On 4/21/21 9:14 AM, Simon Glass wrote: > 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?
The problem here is that CONFIG_AUTOBOOT_STOP_STR_{CRYPT,SHA256} are strings which can't be checked with IS_ENABLED(). >> - >> #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 OK > 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! I've simply c&p'ed the prototype of the existing functions :) static int passwd_abort_sha256(uint64_t etime) static int passwd_abort_key(uint64_t etime) >> +{ >> + 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. same as above, this is a c&p from passwd_abort_sha256() I had started by including my functionality into passwd_abort_sha256(), when I realized that it won't work like that I decided to c&p the entire implementation... should I still change both? those variable names and the uint64_t in the arguments? > >> + int abort = 0; >> + >> + if (IS_ENABLED(HAS_STOP_STR_CRYPT) && !crypt_env_str) > > We normally use IS_ENABLED with a CONFIG_.... I don't see a different way than either this one or introducing a separate enable switch in Kconfig (which would in turn then either require different behavior for enabling CONFIG_AUTOBOOT_STOP_STR_SHA256 vs CONFIG_AUTOBOOT_STOP_STR_CRYPT or we'd have to break the existing flow of CONFIG_AUTOBOOT_STOP_STR_SHA256). > >> + 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 OK > >> + 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 >