mirror of
https://github.com/leahneukirchen/mblaze
synced 2024-11-11 13:10:32 +00:00
5280abfa10
We one-time-pad the timestamp with a random key instead. This will provide enough entropy to be unique, but not leak the system date. Even with a bad RNG state it should guarantee uniqueness, however.
124 lines
2.7 KiB
C
124 lines
2.7 KiB
C
#include <sys/socket.h>
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#include <sys/stat.h>
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#include <sys/time.h>
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#include <sys/types.h>
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#include <fcntl.h>
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#include <netdb.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <time.h>
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#include <unistd.h>
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#include "blaze822.h"
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void
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printb36(uint64_t x)
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{
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static char const base36[] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
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char outbuf[16];
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char *o = outbuf + sizeof outbuf;
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*--o = 0;
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do { *--o = base36[x % 36]; } while (x /= 36);
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fputs(o, stdout);
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}
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int main()
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{
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char hostbuf[1024];
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char *host = 0;
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char *f = blaze822_home_file("profile");
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struct message *config = blaze822(f);
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if (config) // try FQDN: first
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host = blaze822_hdr(config, "fqdn");
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if (!host && gethostname(hostbuf, sizeof hostbuf) == 0) {
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// termination not posix guaranteed
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hostbuf[sizeof hostbuf - 1] = 0;
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struct addrinfo hints = { .ai_family = AF_UNSPEC,
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.ai_socktype = SOCK_STREAM,
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.ai_flags = AI_CANONNAME };
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struct addrinfo *info;
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if (getaddrinfo(hostbuf, 0, &hints, &info) == 0) {
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// sanity checks: no (null), at least one dot,
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// doesn't start with localhost.
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if (info &&
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info->ai_canonname &&
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strchr(info->ai_canonname, '.') &&
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strncmp(info->ai_canonname, "localhost.", 10) != 0)
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host = info->ai_canonname;
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}
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}
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if (!host && config) {
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// get address part of Local-Mailbox:
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char *disp, *addr;
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char *from = blaze822_hdr(config, "local-mailbox");
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while (from && (from = blaze822_addr(from, &disp, &addr)))
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if (addr) {
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host = strchr(addr, '@');
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if (host) {
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host++;
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break;
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}
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}
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}
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if (!host) {
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fprintf(stderr,
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"mgenmid: failed to find a FQDN for the Message-ID.\n"
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" Define 'FQDN:' or 'Local-Mailbox:' in"
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" ${MBLAZE:-$HOME/.mblaze}/profile\n"
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" or add a FQDN to /etc/hosts.\n");
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exit(1);
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}
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struct timeval tp;
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gettimeofday(&tp, (struct timezone *)0);
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uint64_t rnd1, rnd2;
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int rndfd = open("/dev/urandom", O_RDONLY);
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if (rndfd >= 0) {
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unsigned char rndb[16];
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if (read(rndfd, rndb, sizeof rndb) != sizeof rndb)
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goto fallback;
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close(rndfd);
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int i;
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for (i = 0, rnd1 = 0; i < 8; i++)
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rnd1 = rnd1*256 + rndb[i];
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for (i = 0, rnd2 = 0; i < 8; i++)
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rnd2 = rnd2*256 + rndb[i+8];
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} else {
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fallback:
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srand48(tp.tv_sec ^ tp.tv_usec ^ getpid());
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rnd1 = ((uint64_t)lrand48() << 32) + lrand48();
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rnd2 = ((uint64_t)lrand48() << 32) + lrand48();
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}
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rnd1 ^= ((uint64_t)tp.tv_sec * 1000000LL + tp.tv_usec);
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rnd1 |= (1ULL << 63); // set highest bit to force full width
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rnd2 |= (1ULL << 63); // set highest bit to force full width
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putchar('<');
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printb36(rnd1);
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putchar('.');
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printb36(rnd2);
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putchar('@');
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fputs(host, stdout);
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putchar('>');
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putchar('\n');
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return 0;
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}
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