91 lines
1.7 KiB
C
91 lines
1.7 KiB
C
/*
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* Copyright (c) 2000,2001 by Solar Designer. See LICENSE.
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*/
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include <errno.h>
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#include <fcntl.h>
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#include "passwdqc.h"
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#define SEPARATORS "_,.;:-!&"
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static int read_loop(int fd, char *buffer, int count)
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{
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int offset, block;
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offset = 0;
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while (count > 0) {
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block = read(fd, &buffer[offset], count);
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if (block < 0) {
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if (errno == EINTR) continue;
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return block;
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}
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if (!block) return offset;
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offset += block;
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count -= block;
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}
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return offset;
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}
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char *_passwdqc_random(passwdqc_params_t *params)
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{
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static char output[0x100];
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int bits;
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int use_separators, count, length, index;
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char *start, *end;
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int fd;
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unsigned char bytes[2];
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if (!(bits = params->random_bits))
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return NULL;
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count = 1 + ((bits - 12) + 14) / 15;
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use_separators = ((bits + 11) / 12 != count);
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length = count * 7 - 1;
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if (length >= sizeof(output) || length > params->max) return NULL;
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if ((fd = open("/dev/urandom", O_RDONLY)) < 0) return NULL;
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length = 0;
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do {
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if (read_loop(fd, bytes, sizeof(bytes)) != sizeof(bytes)) {
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close(fd);
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return NULL;
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}
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index = (((int)bytes[1] & 0x0f) << 8) | (int)bytes[0];
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start = _passwdqc_wordset_4k[index];
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end = memchr(start, '\0', 6);
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if (!end) end = start + 6;
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if (length + (end - start) >= sizeof(output) - 1) {
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close(fd);
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return NULL;
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}
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memcpy(&output[length], start, end - start);
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length += end - start;
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bits -= 12;
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if (use_separators && bits > 3) {
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index = ((int)bytes[1] & 0x70) >> 4;
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output[length++] = SEPARATORS[index];
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bits -= 3;
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} else
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if (bits > 0)
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output[length++] = ' ';
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} while (bits > 0);
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memset(bytes, 0, sizeof(bytes));
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output[length] = '\0';
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close(fd);
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return output;
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}
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