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Diffstat (limited to '')
| -rw-r--r-- | krandom.c | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/krandom.c b/krandom.c new file mode 100644 index 0000000..31804d2 --- /dev/null +++ b/krandom.c @@ -0,0 +1,191 @@ +/* See LICENSE file for copyright and license details. */ +#include <sys/stat.h> +#include <ctype.h> +#include <errno.h> +#include <fcntl.h> +#include <stddef.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +#include <libkeccak.h> + +#include "arg.h" + + +#ifndef URANDOM +# define URANDOM "/dev/urandom" +#endif + + +char *argv0; + + +static void +usage(void) +{ + fprintf(stderr, "usage: %s [-C capacity] [-N output-size] [-R rate] [-S state-size] [-W word-size] [-v]\n", argv0); + exit(1); +} + + +static int +make_spec(struct libkeccak_generalised_spec *restrict gspec, struct libkeccak_spec *restrict spec) +{ + int r; + +#define TEST(CASE, STR) case LIBKECCAK_GENERALISED_SPEC_ERROR_##CASE: return fprintf(stderr, "%s: %s\n", argv0, STR), 1; + if (r = libkeccak_degeneralise_spec(gspec, spec), r) { + switch (r) { + TEST (STATE_NONPOSITIVE, "the state size must be positive"); + TEST (STATE_TOO_LARGE, "the state size is too large, may not exceed 1600"); + TEST (STATE_MOD_25, "the state size must be a multiple of 25"); + TEST (WORD_NONPOSITIVE, "the word size must be positive"); + TEST (WORD_TOO_LARGE, "the word size is too large, may not exceed 64"); + TEST (STATE_WORD_INCOHERENCY, "the state size must be exactly 25 times the word size"); + TEST (CAPACITY_NONPOSITIVE, "the capacity must be positive"); + TEST (CAPACITY_MOD_8, "the capacity must be a multiple of 8"); + TEST (BITRATE_NONPOSITIVE, "the rate must be positive"); + TEST (BITRATE_MOD_8, "the rate must be a multiple of 8"); + TEST (OUTPUT_NONPOSITIVE, "the output size must be positive"); + default: + fprintf(stderr, "%s: unknown error in algorithm parameters\n", argv0); + return 1; + } + } +#undef TEST + +#define TEST(CASE, STR) case LIBKECCAK_SPEC_ERROR_##CASE: return fprintf(stderr, "%s: %s\n", argv0, STR), 1; + if (r = libkeccak_spec_check(spec), r) { + switch (r) { + TEST (BITRATE_NONPOSITIVE, "the rate size must be positive"); + TEST (BITRATE_MOD_8, "the rate must be a multiple of 8"); + TEST (CAPACITY_NONPOSITIVE, "the capacity must be positive"); + TEST (CAPACITY_MOD_8, "the capacity must be a multiple of 8"); + TEST (OUTPUT_NONPOSITIVE, "the output size must be positive"); + TEST (STATE_TOO_LARGE, "the state size is too large, may not exceed 1600"); + TEST (STATE_MOD_25, "the state size must be a multiple of 25"); + TEST (WORD_NON_2_POTENT, "the word size must be a power of 2"); + TEST (WORD_MOD_8, "the word size must be a multiple of 8"); + default: + fprintf(stderr, "%s: unknown error in algorithm parameters\n", argv0); + return 1; + } + } +#undef TEST + + return 0; +} + + +int +main(int argc, char *argv[]) +{ + char *restrict generated_random = NULL; + struct libkeccak_generalised_spec gspec; + struct libkeccak_spec spec; + struct libkeccak_state state; + size_t length, ptr; + ssize_t got; + int r, fd = -1, verbose = 0; + long int *param; + char *arg; + + memset(&state, 0, sizeof(struct libkeccak_state)); + libkeccak_generalised_spec_initialise(&gspec); + + errno = 0; + ARGBEGIN { + case 'R': + param = &gspec.bitrate; + goto set_param; + case 'C': + param = &gspec.capacity; + goto set_param; + case 'N': + case 'O': + param = &gspec.output; + goto set_param; + case 'S': + case 'B': + param = &gspec.state_size; + goto set_param; + case 'W': + param = &gspec.word_size; + set_param: + arg = EARGF(usage()); + if (!isdigit(*arg)) + usage(); + *param = strtol(arg, &arg, 10); + if (errno || *arg) + usage(); + break; + case 'v': + verbose = 1; + break; + default: + usage(); + } ARGEND; + + if (argc) + usage(); + + if ((r = make_spec(&gspec, &spec))) + goto done; + + if (verbose) { + fprintf(stderr, "%s: " "rate: %li\n", argv0, gspec.bitrate); + fprintf(stderr, "%s: " "capacity: %li\n", argv0, gspec.capacity); + fprintf(stderr, "%s: " "output size: %li\n", argv0, gspec.output); + fprintf(stderr, "%s: " "state size: %li\n", argv0, gspec.state_size); + fprintf(stderr, "%s: " "word size: %li\n", argv0, gspec.word_size); + } + + libkeccak_state_initialise(&state, &spec); + + fd = open(URANDOM, O_RDONLY); + if (fd < 0) + goto fail; + for (ptr = 0, length = sizeof(state.S); ptr < length;) { + got = read(fd, (char*)(state.S) + ptr, length - ptr); + if (got <= 0) { + if (!got) { + fprintf(stderr, "%s: %s contained less than %zu bytes\n", argv0, URANDOM, length); + r = 2; + goto done; + } + goto fail; + } + ptr += (size_t)got; + } + close(fd); + fd = -1; + + length = (size_t)((spec.output + 7) / 8); + generated_random = malloc(length); + if (!generated_random) + goto fail; + + for (;;) { + libkeccak_squeeze(&state, generated_random); + got = write(STDOUT_FILENO, generated_random, length); + if (got < 0) { + if (errno == EPIPE) + break; + goto fail; + } + } + +done: + if (fd >= 0) + close(fd); + free(generated_random); + libkeccak_state_fast_destroy(&state); + return r; + +fail: + perror(argv0); + r = 2; + goto done; +} |