diff options
Diffstat (limited to 'src/util/crypto/libcrypto/crypto_sha512crypt.c')
-rw-r--r-- | src/util/crypto/libcrypto/crypto_sha512crypt.c | 381 |
1 files changed, 381 insertions, 0 deletions
diff --git a/src/util/crypto/libcrypto/crypto_sha512crypt.c b/src/util/crypto/libcrypto/crypto_sha512crypt.c new file mode 100644 index 00000000..29900cc9 --- /dev/null +++ b/src/util/crypto/libcrypto/crypto_sha512crypt.c @@ -0,0 +1,381 @@ +/* This file is based on nss_sha512crypt.c which is based on the work of + * Ulrich Drepper (http://people.redhat.com/drepper/SHA-crypt.txt). + * + * libcrypto is used to provide SHA512 and random number generation. + * (http://www.openssl.org/docs/crypto/crypto.html). + * + * Sumit Bose <sbose@redhat.com> + * George McCollister <georgem@novatech-llc.com> + */ +/* SHA512-based Unix crypt implementation. + Released into the Public Domain by Ulrich Drepper <drepper@redhat.com>. */ + +#define _GNU_SOURCE +#include <endian.h> +#include <errno.h> +#include <limits.h> +#include <stdbool.h> +#include <stdint.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/param.h> +#include <sys/types.h> + +#include "util/util.h" + +#include <openssl/evp.h> +#include <openssl/rand.h> + +/* Define our magic string to mark salt for SHA512 "encryption" replacement. */ +const char sha512_salt_prefix[] = "$6$"; +#define SALT_PREF_SIZE (sizeof(sha512_salt_prefix) - 1) + +/* Prefix for optional rounds specification. */ +const char sha512_rounds_prefix[] = "rounds="; +#define ROUNDS_SIZE (sizeof(sha512_rounds_prefix) - 1) + +#define SALT_LEN_MAX 16 +#define ROUNDS_DEFAULT 5000 +#define ROUNDS_MIN 1000 +#define ROUNDS_MAX 999999999 + +/* Table with characters for base64 transformation. */ +const char b64t[64] = + "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"; + +/* base64 conversion function */ +static inline void b64_from_24bit(char **dest, size_t *len, size_t n, + uint8_t b2, uint8_t b1, uint8_t b0) +{ + uint32_t w; + size_t i; + + if (*len < n) n = *len; + + w = (b2 << 16) | (b1 << 8) | b0; + for (i = 0; i < n; i++) { + (*dest)[i] = b64t[w & 0x3f]; + w >>= 6; + } + + *len -= i; + *dest += i; +} + +#define PTR_2_INT(x) ((x) - ((__typeof__ (x)) NULL)) +#define ALIGN64 __alignof__(uint64_t) + +static int sha512_crypt_r(const char *key, + const char *salt, + char *buffer, size_t buflen) +{ + unsigned char temp_result[64] __attribute__((__aligned__(ALIGN64))); + unsigned char alt_result[64] __attribute__((__aligned__(ALIGN64))); + size_t rounds = ROUNDS_DEFAULT; + bool rounds_custom = false; + EVP_MD_CTX alt_ctx; + EVP_MD_CTX ctx; + size_t salt_len; + size_t key_len; + size_t cnt; + char *copied_salt = NULL; + char *copied_key = NULL; + char *p_bytes = NULL; + char *s_bytes = NULL; + int p1, p2, p3, pt, n; + unsigned int part; + char *cp, *tmp; + int ret; + + /* Find beginning of salt string. The prefix should normally always be + * present. Just in case it is not. */ + if (strncmp(salt, sha512_salt_prefix, SALT_PREF_SIZE) == 0) { + /* Skip salt prefix. */ + salt += SALT_PREF_SIZE; + } + + if (strncmp(salt, sha512_rounds_prefix, ROUNDS_SIZE) == 0) { + unsigned long int srounds; + const char *num; + char *endp; + + num = salt + ROUNDS_SIZE; + srounds = strtoul(num, &endp, 10); + if (*endp == '$') { + salt = endp + 1; + if (srounds < ROUNDS_MIN) srounds = ROUNDS_MIN; + if (srounds > ROUNDS_MAX) srounds = ROUNDS_MAX; + rounds = srounds; + rounds_custom = true; + } + } + + salt_len = MIN(strcspn(salt, "$"), SALT_LEN_MAX); + key_len = strlen(key); + + if ((PTR_2_INT(key) % ALIGN64) != 0) { + tmp = (char *)alloca(key_len + ALIGN64); + key = copied_key = memcpy(tmp + ALIGN64 - PTR_2_INT(tmp) % ALIGN64, key, key_len); + } + + if (PTR_2_INT(salt) % ALIGN64 != 0) { + tmp = (char *)alloca(salt_len + ALIGN64); + salt = copied_salt = memcpy(tmp + ALIGN64 - PTR_2_INT(tmp) % ALIGN64, salt, salt_len); + } + + EVP_MD_CTX_init(&ctx); + + EVP_MD_CTX_init(&alt_ctx); + + /* Prepare for the real work. */ + if (!EVP_DigestInit_ex(&ctx, EVP_sha512(), NULL)) { + ret = EIO; + goto done; + } + + /* Add the key string. */ + EVP_DigestUpdate(&ctx, (const unsigned char *)key, key_len); + + /* The last part is the salt string. This must be at most 16 + * characters and it ends at the first `$' character (for + * compatibility with existing implementations). */ + EVP_DigestUpdate(&ctx, (const unsigned char *)salt, salt_len); + + + /* Compute alternate SHA512 sum with input KEY, SALT, and KEY. + * The final result will be added to the first context. */ + if (!EVP_DigestInit_ex(&alt_ctx, EVP_sha512(), NULL)) { + ret = EIO; + goto done; + } + + /* Add key. */ + EVP_DigestUpdate(&alt_ctx, (const unsigned char *)key, key_len); + + /* Add salt. */ + EVP_DigestUpdate(&alt_ctx, (const unsigned char *)salt, salt_len); + + /* Add key again. */ + EVP_DigestUpdate(&alt_ctx, (const unsigned char *)key, key_len); + + /* Now get result of this (64 bytes) and add it to the other context. */ + EVP_DigestFinal_ex(&alt_ctx, alt_result, &part); + + /* Add for any character in the key one byte of the alternate sum. */ + for (cnt = key_len; cnt > 64; cnt -= 64) { + EVP_DigestUpdate(&ctx, alt_result, 64); + } + EVP_DigestUpdate(&ctx, alt_result, cnt); + + /* Take the binary representation of the length of the key and for every + * 1 add the alternate sum, for every 0 the key. */ + for (cnt = key_len; cnt > 0; cnt >>= 1) { + if ((cnt & 1) != 0) { + EVP_DigestUpdate(&ctx, alt_result, 64); + } else { + EVP_DigestUpdate(&ctx, (const unsigned char *)key, key_len); + } + } + + /* Create intermediate result. */ + EVP_DigestFinal_ex(&ctx, alt_result, &part); + + /* Start computation of P byte sequence. */ + if (!EVP_DigestInit_ex(&alt_ctx, EVP_sha512(), NULL)) { + ret = EIO; + goto done; + } + + /* For every character in the password add the entire password. */ + for (cnt = 0; cnt < key_len; cnt++) { + EVP_DigestUpdate(&alt_ctx, (const unsigned char *)key, key_len); + } + + /* Finish the digest. */ + EVP_DigestFinal_ex(&alt_ctx, temp_result, &part); + + /* Create byte sequence P. */ + cp = p_bytes = alloca(key_len); + for (cnt = key_len; cnt >= 64; cnt -= 64) { + cp = mempcpy(cp, temp_result, 64); + } + memcpy(cp, temp_result, cnt); + + /* Start computation of S byte sequence. */ + if (!EVP_DigestInit_ex(&alt_ctx, EVP_sha512(), NULL)) { + ret = EIO; + goto done; + } + + /* For every character in the password add the entire salt. */ + for (cnt = 0; cnt < 16 + alt_result[0]; cnt++) { + EVP_DigestUpdate(&alt_ctx, (const unsigned char *)salt, salt_len); + } + + /* Finish the digest. */ + EVP_DigestFinal_ex(&alt_ctx, temp_result, &part); + + /* Create byte sequence S. */ + cp = s_bytes = alloca(salt_len); + for (cnt = salt_len; cnt >= 64; cnt -= 64) { + cp = mempcpy(cp, temp_result, 64); + } + memcpy(cp, temp_result, cnt); + + /* Repeatedly run the collected hash value through SHA512 to burn CPU cycles. */ + for (cnt = 0; cnt < rounds; cnt++) { + + if (!EVP_DigestInit_ex(&ctx, EVP_sha512(), NULL)) { + ret = EIO; + goto done; + } + + /* Add key or last result. */ + if ((cnt & 1) != 0) { + EVP_DigestUpdate(&ctx, (const unsigned char *)p_bytes, key_len); + } else { + EVP_DigestUpdate(&ctx, alt_result, 64); + } + + /* Add salt for numbers not divisible by 3. */ + if (cnt % 3 != 0) { + EVP_DigestUpdate(&ctx, (const unsigned char *)s_bytes, salt_len); + } + + /* Add key for numbers not divisible by 7. */ + if (cnt % 7 != 0) { + EVP_DigestUpdate(&ctx, (const unsigned char *)p_bytes, key_len); + } + + /* Add key or last result. */ + if ((cnt & 1) != 0) { + EVP_DigestUpdate(&ctx, alt_result, 64); + } else { + EVP_DigestUpdate(&ctx, (const unsigned char *)p_bytes, key_len); + } + + /* Create intermediate result. */ + EVP_DigestFinal_ex(&ctx, alt_result, &part); + } + + /* Now we can construct the result string. + * It consists of three parts. */ + if (buflen <= SALT_PREF_SIZE) { + ret = ERANGE; + goto done; + } + + cp = __stpncpy(buffer, sha512_salt_prefix, SALT_PREF_SIZE); + buflen -= SALT_PREF_SIZE; + + if (rounds_custom) { + n = snprintf(cp, buflen, "%s%zu$", + sha512_rounds_prefix, rounds); + if (n < 0 || n >= buflen) { + ret = ERANGE; + goto done; + } + cp += n; + buflen -= n; + } + + if (buflen <= salt_len + 1) { + ret = ERANGE; + goto done; + } + cp = __stpncpy(cp, salt, salt_len); + *cp++ = '$'; + buflen -= salt_len + 1; + + /* fuzzyfill the base 64 string */ + p1 = 0; + p2 = 21; + p3 = 42; + for (n = 0; n < 21; n++) { + b64_from_24bit(&cp, &buflen, 4, alt_result[p1], alt_result[p2], alt_result[p3]); + if (buflen == 0) { + ret = ERANGE; + goto done; + } + pt = p1; + p1 = p2 + 1; + p2 = p3 + 1; + p3 = pt + 1; + } + /* 64th and last byte */ + b64_from_24bit(&cp, &buflen, 2, 0, 0, alt_result[p3]); + if (buflen == 0) { + ret = ERANGE; + goto done; + } + + *cp = '\0'; + ret = EOK; + +done: + /* Clear the buffer for the intermediate result so that people attaching + * to processes or reading core dumps cannot get any information. We do it + * in this way to clear correct_words[] inside the SHA512 implementation + * as well. */ + EVP_MD_CTX_cleanup(&ctx); + EVP_MD_CTX_cleanup(&alt_ctx); + if (p_bytes) memset(p_bytes, '\0', key_len); + if (s_bytes) memset(s_bytes, '\0', salt_len); + if (copied_key) memset(copied_key, '\0', key_len); + if (copied_salt) memset(copied_salt, '\0', salt_len); + memset(temp_result, '\0', sizeof(temp_result)); + + return ret; +} + +int s3crypt_sha512(TALLOC_CTX *memctx, + const char *key, const char *salt, char **_hash) +{ + char *hash; + int hlen = (sizeof (sha512_salt_prefix) - 1 + + sizeof (sha512_rounds_prefix) + 9 + 1 + + strlen (salt) + 1 + 86 + 1); + int ret; + + hash = talloc_size(memctx, hlen); + if (!hash) return ENOMEM; + + ret = sha512_crypt_r(key, salt, hash, hlen); + if (ret) return ret; + + *_hash = hash; + return ret; +} + +#define SALT_RAND_LEN 12 + +int s3crypt_gen_salt(TALLOC_CTX *memctx, char **_salt) +{ + uint8_t rb[SALT_RAND_LEN]; + char *salt, *cp; + size_t slen; + int ret; + + salt = talloc_size(memctx, SALT_LEN_MAX + 1); + if (!salt) { + return ENOMEM; + } + + ret = RAND_bytes(rb, SALT_RAND_LEN); + if (ret == 0) { + return EIO; + } + + slen = SALT_LEN_MAX; + cp = salt; + b64_from_24bit(&cp, &slen, 4, rb[0], rb[1], rb[2]); + b64_from_24bit(&cp, &slen, 4, rb[3], rb[4], rb[5]); + b64_from_24bit(&cp, &slen, 4, rb[6], rb[7], rb[8]); + b64_from_24bit(&cp, &slen, 4, rb[9], rb[10], rb[11]); + *cp = '\0'; + + *_salt = salt; + + return EOK; +} |