diff options
Diffstat (limited to 'package/network/services/hostapd/patches/061-0001-OpenSSL-Use-constant-time-operations-for-private-big.patch')
| -rw-r--r-- | package/network/services/hostapd/patches/061-0001-OpenSSL-Use-constant-time-operations-for-private-big.patch | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/package/network/services/hostapd/patches/061-0001-OpenSSL-Use-constant-time-operations-for-private-big.patch b/package/network/services/hostapd/patches/061-0001-OpenSSL-Use-constant-time-operations-for-private-big.patch new file mode 100644 index 0000000000..7a73b09ff9 --- /dev/null +++ b/package/network/services/hostapd/patches/061-0001-OpenSSL-Use-constant-time-operations-for-private-big.patch @@ -0,0 +1,88 @@ +From d42c477cc794163a3757956bbffca5cea000923c Mon Sep 17 00:00:00 2001 +From: Jouni Malinen <jouni@codeaurora.org> +Date: Tue, 26 Feb 2019 11:43:03 +0200 +Subject: [PATCH 01/14] OpenSSL: Use constant time operations for private + bignums + +This helps in reducing measurable timing differences in operations +involving private information. BoringSSL has removed BN_FLG_CONSTTIME +and expects specific constant time functions to be called instead, so a +bit different approach is needed depending on which library is used. + +The main operation that needs protection against side channel attacks is +BN_mod_exp() that depends on private keys (the public key validation +step in crypto_dh_derive_secret() is an exception that can use the +faster version since it does not depend on private keys). + +crypto_bignum_div() is currently used only in SAE FFC case with not +safe-prime groups and only with values that do not depend on private +keys, so it is not critical to protect it. + +crypto_bignum_inverse() is currently used only in SAE FFC PWE +derivation. The additional protection here is targeting only OpenSSL. +BoringSSL may need conversion to using BN_mod_inverse_blinded(). + +This is related to CVE-2019-9494 and CVE-2019-9495. + +Signed-off-by: Jouni Malinen <jouni@codeaurora.org> +--- + src/crypto/crypto_openssl.c | 20 +++++++++++++++----- + 1 file changed, 15 insertions(+), 5 deletions(-) + +--- a/src/crypto/crypto_openssl.c ++++ b/src/crypto/crypto_openssl.c +@@ -549,7 +549,8 @@ int crypto_mod_exp(const u8 *base, size_ + bn_result == NULL) + goto error; + +- if (BN_mod_exp(bn_result, bn_base, bn_exp, bn_modulus, ctx) != 1) ++ if (BN_mod_exp_mont_consttime(bn_result, bn_base, bn_exp, bn_modulus, ++ ctx, NULL) != 1) + goto error; + + *result_len = BN_bn2bin(bn_result, result); +@@ -1295,8 +1296,9 @@ int crypto_bignum_exptmod(const struct c + bnctx = BN_CTX_new(); + if (bnctx == NULL) + return -1; +- res = BN_mod_exp((BIGNUM *) d, (const BIGNUM *) a, (const BIGNUM *) b, +- (const BIGNUM *) c, bnctx); ++ res = BN_mod_exp_mont_consttime((BIGNUM *) d, (const BIGNUM *) a, ++ (const BIGNUM *) b, (const BIGNUM *) c, ++ bnctx, NULL); + BN_CTX_free(bnctx); + + return res ? 0 : -1; +@@ -1315,6 +1317,11 @@ int crypto_bignum_inverse(const struct c + bnctx = BN_CTX_new(); + if (bnctx == NULL) + return -1; ++#ifdef OPENSSL_IS_BORINGSSL ++ /* TODO: use BN_mod_inverse_blinded() ? */ ++#else /* OPENSSL_IS_BORINGSSL */ ++ BN_set_flags((BIGNUM *) a, BN_FLG_CONSTTIME); ++#endif /* OPENSSL_IS_BORINGSSL */ + res = BN_mod_inverse((BIGNUM *) c, (const BIGNUM *) a, + (const BIGNUM *) b, bnctx); + BN_CTX_free(bnctx); +@@ -1348,6 +1355,9 @@ int crypto_bignum_div(const struct crypt + bnctx = BN_CTX_new(); + if (bnctx == NULL) + return -1; ++#ifndef OPENSSL_IS_BORINGSSL ++ BN_set_flags((BIGNUM *) a, BN_FLG_CONSTTIME); ++#endif /* OPENSSL_IS_BORINGSSL */ + res = BN_div((BIGNUM *) c, NULL, (const BIGNUM *) a, + (const BIGNUM *) b, bnctx); + BN_CTX_free(bnctx); +@@ -1439,8 +1449,8 @@ int crypto_bignum_legendre(const struct + /* exp = (p-1) / 2 */ + !BN_sub(exp, (const BIGNUM *) p, BN_value_one()) || + !BN_rshift1(exp, exp) || +- !BN_mod_exp(tmp, (const BIGNUM *) a, exp, (const BIGNUM *) p, +- bnctx)) ++ !BN_mod_exp_mont_consttime(tmp, (const BIGNUM *) a, exp, ++ (const BIGNUM *) p, bnctx, NULL)) + goto fail; + + if (BN_is_word(tmp, 1)) |