From 2d8c20bf3cbb6f1afe51389b5da92937e10bfc33 Mon Sep 17 00:00:00 2001 From: Matt Caswell Date: Wed, 10 Feb 2021 16:10:36 +0000 Subject: [PATCH 1/2] Fix Null pointer deref in X509_issuer_and_serial_hash() The OpenSSL public API function X509_issuer_and_serial_hash() attempts to create a unique hash value based on the issuer and serial number data contained within an X509 certificate. However it fails to correctly handle any errors that may occur while parsing the issuer field (which might occur if the issuer field is maliciously constructed). This may subsequently result in a NULL pointer deref and a crash leading to a potential denial of service attack. The function X509_issuer_and_serial_hash() is never directly called by OpenSSL itself so applications are only vulnerable if they use this function directly and they use it on certificates that may have been obtained from untrusted sources. CVE-2021-23841 Reviewed-by: Richard Levitte Reviewed-by: Paul Dale (cherry picked from commit 8130d654d1de922ea224fa18ee3bc7262edc39c0) --- crypto/x509/x509_cmp.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/crypto/x509/x509_cmp.c b/crypto/x509/x509_cmp.c index d1600e1e8..99920e299 100644 --- a/crypto/x509/x509_cmp.c +++ b/crypto/x509/x509_cmp.c @@ -39,6 +39,8 @@ unsigned long X509_issuer_and_serial_hash(X509 *a) if (ctx == NULL) goto err; f = X509_NAME_oneline(a->cert_info.issuer, NULL, 0); + if (f == NULL) + goto err; if (!EVP_DigestInit_ex(ctx, EVP_md5(), NULL)) goto err; if (!EVP_DigestUpdate(ctx, (unsigned char *)f, strlen(f))) From 5eae3d1b48f861145797d24c5bf78e72e78ffb19 Mon Sep 17 00:00:00 2001 From: Matt Caswell Date: Tue, 2 Feb 2021 17:17:23 +0000 Subject: [PATCH 2/2] Don't overflow the output length in EVP_CipherUpdate calls CVE-2021-23840 Reviewed-by: Paul Dale --- crypto/err/openssl.txt | 3 ++- crypto/evp/evp_enc.c | 27 +++++++++++++++++++++++++++ crypto/evp/evp_err.c | 4 +++- include/openssl/evperr.h | 7 +++---- 4 files changed, 35 insertions(+), 6 deletions(-) diff --git a/crypto/err/openssl.txt b/crypto/err/openssl.txt index 3f2d18a5e..87762f658 100644 --- a/crypto/err/openssl.txt +++ b/crypto/err/openssl.txt @@ -1,4 +1,4 @@ -# Copyright 1999-2020 The OpenSSL Project Authors. All Rights Reserved. +# Copyright 1999-2021 The OpenSSL Project Authors. All Rights Reserved. # # Licensed under the OpenSSL license (the "License"). You may not use # this file except in compliance with the License. You can obtain a copy @@ -2562,6 +2562,7 @@ EVP_R_ONLY_ONESHOT_SUPPORTED:177:only oneshot supported EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE:150:\ operation not supported for this keytype EVP_R_OPERATON_NOT_INITIALIZED:151:operaton not initialized +EVP_R_OUTPUT_WOULD_OVERFLOW:184:output would overflow EVP_R_PARTIALLY_OVERLAPPING:162:partially overlapping buffers EVP_R_PBKDF2_ERROR:181:pbkdf2 error EVP_R_PKEY_APPLICATION_ASN1_METHOD_ALREADY_REGISTERED:179:\ diff --git a/crypto/evp/evp_enc.c b/crypto/evp/evp_enc.c index d2ea16fa4..26622b4d7 100644 --- a/crypto/evp/evp_enc.c +++ b/crypto/evp/evp_enc.c @@ -8,6 +8,7 @@ */ #include +#include #include #include "internal/cryptlib.h" #include @@ -382,6 +383,19 @@ static int evp_EncryptDecryptUpdate(EVP_CIPHER_CTX *ctx, return 1; } else { j = bl - i; + + /* + * Once we've processed the first j bytes from in, the amount of + * data left that is a multiple of the block length is: + * (inl - j) & ~(bl - 1) + * We must ensure that this amount of data, plus the one block that + * we process from ctx->buf does not exceed INT_MAX + */ + if (((inl - j) & ~(bl - 1)) > INT_MAX - bl) { + EVPerr(EVP_F_EVP_ENCRYPTDECRYPTUPDATE, + EVP_R_OUTPUT_WOULD_OVERFLOW); + return 0; + } memcpy(&(ctx->buf[i]), in, j); inl -= j; in += j; @@ -529,6 +543,19 @@ int EVP_DecryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl, EVPerr(EVP_F_EVP_DECRYPTUPDATE, EVP_R_PARTIALLY_OVERLAPPING); return 0; } + /* + * final_used is only ever set if buf_len is 0. Therefore the maximum + * length output we will ever see from evp_EncryptDecryptUpdate is + * the maximum multiple of the block length that is <= inl, or just: + * inl & ~(b - 1) + * Since final_used has been set then the final output length is: + * (inl & ~(b - 1)) + b + * This must never exceed INT_MAX + */ + if ((inl & ~(b - 1)) > INT_MAX - b) { + EVPerr(EVP_F_EVP_DECRYPTUPDATE, EVP_R_OUTPUT_WOULD_OVERFLOW); + return 0; + } memcpy(out, ctx->final, b); out += b; fix_len = 1; diff --git a/crypto/evp/evp_err.c b/crypto/evp/evp_err.c index 05481d827..32ac0125d 100644 --- a/crypto/evp/evp_err.c +++ b/crypto/evp/evp_err.c @@ -1,6 +1,6 @@ /* * Generated by util/mkerr.pl DO NOT EDIT - * Copyright 1995-2020 The OpenSSL Project Authors. All Rights Reserved. + * Copyright 1995-2021 The OpenSSL Project Authors. All Rights Reserved. * * Licensed under the OpenSSL license (the "License"). You may not use * this file except in compliance with the License. You can obtain a copy @@ -239,6 +239,8 @@ static const ERR_STRING_DATA EVP_str_reasons[] = { "operation not supported for this keytype"}, {ERR_PACK(ERR_LIB_EVP, 0, EVP_R_OPERATON_NOT_INITIALIZED), "operaton not initialized"}, + {ERR_PACK(ERR_LIB_EVP, 0, EVP_R_OUTPUT_WOULD_OVERFLOW), + "output would overflow"}, {ERR_PACK(ERR_LIB_EVP, 0, EVP_R_PARTIALLY_OVERLAPPING), "partially overlapping buffers"}, {ERR_PACK(ERR_LIB_EVP, 0, EVP_R_PBKDF2_ERROR), "pbkdf2 error"}, diff --git a/include/openssl/evperr.h b/include/openssl/evperr.h index cde68f67e..eb8e0f6c5 100644 --- a/include/openssl/evperr.h +++ b/include/openssl/evperr.h @@ -1,6 +1,6 @@ /* * Generated by util/mkerr.pl DO NOT EDIT - * Copyright 1995-2020 The OpenSSL Project Authors. All Rights Reserved. + * Copyright 1995-2021 The OpenSSL Project Authors. All Rights Reserved. * * Licensed under the OpenSSL license (the "License"). You may not use * this file except in compliance with the License. You can obtain a copy @@ -11,9 +11,7 @@ #ifndef HEADER_EVPERR_H # define HEADER_EVPERR_H -# ifndef HEADER_SYMHACKS_H -# include -# endif +# include # ifdef __cplusplus extern "C" @@ -178,6 +176,7 @@ int ERR_load_EVP_strings(void); # define EVP_R_ONLY_ONESHOT_SUPPORTED 177 # define EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE 150 # define EVP_R_OPERATON_NOT_INITIALIZED 151 +# define EVP_R_OUTPUT_WOULD_OVERFLOW 184 # define EVP_R_PARTIALLY_OVERLAPPING 162 # define EVP_R_PBKDF2_ERROR 181 # define EVP_R_PKEY_APPLICATION_ASN1_METHOD_ALREADY_REGISTERED 179