From 5f69f5c65e483928c4b28ed16af6e5742929f1ee Mon Sep 17 00:00:00 2001 From: Pauli Date: Fri, 6 Oct 2023 10:26:23 +1100 Subject: [PATCH] evp: process key length and iv length early if present evp_cipher_init_internal() takes a params array argument and this is processed late in the initialisation process for some ciphers (AEAD ones). This means that changing the IV length as a parameter will either truncate the IV (very bad if SP 800-38d section 8.2.1 is used) or grab extra uninitialised bytes. Truncation is very bad if SP 800-38d section 8.2.1 is being used to contruct a deterministic IV. This leads to an instant loss of confidentiality. Grabbing extra bytes isn't so serious, it will most likely result in a bad decryption. Problem reported by Tony Battersby of Cybernetics.com but earlier discovered and raised as issue #19822. Fixes CVE-2023-5363 Fixes #19822 Reviewed-by: Hugo Landau Reviewed-by: Matt Caswell --- crypto/evp/evp_enc.c | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) diff --git a/crypto/evp/evp_enc.c b/crypto/evp/evp_enc.c index fec889d2fe..2b8b9f4b6f 100644 --- a/crypto/evp/evp_enc.c +++ b/crypto/evp/evp_enc.c @@ -228,6 +228,42 @@ static int evp_cipher_init_internal(EVP_CIPHER_CTX *ctx, return 0; } +#ifndef FIPS_MODULE + /* + * Fix for CVE-2023-5363 + * Passing in a size as part of the init call takes effect late + * so, force such to occur before the initialisation. + * + * The FIPS provider's internal library context is used in a manner + * such that this is not an issue. + */ + if (params != NULL) { + OSSL_PARAM param_lens[3] = { OSSL_PARAM_END, OSSL_PARAM_END, + OSSL_PARAM_END }; + OSSL_PARAM *q = param_lens; + const OSSL_PARAM *p; + + p = OSSL_PARAM_locate_const(params, OSSL_CIPHER_PARAM_KEYLEN); + if (p != NULL) + memcpy(q++, p, sizeof(*q)); + + /* + * Note that OSSL_CIPHER_PARAM_AEAD_IVLEN is a synomym for + * OSSL_CIPHER_PARAM_IVLEN so both are covered here. + */ + p = OSSL_PARAM_locate_const(params, OSSL_CIPHER_PARAM_IVLEN); + if (p != NULL) + memcpy(q++, p, sizeof(*q)); + + if (q != param_lens) { + if (!EVP_CIPHER_CTX_set_params(ctx, param_lens)) { + ERR_raise(ERR_LIB_EVP, EVP_R_INVALID_LENGTH); + return 0; + } + } + } +#endif + if (enc) { if (ctx->cipher->einit == NULL) { ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR); -- 2.34.1