| From db925ae2e65d0d925adef429afc37f75bd1c2017 Mon Sep 17 00:00:00 2001 |
| From: Richard Levitte <levitte@openssl.org> |
| 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 <tomas@openssl.org> |
| Reviewed-by: Matt Caswell <matt@openssl.org> |
| Reviewed-by: Hugo Landau <hlandau@openssl.org> |
| (Merged from https://github.com/openssl/openssl/pull/22518) |
| |
| (cherry picked from commit ddeb4b6c6d527e54ce9a99cba785c0f7776e54b6) |
| --- |
| 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 e51504b7abd5c..36de321b749be 100644 |
| --- a/crypto/err/openssl.txt |
| +++ b/crypto/err/openssl.txt |
| @@ -500,6 +500,7 @@ 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 6533260f20272..50e0cf54be8cb 100644 |
| --- a/include/openssl/dh.h |
| +++ b/include/openssl/dh.h |
| @@ -141,7 +141,7 @@ 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. |
| @@ -151,10 +151,10 @@ 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 |
| |