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authorNorbert Preining <norbert@preining.info>2019-09-02 13:46:59 +0900
committerNorbert Preining <norbert@preining.info>2019-09-02 13:46:59 +0900
commite0c6872cf40896c7be36b11dcc744620f10adf1d (patch)
tree60335e10d2f4354b0674ec22d7b53f0f8abee672 /support/dktools/dk4memrs.ctr
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+%% options
+
+copyright owner = Dirk Krause
+copyright year = 2015-xxxx
+license = bsd
+
+
+%% header
+
+/** @file
+ Secure memory reset (reset byte buffer
+ to 0x00 bytes and read the buffer to prevent compilers
+ from optimizing the resetting out).
+*/
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** Secure memory reset.
+ This function does not just reset the bytes to 0,
+ it also reads each byte to check it.
+ Reading each byte should prevent the compiler from optimizing
+ out.
+ This function has significantly lower performance than
+ dk4mem_reset(), so use it to clear sensitive memory
+ (i.e. used for passwords, keys...) only.
+
+ CRT on Windows: Not used.
+ @param ptr Start address of memory range.
+ @param sz Size of memory range in bytes.
+ @param erp Error report, may be NULL.
+ @return 1 on success, 0 on error.
+
+ Error codes:
+ - DK4_E_INVALID_ARGUMENTS<br>
+ if ptr is NULL or sz is 0,
+ - DK4_E_BUG<br>
+ if one of the bytes in the buffer is not 0 during check.
+*/
+int
+dk4mem_reset_secure(void *ptr, size_t sz, dk4_er_t *erp);
+
+/** Secure memory release.
+ This function does not just reset the bytes to 0 before releasing
+ memory, it also reads each byte to check it.
+ Reading each byte should prevent the compiler from optimizing
+ out.
+ This function has significantly lower performance than
+ dk4mem_free(), so use it to clear sensitive memory
+ (i.e. used for passwords, keys...) only.
+
+ CRT on Windows: Not used.
+ @param ptr Start address of memory range.
+ @param sz Size of memory range in bytes.
+ @param erp Error report, may be NULL.
+ @return 1 on success, 0 on error.
+
+ Error codes:
+ - DK4_E_INVALID_ARGUMENTS<br>
+ if ptr is NULL or sz is 0,
+ - DK4_E_BUG<br>
+ if one of the bytes in the buffer is not 0 during check.
+*/
+int
+dk4mem_free_secure(void *ptr, size_t sz, dk4_er_t *erp);
+
+#ifdef __cplusplus
+}
+#endif
+
+/** Release memory securely (sanitize memory before releasing it).
+*/
+#define dk4mem_release_secure(ptr,sz,erp) \
+do { if (NULL != ptr) { (void)dk4mem_free_secure(ptr,sz,erp); } ptr = NULL; } while (0)
+
+
+%% module
+
+#include "dk4conf.h"
+
+#ifndef STDIO_H_INCLUDED
+#include <stdio.h>
+#define STDIO_H_INCLUDED 1
+#endif
+#ifndef STDLIB_H_INCLUDED
+#include <stdlib.h>
+#define STDLIB_H_INCLUDED 1
+#endif
+#if DK4_ON_WINDOWS
+#ifndef WINDOWS_H_INCLUDED
+#include <windows.h>
+#define WINDOWS_H_INCLUDED 1
+#endif
+#endif
+
+#include "dk4mem.h"
+
+int
+dk4mem_reset_secure(void *ptr, size_t sz, dk4_er_t *erp)
+{
+#if !DK4_ON_WINDOWS
+ unsigned char *p1;
+#endif
+ int back = 0;
+
+ if ((NULL != ptr) && (0 < sz)) {
+#if DK4_ON_WINDOWS
+ SecureZeroMemory(ptr, sz);
+ back = 1;
+#else
+ DK4_MEMRES(ptr, sz);
+ p1 = (unsigned char *)ptr;
+ back = 1;
+ while(sz--) {
+ if ('\0' != *(p1++)) {
+ back = 0;
+ dk4error_set_simple_error_code(erp, DK4_E_BUG);
+ }
+ }
+#endif
+ } else {
+ dk4error_set_simple_error_code(erp, DK4_E_INVALID_ARGUMENTS);
+ }
+ return back;
+}
+
+
+
+int
+dk4mem_free_secure(void *ptr, size_t sz, dk4_er_t *erp)
+{
+ int back = 0;
+
+ if (NULL != ptr) {
+ if (0 < sz) {
+ back = dk4mem_reset_secure(ptr, sz, erp);
+ } else {
+ back = 1;
+ }
+ dk4mem_free(ptr);
+ } else {
+ dk4error_set_simple_error_code(erp, DK4_E_INVALID_ARGUMENTS);
+ }
+ return back;
+}
+
+
+