Hi Steffen, On Tue, 13 Apr 2021 at 10:16, Steffen Jaeckel <jaeckel-fl...@eyet-services.de> wrote: > > Hook into the autoboot flow as an alternative to the existing > mechanisms. > > Signed-off-by: Steffen Jaeckel <jaeckel-fl...@eyet-services.de> > --- > > common/Kconfig.boot | 23 +++++++++++++--- > common/autoboot.c | 67 +++++++++++++++++++++++++++++++++++++++------ > 2 files changed, 77 insertions(+), 13 deletions(-) > > diff --git a/common/Kconfig.boot b/common/Kconfig.boot > index 9c335f4f8c..59fec48c5d 100644 > --- a/common/Kconfig.boot > +++ b/common/Kconfig.boot > @@ -802,10 +802,16 @@ config AUTOBOOT_ENCRYPTION > depends on AUTOBOOT_KEYED > help > This option allows a string to be entered into U-Boot to stop the > - autoboot. The string itself is hashed and compared against the hash > - in the environment variable 'bootstopkeysha256'. If it matches then > - boot stops and a command-line prompt is presented. > - > + autoboot. > + The behavior depends whether CONFIG_CRYPT_PW is enabled or not. > + In case CONFIG_CRYPT_PW is enabled, the string will be forwarded > + to the crypt-based functionality and be compared against the > + string in the environment variable 'bootstopkeycrypt'. > + In case CONFIG_CRYPT_PW is disabled the string itself is hashed > + and compared against the hash in the environment variable > + 'bootstopkeysha256'. > + If it matches in either case then boot stops and > + a command-line prompt is presented. > This provides a way to ship a secure production device which can > also > be accessed at the U-Boot command line. > > @@ -843,6 +849,15 @@ config AUTOBOOT_KEYED_CTRLC > Setting this variable provides an escape sequence from the > limited "password" strings. > > +config AUTOBOOT_STOP_STR_CRYPT > + string "Stop autobooting via crypt-hashed 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 hashed via > + one of support crypt options and saved in the environment. > + > config AUTOBOOT_STOP_STR_SHA256 > string "Stop autobooting via SHA256 encrypted password" > depends on AUTOBOOT_KEYED && AUTOBOOT_ENCRYPTION > diff --git a/common/autoboot.c b/common/autoboot.c > index 0bb08e7a4c..732a01d0e5 100644 > --- a/common/autoboot.c > +++ b/common/autoboot.c > @@ -23,6 +23,7 @@ > #include <linux/delay.h> > #include <u-boot/sha256.h> > #include <bootcount.h> > +#include <crypt.h> > > DECLARE_GLOBAL_DATA_PTR; > > @@ -38,18 +39,62 @@ DECLARE_GLOBAL_DATA_PTR; > 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 "" > +#if defined(CONFIG_AUTOBOOT_ENCRYPTION) > +#if defined(CONFIG_CRYPT_PW) && defined(CONFIG_AUTOBOOT_STOP_STR_CRYPT) > +#define AUTOBOOT_STOP_STR_ENC CONFIG_AUTOBOOT_STOP_STR_CRYPT > +#define HAS_STOP_STR_CRYPT 1 > +#elif defined(CONFIG_AUTOBOOT_STOP_STR_SHA256) > +#define AUTOBOOT_STOP_STR_ENC CONFIG_AUTOBOOT_STOP_STR_SHA256 > +#endif > +#endif > +#if !defined(AUTOBOOT_STOP_STR_ENC) > +#define AUTOBOOT_STOP_STR_ENC "" > #endif
I wonder if we actually need all this now that things are in Kconfig? Can we use IS_ENABLED() in the code instead? > - > #ifdef CONFIG_USE_AUTOBOOT_MENUKEY > #define AUTOBOOT_MENUKEY CONFIG_USE_AUTOBOOT_MENUKEY > #else > #define AUTOBOOT_MENUKEY 0 > #endif > > +static int passwd_abort_crypt(uint64_t etime) Please add function comment Also unsigned long if you can...if you need 64-bit on 32-bit machines it is u64...but why? That is a very large number of milliseconds! > +{ > + const char *crypt_env_str = env_get("bootstopkeycrypt"); > + char presskey[MAX_DELAY_STOP_STR]; > + u_int presskey_len = 0; uint Can you drop the presskey_ prefix on these. There is no other kind of key, so just 'key' and 'len' (or num_keys) is good enough. > + int abort = 0; > + > + if (IS_ENABLED(HAS_STOP_STR_CRYPT) && !crypt_env_str) We normally use IS_ENABLED with a CONFIG_.... > + crypt_env_str = AUTOBOOT_STOP_STR_ENC; > + > + if (!crypt_env_str) > + return 0; > + > + /* > + * We expect the stop-string to be newline terminated. > + */ /* ... */ is the single-line comment format > + do { > + if (tstc()) { > + /* Check for input string overflow */ > + if (presskey_len >= MAX_DELAY_STOP_STR) > + return 0; > + > + presskey[presskey_len] = getchar(); > + > + if ((presskey[presskey_len] == '\r') || > + (presskey[presskey_len] == '\n')) { > + presskey[presskey_len] = '\0'; > + crypt_compare(crypt_env_str, presskey, > &abort); > + /* you had one chance */ > + break; > + } else { > + presskey_len++; > + } > + } > + } while (get_ticks() <= etime); > + > + return abort; > +} > + > /* > * Use a "constant-length" time compare function for this > * hash compare: > @@ -89,7 +134,7 @@ static int passwd_abort_sha256(uint64_t etime) > int ret; > > if (sha_env_str == NULL) > - sha_env_str = AUTOBOOT_STOP_STR_SHA256; > + sha_env_str = AUTOBOOT_STOP_STR_ENC; > > presskey = malloc_cache_aligned(MAX_DELAY_STOP_STR); > c = strstr(sha_env_str, ":"); > @@ -245,10 +290,14 @@ static int abortboot_key_sequence(int bootdelay) > printf(CONFIG_AUTOBOOT_PROMPT, bootdelay); > # endif > > - if (IS_ENABLED(CONFIG_AUTOBOOT_ENCRYPTION)) > - abort = passwd_abort_sha256(etime); > - else > + if (IS_ENABLED(CONFIG_AUTOBOOT_ENCRYPTION)) { > + if (IS_ENABLED(CONFIG_CRYPT_PW)) > + abort = passwd_abort_crypt(etime); > + else > + abort = passwd_abort_sha256(etime); > + } else { > abort = passwd_abort_key(etime); > + } > if (!abort) > debug_bootkeys("key timeout\n"); > > -- > 2.30.1 > Regards, SImon