[OE-core] [PATCH 7/7] libgcrypt: fix CVE-2019-13627
Anuj Mittal
anuj.mittal at intel.com
Sun Nov 10 14:54:16 UTC 2019
From: Trevor Gamblin <trevor.gamblin at windriver.com>
Backport two fixes for CVE-2019-13627 from upstream
to zeus.
Signed-off-by: Trevor Gamblin <trevor.gamblin at windriver.com>
Signed-off-by: Anuj Mittal <anuj.mittal at intel.com>
---
...cdsa-Fix-use-of-nonce-use-larger-one.patch | 128 ++++++++++++++++++
...Add-mitigation-against-timing-attack.patch | 70 ++++++++++
.../libgcrypt/libgcrypt_1.8.4.bb | 2 +
3 files changed, 200 insertions(+)
create mode 100644 meta/recipes-support/libgcrypt/files/0001-dsa-ecdsa-Fix-use-of-nonce-use-larger-one.patch
create mode 100644 meta/recipes-support/libgcrypt/files/0001-ecc-Add-mitigation-against-timing-attack.patch
diff --git a/meta/recipes-support/libgcrypt/files/0001-dsa-ecdsa-Fix-use-of-nonce-use-larger-one.patch b/meta/recipes-support/libgcrypt/files/0001-dsa-ecdsa-Fix-use-of-nonce-use-larger-one.patch
new file mode 100644
index 0000000000..211e041303
--- /dev/null
+++ b/meta/recipes-support/libgcrypt/files/0001-dsa-ecdsa-Fix-use-of-nonce-use-larger-one.patch
@@ -0,0 +1,128 @@
+From db4e9976cc31b314aafad6626b2894e86ee44d60 Mon Sep 17 00:00:00 2001
+From: NIIBE Yutaka <gniibe at fsij.org>
+Date: Thu, 8 Aug 2019 17:42:02 +0900
+Subject: [PATCH] dsa,ecdsa: Fix use of nonce, use larger one.
+
+Upstream-Status: Backport [https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git;a=commit;h=db4e9976cc3]
+CVE: CVE-2019-13627
+Signed-off-by: Trevor Gamblin <trevor.gamblin at windriver.com>
+
+* cipher/dsa-common.c (_gcry_dsa_modify_k): New.
+* cipher/pubkey-internal.h (_gcry_dsa_modify_k): New.
+* cipher/dsa.c (sign): Use _gcry_dsa_modify_k.
+* cipher/ecc-ecdsa.c (_gcry_ecc_ecdsa_sign): Likewise.
+* cipher/ecc-gost.c (_gcry_ecc_gost_sign): Likewise.
+
+--
+
+Cherry-picked master commit of:
+ 7c2943309d14407b51c8166c4dcecb56a3628567
+
+CVE-id: CVE-2019-13627
+GnuPG-bug-id: 4626
+Signed-off-by: NIIBE Yutaka <gniibe at fsij.org>
+---
+ cipher/dsa-common.c | 24 ++++++++++++++++++++++++
+ cipher/dsa.c | 2 ++
+ cipher/ecc-ecdsa.c | 10 +---------
+ cipher/ecc-gost.c | 2 ++
+ cipher/pubkey-internal.h | 1 +
+ 5 files changed, 30 insertions(+), 9 deletions(-)
+
+diff --git a/cipher/dsa-common.c b/cipher/dsa-common.c
+index 8c0a6843..fe49248d 100644
+--- a/cipher/dsa-common.c
++++ b/cipher/dsa-common.c
+@@ -29,6 +29,30 @@
+ #include "pubkey-internal.h"
+
+
++/*
++ * Modify K, so that computation time difference can be small,
++ * by making K large enough.
++ *
++ * Originally, (EC)DSA computation requires k where 0 < k < q. Here,
++ * we add q (the order), to keep k in a range: q < k < 2*q (or,
++ * addming more q, to keep k in a range: 2*q < k < 3*q), so that
++ * timing difference of the EC multiply (or exponentiation) operation
++ * can be small. The result of (EC)DSA computation is same.
++ */
++void
++_gcry_dsa_modify_k (gcry_mpi_t k, gcry_mpi_t q, int qbits)
++{
++ gcry_mpi_t k1 = mpi_new (qbits+2);
++
++ mpi_resize (k, (qbits+2+BITS_PER_MPI_LIMB-1) / BITS_PER_MPI_LIMB);
++ k->nlimbs = k->alloced;
++ mpi_add (k, k, q);
++ mpi_add (k1, k, q);
++ mpi_set_cond (k, k1, !mpi_test_bit (k, qbits));
++
++ mpi_free (k1);
++}
++
+ /*
+ * Generate a random secret exponent K less than Q.
+ * Note that ECDSA uses this code also to generate D.
+diff --git a/cipher/dsa.c b/cipher/dsa.c
+index 22d8d782..24a53528 100644
+--- a/cipher/dsa.c
++++ b/cipher/dsa.c
+@@ -635,6 +635,8 @@ sign (gcry_mpi_t r, gcry_mpi_t s, gcry_mpi_t input, DSA_secret_key *skey,
+ k = _gcry_dsa_gen_k (skey->q, GCRY_STRONG_RANDOM);
+ }
+
++ _gcry_dsa_modify_k (k, skey->q, qbits);
++
+ /* r = (a^k mod p) mod q */
+ mpi_powm( r, skey->g, k, skey->p );
+ mpi_fdiv_r( r, r, skey->q );
+diff --git a/cipher/ecc-ecdsa.c b/cipher/ecc-ecdsa.c
+index 84a1cf84..97966c3a 100644
+--- a/cipher/ecc-ecdsa.c
++++ b/cipher/ecc-ecdsa.c
+@@ -114,15 +114,7 @@ _gcry_ecc_ecdsa_sign (gcry_mpi_t input, ECC_secret_key *skey,
+ else
+ k = _gcry_dsa_gen_k (skey->E.n, GCRY_STRONG_RANDOM);
+
+- /* Originally, ECDSA computation requires k where 0 < k < n.
+- * Here, we add n (the order of curve), to keep k in a
+- * range: n < k < 2*n, or, addming more n, keep k in a range:
+- * 2*n < k < 3*n, so that timing difference of the EC
+- * multiply operation can be small. The result is same.
+- */
+- mpi_add (k, k, skey->E.n);
+- if (!mpi_test_bit (k, qbits))
+- mpi_add (k, k, skey->E.n);
++ _gcry_dsa_modify_k (k, skey->E.n, qbits);
+
+ _gcry_mpi_ec_mul_point (&I, k, &skey->E.G, ctx);
+ if (_gcry_mpi_ec_get_affine (x, NULL, &I, ctx))
+diff --git a/cipher/ecc-gost.c b/cipher/ecc-gost.c
+index a34fa084..0362a6c7 100644
+--- a/cipher/ecc-gost.c
++++ b/cipher/ecc-gost.c
+@@ -94,6 +94,8 @@ _gcry_ecc_gost_sign (gcry_mpi_t input, ECC_secret_key *skey,
+ mpi_free (k);
+ k = _gcry_dsa_gen_k (skey->E.n, GCRY_STRONG_RANDOM);
+
++ _gcry_dsa_modify_k (k, skey->E.n, qbits);
++
+ _gcry_mpi_ec_mul_point (&I, k, &skey->E.G, ctx);
+ if (_gcry_mpi_ec_get_affine (x, NULL, &I, ctx))
+ {
+diff --git a/cipher/pubkey-internal.h b/cipher/pubkey-internal.h
+index b8167c77..d31e26f3 100644
+--- a/cipher/pubkey-internal.h
++++ b/cipher/pubkey-internal.h
+@@ -84,6 +84,7 @@ _gcry_rsa_pss_verify (gcry_mpi_t value, gcry_mpi_t encoded,
+
+
+ /*-- dsa-common.c --*/
++void _gcry_dsa_modify_k (gcry_mpi_t k, gcry_mpi_t q, int qbits);
+ gcry_mpi_t _gcry_dsa_gen_k (gcry_mpi_t q, int security_level);
+ gpg_err_code_t _gcry_dsa_gen_rfc6979_k (gcry_mpi_t *r_k,
+ gcry_mpi_t dsa_q, gcry_mpi_t dsa_x,
+--
+2.23.0
+
diff --git a/meta/recipes-support/libgcrypt/files/0001-ecc-Add-mitigation-against-timing-attack.patch b/meta/recipes-support/libgcrypt/files/0001-ecc-Add-mitigation-against-timing-attack.patch
new file mode 100644
index 0000000000..db5a55ed26
--- /dev/null
+++ b/meta/recipes-support/libgcrypt/files/0001-ecc-Add-mitigation-against-timing-attack.patch
@@ -0,0 +1,70 @@
+From d5407b78cca9f9d318a4f4d2f6ba2b8388584cd9 Mon Sep 17 00:00:00 2001
+From: NIIBE Yutaka <gniibe at fsij.org>
+Date: Wed, 17 Jul 2019 12:44:50 +0900
+Subject: [PATCH] ecc: Add mitigation against timing attack.
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Upstream-Status: Backport [https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git;a=commit;h=d5407b78c]
+CVE: CVE-2019-13627
+Signed-off-by: Trevor Gamblin <trevor.gamblin at windriver.com>
+
+* cipher/ecc-ecdsa.c (_gcry_ecc_ecdsa_sign): Add the order N to K.
+* mpi/ec.c (_gcry_mpi_ec_mul_point): Compute with NBITS of P or larger.
+
+--
+
+Cherry-picked master commit of:
+ b9577f7c89b4327edc09f2231bc8b31521102c79
+
+CVE-id: CVE-2019-13627
+GnuPG-bug-id: 4626
+Co-authored-by: Ján Jančár <johny at neuromancer.sk>
+Signed-off-by: NIIBE Yutaka <gniibe at fsij.org>
+---
+ cipher/ecc-ecdsa.c | 10 ++++++++++
+ mpi/ec.c | 6 +++++-
+ 2 files changed, 15 insertions(+), 1 deletion(-)
+
+diff --git a/cipher/ecc-ecdsa.c b/cipher/ecc-ecdsa.c
+index 140e8c09..84a1cf84 100644
+--- a/cipher/ecc-ecdsa.c
++++ b/cipher/ecc-ecdsa.c
+@@ -114,6 +114,16 @@ _gcry_ecc_ecdsa_sign (gcry_mpi_t input, ECC_secret_key *skey,
+ else
+ k = _gcry_dsa_gen_k (skey->E.n, GCRY_STRONG_RANDOM);
+
++ /* Originally, ECDSA computation requires k where 0 < k < n.
++ * Here, we add n (the order of curve), to keep k in a
++ * range: n < k < 2*n, or, addming more n, keep k in a range:
++ * 2*n < k < 3*n, so that timing difference of the EC
++ * multiply operation can be small. The result is same.
++ */
++ mpi_add (k, k, skey->E.n);
++ if (!mpi_test_bit (k, qbits))
++ mpi_add (k, k, skey->E.n);
++
+ _gcry_mpi_ec_mul_point (&I, k, &skey->E.G, ctx);
+ if (_gcry_mpi_ec_get_affine (x, NULL, &I, ctx))
+ {
+diff --git a/mpi/ec.c b/mpi/ec.c
+index 89077cd9..adb02600 100644
+--- a/mpi/ec.c
++++ b/mpi/ec.c
+@@ -1309,7 +1309,11 @@ _gcry_mpi_ec_mul_point (mpi_point_t result,
+ unsigned int nbits;
+ int j;
+
+- nbits = mpi_get_nbits (scalar);
++ if (mpi_cmp (scalar, ctx->p) >= 0)
++ nbits = mpi_get_nbits (scalar);
++ else
++ nbits = mpi_get_nbits (ctx->p);
++
+ if (ctx->model == MPI_EC_WEIERSTRASS)
+ {
+ mpi_set_ui (result->x, 1);
+--
+2.23.0
+
diff --git a/meta/recipes-support/libgcrypt/libgcrypt_1.8.4.bb b/meta/recipes-support/libgcrypt/libgcrypt_1.8.4.bb
index 11d078d44a..1bd355133e 100644
--- a/meta/recipes-support/libgcrypt/libgcrypt_1.8.4.bb
+++ b/meta/recipes-support/libgcrypt/libgcrypt_1.8.4.bb
@@ -24,6 +24,8 @@ SRC_URI = "${GNUPG_MIRROR}/libgcrypt/libgcrypt-${PV}.tar.bz2 \
file://0001-Prefetch-GCM-look-up-tables.patch \
file://0002-AES-move-look-up-tables-to-.data-section-and-unshare.patch \
file://0003-GCM-move-look-up-table-to-.data-section-and-unshare-.patch \
+ file://0001-ecc-Add-mitigation-against-timing-attack.patch \
+ file://0001-dsa-ecdsa-Fix-use-of-nonce-use-larger-one.patch \
"
SRC_URI[md5sum] = "fbfdaebbbc6d7e5fbbf6ffdb3e139573"
SRC_URI[sha256sum] = "f638143a0672628fde0cad745e9b14deb85dffb175709cacc1f4fe24b93f2227"
--
2.21.0
More information about the Openembedded-core
mailing list