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+/*
+ * Argon2 reference source code package - reference C implementations
+ *
+ * Copyright 2015
+ * Daniel Dinu, Dmitry Khovratovich, Jean-Philippe Aumasson, and Samuel Neves
+ *
+ * You may use this work under the terms of a Creative Commons CC0 1.0
+ * License/Waiver or the Apache Public License 2.0, at your option. The terms of
+ * these licenses can be found at:
+ *
+ * - CC0 1.0 Universal : https://creativecommons.org/publicdomain/zero/1.0
+ * - Apache 2.0 : https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * You should have received a copy of both of these licenses along with this
+ * software. If not, they may be obtained at the above URLs.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <limits.h>
+#include "encoding.h"
+#include "core.h"
+
+/*
+ * Example code for a decoder and encoder of "hash strings", with Argon2
+ * parameters.
+ *
+ * This code comprises three sections:
+ *
+ * -- The first section contains generic Base64 encoding and decoding
+ * functions. It is conceptually applicable to any hash function
+ * implementation that uses Base64 to encode and decode parameters,
+ * salts and outputs. It could be made into a library, provided that
+ * the relevant functions are made public (non-static) and be given
+ * reasonable names to avoid collisions with other functions.
+ *
+ * -- The second section is specific to Argon2. It encodes and decodes
+ * the parameters, salts and outputs. It does not compute the hash
+ * itself.
+ *
+ * The code was originally written by Thomas Pornin <pornin@bolet.org>,
+ * to whom comments and remarks may be sent. It is released under what
+ * should amount to Public Domain or its closest equivalent; the
+ * following mantra is supposed to incarnate that fact with all the
+ * proper legal rituals:
+ *
+ * ---------------------------------------------------------------------
+ * This file is provided under the terms of Creative Commons CC0 1.0
+ * Public Domain Dedication. To the extent possible under law, the
+ * author (Thomas Pornin) has waived all copyright and related or
+ * neighboring rights to this file. This work is published from: Canada.
+ * ---------------------------------------------------------------------
+ *
+ * Copyright (c) 2015 Thomas Pornin
+ */
+
+/* ==================================================================== */
+/*
+ * Common code; could be shared between different hash functions.
+ *
+ * Note: the Base64 functions below assume that uppercase letters (resp.
+ * lowercase letters) have consecutive numerical codes, that fit on 8
+ * bits. All modern systems use ASCII-compatible charsets, where these
+ * properties are true. If you are stuck with a dinosaur of a system
+ * that still defaults to EBCDIC then you already have much bigger
+ * interoperability issues to deal with.
+ */
+
+/*
+ * Some macros for constant-time comparisons. These work over values in
+ * the 0..255 range. Returned value is 0x00 on "false", 0xFF on "true".
+ */
+#define EQ(x, y) ((((0U - ((unsigned)(x) ^ (unsigned)(y))) >> 8) & 0xFF) ^ 0xFF)
+#define GT(x, y) ((((unsigned)(y) - (unsigned)(x)) >> 8) & 0xFF)
+#define GE(x, y) (GT(y, x) ^ 0xFF)
+#define LT(x, y) GT(y, x)
+#define LE(x, y) GE(y, x)
+
+/*
+ * Convert value x (0..63) to corresponding Base64 character.
+ */
+static int b64_byte_to_char(unsigned x) {
+ return (LT(x, 26) & (x + 'A')) |
+ (GE(x, 26) & LT(x, 52) & (x + ('a' - 26))) |
+ (GE(x, 52) & LT(x, 62) & (x + ('0' - 52))) | (EQ(x, 62) & '+') |
+ (EQ(x, 63) & '/');
+}
+
+/*
+ * Convert character c to the corresponding 6-bit value. If character c
+ * is not a Base64 character, then 0xFF (255) is returned.
+ */
+static unsigned b64_char_to_byte(int c) {
+ unsigned x;
+
+ x = (GE(c, 'A') & LE(c, 'Z') & (c - 'A')) |
+ (GE(c, 'a') & LE(c, 'z') & (c - ('a' - 26))) |
+ (GE(c, '0') & LE(c, '9') & (c - ('0' - 52))) | (EQ(c, '+') & 62) |
+ (EQ(c, '/') & 63);
+ return x | (EQ(x, 0) & (EQ(c, 'A') ^ 0xFF));
+}
+
+/*
+ * Convert some bytes to Base64. 'dst_len' is the length (in characters)
+ * of the output buffer 'dst'; if that buffer is not large enough to
+ * receive the result (including the terminating 0), then (size_t)-1
+ * is returned. Otherwise, the zero-terminated Base64 string is written
+ * in the buffer, and the output length (counted WITHOUT the terminating
+ * zero) is returned.
+ */
+static size_t to_base64(char *dst, size_t dst_len, const void *src,
+ size_t src_len) {
+ size_t olen;
+ const unsigned char *buf;
+ unsigned acc, acc_len;
+
+ olen = (src_len / 3) << 2;
+ switch (src_len % 3) {
+ case 2:
+ olen++;
+ /* fall through */
+ case 1:
+ olen += 2;
+ break;
+ }
+ if (dst_len <= olen) {
+ return (size_t)-1;
+ }
+ acc = 0;
+ acc_len = 0;
+ buf = (const unsigned char *)src;
+ while (src_len-- > 0) {
+ acc = (acc << 8) + (*buf++);
+ acc_len += 8;
+ while (acc_len >= 6) {
+ acc_len -= 6;
+ *dst++ = (char)b64_byte_to_char((acc >> acc_len) & 0x3F);
+ }
+ }
+ if (acc_len > 0) {
+ *dst++ = (char)b64_byte_to_char((acc << (6 - acc_len)) & 0x3F);
+ }
+ *dst++ = 0;
+ return olen;
+}
+
+/*
+ * Decode Base64 chars into bytes. The '*dst_len' value must initially
+ * contain the length of the output buffer '*dst'; when the decoding
+ * ends, the actual number of decoded bytes is written back in
+ * '*dst_len'.
+ *
+ * Decoding stops when a non-Base64 character is encountered, or when
+ * the output buffer capacity is exceeded. If an error occurred (output
+ * buffer is too small, invalid last characters leading to unprocessed
+ * buffered bits), then NULL is returned; otherwise, the returned value
+ * points to the first non-Base64 character in the source stream, which
+ * may be the terminating zero.
+ */
+static const char *from_base64(void *dst, size_t *dst_len, const char *src) {
+ size_t len;
+ unsigned char *buf;
+ unsigned acc, acc_len;
+
+ buf = (unsigned char *)dst;
+ len = 0;
+ acc = 0;
+ acc_len = 0;
+ for (;;) {
+ unsigned d;
+
+ d = b64_char_to_byte(*src);
+ if (d == 0xFF) {
+ break;
+ }
+ src++;
+ acc = (acc << 6) + d;
+ acc_len += 6;
+ if (acc_len >= 8) {
+ acc_len -= 8;
+ if ((len++) >= *dst_len) {
+ return NULL;
+ }
+ *buf++ = (acc >> acc_len) & 0xFF;
+ }
+ }
+
+ /*
+ * If the input length is equal to 1 modulo 4 (which is
+ * invalid), then there will remain 6 unprocessed bits;
+ * otherwise, only 0, 2 or 4 bits are buffered. The buffered
+ * bits must also all be zero.
+ */
+ if (acc_len > 4 || (acc & (((unsigned)1 << acc_len) - 1)) != 0) {
+ return NULL;
+ }
+ *dst_len = len;
+ return src;
+}
+
+/*
+ * Decode decimal integer from 'str'; the value is written in '*v'.
+ * Returned value is a pointer to the next non-decimal character in the
+ * string. If there is no digit at all, or the value encoding is not
+ * minimal (extra leading zeros), or the value does not fit in an
+ * 'unsigned long', then NULL is returned.
+ */
+static const char *decode_decimal(const char *str, unsigned long *v) {
+ const char *orig;
+ unsigned long acc;
+
+ acc = 0;
+ for (orig = str;; str++) {
+ int c;
+
+ c = *str;
+ if (c < '0' || c > '9') {
+ break;
+ }
+ c -= '0';
+ if (acc > (ULONG_MAX / 10)) {
+ return NULL;
+ }
+ acc *= 10;
+ if ((unsigned long)c > (ULONG_MAX - acc)) {
+ return NULL;
+ }
+ acc += (unsigned long)c;
+ }
+ if (str == orig || (*orig == '0' && str != (orig + 1))) {
+ return NULL;
+ }
+ *v = acc;
+ return str;
+}
+
+/* ==================================================================== */
+/*
+ * Code specific to Argon2.
+ *
+ * The code below applies the following format:
+ *
+ * $argon2<T>[$v=<num>]$m=<num>,t=<num>,p=<num>$<bin>$<bin>
+ *
+ * where <T> is either 'd', 'id', or 'i', <num> is a decimal integer (positive,
+ * fits in an 'unsigned long'), and <bin> is Base64-encoded data (no '=' padding
+ * characters, no newline or whitespace).
+ *
+ * The last two binary chunks (encoded in Base64) are, in that order,
+ * the salt and the output. Both are required. The binary salt length and the
+ * output length must be in the allowed ranges defined in argon2.h.
+ *
+ * The ctx struct must contain buffers large enough to hold the salt and pwd
+ * when it is fed into decode_string.
+ */
+
+int decode_string(argon2_context *ctx, const char *str, argon2_type type) {
+
+/* check for prefix */
+#define CC(prefix) \
+ do { \
+ size_t cc_len = strlen(prefix); \
+ if (strncmp(str, prefix, cc_len) != 0) { \
+ return ARGON2_DECODING_FAIL; \
+ } \
+ str += cc_len; \
+ } while ((void)0, 0)
+
+/* optional prefix checking with supplied code */
+#define CC_opt(prefix, code) \
+ do { \
+ size_t cc_len = strlen(prefix); \
+ if (strncmp(str, prefix, cc_len) == 0) { \
+ str += cc_len; \
+ { code; } \
+ } \
+ } while ((void)0, 0)
+
+/* Decoding prefix into decimal */
+#define DECIMAL(x) \
+ do { \
+ unsigned long dec_x; \
+ str = decode_decimal(str, &dec_x); \
+ if (str == NULL) { \
+ return ARGON2_DECODING_FAIL; \
+ } \
+ (x) = dec_x; \
+ } while ((void)0, 0)
+
+
+/* Decoding prefix into uint32_t decimal */
+#define DECIMAL_U32(x) \
+ do { \
+ unsigned long dec_x; \
+ str = decode_decimal(str, &dec_x); \
+ if (str == NULL || dec_x > UINT32_MAX) { \
+ return ARGON2_DECODING_FAIL; \
+ } \
+ (x) = (uint32_t)dec_x; \
+ } while ((void)0, 0)
+
+
+/* Decoding base64 into a binary buffer */
+#define BIN(buf, max_len, len) \
+ do { \
+ size_t bin_len = (max_len); \
+ str = from_base64(buf, &bin_len, str); \
+ if (str == NULL || bin_len > UINT32_MAX) { \
+ return ARGON2_DECODING_FAIL; \
+ } \
+ (len) = (uint32_t)bin_len; \
+ } while ((void)0, 0)
+
+ size_t maxsaltlen = ctx->saltlen;
+ size_t maxoutlen = ctx->outlen;
+ int validation_result;
+ const char* type_string;
+
+ /* We should start with the argon2_type we are using */
+ type_string = argon2_type2string(type, 0);
+ if (!type_string) {
+ return ARGON2_INCORRECT_TYPE;
+ }
+
+ CC("$");
+ CC(type_string);
+
+ /* Reading the version number if the default is suppressed */
+ ctx->version = ARGON2_VERSION_10;
+ CC_opt("$v=", DECIMAL_U32(ctx->version));
+
+ CC("$m=");
+ DECIMAL_U32(ctx->m_cost);
+ CC(",t=");
+ DECIMAL_U32(ctx->t_cost);
+ CC(",p=");
+ DECIMAL_U32(ctx->lanes);
+ ctx->threads = ctx->lanes;
+
+ CC("$");
+ BIN(ctx->salt, maxsaltlen, ctx->saltlen);
+ CC("$");
+ BIN(ctx->out, maxoutlen, ctx->outlen);
+
+ /* The rest of the fields get the default values */
+ ctx->secret = NULL;
+ ctx->secretlen = 0;
+ ctx->ad = NULL;
+ ctx->adlen = 0;
+ ctx->allocate_cbk = NULL;
+ ctx->free_cbk = NULL;
+ ctx->flags = ARGON2_DEFAULT_FLAGS;
+
+ /* On return, must have valid context */
+ validation_result = validate_inputs(ctx);
+ if (validation_result != ARGON2_OK) {
+ return validation_result;
+ }
+
+ /* Can't have any additional characters */
+ if (*str == 0) {
+ return ARGON2_OK;
+ } else {
+ return ARGON2_DECODING_FAIL;
+ }
+#undef CC
+#undef CC_opt
+#undef DECIMAL
+#undef BIN
+}
+
+int encode_string(char *dst, size_t dst_len, argon2_context *ctx,
+ argon2_type type) {
+#define SS(str) \
+ do { \
+ size_t pp_len = strlen(str); \
+ if (pp_len >= dst_len) { \
+ return ARGON2_ENCODING_FAIL; \
+ } \
+ memcpy(dst, str, pp_len + 1); \
+ dst += pp_len; \
+ dst_len -= pp_len; \
+ } while ((void)0, 0)
+
+#define SX(x) \
+ do { \
+ char tmp[30]; \
+ sprintf(tmp, "%lu", (unsigned long)(x)); \
+ SS(tmp); \
+ } while ((void)0, 0)
+
+#define SB(buf, len) \
+ do { \
+ size_t sb_len = to_base64(dst, dst_len, buf, len); \
+ if (sb_len == (size_t)-1) { \
+ return ARGON2_ENCODING_FAIL; \
+ } \
+ dst += sb_len; \
+ dst_len -= sb_len; \
+ } while ((void)0, 0)
+
+ const char* type_string = argon2_type2string(type, 0);
+ int validation_result = validate_inputs(ctx);
+
+ if (!type_string) {
+ return ARGON2_ENCODING_FAIL;
+ }
+
+ if (validation_result != ARGON2_OK) {
+ return validation_result;
+ }
+
+
+ SS("$");
+ SS(type_string);
+
+ SS("$v=");
+ SX(ctx->version);
+
+ SS("$m=");
+ SX(ctx->m_cost);
+ SS(",t=");
+ SX(ctx->t_cost);
+ SS(",p=");
+ SX(ctx->lanes);
+
+ SS("$");
+ SB(ctx->salt, ctx->saltlen);
+
+ SS("$");
+ SB(ctx->out, ctx->outlen);
+ return ARGON2_OK;
+
+#undef SS
+#undef SX
+#undef SB
+}
+
+size_t b64len(uint32_t len) {
+ size_t olen = ((size_t)len / 3) << 2;
+
+ switch (len % 3) {
+ case 2:
+ olen++;
+ /* fall through */
+ case 1:
+ olen += 2;
+ break;
+ }
+
+ return olen;
+}
+
+size_t numlen(uint32_t num) {
+ size_t len = 1;
+ while (num >= 10) {
+ ++len;
+ num = num / 10;
+ }
+ return len;
+}
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