/* * fast-pbkdf2 - Optimal PBKDF2-HMAC calculation * Written in 2015 by Joseph Birr-Pixton * * To the extent possible under law, the author(s) have dedicated all * copyright and related and neighboring rights to this software to the * public domain worldwide. This software is distributed without any * warranty. * * You should have received a copy of the CC0 Public Domain Dedication * along with this software. If not, see * . */ #include "fastpbkdf2.h" #include #include #if defined(__GNUC__) #if TARGET_OS_MACCATALYST #include // Mac Catalyst #else #include // iOS #endif #endif #include /* --- MSVC doesn't support C99 --- */ #ifdef _MSC_VER #define restrict #define _Pragma __pragma #endif /* --- Common useful things --- */ #define MIN(a, b) ((a) > (b)) ? (b) : (a) static inline void write32_be(uint32_t n, uint8_t out[4]) { #if defined(__GNUC__) && __GNUC__ >= 4 && __BYTE_ORDER == __LITTLE_ENDIAN *(uint32_t *)(out) = __builtin_bswap32(n); #else out[0] = (n >> 24) & 0xff; out[1] = (n >> 16) & 0xff; out[2] = (n >> 8) & 0xff; out[3] = n & 0xff; #endif } static inline void write64_be(uint64_t n, uint8_t out[8]) { #if defined(__GNUC__) && __GNUC__ >= 4 && __BYTE_ORDER == __LITTLE_ENDIAN *(uint64_t *)(out) = __builtin_bswap64(n); #else write32_be((n >> 32) & 0xffffffff, out); write32_be(n & 0xffffffff, out + 4); #endif } /* --- Optional OpenMP parallelisation of consecutive blocks --- */ #ifdef WITH_OPENMP #define OPENMP_PARALLEL_FOR _Pragma("omp parallel for") #else #define OPENMP_PARALLEL_FOR #endif /* Prepare block (of blocksz bytes) to contain md padding denoting a msg-size * message (in bytes). block has a prefix of used bytes. * * Message length is expressed in 32 bits (so suitable for sha1, sha256, * sha512). */ static inline void md_pad(uint8_t *block, size_t blocksz, size_t used, size_t msg) { memset(block + used, 0, blocksz - used - 4); block[used] = 0x80; block += blocksz - 4; write32_be((uint32_t)(msg * 8), block); } /* Internal function/type names for hash-specific things. */ #define HMAC_CTX(_name) HMAC_ ## _name ## _ctx #define HMAC_INIT(_name) HMAC_ ## _name ## _init #define HMAC_UPDATE(_name) HMAC_ ## _name ## _update #define HMAC_FINAL(_name) HMAC_ ## _name ## _final #define PBKDF2_F(_name) pbkdf2_f_ ## _name #define PBKDF2(_name) pbkdf2_ ## _name /* This macro expands to decls for the whole implementation for a given * hash function. Arguments are: * * _name like 'sha1', added to symbol names * _blocksz block size, in bytes * _hashsz digest output, in bytes * _ctx hash context type * _init hash context initialisation function * args: (_ctx *c) * _update hash context update function * args: (_ctx *c, const void *data, size_t ndata) * _final hash context finish function * args: (void *out, _ctx *c) * _xform hash context raw block update function * args: (_ctx *c, const void *data) * _xcpy hash context raw copy function (only need copy hash state) * args: (_ctx * restrict out, const _ctx *restrict in) * _xtract hash context state extraction * args: args (_ctx *restrict c, uint8_t *restrict out) * _xxor hash context xor function (only need xor hash state) * args: (_ctx *restrict out, const _ctx *restrict in) * * The resulting function is named PBKDF2(_name). */ #define DECL_PBKDF2(_name, _blocksz, _hashsz, _ctx, _init, _update, _xform, \ _final, _xcpy, _xtract, _xxor) \ typedef struct { \ _ctx inner; \ _ctx outer; \ } HMAC_CTX(_name); \ \ static inline void HMAC_INIT(_name)(HMAC_CTX(_name) * ctx, \ const uint8_t *key, size_t nkey) { \ /* Prepare key: */ \ uint8_t k[_blocksz]; \ \ /* Shorten long keys. */ \ if (nkey > _blocksz) { \ _init(&ctx->inner); \ _update(&ctx->inner, key, nkey); \ _final(k, &ctx->inner); \ \ key = k; \ nkey = _hashsz; \ } \ \ /* Standard doesn't cover case where blocksz < hashsz. */ \ assert(nkey <= _blocksz); \ \ /* Right zero-pad short keys. */ \ if (k != key) memcpy(k, key, nkey); \ if (_blocksz > nkey) memset(k + nkey, 0, _blocksz - nkey); \ \ /* Start inner hash computation */ \ uint8_t blk_inner[_blocksz]; \ uint8_t blk_outer[_blocksz]; \ \ for (size_t i = 0; i < _blocksz; i++) { \ blk_inner[i] = 0x36 ^ k[i]; \ blk_outer[i] = 0x5c ^ k[i]; \ } \ \ _init(&ctx->inner); \ _update(&ctx->inner, blk_inner, sizeof blk_inner); \ \ /* And outer. */ \ _init(&ctx->outer); \ _update(&ctx->outer, blk_outer, sizeof blk_outer); \ } \ \ static inline void HMAC_UPDATE(_name)(HMAC_CTX(_name) * ctx, \ const void *data, size_t ndata) { \ _update(&ctx->inner, data, ndata); \ } \ \ static inline void HMAC_FINAL(_name)(HMAC_CTX(_name) * ctx, \ uint8_t out[_hashsz]) { \ _final(out, &ctx->inner); \ _update(&ctx->outer, out, _hashsz); \ _final(out, &ctx->outer); \ } \ \ /* --- PBKDF2 --- */ \ static inline void PBKDF2_F(_name)( \ const HMAC_CTX(_name) * startctx, uint32_t counter, const uint8_t *salt, \ size_t nsalt, uint32_t iterations, uint8_t *out) { \ uint8_t countbuf[4]; \ write32_be(counter, countbuf); \ \ /* Prepare loop-invariant padding block. */ \ uint8_t Ublock[_blocksz]; \ md_pad(Ublock, _blocksz, _hashsz, _blocksz + _hashsz); \ \ /* First iteration: \ * U_1 = PRF(P, S || INT_32_BE(i)) \ */ \ HMAC_CTX(_name) ctx = *startctx; \ HMAC_UPDATE(_name)(&ctx, salt, nsalt); \ HMAC_UPDATE(_name)(&ctx, countbuf, sizeof countbuf); \ HMAC_FINAL(_name)(&ctx, Ublock); \ _ctx result = ctx.outer; \ \ /* Subsequent iterations: \ * U_c = PRF(P, U_{c-1}) \ */ \ for (uint32_t i = 1; i < iterations; i++) { \ /* Complete inner hash with previous U */ \ _xcpy(&ctx.inner, &startctx->inner); \ _xform(&ctx.inner, Ublock); \ _xtract(&ctx.inner, Ublock); \ /* Complete outer hash with inner output */ \ _xcpy(&ctx.outer, &startctx->outer); \ _xform(&ctx.outer, Ublock); \ _xtract(&ctx.outer, Ublock); \ _xxor(&result, &ctx.outer); \ } \ \ /* Reform result into output buffer. */ \ _xtract(&result, out); \ } \ \ static inline void PBKDF2(_name)( \ const uint8_t *pw, size_t npw, const uint8_t *salt, size_t nsalt, \ uint32_t iterations, uint8_t *out, size_t nout) { \ assert(iterations); \ assert(out &&nout); \ \ /* Starting point for inner loop. */ \ HMAC_CTX(_name) ctx; \ HMAC_INIT(_name)(&ctx, pw, npw); \ \ /* How many blocks do we need? */ \ uint32_t blocks_needed = (uint32_t)(nout + _hashsz - 1) / _hashsz; \ \ OPENMP_PARALLEL_FOR \ for (uint32_t counter = 1; counter <= blocks_needed; counter++) { \ uint8_t block[_hashsz]; \ PBKDF2_F(_name)(&ctx, counter, salt, nsalt, iterations, block); \ \ size_t offset = (counter - 1) * _hashsz; \ size_t taken = MIN(nout - offset, _hashsz); \ memcpy(out + offset, block, taken); \ } \ } static inline void sha1_extract(SHA_CTX *restrict ctx, uint8_t *restrict out) { write32_be(ctx->h0, out); write32_be(ctx->h1, out + 4); write32_be(ctx->h2, out + 8); write32_be(ctx->h3, out + 12); write32_be(ctx->h4, out + 16); } static inline void sha1_cpy(SHA_CTX *restrict out, const SHA_CTX *restrict in) { out->h0 = in->h0; out->h1 = in->h1; out->h2 = in->h2; out->h3 = in->h3; out->h4 = in->h4; } static inline void sha1_xor(SHA_CTX *restrict out, const SHA_CTX *restrict in) { out->h0 ^= in->h0; out->h1 ^= in->h1; out->h2 ^= in->h2; out->h3 ^= in->h3; out->h4 ^= in->h4; } DECL_PBKDF2(sha1, SHA_CBLOCK, SHA_DIGEST_LENGTH, SHA_CTX, SHA1_Init, SHA1_Update, SHA1_Transform, SHA1_Final, sha1_cpy, sha1_extract, sha1_xor) static inline void sha256_extract(SHA256_CTX *restrict ctx, uint8_t *restrict out) { write32_be(ctx->h[0], out); write32_be(ctx->h[1], out + 4); write32_be(ctx->h[2], out + 8); write32_be(ctx->h[3], out + 12); write32_be(ctx->h[4], out + 16); write32_be(ctx->h[5], out + 20); write32_be(ctx->h[6], out + 24); write32_be(ctx->h[7], out + 28); } static inline void sha256_cpy(SHA256_CTX *restrict out, const SHA256_CTX *restrict in) { out->h[0] = in->h[0]; out->h[1] = in->h[1]; out->h[2] = in->h[2]; out->h[3] = in->h[3]; out->h[4] = in->h[4]; out->h[5] = in->h[5]; out->h[6] = in->h[6]; out->h[7] = in->h[7]; } static inline void sha256_xor(SHA256_CTX *restrict out, const SHA256_CTX *restrict in) { out->h[0] ^= in->h[0]; out->h[1] ^= in->h[1]; out->h[2] ^= in->h[2]; out->h[3] ^= in->h[3]; out->h[4] ^= in->h[4]; out->h[5] ^= in->h[5]; out->h[6] ^= in->h[6]; out->h[7] ^= in->h[7]; } DECL_PBKDF2(sha256, SHA256_CBLOCK, SHA256_DIGEST_LENGTH, SHA256_CTX, SHA256_Init, SHA256_Update, SHA256_Transform, SHA256_Final, sha256_cpy, sha256_extract, sha256_xor) static inline void sha512_extract(SHA512_CTX *restrict ctx, uint8_t *restrict out) { write64_be(ctx->h[0], out); write64_be(ctx->h[1], out + 8); write64_be(ctx->h[2], out + 16); write64_be(ctx->h[3], out + 24); write64_be(ctx->h[4], out + 32); write64_be(ctx->h[5], out + 40); write64_be(ctx->h[6], out + 48); write64_be(ctx->h[7], out + 56); } static inline void sha512_cpy(SHA512_CTX *restrict out, const SHA512_CTX *restrict in) { out->h[0] = in->h[0]; out->h[1] = in->h[1]; out->h[2] = in->h[2]; out->h[3] = in->h[3]; out->h[4] = in->h[4]; out->h[5] = in->h[5]; out->h[6] = in->h[6]; out->h[7] = in->h[7]; } static inline void sha512_xor(SHA512_CTX *restrict out, const SHA512_CTX *restrict in) { out->h[0] ^= in->h[0]; out->h[1] ^= in->h[1]; out->h[2] ^= in->h[2]; out->h[3] ^= in->h[3]; out->h[4] ^= in->h[4]; out->h[5] ^= in->h[5]; out->h[6] ^= in->h[6]; out->h[7] ^= in->h[7]; } DECL_PBKDF2(sha512, SHA512_CBLOCK, SHA512_DIGEST_LENGTH, SHA512_CTX, SHA512_Init, SHA512_Update, SHA512_Transform, SHA512_Final, sha512_cpy, sha512_extract, sha512_xor) void fastpbkdf2_hmac_sha1(const uint8_t *pw, size_t npw, const uint8_t *salt, size_t nsalt, uint32_t iterations, uint8_t *out, size_t nout) { PBKDF2(sha1)(pw, npw, salt, nsalt, iterations, out, nout); } void fastpbkdf2_hmac_sha256(const uint8_t *pw, size_t npw, const uint8_t *salt, size_t nsalt, uint32_t iterations, uint8_t *out, size_t nout) { PBKDF2(sha256)(pw, npw, salt, nsalt, iterations, out, nout); } void fastpbkdf2_hmac_sha512(const uint8_t *pw, size_t npw, const uint8_t *salt, size_t nsalt, uint32_t iterations, uint8_t *out, size_t nout) { PBKDF2(sha512)(pw, npw, salt, nsalt, iterations, out, nout); }