openssl/providers/implementations/ciphers/cipher_sm4.c
Shane Lontis f75abcc0f0 Fix Use after free when copying cipher ctx
Fixes #10438
issue found by clusterfuzz/ossfuzz

The dest was getting a copy of the src structure which contained a pointer that should point to an offset inside itself - because of the copy it was pointing to the original structure.

The setup for a ctx is mainly done by the initkey method in the PROV_CIPHER_HW structure. Because of this it makes sense that the structure should also contain a copyctx method that is use to resolve any pointers that need to be setup.

A dup_ctx has been added to the cipher_enc tests in evp_test. It does a dup after setup and then frees the original ctx. This detects any floating pointers in the duplicated context that were pointing back to the freed ctx.

Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/10443)
2019-11-18 13:13:05 +10:00

49 lines
1.4 KiB
C

/*
* Copyright 2019 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
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
/* Dispatch functions for cast cipher modes ecb, cbc, ofb, cfb */
#include "cipher_sm4.h"
#include "prov/implementations.h"
static OSSL_OP_cipher_freectx_fn sm4_freectx;
static OSSL_OP_cipher_dupctx_fn sm4_dupctx;
static void sm4_freectx(void *vctx)
{
PROV_SM4_CTX *ctx = (PROV_SM4_CTX *)vctx;
OPENSSL_clear_free(ctx, sizeof(*ctx));
}
static void *sm4_dupctx(void *ctx)
{
PROV_SM4_CTX *in = (PROV_SM4_CTX *)ctx;
PROV_SM4_CTX *ret = OPENSSL_malloc(sizeof(*ret));
if (ret == NULL) {
ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
return NULL;
}
in->base.hw->copyctx(&ret->base, &in->base);
return ret;
}
/* sm4128ecb_functions */
IMPLEMENT_generic_cipher(sm4, SM4, ecb, ECB, 0, 128, 128, 0, block)
/* sm4128cbc_functions */
IMPLEMENT_generic_cipher(sm4, SM4, cbc, CBC, 0, 128, 128, 128, block)
/* sm4128ctr_functions */
IMPLEMENT_generic_cipher(sm4, SM4, ctr, CTR, 0, 128, 8, 128, stream)
/* sm4128ofb128_functions */
IMPLEMENT_generic_cipher(sm4, SM4, ofb128, OFB, 0, 128, 8, 128, stream)
/* sm4128cfb128_functions */
IMPLEMENT_generic_cipher(sm4, SM4, cfb128, CFB, 0, 128, 8, 128, stream)