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-rw-r--r--gnu/packages/patches/openssl-1.0.2-CVE-2018-0495.patch215
1 files changed, 215 insertions, 0 deletions
diff --git a/gnu/packages/patches/openssl-1.0.2-CVE-2018-0495.patch b/gnu/packages/patches/openssl-1.0.2-CVE-2018-0495.patch
new file mode 100644
index 0000000000..2d54ed03b9
--- /dev/null
+++ b/gnu/packages/patches/openssl-1.0.2-CVE-2018-0495.patch
@@ -0,0 +1,215 @@
+Fix CVE-2018-0495:
+
+https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-0495
+https://www.nccgroup.trust/us/our-research/technical-advisory-return-of-the-hidden-number-problem/
+
+Patch copied from upstream source repository:
+
+https://github.com/openssl/openssl/commit/949ff36623eafc3523a9f91784992965018ffb05
+
+From 949ff36623eafc3523a9f91784992965018ffb05 Mon Sep 17 00:00:00 2001
+From: Matt Caswell <matt@openssl.org>
+Date: Fri, 25 May 2018 12:10:13 +0100
+Subject: [PATCH] Add blinding to an ECDSA signature
+
+Keegan Ryan (NCC Group) has demonstrated a side channel attack on an
+ECDSA signature operation. During signing the signer calculates:
+
+s:= k^-1 * (m + r * priv_key) mod order
+
+The addition operation above provides a sufficient signal for a
+flush+reload attack to derive the private key given sufficient signature
+operations.
+
+As a mitigation (based on a suggestion from Keegan) we add blinding to
+the operation so that:
+
+s := k^-1 * blind^-1 (blind * m + blind * r * priv_key) mod order
+
+Since this attack is a localhost side channel only no CVE is assigned.
+
+Reviewed-by: Rich Salz <rsalz@openssl.org>
+---
+ CHANGES | 4 ++
+ crypto/ecdsa/ecdsatest.c | 9 ++++-
+ crypto/ecdsa/ecs_ossl.c | 82 ++++++++++++++++++++++++++++++++--------
+ 3 files changed, 79 insertions(+), 16 deletions(-)
+
+diff --git a/crypto/ecdsa/ecdsatest.c b/crypto/ecdsa/ecdsatest.c
+index 0f301f86d9..a130fc9117 100644
+--- a/crypto/ecdsa/ecdsatest.c
++++ b/crypto/ecdsa/ecdsatest.c
+@@ -137,7 +137,7 @@ int restore_rand(void)
+ return 1;
+ }
+
+-static int fbytes_counter = 0;
++static int fbytes_counter = 0, use_fake = 0;
+ static const char *numbers[8] = {
+ "651056770906015076056810763456358567190100156695615665659",
+ "6140507067065001063065065565667405560006161556565665656654",
+@@ -158,6 +158,11 @@ int fbytes(unsigned char *buf, int num)
+ int ret;
+ BIGNUM *tmp = NULL;
+
++ if (use_fake == 0)
++ return old_rand->bytes(buf, num);
++
++ use_fake = 0;
++
+ if (fbytes_counter >= 8)
+ return 0;
+ tmp = BN_new();
+@@ -199,11 +204,13 @@ int x9_62_test_internal(BIO *out, int nid, const char *r_in, const char *s_in)
+ /* create the key */
+ if ((key = EC_KEY_new_by_curve_name(nid)) == NULL)
+ goto x962_int_err;
++ use_fake = 1;
+ if (!EC_KEY_generate_key(key))
+ goto x962_int_err;
+ BIO_printf(out, ".");
+ (void)BIO_flush(out);
+ /* create the signature */
++ use_fake = 1;
+ signature = ECDSA_do_sign(digest, 20, key);
+ if (signature == NULL)
+ goto x962_int_err;
+diff --git a/crypto/ecdsa/ecs_ossl.c b/crypto/ecdsa/ecs_ossl.c
+index 16d4f59b9b..1d37551803 100644
+--- a/crypto/ecdsa/ecs_ossl.c
++++ b/crypto/ecdsa/ecs_ossl.c
+@@ -252,6 +252,7 @@ static ECDSA_SIG *ecdsa_do_sign(const unsigned char *dgst, int dgst_len,
+ {
+ int ok = 0, i;
+ BIGNUM *kinv = NULL, *s, *m = NULL, *tmp = NULL, *order = NULL;
++ BIGNUM *blind = NULL, *blindm = NULL;
+ const BIGNUM *ckinv;
+ BN_CTX *ctx = NULL;
+ const EC_GROUP *group;
+@@ -269,14 +270,25 @@ static ECDSA_SIG *ecdsa_do_sign(const unsigned char *dgst, int dgst_len,
+ }
+
+ ret = ECDSA_SIG_new();
+- if (!ret) {
++ if (ret == NULL) {
+ ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_MALLOC_FAILURE);
+ return NULL;
+ }
+ s = ret->s;
+
+- if ((ctx = BN_CTX_new()) == NULL || (order = BN_new()) == NULL ||
+- (tmp = BN_new()) == NULL || (m = BN_new()) == NULL) {
++ ctx = BN_CTX_new();
++ if (ctx == NULL) {
++ ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_MALLOC_FAILURE);
++ goto err;
++ }
++
++ BN_CTX_start(ctx);
++ order = BN_CTX_get(ctx);
++ tmp = BN_CTX_get(ctx);
++ m = BN_CTX_get(ctx);
++ blind = BN_CTX_get(ctx);
++ blindm = BN_CTX_get(ctx);
++ if (blindm == NULL) {
+ ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_MALLOC_FAILURE);
+ goto err;
+ }
+@@ -315,26 +327,70 @@ static ECDSA_SIG *ecdsa_do_sign(const unsigned char *dgst, int dgst_len,
+ }
+ }
+
+- if (!BN_mod_mul(tmp, priv_key, ret->r, order, ctx)) {
++ /*
++ * The normal signature calculation is:
++ *
++ * s := k^-1 * (m + r * priv_key) mod order
++ *
++ * We will blind this to protect against side channel attacks
++ *
++ * s := k^-1 * blind^-1 * (blind * m + blind * r * priv_key) mod order
++ */
++
++ /* Generate a blinding value */
++ do {
++ if (!BN_rand(blind, BN_num_bits(order) - 1, -1, 0))
++ goto err;
++ } while (BN_is_zero(blind));
++ BN_set_flags(blind, BN_FLG_CONSTTIME);
++ BN_set_flags(blindm, BN_FLG_CONSTTIME);
++ BN_set_flags(tmp, BN_FLG_CONSTTIME);
++
++ /* tmp := blind * priv_key * r mod order */
++ if (!BN_mod_mul(tmp, blind, priv_key, order, ctx)) {
++ ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB);
++ goto err;
++ }
++ if (!BN_mod_mul(tmp, tmp, ret->r, order, ctx)) {
++ ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB);
++ goto err;
++ }
++
++ /* blindm := blind * m mod order */
++ if (!BN_mod_mul(blindm, blind, m, order, ctx)) {
++ ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB);
++ goto err;
++ }
++
++ /* s : = (blind * priv_key * r) + (blind * m) mod order */
++ if (!BN_mod_add_quick(s, tmp, blindm, order)) {
++ ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB);
++ goto err;
++ }
++
++ /* s:= s * blind^-1 mod order */
++ if (BN_mod_inverse(blind, blind, order, ctx) == NULL) {
+ ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB);
+ goto err;
+ }
+- if (!BN_mod_add_quick(s, tmp, m, order)) {
++ if (!BN_mod_mul(s, s, blind, order, ctx)) {
+ ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB);
+ goto err;
+ }
++
++ /* s := s * k^-1 mod order */
+ if (!BN_mod_mul(s, s, ckinv, order, ctx)) {
+ ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB);
+ goto err;
+ }
++
+ if (BN_is_zero(s)) {
+ /*
+ * if kinv and r have been supplied by the caller don't to
+ * generate new kinv and r values
+ */
+ if (in_kinv != NULL && in_r != NULL) {
+- ECDSAerr(ECDSA_F_ECDSA_DO_SIGN,
+- ECDSA_R_NEED_NEW_SETUP_VALUES);
++ ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ECDSA_R_NEED_NEW_SETUP_VALUES);
+ goto err;
+ }
+ } else
+@@ -349,15 +405,11 @@ static ECDSA_SIG *ecdsa_do_sign(const unsigned char *dgst, int dgst_len,
+ ECDSA_SIG_free(ret);
+ ret = NULL;
+ }
+- if (ctx)
++ if (ctx != NULL) {
++ BN_CTX_end(ctx);
+ BN_CTX_free(ctx);
+- if (m)
+- BN_clear_free(m);
+- if (tmp)
+- BN_clear_free(tmp);
+- if (order)
+- BN_free(order);
+- if (kinv)
++ }
++ if (kinv != NULL)
+ BN_clear_free(kinv);
+ return ret;
+ }
+--
+2.17.1
+
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