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/* See LICENSE file for copyright and license details. */
#include "common.h"
#ifndef TEST
ssize_t
librecrypt_realise_salts(char *restrict out_buffer, size_t size, const char *settings,
ssize_t (*rng)(void *out, size_t n, void *user), void *user)
{
const char *lut;
char pad;
int strict_pad, nul_term = 0;
size_t i, min, nasterisks, prefix, ret = 0u;
size_t count, digit, q, r, left, mid, right;
/* If we are doing output, it should be NUL-terminated */
if (size) {
nul_term = 1;
size -= 1u;
}
/* For each chained algorithm */
while (*settings) {
/* Get the number of '*' that are not in the result
* (hash size specification), and also length of
* the algorithm configuration, so we can identify
* the algorithm next and get its binary data encoding
* format (just calling librecrypt_get_encoding on the
* entire string would get it for the last algorithm
* in the chain) */
nasterisks = 0u;
count = 0u;
for (prefix = 0u; settings[prefix]; prefix++) {
if (settings[prefix] == LIBRECRYPT_HASH_COMPOSITION_DELIMITER)
nasterisks = count;
else if (settings[prefix] == LIBRECRYPT_ALGORITHM_LINK_DELIMITER)
break;
else if (settings[prefix] == '*')
count += 1u;
}
/* Get binary data encoding format */
lut = librecrypt_get_encoding(settings, prefix, &pad, &strict_pad, 0);
if (!lut)
return -1;
pad = strict_pad ? pad : '\0';
/* Process each asterisk-encoded salt */
while (nasterisks--) {
/* Copy text before next '*' */
for (i = 0u; settings[i] != '*'; i++);
min = i < size ? i : size;
memcpy(out_buffer, settings, min);
size -= min;
settings = &settings[i];
ret += i;
/* Skip past the '*' */
settings++;
/* If the '*' is not followed by an unsigned,
* decimal integer include it literally */
if ('0' > settings[1u] || settings[1u] > '9') {
if (size) {
*out_buffer++ = '*';
size -= 1u;
}
ret += 1u;
continue;
}
/* Parse encoded integer */
count = 0u;
while ('0' <= *settings && *settings <= '9') {
digit = (size_t)(*settings++ - '0');
if (count > ((size_t)SSIZE_MAX - digit) / 10u)
goto erange;
count *= 10u;
count += digit;
}
/* Get number of random base-64 characters to generated,
* and the number of padding characters to append */
/* 1 byte (8 bits) requires 2 base-64 characters (12 bits, 4 bits extra),
* 2 bytes (16 bits) requires 3 base-64 characters (18 bits, 2 bits extra), and
* 3 bytes (25 bits) requires 4 base-64 characters (24 bits) exactly */
q = count / 3u;
r = count % 3u;
/* Full alphabet */
left = q * 4u + r;
/* Partial alphabet (extra bits are encoded as 0) */
mid = r ? 1u : 0u;
/* Padding: r==0: no padding,
* r==1: 2 base-64 characters, so 2 padding characters,
* r==2: 3 base-64 characters, so 1 padding characters */
right = (r && pad) ? 3u - r : 0u;
/* Get total length */
if (q > ((size_t)SSIZE_MAX - right) / 4u)
goto erange;
ret += left + mid + right;
/* Make sure we don't write more random characters than
* we have room for; we add `mid` into `left` so we have
* one variable for all random characters */
left += mid;
if (left > size) {
left = 0u;
mid = 0u;
}
/* Write random characters */
if (librecrypt_fill_with_random_(out_buffer, left, rng, user))
return -1;
for (i = 0u; i < left; i++)
out_buffer[i] = lut[((unsigned char *)out_buffer)[i]];
if (mid) {
i = left - 1u;
out_buffer[i] = lut[((unsigned char *)out_buffer)[i] & (r == 1u ? ~15u : ~3u)];
}
out_buffer = &out_buffer[left];
size -= left;
/* Write padding charaters */
right = right < size ? right : size;
for (i = 0u; i < right; i++)
out_buffer[right] = pad;
out_buffer = &out_buffer[right];
size -= right;
}
/* Copy remainder of the algorithm configuration, and the '>' if intermediate */
for (i = 0u; settings[i];)
if (settings[i++] == LIBRECRYPT_ALGORITHM_LINK_DELIMITER)
break;
min = i < size ? i : size;
memcpy(out_buffer, settings, min);
size -= min;
settings = &settings[i];
ret += i;
}
/* NUL-terminate the output if we were doing output */
if (nul_term)
*out_buffer = '\0';
/* Return the number of written bytes (excluding NUL byte):
* the length of the new password hash string, but ensure
* the new salts where not so large that our return value
* is out of range */
if (ret > (size_t)SSIZE_MAX)
goto erange;
return (ssize_t)ret;
erange:
errno = ERANGE;
return -1;
}
#else
int
main(void)
{
SET_UP_ALARM();
return 0;
}
#endif
/* TODO test */
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