From ddeb4b6c6d527e54ce9a99cba785c0f7776e54b6 Mon Sep 17 00:00:00 2001 From: Richard Levitte Date: Fri, 20 Oct 2023 09:18:19 +0200 Subject: [PATCH] Make DH_check_pub_key() and DH_generate_key() safer yet We already check for an excessively large P in DH_generate_key(), but not in DH_check_pub_key(), and none of them check for an excessively large Q. This change adds all the missing excessive size checks of P and Q. It's to be noted that behaviours surrounding excessively sized P and Q differ. DH_check() raises an error on the excessively sized P, but only sets a flag for the excessively sized Q. This behaviour is mimicked in DH_check_pub_key(). Reviewed-by: Tomas Mraz Reviewed-by: Matt Caswell Reviewed-by: Hugo Landau (Merged from https://github.com/openssl/openssl/pull/22518) --- crypto/dh/dh_check.c | 12 ++++++++++++ crypto/dh/dh_err.c | 3 ++- crypto/dh/dh_key.c | 12 ++++++++++++ crypto/err/openssl.txt | 1 + include/crypto/dherr.h | 2 +- include/openssl/dh.h | 6 +++--- include/openssl/dherr.h | 3 ++- 7 files changed, 33 insertions(+), 6 deletions(-) diff --git a/crypto/dh/dh_check.c b/crypto/dh/dh_check.c index 7ba2beae7fd6b..e20eb62081c5e 100644 --- a/crypto/dh/dh_check.c +++ b/crypto/dh/dh_check.c @@ -249,6 +249,18 @@ int DH_check_pub_key_ex(const DH *dh, const BIGNUM *pub_key) */ int DH_check_pub_key(const DH *dh, const BIGNUM *pub_key, int *ret) { + /* Don't do any checks at all with an excessively large modulus */ + if (BN_num_bits(dh->params.p) > OPENSSL_DH_CHECK_MAX_MODULUS_BITS) { + ERR_raise(ERR_LIB_DH, DH_R_MODULUS_TOO_LARGE); + *ret = DH_MODULUS_TOO_LARGE | DH_CHECK_PUBKEY_INVALID; + return 0; + } + + if (dh->params.q != NULL && BN_ucmp(dh->params.p, dh->params.q) < 0) { + *ret |= DH_CHECK_INVALID_Q_VALUE | DH_CHECK_PUBKEY_INVALID; + return 1; + } + return ossl_ffc_validate_public_key(&dh->params, pub_key, ret); } diff --git a/crypto/dh/dh_err.c b/crypto/dh/dh_err.c index 4152397426cc9..f76ac0dd1463f 100644 --- a/crypto/dh/dh_err.c +++ b/crypto/dh/dh_err.c @@ -1,6 +1,6 @@ /* * Generated by util/mkerr.pl DO NOT EDIT - * Copyright 1995-2021 The OpenSSL Project Authors. All Rights Reserved. + * Copyright 1995-2023 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 @@ -54,6 +54,7 @@ static const ERR_STRING_DATA DH_str_reasons[] = { {ERR_PACK(ERR_LIB_DH, 0, DH_R_PARAMETER_ENCODING_ERROR), "parameter encoding error"}, {ERR_PACK(ERR_LIB_DH, 0, DH_R_PEER_KEY_ERROR), "peer key error"}, + {ERR_PACK(ERR_LIB_DH, 0, DH_R_Q_TOO_LARGE), "q too large"}, {ERR_PACK(ERR_LIB_DH, 0, DH_R_SHARED_INFO_ERROR), "shared info error"}, {ERR_PACK(ERR_LIB_DH, 0, DH_R_UNABLE_TO_CHECK_GENERATOR), "unable to check generator"}, diff --git a/crypto/dh/dh_key.c b/crypto/dh/dh_key.c index d84ea99241b9e..afc49f5cdc87d 100644 --- a/crypto/dh/dh_key.c +++ b/crypto/dh/dh_key.c @@ -49,6 +49,12 @@ int ossl_dh_compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh) goto err; } + if (dh->params.q != NULL + && BN_num_bits(dh->params.q) > OPENSSL_DH_MAX_MODULUS_BITS) { + ERR_raise(ERR_LIB_DH, DH_R_Q_TOO_LARGE); + goto err; + } + if (BN_num_bits(dh->params.p) < DH_MIN_MODULUS_BITS) { ERR_raise(ERR_LIB_DH, DH_R_MODULUS_TOO_SMALL); return 0; @@ -267,6 +273,12 @@ static int generate_key(DH *dh) return 0; } + if (dh->params.q != NULL + && BN_num_bits(dh->params.q) > OPENSSL_DH_MAX_MODULUS_BITS) { + ERR_raise(ERR_LIB_DH, DH_R_Q_TOO_LARGE); + return 0; + } + if (BN_num_bits(dh->params.p) < DH_MIN_MODULUS_BITS) { ERR_raise(ERR_LIB_DH, DH_R_MODULUS_TOO_SMALL); return 0; diff --git a/crypto/err/openssl.txt b/crypto/err/openssl.txt index a1e6bbb617fcb..69e4f61aa1801 100644 --- a/crypto/err/openssl.txt +++ b/crypto/err/openssl.txt @@ -513,6 +513,7 @@ DH_R_NO_PARAMETERS_SET:107:no parameters set DH_R_NO_PRIVATE_VALUE:100:no private value DH_R_PARAMETER_ENCODING_ERROR:105:parameter encoding error DH_R_PEER_KEY_ERROR:111:peer key error +DH_R_Q_TOO_LARGE:130:q too large DH_R_SHARED_INFO_ERROR:113:shared info error DH_R_UNABLE_TO_CHECK_GENERATOR:121:unable to check generator DSA_R_BAD_FFC_PARAMETERS:114:bad ffc parameters diff --git a/include/crypto/dherr.h b/include/crypto/dherr.h index bb24d131eb887..519327f795742 100644 --- a/include/crypto/dherr.h +++ b/include/crypto/dherr.h @@ -1,6 +1,6 @@ /* * Generated by util/mkerr.pl DO NOT EDIT - * Copyright 2020-2021 The OpenSSL Project Authors. All Rights Reserved. + * Copyright 2020-2023 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 diff --git a/include/openssl/dh.h b/include/openssl/dh.h index 8bc17448a0817..f1c0ed06b375a 100644 --- a/include/openssl/dh.h +++ b/include/openssl/dh.h @@ -144,7 +144,7 @@ DECLARE_ASN1_ITEM(DHparams) # define DH_GENERATOR_3 3 # define DH_GENERATOR_5 5 -/* DH_check error codes */ +/* DH_check error codes, some of them shared with DH_check_pub_key */ /* * NB: These values must align with the equivalently named macros in * internal/ffc.h. @@ -154,10 +154,10 @@ DECLARE_ASN1_ITEM(DHparams) # define DH_UNABLE_TO_CHECK_GENERATOR 0x04 # define DH_NOT_SUITABLE_GENERATOR 0x08 # define DH_CHECK_Q_NOT_PRIME 0x10 -# define DH_CHECK_INVALID_Q_VALUE 0x20 +# define DH_CHECK_INVALID_Q_VALUE 0x20 /* +DH_check_pub_key */ # define DH_CHECK_INVALID_J_VALUE 0x40 # define DH_MODULUS_TOO_SMALL 0x80 -# define DH_MODULUS_TOO_LARGE 0x100 +# define DH_MODULUS_TOO_LARGE 0x100 /* +DH_check_pub_key */ /* DH_check_pub_key error codes */ # define DH_CHECK_PUBKEY_TOO_SMALL 0x01 diff --git a/include/openssl/dherr.h b/include/openssl/dherr.h index 5d2a762a96f8c..074a70145f9f5 100644 --- a/include/openssl/dherr.h +++ b/include/openssl/dherr.h @@ -1,6 +1,6 @@ /* * Generated by util/mkerr.pl DO NOT EDIT - * Copyright 1995-2021 The OpenSSL Project Authors. All Rights Reserved. + * Copyright 1995-2023 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 @@ -50,6 +50,7 @@ # define DH_R_NO_PRIVATE_VALUE 100 # define DH_R_PARAMETER_ENCODING_ERROR 105 # define DH_R_PEER_KEY_ERROR 111 +# define DH_R_Q_TOO_LARGE 130 # define DH_R_SHARED_INFO_ERROR 113 # define DH_R_UNABLE_TO_CHECK_GENERATOR 121