freebsd-dev/sys/kern/kern_uuid.c
Marcel Moolenaar ba7f4cdc97 Further restrict the MAC addresses that we use for UUID generation
to those that are universally administered. While it is possible to
add locally administered MAC addresses, it's unclear whether those
are (expected) to be more unique than random multicast MAC addresses
or not.

With many U-Boot configurations assigning fixed and non-official MAC
addresses to ethernet ports and without setting the 'X' flag, this
change may have very little value in the embedded (development)
space. Uniqueness of the universally administered addresses is non-
existent on the (H/W) bench and questionable under the (S/W) desk.
In short: this change is aimed at production environments...
2013-07-24 18:13:43 +00:00

427 lines
11 KiB
C

/*-
* Copyright (c) 2002 Marcel Moolenaar
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/endian.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/sbuf.h>
#include <sys/socket.h>
#include <sys/sysproto.h>
#include <sys/systm.h>
#include <sys/jail.h>
#include <sys/uuid.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_types.h>
#include <net/vnet.h>
/*
* See also:
* http://www.opengroup.org/dce/info/draft-leach-uuids-guids-01.txt
* http://www.opengroup.org/onlinepubs/009629399/apdxa.htm
*
* Note that the generator state is itself an UUID, but the time and clock
* sequence fields are written in the native byte order.
*/
CTASSERT(sizeof(struct uuid) == 16);
/* We use an alternative, more convenient representation in the generator. */
struct uuid_private {
union {
uint64_t ll; /* internal. */
struct {
uint32_t low;
uint16_t mid;
uint16_t hi;
} x;
} time;
uint16_t seq; /* Big-endian. */
uint16_t node[UUID_NODE_LEN>>1];
};
CTASSERT(sizeof(struct uuid_private) == 16);
struct uuid_macaddr {
uint16_t state;
#define UUID_ETHER_EMPTY 0
#define UUID_ETHER_RANDOM 1
#define UUID_ETHER_UNIQUE 2
uint16_t node[UUID_NODE_LEN>>1];
};
static struct uuid_private uuid_last;
#define UUID_NETHER 4
static struct uuid_macaddr uuid_ether[UUID_NETHER];
static struct mtx uuid_mutex;
MTX_SYSINIT(uuid_lock, &uuid_mutex, "UUID generator mutex lock", MTX_DEF);
/*
* Return the first MAC address added in the array. If it's empty, then
* construct a sufficiently random multicast MAC address first. Any
* addresses added later will bump the random MAC address up tp the next
* index.
*/
static void
uuid_node(uint16_t *node)
{
int i;
if (uuid_ether[0].state == UUID_ETHER_EMPTY) {
for (i = 0; i < (UUID_NODE_LEN>>1); i++)
uuid_ether[0].node[i] = (uint16_t)arc4random();
*((uint8_t*)uuid_ether[0].node) |= 0x01;
uuid_ether[0].state = UUID_ETHER_RANDOM;
}
for (i = 0; i < (UUID_NODE_LEN>>1); i++)
node[i] = uuid_ether[0].node[i];
}
/*
* Get the current time as a 60 bit count of 100-nanosecond 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 bintime bt;
uint64_t time = 0x01B21DD213814000LL;
bintime(&bt);
time += (uint64_t)bt.sec * 10000000LL;
time += (10000000LL * (uint32_t)(bt.frac >> 32)) >> 32;
return (time & ((1LL << 60) - 1LL));
}
struct uuid *
kern_uuidgen(struct uuid *store, size_t count)
{
struct uuid_private uuid;
uint64_t time;
size_t n;
mtx_lock(&uuid_mutex);
uuid_node(uuid.node);
time = uuid_time();
if (uuid_last.time.ll == 0LL || uuid_last.node[0] != uuid.node[0] ||
uuid_last.node[1] != uuid.node[1] ||
uuid_last.node[2] != uuid.node[2])
uuid.seq = (uint16_t)arc4random() & 0x3fff;
else if (uuid_last.time.ll >= time)
uuid.seq = (uuid_last.seq + 1) & 0x3fff;
else
uuid.seq = uuid_last.seq;
uuid_last = uuid;
uuid_last.time.ll = (time + count - 1) & ((1LL << 60) - 1LL);
mtx_unlock(&uuid_mutex);
/* Set sequence and variant and deal with byte order. */
uuid.seq = htobe16(uuid.seq | 0x8000);
for (n = 0; n < count; n++) {
/* Set time and version (=1). */
uuid.time.x.low = (uint32_t)time;
uuid.time.x.mid = (uint16_t)(time >> 32);
uuid.time.x.hi = ((uint16_t)(time >> 48) & 0xfff) | (1 << 12);
store[n] = *(struct uuid *)&uuid;
time++;
}
return (store);
}
#ifndef _SYS_SYSPROTO_H_
struct uuidgen_args {
struct uuid *store;
int count;
};
#endif
int
sys_uuidgen(struct thread *td, struct uuidgen_args *uap)
{
struct uuid *store;
size_t count;
int error;
/*
* Limit the number of UUIDs that can be created at the same time
* to some arbitrary number. This isn't really necessary, but I
* like to have some sort of upper-bound that's less than 2G :-)
* XXX probably needs to be tunable.
*/
if (uap->count < 1 || uap->count > 2048)
return (EINVAL);
count = uap->count;
store = malloc(count * sizeof(struct uuid), M_TEMP, M_WAITOK);
kern_uuidgen(store, count);
error = copyout(store, uap->store, count * sizeof(struct uuid));
free(store, M_TEMP);
return (error);
}
int
uuid_ether_add(const uint8_t *addr)
{
int i, sum;
/*
* Validate input. No multicast (flag 0x1), no locally administered
* (flag 0x2) and no 'all-zeroes' addresses.
*/
if (addr[0] & 0x03)
return (EINVAL);
sum = 0;
for (i = 0; i < UUID_NODE_LEN; i++)
sum += addr[i];
if (sum == 0)
return (EINVAL);
mtx_lock(&uuid_mutex);
/* Make sure the MAC isn't known already and that there's space. */
i = 0;
while (i < UUID_NETHER && uuid_ether[i].state == UUID_ETHER_UNIQUE) {
if (!bcmp(addr, uuid_ether[i].node, UUID_NODE_LEN)) {
mtx_unlock(&uuid_mutex);
return (EEXIST);
}
i++;
}
if (i == UUID_NETHER) {
mtx_unlock(&uuid_mutex);
return (ENOSPC);
}
/* Insert MAC at index, moving the non-empty entry if possible. */
if (uuid_ether[i].state == UUID_ETHER_RANDOM && i < UUID_NETHER - 1)
uuid_ether[i + 1] = uuid_ether[i];
uuid_ether[i].state = UUID_ETHER_UNIQUE;
bcopy(addr, uuid_ether[i].node, UUID_NODE_LEN);
mtx_unlock(&uuid_mutex);
return (0);
}
int
uuid_ether_del(const uint8_t *addr)
{
int i;
mtx_lock(&uuid_mutex);
i = 0;
while (i < UUID_NETHER && uuid_ether[i].state == UUID_ETHER_UNIQUE &&
bcmp(addr, uuid_ether[i].node, UUID_NODE_LEN))
i++;
if (i == UUID_NETHER || uuid_ether[i].state != UUID_ETHER_UNIQUE) {
mtx_unlock(&uuid_mutex);
return (ENOENT);
}
/* Remove it by shifting higher index entries down. */
while (i < UUID_NETHER - 1 && uuid_ether[i].state != UUID_ETHER_EMPTY) {
uuid_ether[i] = uuid_ether[i + 1];
i++;
}
if (uuid_ether[i].state != UUID_ETHER_EMPTY) {
uuid_ether[i].state = UUID_ETHER_EMPTY;
bzero(uuid_ether[i].node, UUID_NODE_LEN);
}
mtx_unlock(&uuid_mutex);
return (0);
}
int
snprintf_uuid(char *buf, size_t sz, struct uuid *uuid)
{
struct uuid_private *id;
int cnt;
id = (struct uuid_private *)uuid;
cnt = snprintf(buf, sz, "%08x-%04x-%04x-%04x-%04x%04x%04x",
id->time.x.low, id->time.x.mid, id->time.x.hi, be16toh(id->seq),
be16toh(id->node[0]), be16toh(id->node[1]), be16toh(id->node[2]));
return (cnt);
}
int
printf_uuid(struct uuid *uuid)
{
char buf[38];
snprintf_uuid(buf, sizeof(buf), uuid);
return (printf("%s", buf));
}
int
sbuf_printf_uuid(struct sbuf *sb, struct uuid *uuid)
{
char buf[38];
snprintf_uuid(buf, sizeof(buf), uuid);
return (sbuf_printf(sb, "%s", buf));
}
/*
* Encode/Decode UUID into byte-stream.
* http://www.opengroup.org/dce/info/draft-leach-uuids-guids-01.txt
*
* 0 1 2 3
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | time_low |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | time_mid | time_hi_and_version |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* |clk_seq_hi_res | clk_seq_low | node (0-1) |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | node (2-5) |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
void
le_uuid_enc(void *buf, struct uuid const *uuid)
{
u_char *p;
int i;
p = buf;
le32enc(p, uuid->time_low);
le16enc(p + 4, uuid->time_mid);
le16enc(p + 6, uuid->time_hi_and_version);
p[8] = uuid->clock_seq_hi_and_reserved;
p[9] = uuid->clock_seq_low;
for (i = 0; i < _UUID_NODE_LEN; i++)
p[10 + i] = uuid->node[i];
}
void
le_uuid_dec(void const *buf, struct uuid *uuid)
{
u_char const *p;
int i;
p = buf;
uuid->time_low = le32dec(p);
uuid->time_mid = le16dec(p + 4);
uuid->time_hi_and_version = le16dec(p + 6);
uuid->clock_seq_hi_and_reserved = p[8];
uuid->clock_seq_low = p[9];
for (i = 0; i < _UUID_NODE_LEN; i++)
uuid->node[i] = p[10 + i];
}
void
be_uuid_enc(void *buf, struct uuid const *uuid)
{
u_char *p;
int i;
p = buf;
be32enc(p, uuid->time_low);
be16enc(p + 4, uuid->time_mid);
be16enc(p + 6, uuid->time_hi_and_version);
p[8] = uuid->clock_seq_hi_and_reserved;
p[9] = uuid->clock_seq_low;
for (i = 0; i < _UUID_NODE_LEN; i++)
p[10 + i] = uuid->node[i];
}
void
be_uuid_dec(void const *buf, struct uuid *uuid)
{
u_char const *p;
int i;
p = buf;
uuid->time_low = be32dec(p);
uuid->time_mid = le16dec(p + 4);
uuid->time_hi_and_version = be16dec(p + 6);
uuid->clock_seq_hi_and_reserved = p[8];
uuid->clock_seq_low = p[9];
for (i = 0; i < _UUID_NODE_LEN; i++)
uuid->node[i] = p[10 + i];
}
int
parse_uuid(const char *str, struct uuid *uuid)
{
u_int c[11];
int n;
/* An empty string represents a nil UUID. */
if (*str == '\0') {
bzero(uuid, sizeof(*uuid));
return (0);
}
/* The UUID string representation has a fixed length. */
if (strlen(str) != 36)
return (EINVAL);
/*
* We only work with "new" UUIDs. New UUIDs have the form:
* 01234567-89ab-cdef-0123-456789abcdef
* The so called "old" UUIDs, which we don't support, have the form:
* 0123456789ab.cd.ef.01.23.45.67.89.ab
*/
if (str[8] != '-')
return (EINVAL);
n = sscanf(str, "%8x-%4x-%4x-%2x%2x-%2x%2x%2x%2x%2x%2x", c + 0, c + 1,
c + 2, c + 3, c + 4, c + 5, c + 6, c + 7, c + 8, c + 9, c + 10);
/* Make sure we have all conversions. */
if (n != 11)
return (EINVAL);
/* Successful scan. Build the UUID. */
uuid->time_low = c[0];
uuid->time_mid = c[1];
uuid->time_hi_and_version = c[2];
uuid->clock_seq_hi_and_reserved = c[3];
uuid->clock_seq_low = c[4];
for (n = 0; n < 6; n++)
uuid->node[n] = c[n + 5];
/* Check semantics... */
return (((c[3] & 0x80) != 0x00 && /* variant 0? */
(c[3] & 0xc0) != 0x80 && /* variant 1? */
(c[3] & 0xe0) != 0xc0) ? EINVAL : 0); /* variant 2? */
}