mirror of
https://gitlab.com/cryptsetup/cryptsetup.git
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103 lines
2.3 KiB
C
103 lines
2.3 KiB
C
/*
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* utils_safe_memory - safe memory helpers
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*
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* Copyright (C) 2009-2020 Red Hat, Inc. All rights reserved.
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* Copyright (C) 2009-2020 Milan Broz
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include <stdlib.h>
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#include <string.h>
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#include "libcryptsetup.h"
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struct safe_allocation {
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size_t size;
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char data[0];
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};
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/*
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* Replacement for memset(s, 0, n) on stack that can be optimized out
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* Also used in safe allocations for explicit memory wipe.
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*/
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void crypt_safe_memzero(void *data, size_t size)
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{
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#ifdef HAVE_EXPLICIT_BZERO
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explicit_bzero(data, size);
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#else
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volatile uint8_t *p = (volatile uint8_t *)data;
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while(size--)
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*p++ = 0;
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#endif
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}
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/* safe allocations */
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void *crypt_safe_alloc(size_t size)
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{
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struct safe_allocation *alloc;
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if (!size || size > (SIZE_MAX - offsetof(struct safe_allocation, data)))
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return NULL;
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alloc = malloc(size + offsetof(struct safe_allocation, data));
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if (!alloc)
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return NULL;
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alloc->size = size;
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crypt_safe_memzero(&alloc->data, size);
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/* coverity[leaked_storage] */
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return &alloc->data;
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}
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void crypt_safe_free(void *data)
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{
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struct safe_allocation *alloc;
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if (!data)
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return;
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alloc = (struct safe_allocation *)
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((char *)data - offsetof(struct safe_allocation, data));
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crypt_safe_memzero(data, alloc->size);
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alloc->size = 0x55aa55aa;
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free(alloc);
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}
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void *crypt_safe_realloc(void *data, size_t size)
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{
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struct safe_allocation *alloc;
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void *new_data;
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new_data = crypt_safe_alloc(size);
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if (new_data && data) {
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alloc = (struct safe_allocation *)
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((char *)data - offsetof(struct safe_allocation, data));
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if (size > alloc->size)
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size = alloc->size;
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memcpy(new_data, data, size);
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}
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crypt_safe_free(data);
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return new_data;
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}
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