diff options
Diffstat (limited to 'gnu/packages/patches/openssl-1.1.0-CVE-2018-0495.patch')
| -rw-r--r-- | gnu/packages/patches/openssl-1.1.0-CVE-2018-0495.patch | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/gnu/packages/patches/openssl-1.1.0-CVE-2018-0495.patch b/gnu/packages/patches/openssl-1.1.0-CVE-2018-0495.patch new file mode 100644 index 0000000000..15dedbcbd0 --- /dev/null +++ b/gnu/packages/patches/openssl-1.1.0-CVE-2018-0495.patch @@ -0,0 +1,152 @@ +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/0c27d793745c7837b13646302b6890a556b7017a + +From 0c27d793745c7837b13646302b6890a556b7017a 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/ec/ecdsa_ossl.c | 70 +++++++++++++++++++++++++++++++++++++----- + 2 files changed, 67 insertions(+), 7 deletions(-) + +diff --git a/crypto/ec/ecdsa_ossl.c b/crypto/ec/ecdsa_ossl.c +index 72e2f0f28b..449be0e92a 100644 +--- a/crypto/ec/ecdsa_ossl.c ++++ b/crypto/ec/ecdsa_ossl.c +@@ -210,7 +210,8 @@ ECDSA_SIG *ossl_ecdsa_sign_sig(const unsigned char *dgst, int dgst_len, + EC_KEY *eckey) + { + int ok = 0, i; +- BIGNUM *kinv = NULL, *s, *m = NULL, *tmp = NULL; ++ BIGNUM *kinv = NULL, *s, *m = NULL, *tmp = NULL, *blind = NULL; ++ BIGNUM *blindm = NULL; + const BIGNUM *order, *ckinv; + BN_CTX *ctx = NULL; + const EC_GROUP *group; +@@ -243,8 +244,18 @@ ECDSA_SIG *ossl_ecdsa_sign_sig(const unsigned char *dgst, int dgst_len, + } + s = ret->s; + +- if ((ctx = BN_CTX_new()) == NULL || +- (tmp = BN_new()) == NULL || (m = BN_new()) == NULL) { ++ ctx = BN_CTX_secure_new(); ++ if (ctx == NULL) { ++ ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_MALLOC_FAILURE); ++ goto err; ++ } ++ ++ BN_CTX_start(ctx); ++ tmp = BN_CTX_get(ctx); ++ m = BN_CTX_get(ctx); ++ blind = BN_CTX_get(ctx); ++ blindm = BN_CTX_get(ctx); ++ if (blindm == NULL) { + ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_MALLOC_FAILURE); + goto err; + } +@@ -284,18 +295,64 @@ ECDSA_SIG *ossl_ecdsa_sign_sig(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, BN_RAND_TOP_ANY, ++ BN_RAND_BOTTOM_ANY)) ++ 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)) { + ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB); + goto err; + } +- if (!BN_mod_add_quick(s, tmp, m, order)) { ++ if (!BN_mod_mul(tmp, tmp, ret->r, order, ctx)) { + ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB); + goto err; + } ++ ++ /* blindm := blind * m mod order */ ++ if (!BN_mod_mul(blindm, blind, m, order, ctx)) { ++ ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB); ++ goto err; ++ } ++ ++ /* s : = (blind * priv_key * r) + (blind * m) mod order */ ++ if (!BN_mod_add_quick(s, tmp, blindm, order)) { ++ ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB); ++ goto err; ++ } ++ ++ /* s:= s * blind^-1 mod order */ ++ if (BN_mod_inverse(blind, blind, order, ctx) == NULL) { ++ ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB); ++ goto err; ++ } ++ if (!BN_mod_mul(s, s, blind, order, ctx)) { ++ ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB); ++ goto err; ++ } ++ ++ /* s := s * k^-1 mod order */ + if (!BN_mod_mul(s, s, ckinv, order, ctx)) { + ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB); + goto err; + } ++ + if (BN_is_zero(s)) { + /* + * if kinv and r have been supplied by the caller don't to +@@ -317,9 +374,8 @@ ECDSA_SIG *ossl_ecdsa_sign_sig(const unsigned char *dgst, int dgst_len, + ECDSA_SIG_free(ret); + ret = NULL; + } ++ BN_CTX_end(ctx); + BN_CTX_free(ctx); +- BN_clear_free(m); +- BN_clear_free(tmp); + BN_clear_free(kinv); + return ret; + } +-- +2.17.1 + |