diff options
author | Norbert Preining <norbert@preining.info> | 2019-09-02 13:46:59 +0900 |
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committer | Norbert Preining <norbert@preining.info> | 2019-09-02 13:46:59 +0900 |
commit | e0c6872cf40896c7be36b11dcc744620f10adf1d (patch) | |
tree | 60335e10d2f4354b0674ec22d7b53f0f8abee672 /support/dktools/dk4memrs.ctr |
Initial commit
Diffstat (limited to 'support/dktools/dk4memrs.ctr')
-rw-r--r-- | support/dktools/dk4memrs.ctr | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/support/dktools/dk4memrs.ctr b/support/dktools/dk4memrs.ctr new file mode 100644 index 0000000000..735df8db5a --- /dev/null +++ b/support/dktools/dk4memrs.ctr @@ -0,0 +1,149 @@ +%% 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; +} + + + |