_to_infinity,
-        0 /* set_Jprojective_coordinates_GFp */ ,
-        0 /* get_Jprojective_coordinates_GFp */ ,
-        ec_GF2m_simple_point_set_affine_coordinates,
-        ec_GF2m_simple_point_get_affine_coordinates,
-        0, 0, 0,
-        ec_GF2m_simple_add,
-        ec_GF2m_simple_dbl,
-        ec_GF2m_simple_invert,
-        ec_GF2m_simple_is_at_infinity,
-        ec_GF2m_simple_is_on_curve,
-        ec_GF2m_simple_cmp,
-        ec_GF2m_simple_make_affine,
-        ec_GF2m_simple_points_make_affine,
-
-        /*
-         * the following three method functions are defined in ec2_mult.c
-         */
-        ec_GF2m_simple_mul,
-        ec_GF2m_precompute_mult,
-        ec_GF2m_have_precompute_mult,
-
-        ec_GF2m_simple_field_mul,
-        ec_GF2m_simple_field_sqr,
-        ec_GF2m_simple_field_div,
-        0 /* field_encode */ ,
-        0 /* field_decode */ ,
-        0,                      /* field_set_to_one */
-        ec_key_simple_priv2oct,
-        ec_key_simple_oct2priv,
-        0, /* set private */
-        ec_key_simple_generate_key,
-        ec_key_simple_check_key,
-        ec_key_simple_generate_public_key,
-        0, /* keycopy */
-        0, /* keyfinish */
-        ecdh_simple_compute_key,
-        0  /* blind_coordinates */
-    };
-
-    return &ret;
-}
-
 /*
  * Initialize a GF(2^m)-based EC_GROUP structure. Note that all other members
  * are handled by EC_GROUP_new.
@@ -757,4 +696,81 @@ int ec_GF2m_simple_field_div(const EC_GROUP *group, BIGNUM *r,
     return BN_GF2m_mod_div(r, a, b, group->field, ctx);
 }
 
+/*-
+ * Computes the multiplicative inverse of a in GF(2^m), storing the result in r.
+ * If a is zero (or equivalent), you'll get a EC_R_CANNOT_INVERT error.
+ * SCA hardening is with blinding: BN_GF2m_mod_inv does that.
+ */
+static int ec_GF2m_simple_field_inv(const EC_GROUP *group, BIGNUM *r,
+                                    const BIGNUM *a, BN_CTX *ctx)
+{
+    int ret;
+
+    if (!(ret = BN_GF2m_mod_inv(r, a, group->field, ctx)))
+        ECerr(EC_F_EC_GF2M_SIMPLE_FIELD_INV, EC_R_CANNOT_INVERT);
+    return ret;
+}
+
+const EC_METHOD *EC_GF2m_simple_method(void)
+{
+    static const EC_METHOD ret = {
+        EC_FLAGS_DEFAULT_OCT,
+        NID_X9_62_characteristic_two_field,
+        ec_GF2m_simple_group_init,
+        ec_GF2m_simple_group_finish,
+        ec_GF2m_simple_group_clear_finish,
+        ec_GF2m_simple_group_copy,
+        ec_GF2m_simple_group_set_curve,
+        ec_GF2m_simple_group_get_curve,
+        ec_GF2m_simple_group_get_degree,
+        ec_group_simple_order_bits,
+        ec_GF2m_simple_group_check_discriminant,
+        ec_GF2m_simple_point_init,
+        ec_GF2m_simple_point_finish,
+        ec_GF2m_simple_point_clear_finish,
+        ec_GF2m_simple_point_copy,
+        ec_GF2m_simple_point_set_to_infinity,
+        0 /* set_Jprojective_coordinates_GFp */ ,
+        0 /* get_Jprojective_coordinates_GFp */ ,
+        ec_GF2m_simple_point_set_affine_coordinates,
+        ec_GF2m_simple_point_get_affine_coordinates,
+        0, 0, 0,
+        ec_GF2m_simple_add,
+        ec_GF2m_simple_dbl,
+        ec_GF2m_simple_invert,
+        ec_GF2m_simple_is_at_infinity,
+        ec_GF2m_simple_is_on_curve,
+        ec_GF2m_simple_cmp,
+        ec_GF2m_simple_make_affine,
+        ec_GF2m_simple_points_make_affine,
+
+        /*
+         * the following three method functions are defined in ec2_mult.c
+         */
+        ec_GF2m_simple_mul,
+        ec_GF2m_precompute_mult,
+        ec_GF2m_have_precompute_mult,
+
+        ec_GF2m_simple_field_mul,
+        ec_GF2m_simple_field_sqr,
+        ec_GF2m_simple_field_div,
+        ec_GF2m_simple_field_inv,
+        0 /* field_encode */ ,
+        0 /* field_decode */ ,
+        0,                      /* field_set_to_one */
+        ec_key_simple_priv2oct,
+        ec_key_simple_oct2priv,
+        0, /* set private */
+        ec_key_simple_generate_key,
+        ec_key_simple_check_key,
+        ec_key_simple_generate_public_key,
+        0, /* keycopy */
+        0, /* keyfinish */
+        ecdh_simple_compute_key,
+        0  /* blind_coordinates */
+    };
+
+    return &ret;
+}
+
 #endif
diff --git a/crypto/ec/ec_err.c b/crypto/ec/ec_err.c
index 717c92e..aeee2e8 100644
--- a/crypto/ec/ec_err.c
+++ b/crypto/ec/ec_err.c
@@ -1,6 +1,6 @@
 /*
  * Generated by util/mkerr.pl DO NOT EDIT
- * Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 1995-2019 The OpenSSL Project Authors. All Rights Reserved.
  *
  * Licensed under the OpenSSL license (the "License").  You may not use
  * this file except in compliance with the License.  You can obtain a copy
@@ -58,6 +58,7 @@ static ERR_STRING_DATA EC_str_functs[] = {
     {ERR_FUNC(EC_F_EC_ASN1_GROUP2FIELDID), "ec_asn1_group2fieldid"},
     {ERR_FUNC(EC_F_EC_GF2M_MONTGOMERY_POINT_MULTIPLY),
      "ec_GF2m_montgomery_point_multiply"},
+    {ERR_FUNC(EC_F_EC_GF2M_SIMPLE_FIELD_INV), "ec_GF2m_simple_field_inv"},
     {ERR_FUNC(EC_F_EC_GF2M_SIMPLE_GROUP_CHECK_DISCRIMINANT),
      "ec_GF2m_simple_group_check_discriminant"},
     {ERR_FUNC(EC_F_EC_GF2M_SIMPLE_GROUP_SET_CURVE),
@@ -72,6 +73,7 @@ static ERR_STRING_DATA EC_str_functs[] = {
      "ec_GF2m_simple_set_compressed_coordinates"},
     {ERR_FUNC(EC_F_EC_GFP_MONT_FIELD_DECODE), "ec_GFp_mont_field_decode"},
     {ERR_FUNC(EC_F_EC_GFP_MONT_FIELD_ENCODE), "ec_GFp_mont_field_encode"},
+    {ERR_FUNC(EC_F_EC_GFP_MONT_FIELD_INV), "ec_GFp_mont_field_inv"},
     {ERR_FUNC(EC_F_EC_GFP_MONT_FIELD_MUL), "ec_GFp_mont_field_mul"},
     {ERR_FUNC(EC_F_EC_GFP_MONT_FIELD_SET_TO_ONE),
      "ec_GFp_mont_field_set_to_one"},
@@ -99,6 +101,7 @@ static ERR_STRING_DATA EC_str_functs[] = {
      "ec_GFp_nist_group_set_curve"},
     {ERR_FUNC(EC_F_EC_GFP_SIMPLE_BLIND_COORDINATES),
      "ec_GFp_simple_blind_coordinates"},
+    {ERR_FUNC(EC_F_EC_GFP_SIMPLE_FIELD_INV), "ec_GFp_simple_field_inv"},
     {ERR_FUNC(EC_F_EC_GFP_SIMPLE_GROUP_CHECK_DISCRIMINANT),
      "ec_GFp_simple_group_check_discriminant"},
     {ERR_FUNC(EC_F_EC_GFP_SIMPLE_GROUP_SET_CURVE),
@@ -211,6 +214,7 @@ static ERR_STRING_DATA EC_str_reasons[] = {
     {ERR_REASON(EC_R_BAD_SIGNATURE), "bad signature"},
     {ERR_REASON(EC_R_BIGNUM_OUT_OF_RANGE), "bignum out of range"},
     {ERR_REASON(EC_R_BUFFER_TOO_SMALL), "buffer too small"},
+    {ERR_REASON(EC_R_CANNOT_INVERT), "cannot invert"},
     {ERR_REASON(EC_R_COORDINATES_OUT_OF_RANGE), "coordinates out of range"},
     {ERR_REASON(EC_R_CURVE_DOES_NOT_SUPPORT_ECDH),
      "curve does not support ecdh"},
diff --git a/crypto/ec/ec_lcl.h b/crypto/ec/ec_lcl.h
index ca1776e..2e85597 100644
--- a/crypto/ec/ec_lcl.h
+++ b/crypto/ec/ec_lcl.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2001-2018 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 2001-2019 The OpenSSL Project Authors. All Rights Reserved.
  *
  * Licensed under the OpenSSL license (the "License").  You may not use
  * this file except in compliance with the License.  You can obtain a copy
@@ -150,6 +150,13 @@ struct ec_method_st {
     int (*field_sqr) (const EC_GROUP *, BIGNUM *r, const BIGNUM *a, BN_CTX *);
     int (*field_div) (const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
                       const BIGNUM *b, BN_CTX *);
+    /*-
+     * 'field_inv' computes the multipicative inverse of a in the field,
+     * storing the result in r.
+     *
+     * If 'a' is zero (or equivalent), you'll get an EC_R_CANNOT_INVERT error.
+     */
+    int (*field_inv) (const EC_GROUP *, BIGNUM *r, const BIGNUM *a, BN_CTX *);
     /* e.g. to Montgomery */
     int (*field_encode) (const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
                          BN_CTX *);
@@ -376,6 +383,8 @@ int ec_GFp_simple_field_mul(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
                             const BIGNUM *b, BN_CTX *);
 int ec_GFp_simple_field_sqr(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
                             BN_CTX *);
+int ec_GFp_simple_field_inv(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
+                            BN_CTX *);
 int ec_GFp_simple_blind_coordinates(const EC_GROUP *group, EC_POINT *p,
                                     BN_CTX *ctx);
 
@@ -390,6 +399,8 @@ int ec_GFp_mont_field_mul(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
                           const BIGNUM *b, BN_CTX *);
 int ec_GFp_mont_field_sqr(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
                           BN_CTX *);
+int ec_GFp_mont_field_inv(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
+                          BN_CTX *);
 int ec_GFp_mont_field_encode(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
                              BN_CTX *);
 int ec_GFp_mont_field_decode(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
diff --git a/crypto/ec/ecp_mont.c b/crypto/ec/ecp_mont.c
index d837d4d..8ecd53a 100644
--- a/crypto/ec/ecp_mont.c
+++ b/crypto/ec/ecp_mont.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2001-2018 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 2001-2019 The OpenSSL Project Authors. All Rights Reserved.
  *
  * Licensed under the OpenSSL license (the "License").  You may not use
  * this file except in compliance with the License.  You can obtain a copy
@@ -55,6 +55,7 @@ const EC_METHOD *EC_GFp_mont_method(void)
         ec_GFp_mont_field_mul,
         ec_GFp_mont_field_sqr,
         0 /* field_div */ ,
+        ec_GFp_mont_field_inv,
         ec_GFp_mont_field_encode,
         ec_GFp_mont_field_decode,
         ec_GFp_mont_field_set_to_one,
@@ -207,6 +208,54 @@ int ec_GFp_mont_field_sqr(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
     return BN_mod_mul_montgomery(r, a, a, group->field_data1, ctx);
 }
 
+/*-
+ * Computes the multiplicative inverse of a in GF(p), storing the result in r.
+ * If a is zero (or equivalent), you'll get a EC_R_CANNOT_INVERT error.
+ * We have a Mont structure, so SCA hardening is FLT inversion.
+ */
+int ec_GFp_mont_field_inv(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
+                            BN_CTX *ctx)
+{
+    BIGNUM *e = NULL;
+    BN_CTX *new_ctx = NULL;
+    int ret = 0;
+
+    if (group->field_data1 == NULL)
+        return 0;
+
+    if (ctx == NULL && (ctx = new_ctx = BN_CTX_secure_new()) == NULL)
+        return 0;
+
+    BN_CTX_start(ctx);
+    if ((e = BN_CTX_get(ctx)) == NULL)
+        goto err;
+
+    /* Inverse in constant time with Fermats Little Theorem */
+    if (!BN_set_word(e, 2))
+        goto err;
+    if (!BN_sub(e, group->field, e))
+        goto err;
+    /*-
+     * Exponent e is public.
+     * No need for scatter-gather or BN_FLG_CONSTTIME.
+     */
+    if (!BN_mod_exp_mont(r, a, e, group->field, ctx, group->field_data1))
+        goto err;
+
+    /* throw an error on zero */
+    if (BN_is_zero(r)) {
+        ECerr(EC_F_EC_GFP_MONT_FIELD_INV, EC_R_CANNOT_INVERT);
+        goto err;
+    }
+
+    ret = 1;
+
+  err:
+    BN_CTX_end(ctx);
+    BN_CTX_free(new_ctx);
+    return ret;
+}
+
 int ec_GFp_mont_field_encode(const EC_GROUP *group, BIGNUM *r,
                              const BIGNUM *a, BN_CTX *ctx)
 {
diff --git a/crypto/ec/ecp_nist.c b/crypto/ec/ecp_nist.c
index 143f21f..c874380 100644
--- a/crypto/ec/ecp_nist.c
+++ b/crypto/ec/ecp_nist.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2001-2018 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 2001-2019 The OpenSSL Project Authors. All Rights Reserved.
  *
  * Licensed under the OpenSSL license (the "License").  You may not use
  * this file except in compliance with the License.  You can obtain a copy
@@ -57,6 +57,7 @@ const EC_METHOD *EC_GFp_nist_method(void)
         ec_GFp_nist_field_mul,
         ec_GFp_nist_field_sqr,
         0 /* field_div */ ,
+        ec_GFp_simple_field_inv,
         0 /* field_encode */ ,
         0 /* field_decode */ ,
         0,                      /* field_set_to_one */
diff --git a/crypto/ec/ecp_nistp224.c b/crypto/ec/ecp_nistp224.c
index 52056ff..651dcb1 100644
--- a/crypto/ec/ecp_nistp224.c
+++ b/crypto/ec/ecp_nistp224.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2018 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 2010-2019 The OpenSSL Project Authors. All Rights Reserved.
  *
  * Licensed under the OpenSSL license (the "License").  You may not use
  * this file except in compliance with the License.  You can obtain a copy
@@ -279,6 +279,7 @@ const EC_METHOD *EC_GFp_nistp224_method(void)
         ec_GFp_nist_field_mul,
         ec_GFp_nist_field_sqr,
         0 /* field_div */ ,
+        ec_GFp_simple_field_inv,
         0 /* field_encode */ ,
         0 /* field_decode */ ,
         0,                      /* field_set_to_one */
diff --git a/crypto/ec/ecp_nistp256.c b/crypto/ec/ecp_nistp256.c
index ffd2a7d..dfd98c6 100644
--- a/crypto/ec/ecp_nistp256.c
+++ b/crypto/ec/ecp_nistp256.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2016 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 2011-2019 The OpenSSL Project Authors. All Rights Reserved.
  *
  * Licensed under the OpenSSL license (the "License").  You may not use
  * this file except in compliance with the License.  You can obtain a copy
@@ -1810,6 +1810,7 @@ const EC_METHOD *EC_GFp_nistp256_method(void)
         ec_GFp_nist_field_mul,
         ec_GFp_nist_field_sqr,
         0 /* field_div */ ,
+        ec_GFp_simple_field_inv,
         0 /* field_encode */ ,
         0 /* field_decode */ ,
         0,                      /* field_set_to_one */
diff --git a/crypto/ec/ecp_nistp521.c b/crypto/ec/ecp_nistp521.c
index 0a82abc..ddfef91 100644
--- a/crypto/ec/ecp_nistp521.c
+++ b/crypto/ec/ecp_nistp521.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2011-2018 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 2011-2019 The OpenSSL Project Authors. All Rights Reserved.
  *
  * Licensed under the OpenSSL license (the "License").  You may not use
  * this file except in compliance with the License.  You can obtain a copy
@@ -1631,6 +1631,7 @@ const EC_METHOD *EC_GFp_nistp521_method(void)
         ec_GFp_nist_field_mul,
         ec_GFp_nist_field_sqr,
         0 /* field_div */ ,
+        ec_GFp_simple_field_inv,
         0 /* field_encode */ ,
         0 /* field_decode */ ,
         0,                      /* field_set_to_one */
diff --git a/crypto/ec/ecp_nistz256.c b/crypto/ec/ecp_nistz256.c
index 7eafce6..e1170b4 100644
--- a/crypto/ec/ecp_nistz256.c
+++ b/crypto/ec/ecp_nistz256.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2018 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 2014-2019 The OpenSSL Project Authors. All Rights Reserved.
  *
  * Licensed under the OpenSSL license (the "License").  You may not use
  * this file except in compliance with the License.  You can obtain a copy
@@ -1525,6 +1525,7 @@ const EC_METHOD *EC_GFp_nistz256_method(void)
         ec_GFp_mont_field_mul,
         ec_GFp_mont_field_sqr,
         0,                                          /* field_div */
+        ec_GFp_mont_field_inv,
         ec_GFp_mont_field_encode,
         ec_GFp_mont_field_decode,
         ec_GFp_mont_field_set_to_one,
diff --git a/crypto/ec/ecp_smpl.c b/crypto/ec/ecp_smpl.c
index 2015f11..d8db1ea 100644
--- a/crypto/ec/ecp_smpl.c
+++ b/crypto/ec/ecp_smpl.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2001-2018 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 2001-2019 The OpenSSL Project Authors. All Rights Reserved.
  *
  * Licensed under the OpenSSL license (the "License").  You may not use
  * this file except in compliance with the License.  You can obtain a copy
@@ -56,6 +56,7 @@ const EC_METHOD *EC_GFp_simple_method(void)
         ec_GFp_simple_field_mul,
         ec_GFp_simple_field_sqr,
         0 /* field_div */ ,
+        ec_GFp_simple_field_inv,
         0 /* field_encode */ ,
         0 /* field_decode */ ,
         0,                      /* field_set_to_one */
@@ -554,7 +555,7 @@ int ec_GFp_simple_point_get_affine_coordinates(const EC_GROUP *group,
             }
         }
     } else {
-        if (!BN_mod_inverse(Z_1, Z_, group->field, ctx)) {
+        if (!group->meth->field_inv(group, Z_1, Z_, ctx)) {
             ECerr(EC_F_EC_GFP_SIMPLE_POINT_GET_AFFINE_COORDINATES,
                   ERR_R_BN_LIB);
             goto err;
@@ -1267,7 +1268,7 @@ int ec_GFp_simple_points_make_affine(const EC_GROUP *group, size_t num,
      * points[i]->Z by its inverse.
      */
 
-    if (!BN_mod_inverse(tmp, prod_Z[num - 1], group->field, ctx)) {
+    if (!group->meth->field_inv(group, tmp, prod_Z[num - 1], ctx)) {
         ECerr(EC_F_EC_GFP_SIMPLE_POINTS_MAKE_AFFINE, ERR_R_BN_LIB);
         goto err;
     }
@@ -1371,6 +1372,50 @@ int ec_GFp_simple_field_sqr(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
 }
 
 /*-
+ * Computes the multiplicative inverse of a in GF(p), storing the result in r.
+ * If a is zero (or equivalent), you'll get a EC_R_CANNOT_INVERT error.
+ * Since we don't have a Mont structure here, SCA hardening is with blinding.
+ */
+int ec_GFp_simple_field_inv(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
+                            BN_CTX *ctx)
+{
+    BIGNUM *e = NULL;
+    BN_CTX *new_ctx = NULL;
+    int ret = 0;
+
+    if (ctx == NULL && (ctx = new_ctx = BN_CTX_secure_new()) == NULL)
+        return 0;
+
+    BN_CTX_start(ctx);
+    if ((e = BN_CTX_get(ctx)) == NULL)
+        goto err;
+
+    do {
+        if (!BN_rand_range(e, group->field))
+        goto err;
+    } while (BN_is_zero(e));
+
+    /* r := a * e */
+    if (!group->meth->field_mul(group, r, a, e, ctx))
+        goto err;
+    /* r := 1/(a * e) */
+    if (!BN_mod_inverse(r, r, group->field, ctx)) {
+        ECerr(EC_F_EC_GFP_SIMPLE_FIELD_INV, EC_R_CANNOT_INVERT);
+        goto err;
+    }
+    /* r := e/(a * e) = 1/a */
+    if (!group->meth->field_mul(group, r, r, e, ctx))
+        goto err;
+
+    ret = 1;
+
+ err:
+    BN_CTX_end(ctx);
+    BN_CTX_free(new_ctx);
+    return ret;
+}
+
+/*-
  * Apply randomization of EC point projective coordinates:
  *
  *   (X, Y ,Z ) = (lambda^2*X, lambda^3*Y, lambda*Z)
diff --git a/include/openssl/ec.h b/include/openssl/ec.h
index d6b36c7..bea6b8c 100644
--- a/include/openssl/ec.h
+++ b/include/openssl/ec.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 2002-2019 The OpenSSL Project Authors. All Rights Reserved.
  *
  * Licensed under the OpenSSL license (the "License").  You may not use
  * this file except in compliance with the License.  You can obtain a copy
@@ -1399,6 +1399,7 @@ int ERR_load_EC_strings(void);
 # define EC_F_EC_ASN1_GROUP2CURVE                         153
 # define EC_F_EC_ASN1_GROUP2FIELDID                       154
 # define EC_F_EC_GF2M_MONTGOMERY_POINT_MULTIPLY           208
+# define EC_F_EC_GF2M_SIMPLE_FIELD_INV                    296
 # define EC_F_EC_GF2M_SIMPLE_GROUP_CHECK_DISCRIMINANT     159
 # define EC_F_EC_GF2M_SIMPLE_GROUP_SET_CURVE              195
 # define EC_F_EC_GF2M_SIMPLE_OCT2POINT                    160
@@ -1408,6 +1409,7 @@ int ERR_load_EC_strings(void);
 # define EC_F_EC_GF2M_SIMPLE_SET_COMPRESSED_COORDINATES   164
 # define EC_F_EC_GFP_MONT_FIELD_DECODE                    133
 # define EC_F_EC_GFP_MONT_FIELD_ENCODE                    134
+# define EC_F_EC_GFP_MONT_FIELD_INV                       297
 # define EC_F_EC_GFP_MONT_FIELD_MUL                       131
 # define EC_F_EC_GFP_MONT_FIELD_SET_TO_ONE                209
 # define EC_F_EC_GFP_MONT_FIELD_SQR                       132
@@ -1425,6 +1427,7 @@ int ERR_load_EC_strings(void);
 # define EC_F_EC_GFP_NIST_FIELD_SQR                       201
 # define EC_F_EC_GFP_NIST_GROUP_SET_CURVE                 202
 # define EC_F_EC_GFP_SIMPLE_BLIND_COORDINATES             287
+# define EC_F_EC_GFP_SIMPLE_FIELD_INV                     298
 # define EC_F_EC_GFP_SIMPLE_GROUP_CHECK_DISCRIMINANT      165
 # define EC_F_EC_GFP_SIMPLE_GROUP_SET_CURVE               166
 # define EC_F_EC_GFP_SIMPLE_MAKE_AFFINE                   102
@@ -1514,6 +1517,7 @@ int ERR_load_EC_strings(void);
 # define EC_R_BAD_SIGNATURE                               156
 # define EC_R_BIGNUM_OUT_OF_RANGE                         144
 # define EC_R_BUFFER_TOO_SMALL                            100
+# define EC_R_CANNOT_INVERT                               165
 # define EC_R_COORDINATES_OUT_OF_RANGE                    146
 # define EC_R_CURVE_DOES_NOT_SUPPORT_ECDH                 160
 # define EC_R_CURVE_DOES_NOT_SUPPORT_SIGNING              159
diff --git a/test/build.info b/test/build.info
index 2367ab8..a5fe0d6 100644
--- a/test/build.info
+++ b/test/build.info
@@ -314,6 +314,15 @@ IF[{- !$disabled{tests} -}]
     INCLUDE[shlibloadtest]=../include
   ENDIF
 
+
+  IF[{- !$disabled{ec} -}]
+    PROGRAMS_NO_INST=ec_internal_test
+
+    SOURCE[ec_internal_test]=ec_internal_test.c testutil.c
+    INCLUDE[ec_internal_test]=.. ../include ../crypto/ec ../crypto/include
+    DEPEND[ec_internal_test]=../libcrypto
+  ENDIF
+
   SOURCE[errtest]=errtest.c testutil.c
   INCLUDE[errtest]=../include
   DEPEND[errtest]=../libcrypto
diff --git a/test/ec_internal_test.c b/test/ec_internal_test.c
new file mode 100644
index 0000000..62f7c96
--- /dev/null
+++ b/test/ec_internal_test.c
@@ -0,0 +1,220 @@
+/*
+ * Copyright 2019 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the Apache License 2.0 (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#include <openssl/ec.h>
+#include "ec_lcl.h"
+#include <openssl/objects.h>
+
+#include "testutil.h"
+
+static size_t crv_len = 0;
+static EC_builtin_curve *curves = NULL;
+
+/* sanity checks field_inv function pointer in EC_METHOD */
+static int group_field_tests(const EC_GROUP *group, BN_CTX *ctx)
+{
+    BIGNUM *a = NULL, *b = NULL, *c = NULL;
+    int ret = 0;
+
+    if (group->meth->field_inv == NULL || group->meth->field_mul == NULL)
+        return 1;
+
+    BN_CTX_start(ctx);
+    a = BN_CTX_get(ctx);
+    b = BN_CTX_get(ctx);
+    TEST_check(NULL != (c = BN_CTX_get(ctx)));
+
+    /* 1/1 = 1 */
+    TEST_check(group->meth->field_inv(group, b, BN_value_one(), ctx));
+    TEST_check(BN_is_one(b));
+
+    /* (1/a)*a = 1 */
+    TEST_check(BN_pseudo_rand(a, BN_num_bits(group->field) - 1,
+                              BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ANY));
+    TEST_check(group->meth->field_inv(group, b, a, ctx));
+    if (group->meth->field_encode) {
+        TEST_check(group->meth->field_encode(group, a, a, ctx));
+        TEST_check(group->meth->field_encode(group, b, b, ctx));
+    }
+    TEST_check(group->meth->field_mul(group, c, a, b, ctx));
+    if (group->meth->field_decode) {
+        TEST_check(group->meth->field_decode(group, c, c, ctx));
+    }
+    TEST_check(BN_is_one(c));
+
+    /* 1/0 = error */
+    BN_zero(a);
+    TEST_check(!group->meth->field_inv(group, b, a, ctx));
+    TEST_check(ERR_GET_LIB(ERR_peek_last_error()) == ERR_LIB_EC);
+    TEST_check(ERR_GET_REASON(ERR_peek_last_error()) == EC_R_CANNOT_INVERT);
+
+    /* 1/p = error */
+    TEST_check(!group->meth->field_inv(group, b, group->field, ctx));
+    TEST_check(ERR_GET_LIB(ERR_peek_last_error()) == ERR_LIB_EC);
+    TEST_check(ERR_GET_REASON(ERR_peek_last_error()) == EC_R_CANNOT_INVERT);
+
+    ERR_clear_error();
+    ret = 1;
+
+    BN_CTX_end(ctx);
+    return ret;
+}
+
+#define EC_GROUP_set_curve(g,p,a,b,ctx) \
+    EC_GROUP_set_curve_GFp(g,p,a,b,ctx)
+
+/* wrapper for group_field_tests for explicit curve params and EC_METHOD */
+static int field_tests(const EC_METHOD *meth, const unsigned char *params,
+                       int len)
+{
+    BN_CTX *ctx = NULL;
+    BIGNUM *p = NULL, *a = NULL, *b = NULL;
+    EC_GROUP *group = NULL;
+    int ret = 0;
+
+    TEST_check(NULL != (ctx = BN_CTX_new()));
+
+    BN_CTX_start(ctx);
+    p = BN_CTX_get(ctx);
+    a = BN_CTX_get(ctx);
+    TEST_check(NULL != (b = BN_CTX_get(ctx)));
+
+    TEST_check(NULL != (group = EC_GROUP_new(meth)));
+    TEST_check(BN_bin2bn(params, len, p));
+    TEST_check(BN_bin2bn(params + len, len, a));
+    TEST_check(BN_bin2bn(params + 2 * len, len, b));
+    TEST_check(EC_GROUP_set_curve(group, p, a, b, ctx));
+    TEST_check(group_field_tests(group, ctx));
+
+    ret = 1;
+
+
+    BN_CTX_end(ctx);
+    BN_CTX_free(ctx);
+    if (group != NULL)
+        EC_GROUP_free(group);
+    return ret;
+}
+#undef EC_GROUP_set_curve
+
+/* NIST prime curve P-256 */
+static const unsigned char params_p256[] = {
+    /* p */
+    0xFF, 0xFF, 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+    /* a */
+    0xFF, 0xFF, 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFC,
+    /* b */
+    0x5A, 0xC6, 0x35, 0xD8, 0xAA, 0x3A, 0x93, 0xE7, 0xB3, 0xEB, 0xBD, 0x55,
+    0x76, 0x98, 0x86, 0xBC, 0x65, 0x1D, 0x06, 0xB0, 0xCC, 0x53, 0xB0, 0xF6,
+    0x3B, 0xCE, 0x3C, 0x3E, 0x27, 0xD2, 0x60, 0x4B
+};
+
+#ifndef OPENSSL_NO_EC2M
+/* NIST binary curve B-283 */
+static const unsigned char params_b283[] = {
+    /* p */
+    0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 0xA1,
+    /* a */
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
+    /* b */
+    0x02, 0x7B, 0x68, 0x0A, 0xC8, 0xB8, 0x59, 0x6D, 0xA5, 0xA4, 0xAF, 0x8A,
+    0x19, 0xA0, 0x30, 0x3F, 0xCA, 0x97, 0xFD, 0x76, 0x45, 0x30, 0x9F, 0xA2,
+    0xA5, 0x81, 0x48, 0x5A, 0xF6, 0x26, 0x3E, 0x31, 0x3B, 0x79, 0xA2, 0xF5
+};
+#endif
+
+/* test EC_GFp_simple_method directly */
+static int field_tests_ecp_simple(void)
+{
+    fprintf(stdout, "Testing EC_GFp_simple_method()\n");
+    return field_tests(EC_GFp_simple_method(), params_p256,
+                       sizeof(params_p256) / 3);
+}
+
+/* test EC_GFp_mont_method directly */
+static int field_tests_ecp_mont(void)
+{
+    fprintf(stdout, "Testing EC_GFp_mont_method()\n");
+    return field_tests(EC_GFp_mont_method(), params_p256,
+                       sizeof(params_p256) / 3);
+}
+
+#ifndef OPENSSL_NO_EC2M
+/* test EC_GF2m_simple_method directly */
+static int field_tests_ec2_simple(void)
+{
+    fprintf(stdout, "Testing EC_GF2m_simple_method()\n");
+    return field_tests(EC_GF2m_simple_method(), params_b283,
+                       sizeof(params_b283) / 3);
+}
+#endif
+
+/* test default method for a named curve */
+static int field_tests_default(int n)
+{
+    BN_CTX *ctx = NULL;
+    EC_GROUP *group = NULL;
+    int nid = curves[n].nid;
+    int ret = 0;
+
+    fprintf(stdout, "Testing curve %s\n", OBJ_nid2sn(nid));
+
+    TEST_check(NULL != (group = EC_GROUP_new_by_curve_name(nid)));
+    TEST_check(NULL != (ctx = BN_CTX_new()));
+    TEST_check(group_field_tests(group, ctx));
+
+    ret = 1;
+
+    if (group != NULL)
+        EC_GROUP_free(group);
+    if (ctx != NULL)
+        BN_CTX_free(ctx);
+    return ret;
+}
+
+static int setup_tests(void)
+{
+    crv_len = EC_get_builtin_curves(NULL, 0);
+    TEST_check(NULL != (curves = OPENSSL_malloc(sizeof(*curves) * crv_len)));
+    TEST_check(EC_get_builtin_curves(curves, crv_len));
+
+    ADD_TEST(field_tests_ecp_simple);
+    ADD_TEST(field_tests_ecp_mont);
+#ifndef OPENSSL_NO_EC2M
+    ADD_TEST(field_tests_ec2_simple);
+#endif
+    ADD_ALL_TESTS(field_tests_default, crv_len);
+    return 1;
+}
+
+static void cleanup_tests(void)
+{
+    OPENSSL_free(curves);
+}
+
+int main(int argc, char **argv)
+{
+    int ret;
+
+    setup_tests();
+
+    ret = run_tests(argv[0]);
+
+    cleanup_tests();
+
+    return ret;
+}
diff --git a/test/recipes/03-test_internal_ec.t b/test/recipes/03-test_internal_ec.t
new file mode 100644
index 0000000..0d31d0a
--- /dev/null
+++ b/test/recipes/03-test_internal_ec.t
@@ -0,0 +1,19 @@
+#! /usr/bin/env perl
+# Copyright 2019 The OpenSSL Project Authors. All Rights Reserved.
+#
+# Licensed under the Apache License 2.0 (the "License").  You may not use
+# this file except in compliance with the License.  You can obtain a copy
+# in the file LICENSE in the source distribution or at
+# https://www.openssl.org/source/license.html
+
+use strict;
+use OpenSSL::Test;              # get 'plan'
+use OpenSSL::Test::Simple;
+use OpenSSL::Test::Utils;
+
+setup("test_internal_ec");
+
+plan skip_all => "This test is unsupported in a no-ec build"
+    if disabled("ec");
+
+simple_test("test_internal_ec", "ec_internal_test");


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