diff options
author | Matt Caswell <matt@openssl.org> | 2021-02-02 17:17:23 +0000 |
---|---|---|
committer | Matt Caswell <matt@openssl.org> | 2021-02-16 11:42:35 +0000 |
commit | 6a51b9e1d0cf0bf8515f7201b68fb0a3482b3dc1 (patch) | |
tree | 2b8bd698a2abd611cdcaac10f6599a4cc6042662 /crypto | |
parent | 481a88f13c44996a008195791ea0dc076b968774 (diff) |
Don't overflow the output length in EVP_CipherUpdate calls
CVE-2021-23840
Reviewed-by: Paul Dale <pauli@openssl.org>
Diffstat (limited to 'crypto')
-rw-r--r-- | crypto/err/openssl.txt | 3 | ||||
-rw-r--r-- | crypto/evp/evp_enc.c | 27 | ||||
-rw-r--r-- | crypto/evp/evp_err.c | 4 |
3 files changed, 32 insertions, 2 deletions
diff --git a/crypto/err/openssl.txt b/crypto/err/openssl.txt index 815460b24f..7e1776375d 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 @@ -2283,6 +2283,7 @@ 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 b9b6490fe0..0843caf4f0 100644 --- a/crypto/evp/evp_enc.c +++ b/crypto/evp/evp_enc.c @@ -8,6 +8,7 @@ */ #include <stdio.h> +#include <limits.h> #include <assert.h> #include "internal/cryptlib.h" #include <openssl/evp.h> @@ -355,6 +356,19 @@ 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; @@ -502,6 +516,19 @@ 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 05481d827f..32ac0125de 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"}, |