This patch adds the feature to only stop the autobooting, and therefor 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.
This feature is enabled by defined these config options: CONFIG_AUTOBOOT_KEYED CONFIG_AUTOBOOT_STOP_STR_SHA256
Signed-off-by: Stefan Roese sr@denx.de --- common/autoboot.c | 45 ++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 44 insertions(+), 1 deletion(-)
diff --git a/common/autoboot.c b/common/autoboot.c index c27cc2c..4635551 100644 --- a/common/autoboot.c +++ b/common/autoboot.c @@ -12,6 +12,7 @@ #include <fdtdec.h> #include <menu.h> #include <post.h> +#include <u-boot/sha256.h>
DECLARE_GLOBAL_DATA_PTR;
@@ -35,6 +36,11 @@ static int abortboot_keyed(int bootdelay) { int abort = 0; uint64_t etime = endtick(bootdelay); +#if defined(CONFIG_AUTOBOOT_STOP_STR_SHA256) + const char *sha_env_str = getenv("bootstopkeysha256"); + u8 sha_env[SHA256_SUM_LEN]; + u8 sha[SHA256_SUM_LEN]; +#else struct { char *str; u_int len; @@ -46,10 +52,11 @@ static int abortboot_keyed(int bootdelay) { .str = getenv("bootstopkey"), .retry = 0 }, { .str = getenv("bootstopkey2"), .retry = 0 }, }; + u_int presskey_max = 0; +#endif
char presskey[MAX_DELAY_STOP_STR]; u_int presskey_len = 0; - u_int presskey_max = 0; u_int i;
#ifndef CONFIG_ZERO_BOOTDELAY_CHECK @@ -61,6 +68,41 @@ static int abortboot_keyed(int bootdelay) printf(CONFIG_AUTOBOOT_PROMPT); # endif
+#if defined(CONFIG_AUTOBOOT_STOP_STR_SHA256) + 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 + */ + for (i = 0; i < SHA256_SUM_LEN; i++) { + char chr[3]; + + strncpy(chr, &sha_env_str[i * 2], 2); + sha_env[i] = simple_strtoul(chr, NULL, 16); + } + + /* + * 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()) { + presskey[presskey_len++] = getc(); + + /* Calculate sha256 upon each new char */ + sha256_csum_wd((unsigned char *)presskey, presskey_len, + sha, CHUNKSZ_SHA256); + + /* And check if sha matches saved value in env */ + if (memcmp(sha, sha_env, SHA256_SUM_LEN) == 0) + abort = 1; + } + } while (!abort && get_ticks() <= etime); +#else # ifdef CONFIG_AUTOBOOT_DELAY_STR if (delaykey[0].str == NULL) delaykey[0].str = CONFIG_AUTOBOOT_DELAY_STR; @@ -124,6 +166,7 @@ static int abortboot_keyed(int bootdelay) } } } while (!abort && get_ticks() <= etime); +#endif
if (!abort) debug_bootkeys("key timeout\n");