/* * Copyright 2015-2016 The OpenSSL Project Authors. All Rights Reserved. * * Licensed under the OpenSSL license (the "License"). You may not use * this file except in compliance with the License. You can obtain a copy * in the file LICENSE in the source distribution or at * https://www.openssl.org/source/license.html */ #include #include #include #include #include #include "../internal.h" // This file implements scrypt, described in RFC 7914. // // Note scrypt refers to both "blocks" and a "block size" parameter, r. These // are two different notions of blocks. A Salsa20 block is 64 bytes long, // represented in this implementation by 16 |uint32_t|s. |r| determines the // number of 64-byte Salsa20 blocks in a scryptBlockMix block, which is 2 * |r| // Salsa20 blocks. This implementation refers to them as Salsa20 blocks and // scrypt blocks, respectively. // A block_t is a Salsa20 block. #define SCRYPT_BLOCK_WORD_CNT 16 typedef struct { uint32_t words[SCRYPT_BLOCK_WORD_CNT]; } block_t; OPENSSL_STATIC_ASSERT(sizeof(block_t) == 64, block_t_has_padding) // salsa208_word_specification implements the Salsa20/8 core function, also // described in RFC 7914, section 3. It modifies the block at |inout| // in-place. static void salsa208_word_specification(block_t *inout) { block_t x; OPENSSL_memcpy(&x, inout, sizeof(x)); for (int i = 8; i > 0; i -= 2) { x.words[4] ^= CRYPTO_rotl_u32(x.words[0] + x.words[12], 7); x.words[8] ^= CRYPTO_rotl_u32(x.words[4] + x.words[0], 9); x.words[12] ^= CRYPTO_rotl_u32(x.words[8] + x.words[4], 13); x.words[0] ^= CRYPTO_rotl_u32(x.words[12] + x.words[8], 18); x.words[9] ^= CRYPTO_rotl_u32(x.words[5] + x.words[1], 7); x.words[13] ^= CRYPTO_rotl_u32(x.words[9] + x.words[5], 9); x.words[1] ^= CRYPTO_rotl_u32(x.words[13] + x.words[9], 13); x.words[5] ^= CRYPTO_rotl_u32(x.words[1] + x.words[13], 18); x.words[14] ^= CRYPTO_rotl_u32(x.words[10] + x.words[6], 7); x.words[2] ^= CRYPTO_rotl_u32(x.words[14] + x.words[10], 9); x.words[6] ^= CRYPTO_rotl_u32(x.words[2] + x.words[14], 13); x.words[10] ^= CRYPTO_rotl_u32(x.words[6] + x.words[2], 18); x.words[3] ^= CRYPTO_rotl_u32(x.words[15] + x.words[11], 7); x.words[7] ^= CRYPTO_rotl_u32(x.words[3] + x.words[15], 9); x.words[11] ^= CRYPTO_rotl_u32(x.words[7] + x.words[3], 13); x.words[15] ^= CRYPTO_rotl_u32(x.words[11] + x.words[7], 18); x.words[1] ^= CRYPTO_rotl_u32(x.words[0] + x.words[3], 7); x.words[2] ^= CRYPTO_rotl_u32(x.words[1] + x.words[0], 9); x.words[3] ^= CRYPTO_rotl_u32(x.words[2] + x.words[1], 13); x.words[0] ^= CRYPTO_rotl_u32(x.words[3] + x.words[2], 18); x.words[6] ^= CRYPTO_rotl_u32(x.words[5] + x.words[4], 7); x.words[7] ^= CRYPTO_rotl_u32(x.words[6] + x.words[5], 9); x.words[4] ^= CRYPTO_rotl_u32(x.words[7] + x.words[6], 13); x.words[5] ^= CRYPTO_rotl_u32(x.words[4] + x.words[7], 18); x.words[11] ^= CRYPTO_rotl_u32(x.words[10] + x.words[9], 7); x.words[8] ^= CRYPTO_rotl_u32(x.words[11] + x.words[10], 9); x.words[9] ^= CRYPTO_rotl_u32(x.words[8] + x.words[11], 13); x.words[10] ^= CRYPTO_rotl_u32(x.words[9] + x.words[8], 18); x.words[12] ^= CRYPTO_rotl_u32(x.words[15] + x.words[14], 7); x.words[13] ^= CRYPTO_rotl_u32(x.words[12] + x.words[15], 9); x.words[14] ^= CRYPTO_rotl_u32(x.words[13] + x.words[12], 13); x.words[15] ^= CRYPTO_rotl_u32(x.words[14] + x.words[13], 18); } for (int i = 0; i < 16; ++i) { inout->words[i] += x.words[i]; } } // xor_block sets |*out| to be |*a| XOR |*b|. static void xor_block(block_t *out, const block_t *a, const block_t *b) { for (size_t i = 0; i < 16; i++) { out->words[i] = a->words[i] ^ b->words[i]; } } // scryptBlockMix implements the function described in RFC 7914, section 4. B' // is written to |out|. |out| and |B| may not alias and must be each one scrypt // block (2 * |r| Salsa20 blocks) long. static void scryptBlockMix(block_t *out, const block_t *B, uint64_t r) { assert(out != B); block_t X; OPENSSL_memcpy(&X, &B[r * 2 - 1], sizeof(X)); for (uint64_t i = 0; i < r * 2; i++) { xor_block(&X, &X, &B[i]); salsa208_word_specification(&X); // This implements the permutation in step 3. OPENSSL_memcpy(&out[i / 2 + (i & 1) * r], &X, sizeof(X)); } } // scryptROMix implements the function described in RFC 7914, section 5. |B| is // an scrypt block (2 * |r| Salsa20 blocks) and is modified in-place. |T| and // |V| are scratch space allocated by the caller. |T| must have space for one // scrypt block (2 * |r| Salsa20 blocks). |V| must have space for |N| scrypt // blocks (2 * |r| * |N| Salsa20 blocks). static void scryptROMix(block_t *B, uint64_t r, uint64_t N, block_t *T, block_t *V) { // Steps 1 and 2. #ifdef OPENSSL_BIG_ENDIAN for(size_t i = 0; i < (2 * r * SCRYPT_BLOCK_WORD_CNT); i++) { CRYPTO_store_u32_le(&V->words[i], B->words[i]); } #else OPENSSL_memcpy(V, B, 2 * r * sizeof(block_t)); #endif for (uint64_t i = 1; i < N; i++) { scryptBlockMix(&V[2 * r * i /* scrypt block i */], &V[2 * r * (i - 1) /* scrypt block i-1 */], r); } scryptBlockMix(B, &V[2 * r * (N - 1) /* scrypt block N-1 */], r); // Step 3. for (uint64_t i = 0; i < N; i++) { // Note this assumes |N| <= 2^32 and is a power of 2. uint32_t j = B[2 * r - 1].words[0] & (N - 1); for (size_t k = 0; k < 2 * r; k++) { xor_block(&T[k], &B[k], &V[2 * r * j + k]); } scryptBlockMix(B, T, r); } #ifdef OPENSSL_BIG_ENDIAN for(size_t i = 0; i < (2 * r * SCRYPT_BLOCK_WORD_CNT); i++) { CRYPTO_store_u32_le(&B->words[i], B->words[i]); } #endif } // SCRYPT_PR_MAX is the maximum value of p * r. This is equivalent to the // bounds on p in section 6: // // p <= ((2^32-1) * hLen) / MFLen iff // p <= ((2^32-1) * 32) / (128 * r) iff // p * r <= (2^30-1) #define SCRYPT_PR_MAX ((1 << 30) - 1) // SCRYPT_MAX_MEM is the default maximum memory that may be allocated by // |EVP_PBE_scrypt|. #define SCRYPT_MAX_MEM (1024 * 1024 * 32) int EVP_PBE_scrypt(const char *password, size_t password_len, const uint8_t *salt, size_t salt_len, uint64_t N, uint64_t r, uint64_t p, size_t max_mem, uint8_t *out_key, size_t key_len) { if (r == 0 || p == 0 || p > SCRYPT_PR_MAX / r || // |N| must be a power of two. N < 2 || (N & (N - 1)) || // We only support |N| <= 2^32 in |scryptROMix|. N > UINT64_C(1) << 32 || // Check that |N| < 2^(128×r / 8). (16 * r <= 63 && N >= UINT64_C(1) << (16 * r))) { OPENSSL_PUT_ERROR(EVP, EVP_R_INVALID_PARAMETERS); return 0; } // Determine the amount of memory needed. B, T, and V are |p|, 1, and |N| // scrypt blocks, respectively. Each scrypt block is 2*|r| |block_t|s. if (max_mem == 0) { max_mem = SCRYPT_MAX_MEM; } size_t max_scrypt_blocks = max_mem / (2 * r * sizeof(block_t)); if (max_scrypt_blocks < p + 1 || max_scrypt_blocks - p - 1 < N) { OPENSSL_PUT_ERROR(EVP, EVP_R_MEMORY_LIMIT_EXCEEDED); return 0; } // Allocate and divide up the scratch space. |max_mem| fits in a size_t, which // is no bigger than uint64_t, so none of these operations may overflow. OPENSSL_STATIC_ASSERT(UINT64_MAX >= SIZE_MAX, size_t_exceeds_uint64_t) size_t B_blocks = p * 2 * r; size_t B_bytes = B_blocks * sizeof(block_t); size_t T_blocks = 2 * r; size_t V_blocks = N * 2 * r; block_t *B = OPENSSL_calloc((B_blocks + T_blocks + V_blocks), sizeof(block_t)); if (B == NULL) { return 0; } int ret = 0; block_t *T = B + B_blocks; block_t *V = T + T_blocks; // NOTE: PKCS5_PBKDF2_HMAC can only fail due to allocation failure // or |iterations| of 0 (we pass 1 here). This is consistent with // the documented failure conditions of EVP_PBE_scrypt. if (!PKCS5_PBKDF2_HMAC(password, password_len, salt, salt_len, 1, EVP_sha256(), B_bytes, (uint8_t *)B)) { goto err; } for (uint64_t i = 0; i < p; i++) { scryptROMix(B + 2 * r * i, r, N, T, V); } if (!PKCS5_PBKDF2_HMAC(password, password_len, (const uint8_t *)B, B_bytes, 1, EVP_sha256(), key_len, out_key)) { goto err; } ret = 1; err: OPENSSL_free(B); return ret; }