diff options
| author | Richard Levitte <levitte@openssl.org> | 2023-10-20 09:18:19 +0200 |
|---|---|---|
| committer | Hugo Landau <hlandau@openssl.org> | 2023-11-06 07:55:01 +0000 |
| commit | ec061bf8ff2add8050599058557178c03295bcc0 (patch) | |
| tree | 29c7316a658b332b0ec6168847e7041d5b0985a6 /crypto/dh | |
| parent | 4ede274cf9b7b9f946fa243c798c961213d1f053 (diff) | |
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/22453)
Diffstat (limited to 'crypto/dh')
| -rw-r--r-- | crypto/dh/dh_check.c | 12 | ||||
| -rw-r--r-- | crypto/dh/dh_err.c | 3 | ||||
| -rw-r--r-- | crypto/dh/dh_key.c | 12 |
3 files changed, 26 insertions, 1 deletions
diff --git a/crypto/dh/dh_check.c b/crypto/dh/dh_check.c index 7ba2beae7f..e20eb62081 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 f1f4fb6a37..4d6d2acd98 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 1995-2022 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 @@ -55,6 +55,7 @@ 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 8ab75e06d7..7132b9b68e 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; @@ -271,6 +277,12 @@ 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; |