the responsibility of the user to select only such arguments
that are valid in the given context.
+config AUTOBOOT_ENCRYPTION
+ bool "Enable encryption in autoboot stopping"
+ depends on AUTOBOOT_KEYED
+ default n
+
config AUTOBOOT_DELAY_STR
string "Delay autobooting via specific input key / string"
- depends on AUTOBOOT_KEYED
+ depends on AUTOBOOT_KEYED && !AUTOBOOT_ENCRYPTION
help
This option delays the automatic boot feature by issuing
a specific input key or string. If CONFIG_AUTOBOOT_DELAY_STR
config AUTOBOOT_STOP_STR
string "Stop autobooting via specific input key / string"
- depends on AUTOBOOT_KEYED
+ depends on AUTOBOOT_KEYED && !AUTOBOOT_ENCRYPTION
help
This option enables stopping (aborting) of the automatic
boot feature only by issuing a specific input key or
config AUTOBOOT_KEYED_CTRLC
bool "Enable Ctrl-C autoboot interruption"
- depends on AUTOBOOT_KEYED
+ depends on AUTOBOOT_KEYED && !AUTOBOOT_ENCRYPTION
default n
help
This option allows for the boot sequence to be interrupted
Setting this variable provides an escape sequence from the
limited "password" strings.
+config AUTOBOOT_STOP_STR_SHA256
+ string "Stop autobooting via SHA256 encrypted password"
+ depends on AUTOBOOT_KEYED && AUTOBOOT_ENCRYPTION
+ help
+ This option adds the feature to only stop the autobooting,
+ and therefore boot into the U-Boot prompt, when the input
+ string / password matches a values that is encypted via
+ a SHA256 hash and saved in the environment.
+
endmenu
comment "Commands"
#include <fdtdec.h>
#include <menu.h>
#include <post.h>
+#include <u-boot/sha256.h>
DECLARE_GLOBAL_DATA_PTR;
/* Stored value of bootdelay, used by autoboot_command() */
static int stored_bootdelay;
-/***************************************************************************
- * Watch for 'delay' seconds for autoboot stop or autoboot delay string.
- * returns: 0 - no key string, allow autoboot 1 - got key string, abort
+#if defined(CONFIG_AUTOBOOT_KEYED)
+#if defined(CONFIG_AUTOBOOT_STOP_STR_SHA256)
+
+/*
+ * Use a "constant-length" time compare function for this
+ * hash compare:
+ *
+ * https://crackstation.net/hashing-security.htm
*/
-# if defined(CONFIG_AUTOBOOT_KEYED)
-static int abortboot_keyed(int bootdelay)
+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;
+}
+
+static int passwd_abort(uint64_t etime)
+{
+ const char *sha_env_str = getenv("bootstopkeysha256");
+ u8 sha_env[SHA256_SUM_LEN];
+ u8 sha[SHA256_SUM_LEN];
+ char presskey[MAX_DELAY_STOP_STR];
+ const char *algo_name = "sha256";
+ u_int presskey_len = 0;
+ int abort = 0;
+ int size;
+ int ret;
+
+ if (sha_env_str == NULL)
+ sha_env_str = CONFIG_AUTOBOOT_STOP_STR_SHA256;
+
+ /*
+ * 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;
+ }
+
+ /*
+ * 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)
+ return 0;
+
+ presskey[presskey_len++] = getc();
+
+ /* 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);
+
+ return abort;
+}
+#else
+static int passwd_abort(uint64_t etime)
{
int abort = 0;
- uint64_t etime = endtick(bootdelay);
struct {
char *str;
u_int len;
u_int presskey_max = 0;
u_int i;
-#ifndef CONFIG_ZERO_BOOTDELAY_CHECK
- if (bootdelay == 0)
- return 0;
-#endif
-
-# 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
-
# ifdef CONFIG_AUTOBOOT_DELAY_STR
if (delaykey[0].str == NULL)
delaykey[0].str = CONFIG_AUTOBOOT_DELAY_STR;
}
} while (!abort && get_ticks() <= etime);
+ return abort;
+}
+#endif
+
+/***************************************************************************
+ * 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_keyed(int bootdelay)
+{
+ int abort;
+ uint64_t etime = endtick(bootdelay);
+
+#ifndef CONFIG_ZERO_BOOTDELAY_CHECK
+ if (bootdelay == 0)
+ return 0;
+#endif
+
+# 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
+
+ abort = passwd_abort(etime);
if (!abort)
debug_bootkeys("key timeout\n");
}
#ifndef USE_HOSTCC
+int hash_parse_string(const char *algo_name, const char *str, uint8_t *result)
+{
+ struct hash_algo *algo;
+ int ret;
+ int i;
+
+ ret = hash_lookup_algo(algo_name, &algo);
+ if (ret)
+ return ret;
+
+ for (i = 0; i < algo->digest_size; i++) {
+ char chr[3];
+
+ strncpy(chr, &str[i * 2], 2);
+ result[i] = simple_strtoul(chr, NULL, 16);
+ }
+
+ return 0;
+}
+
/**
* store_result: Store the resulting sum to an address or variable
*
buf = map_sysmem(addr, algo->digest_size);
memcpy(vsum, buf, algo->digest_size);
} else {
- unsigned int i;
char *vsum_str;
int digits = algo->digest_size * 2;
}
}
- for (i = 0; i < algo->digest_size; i++) {
- char *nullp = vsum_str + (i + 1) * 2;
- char end = *nullp;
-
- *nullp = '\0';
- vsum[i] = simple_strtoul(vsum_str + (i * 2), NULL, 16);
- *nullp = end;
- }
+ hash_parse_string(algo->name, vsum_str, vsum);
}
return 0;
}
projects / u-boot / commitdiff