Module Name: src
Committed By: riastradh
Date: Sat Oct 4 10:30:13 UTC 2014
Modified Files:
src/sbin/gpt: gpt_uuid.c
Log Message:
Make gpt(8) generate v4 (random) uuids.
Don't needlessly leak your date/time and MAC address when you edit
the disk.
Read from /dev/urandom rather than calling arc4random or anything,
since this is a tool. (Cygwin seems to have /dev/urandom, but yell
if this breaks the build on your exotic platform because it lacks
/dev/urandom.)
ok apb
To generate a diff of this commit:
cvs rdiff -u -r1.7 -r1.8 src/sbin/gpt/gpt_uuid.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sbin/gpt/gpt_uuid.c
diff -u src/sbin/gpt/gpt_uuid.c:1.7 src/sbin/gpt/gpt_uuid.c:1.8
--- src/sbin/gpt/gpt_uuid.c:1.7 Fri Oct 3 20:30:06 2014
+++ src/sbin/gpt/gpt_uuid.c Sat Oct 4 10:30:13 2014
@@ -1,4 +1,4 @@
-/* $NetBSD: gpt_uuid.c,v 1.7 2014/10/03 20:30:06 christos Exp $ */
+/* $NetBSD: gpt_uuid.c,v 1.8 2014/10/04 10:30:13 riastradh Exp $ */
/*-
* Copyright (c) 2014 The NetBSD Foundation, Inc.
@@ -32,10 +32,13 @@
#include <sys/cdefs.h>
#ifdef __RCSID
-__RCSID("$NetBSD: gpt_uuid.c,v 1.7 2014/10/03 20:30:06 christos Exp $");
+__RCSID("$NetBSD: gpt_uuid.c,v 1.8 2014/10/04 10:30:13 riastradh Exp $");
#endif
+#include <err.h>
+#include <fcntl.h>
#include <stdio.h>
+#include <unistd.h>
#include "map.h"
#include "gpt.h"
@@ -56,12 +59,6 @@ struct dce_uuid {
uint8_t node[6];
};
-struct kern_uuid {
- uint64_t ll;
- uint16_t seq;
- uint8_t node[6];
-};
-
static const struct {
struct dce_uuid u;
const char *n;
@@ -238,96 +235,35 @@ gpt_uuid_create(gpt_type_t t, gpt_uuid_t
utf8_to_utf16((const uint8_t *)gpt_nv[t].d, b, s / sizeof(*b));
}
-#if !defined(HAVE_NBTOOL_CONFIG_H)
-#include <sys/types.h>
-#include <sys/uuid.h>
-#else
-#include <time.h>
-/*
- * Get the current time as a 5x bit count of 100000-microsecond intervals
- * since 00:00:00.00, October 15,1582. We apply a magic offset to convert
- * the Unix time since 00:00:00.00, January 1, 1970 to the date of the
- * Gregorian reform to the Christian calendar.
- */
-static uint64_t
-uuid_time(void)
-{
- struct timeval tv;
- uint64_t xtime = 0x01B21DD213814000LL;
-
- (void)gettimeofday(&tv, NULL);
- xtime += (uint64_t)tv.tv_sec * 10000000LL;
- xtime += (uint64_t)(tv.tv_usec / 100000);
- return (xtime & ((1LL << 60) - 1LL));
-}
-
-/*
- * No portable way to get ethernet, use hostid instead
- */
-static void
-uuid_node(uint8_t node[6])
-{
- long hid = gethostid();
- node[0] = 'N';
- node[1] = 'B';
- node[2] = (hid >> 24) & 0xff;
- node[3] = (hid >> 16) & 0xff;
- node[4] = (hid >> 8) & 0xff;
- node[5] = (hid >> 0) & 0xff;
-}
-
-static void
-uuid_generate(void *u, uint64_t *timep, int count)
-{
- static struct kern_uuid uuid_last;
- uint64_t xtime, ltime;
- uint16_t lseq;
- struct kern_uuid *uuid = u;
-
- uuid_node(uuid->node);
- xtime = uuid_time();
- *timep = xtime;
-
- if (uuid_last.ll == 0LL || uuid_last.node[0] != uuid->node[0] ||
- uuid_last.node[1] != uuid->node[1] ||
- uuid_last.node[2] != uuid->node[2]) {
- srandom((unsigned int) xtime);
- uuid->seq = (uint16_t)random() & 0x3fff;
- } else if (uuid_last.ll >= xtime)
- uuid->seq = (uuid_last.seq + 1) & 0x3fff;
-
- uuid_last = *uuid;
- uuid_last.ll = (xtime + count - 1) & ((1LL << 60) - 1LL);
-}
-
-static void
-uuidgen(struct dce_uuid *store, int count)
-{
- uint64_t xtime;
- struct kern_uuid uuid;
- int i;
-
- /* Generate the base UUID. */
- uuid_generate(&uuid, &xtime, count);
-
- for (i = 0; i < count; xtime++, i++) {
- /* Set time and version (=1) and deal with byte order. */
- store[i].time_low = (uint32_t)xtime;
- store[i].time_mid = (uint16_t)(xtime >> 32);
- store[i].time_hi_and_version =
- ((uint16_t)(xtime >> 48) & 0xfff) | (1 << 12);
- store[i].clock_seq_hi_and_reserved = (uuid.seq >> 16) | 0x80;
- store[i].clock_seq_low = uuid.seq & 0xff;
- memcpy(store[i].node, uuid.node, sizeof(uuid.node));
- }
-}
-#endif
-
void
gpt_uuid_generate(gpt_uuid_t t)
{
struct dce_uuid u;
+ int fd;
+ uint8_t *p;
+ size_t n;
+ ssize_t nread;
+
+ /* Randomly generate the content. */
+ fd = open("/dev/urandom", O_RDONLY | O_CLOEXEC);
+ if (fd == -1)
+ err(1, "open(/dev/urandom)");
+ for (p = (void *)&u, n = sizeof u; 0 < n; p += nread, n -= nread) {
+ nread = read(fd, p, n);
+ if (nread < 0)
+ err(1, "read(/dev/urandom)");
+ if ((size_t)nread > n)
+ errx(1, "read too much: %zd > %zu", nread, n);
+ }
+ (void)close(fd);
+
+ /* Set the version number to 4. */
+ u.time_hi_and_version &= ~(uint32_t)0xf000;
+ u.time_hi_and_version |= 0x4000;
+
+ /* Fix the reserved bits. */
+ u.clock_seq_hi_and_reserved &= ~(uint8_t)0x40;
+ u.clock_seq_hi_and_reserved |= 0x80;
- uuidgen((void *)&u, 1);
gpt_dce_to_uuid(&u, t);
}
