mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-18 17:54:13 +08:00
62d16b5a3f
debug_putstr() is used to output strings without using printf-like
formatting but debug_putstr(v) is defined as early_printk(v) in
arch/x86/lib/kaslr.c.
This makes clang reports the following warning when building
with -Wformat-security:
arch/x86/lib/kaslr.c:57:15: warning: format string is not a string
literal (potentially insecure) [-Wformat-security]
debug_putstr(purpose);
^~~~~~~
Fix this by using "%s" in early_printk().
Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20160806102039.27221-1-nicolas.iooss_linux@m4x.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
91 lines
2.1 KiB
C
91 lines
2.1 KiB
C
/*
|
|
* Entropy functions used on early boot for KASLR base and memory
|
|
* randomization. The base randomization is done in the compressed
|
|
* kernel and memory randomization is done early when the regular
|
|
* kernel starts. This file is included in the compressed kernel and
|
|
* normally linked in the regular.
|
|
*/
|
|
#include <asm/kaslr.h>
|
|
#include <asm/msr.h>
|
|
#include <asm/archrandom.h>
|
|
#include <asm/e820.h>
|
|
#include <asm/io.h>
|
|
|
|
/*
|
|
* When built for the regular kernel, several functions need to be stubbed out
|
|
* or changed to their regular kernel equivalent.
|
|
*/
|
|
#ifndef KASLR_COMPRESSED_BOOT
|
|
#include <asm/cpufeature.h>
|
|
#include <asm/setup.h>
|
|
|
|
#define debug_putstr(v) early_printk("%s", v)
|
|
#define has_cpuflag(f) boot_cpu_has(f)
|
|
#define get_boot_seed() kaslr_offset()
|
|
#endif
|
|
|
|
#define I8254_PORT_CONTROL 0x43
|
|
#define I8254_PORT_COUNTER0 0x40
|
|
#define I8254_CMD_READBACK 0xC0
|
|
#define I8254_SELECT_COUNTER0 0x02
|
|
#define I8254_STATUS_NOTREADY 0x40
|
|
static inline u16 i8254(void)
|
|
{
|
|
u16 status, timer;
|
|
|
|
do {
|
|
outb(I8254_PORT_CONTROL,
|
|
I8254_CMD_READBACK | I8254_SELECT_COUNTER0);
|
|
status = inb(I8254_PORT_COUNTER0);
|
|
timer = inb(I8254_PORT_COUNTER0);
|
|
timer |= inb(I8254_PORT_COUNTER0) << 8;
|
|
} while (status & I8254_STATUS_NOTREADY);
|
|
|
|
return timer;
|
|
}
|
|
|
|
unsigned long kaslr_get_random_long(const char *purpose)
|
|
{
|
|
#ifdef CONFIG_X86_64
|
|
const unsigned long mix_const = 0x5d6008cbf3848dd3UL;
|
|
#else
|
|
const unsigned long mix_const = 0x3f39e593UL;
|
|
#endif
|
|
unsigned long raw, random = get_boot_seed();
|
|
bool use_i8254 = true;
|
|
|
|
debug_putstr(purpose);
|
|
debug_putstr(" KASLR using");
|
|
|
|
if (has_cpuflag(X86_FEATURE_RDRAND)) {
|
|
debug_putstr(" RDRAND");
|
|
if (rdrand_long(&raw)) {
|
|
random ^= raw;
|
|
use_i8254 = false;
|
|
}
|
|
}
|
|
|
|
if (has_cpuflag(X86_FEATURE_TSC)) {
|
|
debug_putstr(" RDTSC");
|
|
raw = rdtsc();
|
|
|
|
random ^= raw;
|
|
use_i8254 = false;
|
|
}
|
|
|
|
if (use_i8254) {
|
|
debug_putstr(" i8254");
|
|
random ^= i8254();
|
|
}
|
|
|
|
/* Circular multiply for better bit diffusion */
|
|
asm("mul %3"
|
|
: "=a" (random), "=d" (raw)
|
|
: "a" (random), "rm" (mix_const));
|
|
random += raw;
|
|
|
|
debug_putstr("...\n");
|
|
|
|
return random;
|
|
}
|