60 lines
1.4 KiB
C
60 lines
1.4 KiB
C
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/* Copyright 2015-2016 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. */
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#include <errno.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <syscall.h>
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#include <unistd.h>
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#include <string.h>
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#include "curve25519.h"
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#include "base64.h"
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#ifdef __NR_getrandom
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static inline ssize_t get_random_bytes(uint8_t *out, size_t len)
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{
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return syscall(__NR_getrandom, out, len, 0);
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}
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#else
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#include <fcntl.h>
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static inline ssize_t get_random_bytes(uint8_t *out, size_t len)
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{
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ssize_t ret;
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int fd = open("/dev/urandom", O_RDONLY);
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if (fd < 0)
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return fd;
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ret = read(fd, out, len);
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close(fd);
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return ret;
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}
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#endif
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int genkey_main(int argc, char *argv[])
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{
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unsigned char private_key[CURVE25519_POINT_SIZE];
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char private_key_base64[b64_len(CURVE25519_POINT_SIZE)];
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struct stat stat;
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if (!fstat(STDOUT_FILENO, &stat) && S_ISREG(stat.st_mode) && stat.st_mode & S_IRWXO)
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fputs("Warning: writing to world accessible file.\nConsider setting the umask to 077 and trying again.\n", stderr);
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if (get_random_bytes(private_key, CURVE25519_POINT_SIZE) != CURVE25519_POINT_SIZE) {
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perror("getrandom");
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return 1;
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}
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if (argc && !strcmp(argv[0], "genkey"))
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curve25519_normalize_secret(private_key);
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if (b64_ntop(private_key, sizeof(private_key), private_key_base64, sizeof(private_key_base64)) < 0) {
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errno = EINVAL;
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perror("b64");
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return 1;
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}
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puts(private_key_base64);
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return 0;
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}
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