linux/arch/powerpc/xmon/nonstdio.c
Kees Cook 50b66dbf87 powerpc/xmon: avoid format string leaking to printk
This makes sure format strings cannot leak into printk (the string has
already been correctly processed for format arguments).

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-06-11 17:04:03 +10:00

133 lines
2.2 KiB
C

/*
* Copyright (C) 1996-2005 Paul Mackerras.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/string.h>
#include <asm/udbg.h>
#include <asm/time.h>
#include "nonstdio.h"
static int xmon_write(const void *ptr, int nb)
{
return udbg_write(ptr, nb);
}
static int xmon_readchar(void)
{
if (udbg_getc)
return udbg_getc();
return -1;
}
int xmon_putchar(int c)
{
char ch = c;
if (c == '\n')
xmon_putchar('\r');
return xmon_write(&ch, 1) == 1? c: -1;
}
static char line[256];
static char *lineptr;
static int lineleft;
static int xmon_getchar(void)
{
int c;
if (lineleft == 0) {
lineptr = line;
for (;;) {
c = xmon_readchar();
if (c == -1 || c == 4)
break;
if (c == '\r' || c == '\n') {
*lineptr++ = '\n';
xmon_putchar('\n');
break;
}
switch (c) {
case 0177:
case '\b':
if (lineptr > line) {
xmon_putchar('\b');
xmon_putchar(' ');
xmon_putchar('\b');
--lineptr;
}
break;
case 'U' & 0x1F:
while (lineptr > line) {
xmon_putchar('\b');
xmon_putchar(' ');
xmon_putchar('\b');
--lineptr;
}
break;
default:
if (lineptr >= &line[sizeof(line) - 1])
xmon_putchar('\a');
else {
xmon_putchar(c);
*lineptr++ = c;
}
}
}
lineleft = lineptr - line;
lineptr = line;
}
if (lineleft == 0)
return -1;
--lineleft;
return *lineptr++;
}
char *xmon_gets(char *str, int nb)
{
char *p;
int c;
for (p = str; p < str + nb - 1; ) {
c = xmon_getchar();
if (c == -1) {
if (p == str)
return NULL;
break;
}
*p++ = c;
if (c == '\n')
break;
}
*p = 0;
return str;
}
void xmon_printf(const char *format, ...)
{
va_list args;
static char xmon_outbuf[1024];
int rc, n;
va_start(args, format);
n = vsnprintf(xmon_outbuf, sizeof(xmon_outbuf), format, args);
va_end(args);
rc = xmon_write(xmon_outbuf, n);
if (n && rc == 0) {
/* No udbg hooks, fallback to printk() - dangerous */
printk("%s", xmon_outbuf);
}
}
void xmon_puts(const char *str)
{
xmon_write(str, strlen(str));
}