u-boot/common/autoboot.c

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// SPDX-License-Identifier: GPL-2.0+
/*
* (C) Copyright 2000
* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
*/
#include <common.h>
#include <autoboot.h>
#include <bootretry.h>
#include <cli.h>
#include <command.h>
#include <console.h>
#include <env.h>
#include <fdtdec.h>
#include <hash.h>
#include <log.h>
#include <malloc.h>
#include <memalign.h>
#include <menu.h>
#include <post.h>
#include <time.h>
#include <asm/global_data.h>
#include <linux/delay.h>
#include <u-boot/sha256.h>
#include <bootcount.h>
DECLARE_GLOBAL_DATA_PTR;
#define MAX_DELAY_STOP_STR 64
#ifndef DEBUG_BOOTKEYS
#define DEBUG_BOOTKEYS 0
#endif
#define debug_bootkeys(fmt, args...) \
debug_cond(DEBUG_BOOTKEYS, fmt, ##args)
/* Stored value of bootdelay, used by autoboot_command() */
static int stored_bootdelay;
static int menukey;
#ifdef CONFIG_AUTOBOOT_ENCRYPTION
#define AUTOBOOT_STOP_STR_SHA256 CONFIG_AUTOBOOT_STOP_STR_SHA256
#else
#define AUTOBOOT_STOP_STR_SHA256 ""
#endif
#ifdef CONFIG_AUTOBOOT_USE_MENUKEY
#define AUTOBOOT_MENUKEY CONFIG_AUTOBOOT_MENUKEY
#else
#define AUTOBOOT_MENUKEY 0
#endif
/*
* Use a "constant-length" time compare function for this
* hash compare:
*
* https://crackstation.net/hashing-security.htm
*/
static int slow_equals(u8 *a, u8 *b, int len)
{
int diff = 0;
int i;
for (i = 0; i < len; i++)
diff |= a[i] ^ b[i];
return diff == 0;
}
/**
* passwd_abort_sha256() - check for a hashed key sequence to abort booting
*
* This checks for the user entering a SHA256 hash within a given time.
*
* @etime: Timeout value ticks (stop when get_ticks() reachs this)
* @return 0 if autoboot should continue, 1 if it should stop
*/
static int passwd_abort_sha256(uint64_t etime)
{
const char *sha_env_str = env_get("bootstopkeysha256");
u8 sha_env[SHA256_SUM_LEN];
u8 *sha;
char *presskey;
char *c;
const char *algo_name = "sha256";
u_int presskey_len = 0;
int abort = 0;
int size = sizeof(sha);
int ret;
if (sha_env_str == NULL)
sha_env_str = AUTOBOOT_STOP_STR_SHA256;
presskey = malloc_cache_aligned(MAX_DELAY_STOP_STR);
c = strstr(sha_env_str, ":");
if (c && (c - sha_env_str < MAX_DELAY_STOP_STR)) {
/* preload presskey with salt */
memcpy(presskey, sha_env_str, c - sha_env_str);
presskey_len = c - sha_env_str;
sha_env_str = c + 1;
}
/*
* Generate the binary value from the environment hash value
* so that we can compare this value with the computed hash
* from the user input
*/
ret = hash_parse_string(algo_name, sha_env_str, sha_env);
if (ret) {
printf("Hash %s not supported!\n", algo_name);
return 0;
}
sha = malloc_cache_aligned(SHA256_SUM_LEN);
size = SHA256_SUM_LEN;
/*
* We don't know how long the stop-string is, so we need to
* generate the sha256 hash upon each input character and
* compare the value with the one saved in the environment
*/
do {
if (tstc()) {
/* Check for input string overflow */
if (presskey_len >= MAX_DELAY_STOP_STR) {
free(presskey);
free(sha);
return 0;
}
presskey[presskey_len++] = getchar();
/* Calculate sha256 upon each new char */
hash_block(algo_name, (const void *)presskey,
presskey_len, sha, &size);
/* And check if sha matches saved value in env */
if (slow_equals(sha, sha_env, SHA256_SUM_LEN))
abort = 1;
}
} while (!abort && get_ticks() <= etime);
free(presskey);
free(sha);
return abort;
}
/**
* passwd_abort_key() - check for a key sequence to aborted booting
*
* This checks for the user entering a string within a given time.
*
* @etime: Timeout value ticks (stop when get_ticks() reachs this)
* @return 0 if autoboot should continue, 1 if it should stop
*/
static int passwd_abort_key(uint64_t etime)
{
int abort = 0;
struct {
char *str;
u_int len;
int retry;
}
delaykey[] = {
{ .str = env_get("bootdelaykey"), .retry = 1 },
{ .str = env_get("bootstopkey"), .retry = 0 },
};
char presskey[MAX_DELAY_STOP_STR];
int presskey_len = 0;
int presskey_max = 0;
int i;
# ifdef CONFIG_AUTOBOOT_DELAY_STR
if (delaykey[0].str == NULL)
delaykey[0].str = CONFIG_AUTOBOOT_DELAY_STR;
# endif
# ifdef CONFIG_AUTOBOOT_STOP_STR
if (delaykey[1].str == NULL)
delaykey[1].str = CONFIG_AUTOBOOT_STOP_STR;
# endif
for (i = 0; i < sizeof(delaykey) / sizeof(delaykey[0]); i++) {
delaykey[i].len = delaykey[i].str == NULL ?
0 : strlen(delaykey[i].str);
delaykey[i].len = delaykey[i].len > MAX_DELAY_STOP_STR ?
MAX_DELAY_STOP_STR : delaykey[i].len;
presskey_max = presskey_max > delaykey[i].len ?
presskey_max : delaykey[i].len;
debug_bootkeys("%s key:<%s>\n",
delaykey[i].retry ? "delay" : "stop",
delaykey[i].str ? delaykey[i].str : "NULL");
}
/* In order to keep up with incoming data, check timeout only
* when catch up.
*/
do {
if (tstc()) {
if (presskey_len < presskey_max) {
presskey[presskey_len++] = getchar();
} else {
for (i = 0; i < presskey_max - 1; i++)
presskey[i] = presskey[i + 1];
presskey[i] = getchar();
}
}
for (i = 0; i < sizeof(delaykey) / sizeof(delaykey[0]); i++) {
if (delaykey[i].len > 0 &&
presskey_len >= delaykey[i].len &&
memcmp(presskey + presskey_len -
delaykey[i].len, delaykey[i].str,
delaykey[i].len) == 0) {
debug_bootkeys("got %skey\n",
delaykey[i].retry ? "delay" :
"stop");
/* don't retry auto boot */
if (!delaykey[i].retry)
bootretry_dont_retry();
abort = 1;
}
}
} while (!abort && get_ticks() <= etime);
return abort;
}
/***************************************************************************
* Watch for 'delay' seconds for autoboot stop or autoboot delay string.
* returns: 0 - no key string, allow autoboot 1 - got key string, abort
*/
static int abortboot_key_sequence(int bootdelay)
{
int abort;
uint64_t etime = endtick(bootdelay);
# ifdef CONFIG_AUTOBOOT_PROMPT
/*
* CONFIG_AUTOBOOT_PROMPT includes the %d for all boards.
* To print the bootdelay value upon bootup.
*/
printf(CONFIG_AUTOBOOT_PROMPT, bootdelay);
# endif
if (IS_ENABLED(CONFIG_AUTOBOOT_ENCRYPTION))
abort = passwd_abort_sha256(etime);
else
abort = passwd_abort_key(etime);
if (!abort)
debug_bootkeys("key timeout\n");
return abort;
}
static int abortboot_single_key(int bootdelay)
{
int abort = 0;
unsigned long ts;
printf("Hit any key to stop autoboot: %2d ", bootdelay);
/*
* Check if key already pressed
*/
if (tstc()) { /* we got a key press */
getchar(); /* consume input */
puts("\b\b\b 0");
abort = 1; /* don't auto boot */
}
while ((bootdelay > 0) && (!abort)) {
--bootdelay;
/* delay 1000 ms */
ts = get_timer(0);
do {
if (tstc()) { /* we got a key press */
int key;
abort = 1; /* don't auto boot */
bootdelay = 0; /* no more delay */
key = getchar();/* consume input */
if (IS_ENABLED(CONFIG_AUTOBOOT_USE_MENUKEY))
menukey = key;
break;
}
udelay(10000);
} while (!abort && get_timer(ts) < 1000);
printf("\b\b\b%2d ", bootdelay);
}
putc('\n');
return abort;
}
static int abortboot(int bootdelay)
{
int abort = 0;
if (bootdelay >= 0) {
if (IS_ENABLED(CONFIG_AUTOBOOT_KEYED))
abort = abortboot_key_sequence(bootdelay);
else
abort = abortboot_single_key(bootdelay);
}
if (IS_ENABLED(CONFIG_SILENT_CONSOLE) && abort)
gd->flags &= ~GD_FLG_SILENT;
return abort;
}
static void process_fdt_options(const void *blob)
{
#ifdef CONFIG_SYS_TEXT_BASE
ulong addr;
/* Add an env variable to point to a kernel payload, if available */
addr = fdtdec_get_config_int(gd->fdt_blob, "kernel-offset", 0);
if (addr)
env_set_addr("kernaddr", (void *)(CONFIG_SYS_TEXT_BASE + addr));
/* Add an env variable to point to a root disk, if available */
addr = fdtdec_get_config_int(gd->fdt_blob, "rootdisk-offset", 0);
if (addr)
env_set_addr("rootaddr", (void *)(CONFIG_SYS_TEXT_BASE + addr));
#endif /* CONFIG_SYS_TEXT_BASE */
}
const char *bootdelay_process(void)
{
char *s;
int bootdelay;
bootcount_inc();
s = env_get("bootdelay");
bootdelay = s ? (int)simple_strtol(s, NULL, 10) : CONFIG_BOOTDELAY;
if (IS_ENABLED(CONFIG_OF_CONTROL))
bootdelay = fdtdec_get_config_int(gd->fdt_blob, "bootdelay",
bootdelay);
debug("### main_loop entered: bootdelay=%d\n\n", bootdelay);
if (IS_ENABLED(CONFIG_AUTOBOOT_MENU_SHOW))
bootdelay = menu_show(bootdelay);
bootretry_init_cmd_timeout();
#ifdef CONFIG_POST
if (gd->flags & GD_FLG_POSTFAIL) {
s = env_get("failbootcmd");
} else
#endif /* CONFIG_POST */
if (bootcount_error())
s = env_get("altbootcmd");
else
s = env_get("bootcmd");
if (IS_ENABLED(CONFIG_OF_CONTROL))
process_fdt_options(gd->fdt_blob);
stored_bootdelay = bootdelay;
return s;
}
void autoboot_command(const char *s)
{
debug("### main_loop: bootcmd=\"%s\"\n", s ? s : "<UNDEFINED>");
if (s && (stored_bootdelay == -2 ||
(stored_bootdelay != -1 && !abortboot(stored_bootdelay)))) {
bool lock;
int prev;
lock = IS_ENABLED(CONFIG_AUTOBOOT_KEYED) &&
!IS_ENABLED(CONFIG_AUTOBOOT_KEYED_CTRLC);
if (lock)
prev = disable_ctrlc(1); /* disable Ctrl-C checking */
run_command_list(s, -1, 0);
if (lock)
disable_ctrlc(prev); /* restore Ctrl-C checking */
}
if (IS_ENABLED(CONFIG_AUTOBOOT_USE_MENUKEY) &&
menukey == AUTOBOOT_MENUKEY) {
s = env_get("menucmd");
if (s)
run_command_list(s, -1, 0);
}
}