Add the basic functionality required to support the standard crypt format. The files crypt-sha256.c and crypt-sha512.c originate from libxcrypt and their formatting is therefor retained. The integration is done via a crypt_compare() function in crypt.c.

``` libxcrypt $ git describe --long --always --all tags/v4.4.17-0-g6b110bc ```

Signed-off-by: Steffen Jaeckel jaeckel-floss@eyet-services.de ---

include/crypt.h | 13 ++ lib/Kconfig | 1 + lib/Makefile | 1 + lib/crypt/Kconfig | 29 ++++ lib/crypt/Makefile | 10 ++ lib/crypt/alg-sha256.h | 17 ++ lib/crypt/alg-sha512.h | 17 ++ lib/crypt/crypt-port.h | 28 ++++ lib/crypt/crypt-sha256.c | 313 +++++++++++++++++++++++++++++++++++++ lib/crypt/crypt-sha512.c | 328 +++++++++++++++++++++++++++++++++++++++ lib/crypt/crypt.c | 73 +++++++++ 11 files changed, 830 insertions(+) create mode 100644 include/crypt.h create mode 100644 lib/crypt/Kconfig create mode 100644 lib/crypt/Makefile create mode 100644 lib/crypt/alg-sha256.h create mode 100644 lib/crypt/alg-sha512.h create mode 100644 lib/crypt/crypt-port.h create mode 100644 lib/crypt/crypt-sha256.c create mode 100644 lib/crypt/crypt-sha512.c create mode 100644 lib/crypt/crypt.c

diff --git a/include/crypt.h b/include/crypt.h new file mode 100644 index 0000000000..e0be2832ff --- /dev/null +++ b/include/crypt.h @@ -0,0 +1,13 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* Copyright (C) 2020 Steffen Jaeckel jaeckel-floss@eyet-services.de */ + +/** + * Compare should with the processed passphrase. + * + * @should The crypt-style string to compare against + * @passphrase The plaintext passphrase + * @equal Pointer to an int where the result is stored + * '0' = unequal + * '1' = equal + */ +void crypt_compare(const char *should, const char *passphrase, int *equal); diff --git a/lib/Kconfig b/lib/Kconfig index 80ff2443cb..99a4e1a5a7 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -297,6 +297,7 @@ config AES

source lib/rsa/Kconfig source lib/crypto/Kconfig +source lib/crypt/Kconfig

config TPM bool "Trusted Platform Module (TPM) Support" diff --git a/lib/Makefile b/lib/Makefile index c42d4e1233..ab78f32eb1 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -64,6 +64,7 @@ obj-$(CONFIG_$(SPL_)RSA) += rsa/ obj-$(CONFIG_SHA1) += sha1.o obj-$(CONFIG_SHA256) += sha256.o obj-$(CONFIG_SHA512_ALGO) += sha512.o +obj-$(CONFIG_CRYPT_PW) += crypt/

obj-$(CONFIG_$(SPL_)ZLIB) += zlib/ obj-$(CONFIG_$(SPL_)ZSTD) += zstd/ diff --git a/lib/crypt/Kconfig b/lib/crypt/Kconfig new file mode 100644 index 0000000000..6f828cefd6 --- /dev/null +++ b/lib/crypt/Kconfig @@ -0,0 +1,29 @@ +config CRYPT_PW + bool "Add crypt support for password-based unlock" + help + Enable support for crypt-style hashed passphrases. + This will then be used as the mechanism of choice to + verify whether the entered password to unlock the + console is correct or not. + To make it fully functional, one has also to enable + CONFIG_AUTOBOOT_KEYED and CONFIG_AUTOBOOT_ENCRYPTION + +if CRYPT_PW + +config CRYPT_PW_SHA256 + bool "Provide sha256crypt" + select SHA256 + select SHA256_ALGO + help + Enables support for the sha256crypt password-hashing algorithm. + The prefix is "$5$". + +config CRYPT_PW_SHA512 + bool "Provide sha512crypt" + select SHA512 + select SHA512_ALGO + help + Enables support for the sha512crypt password-hashing algorithm. + The prefix is "$6$". + +endif diff --git a/lib/crypt/Makefile b/lib/crypt/Makefile new file mode 100644 index 0000000000..290231064c --- /dev/null +++ b/lib/crypt/Makefile @@ -0,0 +1,10 @@ +# SPDX-License-Identifier: GPL-2.0+ +# +# Copyright (c) 2013, Google Inc. +# +# (C) Copyright 2000-2007 +# Wolfgang Denk, DENX Software Engineering, wd@denx.de. + +obj-$(CONFIG_CRYPT_PW) += crypt.o +obj-$(CONFIG_CRYPT_PW_SHA256) += crypt-sha256.o +obj-$(CONFIG_CRYPT_PW_SHA512) += crypt-sha512.o diff --git a/lib/crypt/alg-sha256.h b/lib/crypt/alg-sha256.h new file mode 100644 index 0000000000..e4b29c9f31 --- /dev/null +++ b/lib/crypt/alg-sha256.h @@ -0,0 +1,17 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* Copyright (C) 2020 Steffen Jaeckel jaeckel-floss@eyet-services.de */ + +#ifndef USE_HOSTCC +#include "common.h" +#else +#include <string.h> +#endif + +#include "u-boot/sha256.h" + +#define INCLUDE_sha256crypt 1 + +#define SHA256_CTX sha256_context +#define SHA256_Init sha256_starts +#define SHA256_Update(c, i, l) sha256_update(c, (const void *)i, l) +#define SHA256_Final(b, c) sha256_finish(c, b) diff --git a/lib/crypt/alg-sha512.h b/lib/crypt/alg-sha512.h new file mode 100644 index 0000000000..93b6109fae --- /dev/null +++ b/lib/crypt/alg-sha512.h @@ -0,0 +1,17 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* Copyright (C) 2020 Steffen Jaeckel jaeckel-floss@eyet-services.de */ + +#ifndef USE_HOSTCC +#include "common.h" +#else +#include <string.h> +#endif + +#include "u-boot/sha512.h" + +#define INCLUDE_sha512crypt 1 + +#define SHA512_CTX sha512_context +#define SHA512_Init sha512_starts +#define SHA512_Update(c, i, l) sha512_update(c, (const void *)i, l) +#define SHA512_Final(b, c) sha512_finish(c, b) diff --git a/lib/crypt/crypt-port.h b/lib/crypt/crypt-port.h new file mode 100644 index 0000000000..680ffe9349 --- /dev/null +++ b/lib/crypt/crypt-port.h @@ -0,0 +1,28 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* Copyright (C) 2020 Steffen Jaeckel jaeckel-floss@eyet-services.de */ + +#include <linux/types.h> +#include <vsprintf.h> + +#define NO_GENSALT +#define CRYPT_OUTPUT_SIZE 384 +#define ALG_SPECIFIC_SIZE 8192 + +#define ARG_UNUSED(x) (x) + +#define static_assert(a, b) _Static_assert(a, b) + +#define strtoul(cp, endp, base) simple_strtoul(cp, endp, base) + +extern const unsigned char ascii64[65]; + +#define b64t ((const char *)ascii64) + +void crypt_sha256crypt_rn(const char *phrase, size_t phr_size, + const char *setting, size_t ARG_UNUSED(set_size), + uint8_t *output, size_t out_size, void *scratch, + size_t scr_size); +void crypt_sha512crypt_rn(const char *phrase, size_t phr_size, + const char *setting, size_t ARG_UNUSED(set_size), + uint8_t *output, size_t out_size, void *scratch, + size_t scr_size); diff --git a/lib/crypt/crypt-sha256.c b/lib/crypt/crypt-sha256.c new file mode 100644 index 0000000000..37127d41e1 --- /dev/null +++ b/lib/crypt/crypt-sha256.c @@ -0,0 +1,313 @@ +/* One way encryption based on the SHA256-based Unix crypt implementation. + * + * Written by Ulrich Drepper <drepper at redhat.com> in 2007 [1]. + * Modified by Zack Weinberg <zackw at panix.com> in 2017, 2018. + * Composed by Björn Esser <besser82 at fedoraproject.org> in 2018. + * Modified by Björn Esser <besser82 at fedoraproject.org> in 2020. + * Modified by Steffen Jaeckel <jaeckel-floss at eyet-services.de> in 2020. + * To the extent possible under law, the named authors have waived all + * copyright and related or neighboring rights to this work. + * + * See https://creativecommons.org/publicdomain/zero/1.0/ for further + * details. + * + * This file is a modified except from [2], lines 648 up to 909. + * + * [1] https://www.akkadia.org/drepper/sha-crypt.html + * [2] https://www.akkadia.org/drepper/SHA-crypt.txt + */ + +#include "crypt-port.h" +#include "alg-sha256.h" + +#include <errno.h> +#include <stdio.h> +#include <stdlib.h> + +#if INCLUDE_sha256crypt + +/* Define our magic string to mark salt for SHA256 "encryption" + replacement. */ +static const char sha256_salt_prefix[] = "$5$"; + +/* Prefix for optional rounds specification. */ +static const char sha256_rounds_prefix[] = "rounds="; + +/* Maximum salt string length. */ +#define SALT_LEN_MAX 16 +/* Default number of rounds if not explicitly specified. */ +#define ROUNDS_DEFAULT 5000 +/* Minimum number of rounds. */ +#define ROUNDS_MIN 1000 +/* Maximum number of rounds. */ +#define ROUNDS_MAX 999999999 + +/* The maximum possible length of a SHA256-hashed password string, + including the terminating NUL character. Prefix (including its NUL) + + rounds tag ("rounds=$" = "rounds=\0") + strlen(ROUNDS_MAX) + + salt (up to SALT_LEN_MAX chars) + '$' + hash (43 chars). */ + +#define LENGTH_OF_NUMBER(n) (sizeof #n - 1) + +#define SHA256_HASH_LENGTH \ + (sizeof (sha256_salt_prefix) + sizeof (sha256_rounds_prefix) + \ + LENGTH_OF_NUMBER (ROUNDS_MAX) + SALT_LEN_MAX + 1 + 43) + +static_assert (SHA256_HASH_LENGTH <= CRYPT_OUTPUT_SIZE, + "CRYPT_OUTPUT_SIZE is too small for SHA256"); + +/* A sha256_buffer holds all of the sensitive intermediate data. */ +struct sha256_buffer +{ + SHA256_CTX ctx; + uint8_t result[32]; + uint8_t p_bytes[32]; + uint8_t s_bytes[32]; +}; + +static_assert (sizeof (struct sha256_buffer) <= ALG_SPECIFIC_SIZE, + "ALG_SPECIFIC_SIZE is too small for SHA256"); + + +/* Feed CTX with LEN bytes of a virtual byte sequence consisting of + BLOCK repeated over and over indefinitely. */ +static void +SHA256_Update_recycled (SHA256_CTX *ctx, + unsigned char block[32], size_t len) +{ + size_t cnt; + for (cnt = len; cnt >= 32; cnt -= 32) + SHA256_Update (ctx, block, 32); + SHA256_Update (ctx, block, cnt); +} + +void +crypt_sha256crypt_rn (const char *phrase, size_t phr_size, + const char *setting, size_t ARG_UNUSED (set_size), + uint8_t *output, size_t out_size, + void *scratch, size_t scr_size) +{ + /* This shouldn't ever happen, but... */ + if (out_size < SHA256_HASH_LENGTH + || scr_size < sizeof (struct sha256_buffer)) + { + errno = ERANGE; + return; + } + + struct sha256_buffer *buf = scratch; + SHA256_CTX *ctx = &buf->ctx; + uint8_t *result = buf->result; + uint8_t *p_bytes = buf->p_bytes; + uint8_t *s_bytes = buf->s_bytes; + char *cp = (char *)output; + const char *salt = setting; + + size_t salt_size; + size_t cnt; + /* Default number of rounds. */ + size_t rounds = ROUNDS_DEFAULT; + bool rounds_custom = false; + + /* Find beginning of salt string. The prefix should normally always + be present. Just in case it is not. */ + if (strncmp (sha256_salt_prefix, salt, sizeof (sha256_salt_prefix) - 1) == 0) + /* Skip salt prefix. */ + salt += sizeof (sha256_salt_prefix) - 1; + + if (strncmp (salt, sha256_rounds_prefix, sizeof (sha256_rounds_prefix) - 1) + == 0) + { + const char *num = salt + sizeof (sha256_rounds_prefix) - 1; + /* Do not allow an explicit setting of zero rounds, nor of the + default number of rounds, nor leading zeroes on the rounds. */ + if (!(*num >= '1' && *num <= '9')) + { + errno = EINVAL; + return; + } + + errno = 0; + char *endp; + rounds = strtoul (num, &endp, 10); + if (endp == num || *endp != '$' + || rounds < ROUNDS_MIN + || rounds > ROUNDS_MAX + || errno) + { + errno = EINVAL; + return; + } + salt = endp + 1; + rounds_custom = true; + } + + /* The salt ends at the next '$' or the end of the string. + Ensure ':' does not appear in the salt (it is used as a separator in /etc/passwd). + Also check for '\n', as in /etc/passwd the whole parameters of the user data must + be on a single line. */ + salt_size = strcspn (salt, "$:\n"); + if (!(salt[salt_size] == '$' || !salt[salt_size])) + { + errno = EINVAL; + return; + } + + /* Ensure we do not use more salt than SALT_LEN_MAX. */ + if (salt_size > SALT_LEN_MAX) + salt_size = SALT_LEN_MAX; + + /* Compute alternate SHA256 sum with input PHRASE, SALT, and PHRASE. The + final result will be added to the first context. */ + SHA256_Init (ctx); + + /* Add phrase. */ + SHA256_Update (ctx, phrase, phr_size); + + /* Add salt. */ + SHA256_Update (ctx, salt, salt_size); + + /* Add phrase again. */ + SHA256_Update (ctx, phrase, phr_size); + + /* Now get result of this (32 bytes). */ + SHA256_Final (result, ctx); + + /* Prepare for the real work. */ + SHA256_Init (ctx); + + /* Add the phrase string. */ + SHA256_Update (ctx, phrase, phr_size); + + /* The last part is the salt string. This must be at most 8 + characters and it ends at the first `$' character (for + compatibility with existing implementations). */ + SHA256_Update (ctx, salt, salt_size); + + /* Add for any character in the phrase one byte of the alternate sum. */ + for (cnt = phr_size; cnt > 32; cnt -= 32) + SHA256_Update (ctx, result, 32); + SHA256_Update (ctx, result, cnt); + + /* Take the binary representation of the length of the phrase and for every + 1 add the alternate sum, for every 0 the phrase. */ + for (cnt = phr_size; cnt > 0; cnt >>= 1) + if ((cnt & 1) != 0) + SHA256_Update (ctx, result, 32); + else + SHA256_Update (ctx, phrase, phr_size); + + /* Create intermediate result. */ + SHA256_Final (result, ctx); + + /* Start computation of P byte sequence. */ + SHA256_Init (ctx); + + /* For every character in the password add the entire password. */ + for (cnt = 0; cnt < phr_size; ++cnt) + SHA256_Update (ctx, phrase, phr_size); + + /* Finish the digest. */ + SHA256_Final (p_bytes, ctx); + + /* Start computation of S byte sequence. */ + SHA256_Init (ctx); + + /* For every character in the password add the entire password. */ + for (cnt = 0; cnt < (size_t) 16 + (size_t) result[0]; ++cnt) + SHA256_Update (ctx, salt, salt_size); + + /* Finish the digest. */ + SHA256_Final (s_bytes, ctx); + + /* Repeatedly run the collected hash value through SHA256 to burn + CPU cycles. */ + for (cnt = 0; cnt < rounds; ++cnt) + { + /* New context. */ + SHA256_Init (ctx); + + /* Add phrase or last result. */ + if ((cnt & 1) != 0) + SHA256_Update_recycled (ctx, p_bytes, phr_size); + else + SHA256_Update (ctx, result, 32); + + /* Add salt for numbers not divisible by 3. */ + if (cnt % 3 != 0) + SHA256_Update_recycled (ctx, s_bytes, salt_size); + + /* Add phrase for numbers not divisible by 7. */ + if (cnt % 7 != 0) + SHA256_Update_recycled (ctx, p_bytes, phr_size); + + /* Add phrase or last result. */ + if ((cnt & 1) != 0) + SHA256_Update (ctx, result, 32); + else + SHA256_Update_recycled (ctx, p_bytes, phr_size); + + /* Create intermediate result. */ + SHA256_Final (result, ctx); + } + + /* Now we can construct the result string. It consists of four + parts, one of which is optional. We already know that there + is sufficient space at CP for the longest possible result string. */ + memcpy (cp, sha256_salt_prefix, sizeof (sha256_salt_prefix) - 1); + cp += sizeof (sha256_salt_prefix) - 1; + + if (rounds_custom) + { + int n = snprintf (cp, + SHA256_HASH_LENGTH - (sizeof (sha256_salt_prefix) - 1), + "%s%zu$", sha256_rounds_prefix, rounds); + cp += n; + } + + memcpy (cp, salt, salt_size); + cp += salt_size; + *cp++ = '$'; + +#define b64_from_24bit(B2, B1, B0, N) \ + do { \ + unsigned int w = ((((unsigned int)(B2)) << 16) | \ + (((unsigned int)(B1)) << 8) | \ + ((unsigned int)(B0))); \ + int n = (N); \ + while (n-- > 0) \ + { \ + *cp++ = b64t[w & 0x3f]; \ + w >>= 6; \ + } \ + } while (0) + + b64_from_24bit (result[0], result[10], result[20], 4); + b64_from_24bit (result[21], result[1], result[11], 4); + b64_from_24bit (result[12], result[22], result[2], 4); + b64_from_24bit (result[3], result[13], result[23], 4); + b64_from_24bit (result[24], result[4], result[14], 4); + b64_from_24bit (result[15], result[25], result[5], 4); + b64_from_24bit (result[6], result[16], result[26], 4); + b64_from_24bit (result[27], result[7], result[17], 4); + b64_from_24bit (result[18], result[28], result[8], 4); + b64_from_24bit (result[9], result[19], result[29], 4); + b64_from_24bit (0, result[31], result[30], 3); + + *cp = '\0'; +} + +#ifndef NO_GENSALT + +void +gensalt_sha256crypt_rn (unsigned long count, + const uint8_t *rbytes, size_t nrbytes, + uint8_t *output, size_t output_size) +{ + gensalt_sha_rn ('5', SALT_LEN_MAX, ROUNDS_DEFAULT, ROUNDS_MIN, ROUNDS_MAX, + count, rbytes, nrbytes, output, output_size); +} + +#endif + +#endif diff --git a/lib/crypt/crypt-sha512.c b/lib/crypt/crypt-sha512.c new file mode 100644 index 0000000000..3616019445 --- /dev/null +++ b/lib/crypt/crypt-sha512.c @@ -0,0 +1,328 @@ +/* One way encryption based on the SHA512-based Unix crypt implementation. + * + * Written by Ulrich Drepper <drepper at redhat.com> in 2007 [1]. + * Modified by Zack Weinberg <zackw at panix.com> in 2017, 2018. + * Composed by Björn Esser <besser82 at fedoraproject.org> in 2018. + * Modified by Björn Esser <besser82 at fedoraproject.org> in 2020. + * Modified by Steffen Jaeckel <jaeckel-floss at eyet-services.de> in 2020. + * To the extent possible under law, the named authors have waived all + * copyright and related or neighboring rights to this work. + * + * See https://creativecommons.org/publicdomain/zero/1.0/ for further + * details. + * + * This file is a modified except from [2], lines 1403 up to 1676. + * + * [1] https://www.akkadia.org/drepper/sha-crypt.html + * [2] https://www.akkadia.org/drepper/SHA-crypt.txt + */ + +#include "crypt-port.h" +#include "alg-sha512.h" + +#include <errno.h> +#include <stdio.h> +#include <stdlib.h> + +#if INCLUDE_sha512crypt + +/* Define our magic string to mark salt for SHA512 "encryption" + replacement. */ +static const char sha512_salt_prefix[] = "$6$"; + +/* Prefix for optional rounds specification. */ +static const char sha512_rounds_prefix[] = "rounds="; + +/* Maximum salt string length. */ +#define SALT_LEN_MAX 16 +/* Default number of rounds if not explicitly specified. */ +#define ROUNDS_DEFAULT 5000 +/* Minimum number of rounds. */ +#define ROUNDS_MIN 1000 +/* Maximum number of rounds. */ +#define ROUNDS_MAX 999999999 + +/* The maximum possible length of a SHA512-hashed password string, + including the terminating NUL character. Prefix (including its NUL) + + rounds tag ("rounds=$" = "rounds=\0") + strlen(ROUNDS_MAX) + + salt (up to SALT_LEN_MAX chars) + '$' + hash (86 chars). */ + +#define LENGTH_OF_NUMBER(n) (sizeof #n - 1) + +#define SHA512_HASH_LENGTH \ + (sizeof (sha512_salt_prefix) + sizeof (sha512_rounds_prefix) + \ + LENGTH_OF_NUMBER (ROUNDS_MAX) + SALT_LEN_MAX + 1 + 86) + +static_assert (SHA512_HASH_LENGTH <= CRYPT_OUTPUT_SIZE, + "CRYPT_OUTPUT_SIZE is too small for SHA512"); + +/* A sha512_buffer holds all of the sensitive intermediate data. */ +struct sha512_buffer +{ + SHA512_CTX ctx; + uint8_t result[64]; + uint8_t p_bytes[64]; + uint8_t s_bytes[64]; +}; + +static_assert (sizeof (struct sha512_buffer) <= ALG_SPECIFIC_SIZE, + "ALG_SPECIFIC_SIZE is too small for SHA512"); + + +/* Subroutine of _xcrypt_crypt_sha512crypt_rn: Feed CTX with LEN bytes of a + virtual byte sequence consisting of BLOCK repeated over and over + indefinitely. */ +static void +sha512_process_recycled_bytes (unsigned char block[64], size_t len, + SHA512_CTX *ctx) +{ + size_t cnt; + for (cnt = len; cnt >= 64; cnt -= 64) + SHA512_Update (ctx, block, 64); + SHA512_Update (ctx, block, cnt); +} + +void +crypt_sha512crypt_rn (const char *phrase, size_t phr_size, + const char *setting, size_t ARG_UNUSED (set_size), + uint8_t *output, size_t out_size, + void *scratch, size_t scr_size) +{ + /* This shouldn't ever happen, but... */ + if (out_size < SHA512_HASH_LENGTH + || scr_size < sizeof (struct sha512_buffer)) + { + errno = ERANGE; + return; + } + + struct sha512_buffer *buf = scratch; + SHA512_CTX *ctx = &buf->ctx; + uint8_t *result = buf->result; + uint8_t *p_bytes = buf->p_bytes; + uint8_t *s_bytes = buf->s_bytes; + char *cp = (char *)output; + const char *salt = setting; + + size_t salt_size; + size_t cnt; + /* Default number of rounds. */ + size_t rounds = ROUNDS_DEFAULT; + bool rounds_custom = false; + + /* Find beginning of salt string. The prefix should normally always + be present. Just in case it is not. */ + if (strncmp (sha512_salt_prefix, salt, sizeof (sha512_salt_prefix) - 1) == 0) + /* Skip salt prefix. */ + salt += sizeof (sha512_salt_prefix) - 1; + + if (strncmp (salt, sha512_rounds_prefix, sizeof (sha512_rounds_prefix) - 1) + == 0) + { + const char *num = salt + sizeof (sha512_rounds_prefix) - 1; + /* Do not allow an explicit setting of zero rounds, nor of the + default number of rounds, nor leading zeroes on the rounds. */ + if (!(*num >= '1' && *num <= '9')) + { + errno = EINVAL; + return; + } + + errno = 0; + char *endp; + rounds = strtoul (num, &endp, 10); + if (endp == num || *endp != '$' + || rounds < ROUNDS_MIN + || rounds > ROUNDS_MAX + || errno) + { + errno = EINVAL; + return; + } + salt = endp + 1; + rounds_custom = true; + } + + /* The salt ends at the next '$' or the end of the string. + Ensure ':' does not appear in the salt (it is used as a separator in /etc/passwd). + Also check for '\n', as in /etc/passwd the whole parameters of the user data must + be on a single line. */ + salt_size = strcspn (salt, "$:\n"); + if (!(salt[salt_size] == '$' || !salt[salt_size])) + { + errno = EINVAL; + return; + } + + /* Ensure we do not use more salt than SALT_LEN_MAX. */ + if (salt_size > SALT_LEN_MAX) + salt_size = SALT_LEN_MAX; + + /* Compute alternate SHA512 sum with input PHRASE, SALT, and PHRASE. The + final result will be added to the first context. */ + SHA512_Init (ctx); + + /* Add phrase. */ + SHA512_Update (ctx, phrase, phr_size); + + /* Add salt. */ + SHA512_Update (ctx, salt, salt_size); + + /* Add phrase again. */ + SHA512_Update (ctx, phrase, phr_size); + + /* Now get result of this (64 bytes) and add it to the other + context. */ + SHA512_Final (result, ctx); + + /* Prepare for the real work. */ + SHA512_Init (ctx); + + /* Add the phrase string. */ + SHA512_Update (ctx, phrase, phr_size); + + /* The last part is the salt string. This must be at most 8 + characters and it ends at the first `$' character (for + compatibility with existing implementations). */ + SHA512_Update (ctx, salt, salt_size); + + /* Add for any character in the phrase one byte of the alternate sum. */ + for (cnt = phr_size; cnt > 64; cnt -= 64) + SHA512_Update (ctx, result, 64); + SHA512_Update (ctx, result, cnt); + + /* Take the binary representation of the length of the phrase and for every + 1 add the alternate sum, for every 0 the phrase. */ + for (cnt = phr_size; cnt > 0; cnt >>= 1) + if ((cnt & 1) != 0) + SHA512_Update (ctx, result, 64); + else + SHA512_Update (ctx, phrase, phr_size); + + /* Create intermediate result. */ + SHA512_Final (result, ctx); + + /* Start computation of P byte sequence. */ + SHA512_Init (ctx); + + /* For every character in the password add the entire password. */ + for (cnt = 0; cnt < phr_size; ++cnt) + SHA512_Update (ctx, phrase, phr_size); + + /* Finish the digest. */ + SHA512_Final (p_bytes, ctx); + + /* Start computation of S byte sequence. */ + SHA512_Init (ctx); + + /* For every character in the password add the entire password. */ + for (cnt = 0; cnt < (size_t) 16 + (size_t) result[0]; ++cnt) + SHA512_Update (ctx, salt, salt_size); + + /* Finish the digest. */ + SHA512_Final (s_bytes, ctx); + + /* Repeatedly run the collected hash value through SHA512 to burn + CPU cycles. */ + for (cnt = 0; cnt < rounds; ++cnt) + { + /* New context. */ + SHA512_Init (ctx); + + /* Add phrase or last result. */ + if ((cnt & 1) != 0) + sha512_process_recycled_bytes (p_bytes, phr_size, ctx); + else + SHA512_Update (ctx, result, 64); + + /* Add salt for numbers not divisible by 3. */ + if (cnt % 3 != 0) + sha512_process_recycled_bytes (s_bytes, salt_size, ctx); + + /* Add phrase for numbers not divisible by 7. */ + if (cnt % 7 != 0) + sha512_process_recycled_bytes (p_bytes, phr_size, ctx); + + /* Add phrase or last result. */ + if ((cnt & 1) != 0) + SHA512_Update (ctx, result, 64); + else + sha512_process_recycled_bytes (p_bytes, phr_size, ctx); + + /* Create intermediate result. */ + SHA512_Final (result, ctx); + } + + /* Now we can construct the result string. It consists of four + parts, one of which is optional. We already know that buflen is + at least sha512_hash_length, therefore none of the string bashing + below can overflow the buffer. */ + + memcpy (cp, sha512_salt_prefix, sizeof (sha512_salt_prefix) - 1); + cp += sizeof (sha512_salt_prefix) - 1; + + if (rounds_custom) + { + int n = snprintf (cp, + SHA512_HASH_LENGTH - (sizeof (sha512_salt_prefix) - 1), + "%s%zu$", sha512_rounds_prefix, rounds); + cp += n; + } + + memcpy (cp, salt, salt_size); + cp += salt_size; + *cp++ = '$'; + +#define b64_from_24bit(B2, B1, B0, N) \ + do { \ + unsigned int w = ((((unsigned int)(B2)) << 16) | \ + (((unsigned int)(B1)) << 8) | \ + ((unsigned int)(B0))); \ + int n = (N); \ + while (n-- > 0) \ + { \ + *cp++ = b64t[w & 0x3f]; \ + w >>= 6; \ + } \ + } while (0) + + b64_from_24bit (result[0], result[21], result[42], 4); + b64_from_24bit (result[22], result[43], result[1], 4); + b64_from_24bit (result[44], result[2], result[23], 4); + b64_from_24bit (result[3], result[24], result[45], 4); + b64_from_24bit (result[25], result[46], result[4], 4); + b64_from_24bit (result[47], result[5], result[26], 4); + b64_from_24bit (result[6], result[27], result[48], 4); + b64_from_24bit (result[28], result[49], result[7], 4); + b64_from_24bit (result[50], result[8], result[29], 4); + b64_from_24bit (result[9], result[30], result[51], 4); + b64_from_24bit (result[31], result[52], result[10], 4); + b64_from_24bit (result[53], result[11], result[32], 4); + b64_from_24bit (result[12], result[33], result[54], 4); + b64_from_24bit (result[34], result[55], result[13], 4); + b64_from_24bit (result[56], result[14], result[35], 4); + b64_from_24bit (result[15], result[36], result[57], 4); + b64_from_24bit (result[37], result[58], result[16], 4); + b64_from_24bit (result[59], result[17], result[38], 4); + b64_from_24bit (result[18], result[39], result[60], 4); + b64_from_24bit (result[40], result[61], result[19], 4); + b64_from_24bit (result[62], result[20], result[41], 4); + b64_from_24bit (0, 0, result[63], 2); + + *cp = '\0'; +} + +#ifndef NO_GENSALT + +void +gensalt_sha512crypt_rn (unsigned long count, + const uint8_t *rbytes, size_t nrbytes, + uint8_t *output, size_t output_size) +{ + gensalt_sha_rn ('6', SALT_LEN_MAX, ROUNDS_DEFAULT, ROUNDS_MIN, ROUNDS_MAX, + count, rbytes, nrbytes, output, output_size); +} + +#endif + +#endif diff --git a/lib/crypt/crypt.c b/lib/crypt/crypt.c new file mode 100644 index 0000000000..4ec6079768 --- /dev/null +++ b/lib/crypt/crypt.c @@ -0,0 +1,73 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* Copyright (C) 2020 Steffen Jaeckel jaeckel-floss@eyet-services.de */ + +#include <common.h> +#include <crypt.h> +#include "crypt-port.h" + +typedef void (*crypt_fn)(const char *, size_t, const char *, size_t, uint8_t *, + size_t, void *, size_t); + +const unsigned char ascii64[65] = + "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"; + +static void equals_constant_time(const void *a_, const void *b_, size_t len, + int *equal) +{ + u8 ret = 0; + const u8 *a = a_, *b = b_; + int i; + + for (i = 0; i < len; i++) + ret |= a[i] ^ b[i]; + + ret |= ret >> 4; + ret |= ret >> 2; + ret |= ret >> 1; + ret &= 1; + + *equal = ret ^ 1; +} + +void crypt_compare(const char *should, const char *passphrase, int *equal) +{ + u8 output[CRYPT_OUTPUT_SIZE], scratch[ALG_SPECIFIC_SIZE]; + size_t n; + struct { + const char *prefix; + crypt_fn crypt; + } crypt_algos[] = { +#if defined(CONFIG_CRYPT_PW_SHA256) + { "$5$", crypt_sha256crypt_rn }, +#endif +#if defined(CONFIG_CRYPT_PW_SHA512) + { "$6$", crypt_sha512crypt_rn }, +#endif + { NULL, NULL } + }; + + *equal = 0; + + for (n = 0; n < ARRAY_SIZE(crypt_algos); ++n) { + if (!crypt_algos[n].prefix) + continue; + if (strncmp(should, crypt_algos[n].prefix, 3) == 0) + break; + } + + if (n >= ARRAY_SIZE(crypt_algos)) + return; + + crypt_algos[n].crypt(passphrase, strlen(passphrase), should, 0, output, + sizeof(output), scratch, sizeof(scratch)); + + /* early return on error, nothing really happened inside the crypt() function */ + if (errno == ERANGE || errno == EINVAL) + return; + + equals_constant_time(should, output, strlen((const char *)output), + equal); + + memset(scratch, 0, sizeof(scratch)); + memset(output, 0, sizeof(output)); +}

Hook into the autoboot flow as an alternative to the existing mechanisms.

Signed-off-by: Steffen Jaeckel jaeckel-floss@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 - #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) +{ + const char *crypt_env_str = env_get("bootstopkeycrypt"); + char presskey[MAX_DELAY_STOP_STR]; + u_int presskey_len = 0; + int abort = 0; + + if (IS_ENABLED(HAS_STOP_STR_CRYPT) && !crypt_env_str) + crypt_env_str = AUTOBOOT_STOP_STR_ENC; + + if (!crypt_env_str) + return 0; + + /* + * We expect the stop-string to be newline terminated. + */ + 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");

While doing code-review internally this got nitpicked by 2 reviewers, so I decided to include this here.

Signed-off-by: Steffen Jaeckel jaeckel-floss@eyet-services.de ---

common/autoboot.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/common/autoboot.c b/common/autoboot.c index 732a01d0e5..5bda3da7b1 100644 --- a/common/autoboot.c +++ b/common/autoboot.c @@ -27,7 +27,7 @@

DECLARE_GLOBAL_DATA_PTR;

-#define MAX_DELAY_STOP_STR 64 +#define DELAY_STOP_STR_MAX_LENGTH 64

#ifndef DEBUG_BOOTKEYS #define DEBUG_BOOTKEYS 0 @@ -59,7 +59,7 @@ static int menukey; static int passwd_abort_crypt(uint64_t etime) { const char *crypt_env_str = env_get("bootstopkeycrypt"); - char presskey[MAX_DELAY_STOP_STR]; + char presskey[DELAY_STOP_STR_MAX_LENGTH]; u_int presskey_len = 0; int abort = 0;

@@ -75,7 +75,7 @@ static int passwd_abort_crypt(uint64_t etime) do { if (tstc()) { /* Check for input string overflow */ - if (presskey_len >= MAX_DELAY_STOP_STR) + if (presskey_len >= DELAY_STOP_STR_MAX_LENGTH) return 0;

presskey[presskey_len] = getchar(); @@ -136,9 +136,9 @@ static int passwd_abort_sha256(uint64_t etime) if (sha_env_str == NULL) sha_env_str = AUTOBOOT_STOP_STR_ENC;

- presskey = malloc_cache_aligned(MAX_DELAY_STOP_STR); + presskey = malloc_cache_aligned(DELAY_STOP_STR_MAX_LENGTH); c = strstr(sha_env_str, ":"); - if (c && (c - sha_env_str < MAX_DELAY_STOP_STR)) { + if (c && (c - sha_env_str < DELAY_STOP_STR_MAX_LENGTH)) { /* preload presskey with salt */ memcpy(presskey, sha_env_str, c - sha_env_str); presskey_len = c - sha_env_str; @@ -165,7 +165,7 @@ static int passwd_abort_sha256(uint64_t etime) do { if (tstc()) { /* Check for input string overflow */ - if (presskey_len >= MAX_DELAY_STOP_STR) { + if (presskey_len >= DELAY_STOP_STR_MAX_LENGTH) { free(presskey); free(sha); return 0; @@ -209,7 +209,7 @@ static int passwd_abort_key(uint64_t etime) { .str = env_get("bootstopkey"), .retry = 0 }, };

- char presskey[MAX_DELAY_STOP_STR]; + char presskey[DELAY_STOP_STR_MAX_LENGTH]; int presskey_len = 0; int presskey_max = 0; int i; @@ -226,8 +226,8 @@ static int passwd_abort_key(uint64_t etime) 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; + delaykey[i].len = delaykey[i].len > DELAY_STOP_STR_MAX_LENGTH ? + DELAY_STOP_STR_MAX_LENGTH : delaykey[i].len;

presskey_max = presskey_max > delaykey[i].len ? presskey_max : delaykey[i].len;

In case a user has to enter a complicated password it is sometimes desireable to give the user more time than the default timeout. Enabling this feature will disable the timeout entirely in case the user presses the <Enter> key before entering any other character.

Signed-off-by: Steffen Jaeckel jaeckel-floss@eyet-services.de ---

cmd/Kconfig | 8 ++++++++ common/autoboot.c | 8 +++++++- 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/cmd/Kconfig b/cmd/Kconfig index c735e81b37..03c07d0f32 100644 --- a/cmd/Kconfig +++ b/cmd/Kconfig @@ -177,6 +177,14 @@ config CMD_SBI help Display information about the SBI implementation.

+config AUTOBOOT_NEVER_TIMEOUT + bool "Make the password entry never time-out" + depends on AUTOBOOT_KEYED && AUTOBOOT_ENCRYPTION + help + This option removes the timeout from the password entry + when the user first presses the <Enter> key before entering + any other character. + endmenu

menu "Boot commands" diff --git a/common/autoboot.c b/common/autoboot.c index 5bda3da7b1..467333db9d 100644 --- a/common/autoboot.c +++ b/common/autoboot.c @@ -62,6 +62,7 @@ static int passwd_abort_crypt(uint64_t etime) char presskey[DELAY_STOP_STR_MAX_LENGTH]; u_int presskey_len = 0; int abort = 0; + int never_timeout = 0;

if (IS_ENABLED(HAS_STOP_STR_CRYPT) && !crypt_env_str) crypt_env_str = AUTOBOOT_STOP_STR_ENC; @@ -82,6 +83,11 @@ static int passwd_abort_crypt(uint64_t etime)

if ((presskey[presskey_len] == '\r') || (presskey[presskey_len] == '\n')) { + if (IS_ENABLED(CONFIG_AUTOBOOT_NEVER_TIMEOUT) && + !presskey_len) { + never_timeout = 1; + continue; + } presskey[presskey_len] = '\0'; crypt_compare(crypt_env_str, presskey, &abort); /* you had one chance */ @@ -90,7 +96,7 @@ static int passwd_abort_crypt(uint64_t etime) presskey_len++; } } - } while (get_ticks() <= etime); + } while (never_timeout || get_ticks() <= etime);

return abort; }