hostap/src/utils/os_internal.c
Jouni Malinen afc3c8b07f Add constant time memory comparison function os_memcmp_const
This function is meant for comparing passwords or hash values where
difference in execution time could provide external observer information
about the location of the difference in the memory buffers. The return
value does not behave like os_memcmp(), i.e., os_memcmp_const() cannot
be used to sort items into a defined order. Unlike os_memcmp(),
execution time of os_memcmp_const() does not depend on the contents of
the compared memory buffers, but only on the total compared length.

Signed-off-by: Jouni Malinen <j@w1.fi>
2014-07-02 12:38:47 +03:00

508 lines
7.8 KiB
C

/*
* wpa_supplicant/hostapd / Internal implementation of OS specific functions
* Copyright (c) 2005-2006, Jouni Malinen <j@w1.fi>
*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
*
* This file is an example of operating system specific wrapper functions.
* This version implements many of the functions internally, so it can be used
* to fill in missing functions from the target system C libraries.
*
* Some of the functions are using standard C library calls in order to keep
* this file in working condition to allow the functions to be tested on a
* Linux target. Please note that OS_NO_C_LIB_DEFINES needs to be defined for
* this file to work correctly. Note that these implementations are only
* examples and are not optimized for speed.
*/
#include "includes.h"
#undef OS_REJECT_C_LIB_FUNCTIONS
#include "os.h"
void os_sleep(os_time_t sec, os_time_t usec)
{
if (sec)
sleep(sec);
if (usec)
usleep(usec);
}
int os_get_time(struct os_time *t)
{
int res;
struct timeval tv;
res = gettimeofday(&tv, NULL);
t->sec = tv.tv_sec;
t->usec = tv.tv_usec;
return res;
}
int os_get_reltime(struct os_reltime *t)
{
int res;
struct timeval tv;
res = gettimeofday(&tv, NULL);
t->sec = tv.tv_sec;
t->usec = tv.tv_usec;
return res;
}
int os_mktime(int year, int month, int day, int hour, int min, int sec,
os_time_t *t)
{
struct tm tm;
if (year < 1970 || month < 1 || month > 12 || day < 1 || day > 31 ||
hour < 0 || hour > 23 || min < 0 || min > 59 || sec < 0 ||
sec > 60)
return -1;
os_memset(&tm, 0, sizeof(tm));
tm.tm_year = year - 1900;
tm.tm_mon = month - 1;
tm.tm_mday = day;
tm.tm_hour = hour;
tm.tm_min = min;
tm.tm_sec = sec;
*t = (os_time_t) mktime(&tm);
return 0;
}
int os_gmtime(os_time_t t, struct os_tm *tm)
{
struct tm *tm2;
time_t t2 = t;
tm2 = gmtime(&t2);
if (tm2 == NULL)
return -1;
tm->sec = tm2->tm_sec;
tm->min = tm2->tm_min;
tm->hour = tm2->tm_hour;
tm->day = tm2->tm_mday;
tm->month = tm2->tm_mon + 1;
tm->year = tm2->tm_year + 1900;
return 0;
}
int os_daemonize(const char *pid_file)
{
if (daemon(0, 0)) {
perror("daemon");
return -1;
}
if (pid_file) {
FILE *f = fopen(pid_file, "w");
if (f) {
fprintf(f, "%u\n", getpid());
fclose(f);
}
}
return -0;
}
void os_daemonize_terminate(const char *pid_file)
{
if (pid_file)
unlink(pid_file);
}
int os_get_random(unsigned char *buf, size_t len)
{
FILE *f;
size_t rc;
f = fopen("/dev/urandom", "rb");
if (f == NULL) {
printf("Could not open /dev/urandom.\n");
return -1;
}
rc = fread(buf, 1, len, f);
fclose(f);
return rc != len ? -1 : 0;
}
unsigned long os_random(void)
{
return random();
}
char * os_rel2abs_path(const char *rel_path)
{
char *buf = NULL, *cwd, *ret;
size_t len = 128, cwd_len, rel_len, ret_len;
if (rel_path[0] == '/')
return os_strdup(rel_path);
for (;;) {
buf = os_malloc(len);
if (buf == NULL)
return NULL;
cwd = getcwd(buf, len);
if (cwd == NULL) {
os_free(buf);
if (errno != ERANGE) {
return NULL;
}
len *= 2;
} else {
break;
}
}
cwd_len = strlen(cwd);
rel_len = strlen(rel_path);
ret_len = cwd_len + 1 + rel_len + 1;
ret = os_malloc(ret_len);
if (ret) {
os_memcpy(ret, cwd, cwd_len);
ret[cwd_len] = '/';
os_memcpy(ret + cwd_len + 1, rel_path, rel_len);
ret[ret_len - 1] = '\0';
}
os_free(buf);
return ret;
}
int os_program_init(void)
{
return 0;
}
void os_program_deinit(void)
{
}
int os_setenv(const char *name, const char *value, int overwrite)
{
return setenv(name, value, overwrite);
}
int os_unsetenv(const char *name)
{
#if defined(__FreeBSD__) || defined(__NetBSD__)
unsetenv(name);
return 0;
#else
return unsetenv(name);
#endif
}
char * os_readfile(const char *name, size_t *len)
{
FILE *f;
char *buf;
f = fopen(name, "rb");
if (f == NULL)
return NULL;
fseek(f, 0, SEEK_END);
*len = ftell(f);
fseek(f, 0, SEEK_SET);
buf = os_malloc(*len);
if (buf == NULL) {
fclose(f);
return NULL;
}
if (fread(buf, 1, *len, f) != *len) {
fclose(f);
os_free(buf);
return NULL;
}
fclose(f);
return buf;
}
void * os_zalloc(size_t size)
{
void *n = os_malloc(size);
if (n)
os_memset(n, 0, size);
return n;
}
void * os_malloc(size_t size)
{
return malloc(size);
}
void * os_realloc(void *ptr, size_t size)
{
return realloc(ptr, size);
}
void os_free(void *ptr)
{
free(ptr);
}
void * os_memcpy(void *dest, const void *src, size_t n)
{
char *d = dest;
const char *s = src;
while (n--)
*d++ = *s++;
return dest;
}
void * os_memmove(void *dest, const void *src, size_t n)
{
if (dest < src)
os_memcpy(dest, src, n);
else {
/* overlapping areas */
char *d = (char *) dest + n;
const char *s = (const char *) src + n;
while (n--)
*--d = *--s;
}
return dest;
}
void * os_memset(void *s, int c, size_t n)
{
char *p = s;
while (n--)
*p++ = c;
return s;
}
int os_memcmp(const void *s1, const void *s2, size_t n)
{
const unsigned char *p1 = s1, *p2 = s2;
if (n == 0)
return 0;
while (*p1 == *p2) {
p1++;
p2++;
n--;
if (n == 0)
return 0;
}
return *p1 - *p2;
}
char * os_strdup(const char *s)
{
char *res;
size_t len;
if (s == NULL)
return NULL;
len = os_strlen(s);
res = os_malloc(len + 1);
if (res)
os_memcpy(res, s, len + 1);
return res;
}
size_t os_strlen(const char *s)
{
const char *p = s;
while (*p)
p++;
return p - s;
}
int os_strcasecmp(const char *s1, const char *s2)
{
/*
* Ignoring case is not required for main functionality, so just use
* the case sensitive version of the function.
*/
return os_strcmp(s1, s2);
}
int os_strncasecmp(const char *s1, const char *s2, size_t n)
{
/*
* Ignoring case is not required for main functionality, so just use
* the case sensitive version of the function.
*/
return os_strncmp(s1, s2, n);
}
char * os_strchr(const char *s, int c)
{
while (*s) {
if (*s == c)
return (char *) s;
s++;
}
return NULL;
}
char * os_strrchr(const char *s, int c)
{
const char *p = s;
while (*p)
p++;
p--;
while (p >= s) {
if (*p == c)
return (char *) p;
p--;
}
return NULL;
}
int os_strcmp(const char *s1, const char *s2)
{
while (*s1 == *s2) {
if (*s1 == '\0')
break;
s1++;
s2++;
}
return *s1 - *s2;
}
int os_strncmp(const char *s1, const char *s2, size_t n)
{
if (n == 0)
return 0;
while (*s1 == *s2) {
if (*s1 == '\0')
break;
s1++;
s2++;
n--;
if (n == 0)
return 0;
}
return *s1 - *s2;
}
char * os_strncpy(char *dest, const char *src, size_t n)
{
char *d = dest;
while (n--) {
*d = *src;
if (*src == '\0')
break;
d++;
src++;
}
return dest;
}
size_t os_strlcpy(char *dest, const char *src, size_t siz)
{
const char *s = src;
size_t left = siz;
if (left) {
/* Copy string up to the maximum size of the dest buffer */
while (--left != 0) {
if ((*dest++ = *s++) == '\0')
break;
}
}
if (left == 0) {
/* Not enough room for the string; force NUL-termination */
if (siz != 0)
*dest = '\0';
while (*s++)
; /* determine total src string length */
}
return s - src - 1;
}
int os_memcmp_const(const void *a, const void *b, size_t len)
{
const u8 *aa = a;
const u8 *bb = b;
size_t i;
u8 res;
for (res = 0, i = 0; i < len; i++)
res |= aa[i] ^ bb[i];
return res;
}
char * os_strstr(const char *haystack, const char *needle)
{
size_t len = os_strlen(needle);
while (*haystack) {
if (os_strncmp(haystack, needle, len) == 0)
return (char *) haystack;
haystack++;
}
return NULL;
}
int os_snprintf(char *str, size_t size, const char *format, ...)
{
va_list ap;
int ret;
/* See http://www.ijs.si/software/snprintf/ for portable
* implementation of snprintf.
*/
va_start(ap, format);
ret = vsnprintf(str, size, format, ap);
va_end(ap);
if (size > 0)
str[size - 1] = '\0';
return ret;
}