freebsd-skq/contrib/bsnmp/snmp_usm/usm_snmp.c
harti c25cce1e4c Update bsnmp to version 1.13. This does not bring user-visible changes.
For developers gensnmptree can now generate functions for enums to convert
between enums and strings and to check the validity of a value.
The sources in FreeBSD are now in sync with the upstream which allows to
bring in IPv6 modifications.
2018-07-03 08:44:40 +00:00

621 lines
17 KiB
C

/*-
* Copyright (c) 2010 The FreeBSD Foundation
* All rights reserved.
*
* This software was developed by Shteryana Sotirova Shopova under
* sponsorship from the FreeBSD Foundation.
*
* 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
*
* $FreeBSD$
*/
#include <sys/queue.h>
#include <sys/types.h>
#include <errno.h>
#include <stdarg.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <syslog.h>
#include "asn1.h"
#include "snmp.h"
#include "snmpmod.h"
#define SNMPTREE_TYPES
#include "usm_tree.h"
#include "usm_oid.h"
static struct lmodule *usm_module;
/* For the registration. */
static const struct asn_oid oid_usm = OIDX_snmpUsmMIB;
static const struct asn_oid oid_usmNoAuthProtocol = OIDX_usmNoAuthProtocol;
static const struct asn_oid oid_usmHMACMD5AuthProtocol = \
OIDX_usmHMACMD5AuthProtocol;
static const struct asn_oid oid_usmHMACSHAAuthProtocol = \
OIDX_usmHMACSHAAuthProtocol;
static const struct asn_oid oid_usmNoPrivProtocol = OIDX_usmNoPrivProtocol;
static const struct asn_oid oid_usmDESPrivProtocol = OIDX_usmDESPrivProtocol;
static const struct asn_oid oid_usmAesCfb128Protocol = OIDX_usmAesCfb128Protocol;
static const struct asn_oid oid_usmUserSecurityName = OIDX_usmUserSecurityName;
/* The registration. */
static uint reg_usm;
static int32_t usm_lock;
static struct usm_user * usm_get_user(const struct asn_oid *, uint);
static struct usm_user * usm_get_next_user(const struct asn_oid *, uint);
static void usm_append_userindex(struct asn_oid *, uint,
const struct usm_user *);
static int usm_user_index_decode(const struct asn_oid *, uint, uint8_t *,
uint32_t *, char *);
int
op_usm_stats(struct snmp_context *ctx __unused, struct snmp_value *val,
uint32_t sub __unused, uint32_t iidx __unused, enum snmp_op op)
{
struct snmpd_usmstat *usmstats;
if (op == SNMP_OP_SET)
return (SNMP_ERR_NOT_WRITEABLE);
if ((usmstats = bsnmpd_get_usm_stats()) == NULL)
return (SNMP_ERR_GENERR);
if (op == SNMP_OP_GET) {
switch (val->var.subs[sub - 1]) {
case LEAF_usmStatsUnsupportedSecLevels:
val->v.uint32 = usmstats->unsupported_seclevels;
break;
case LEAF_usmStatsNotInTimeWindows:
val->v.uint32 = usmstats->not_in_time_windows;
break;
case LEAF_usmStatsUnknownUserNames:
val->v.uint32 = usmstats->unknown_users;
break;
case LEAF_usmStatsUnknownEngineIDs:
val->v.uint32 = usmstats->unknown_engine_ids;
break;
case LEAF_usmStatsWrongDigests:
val->v.uint32 = usmstats->wrong_digests;
break;
case LEAF_usmStatsDecryptionErrors:
val->v.uint32 = usmstats->decrypt_errors;
break;
default:
return (SNMP_ERR_NOSUCHNAME);
}
return (SNMP_ERR_NOERROR);
}
abort();
}
int
op_usm_lock(struct snmp_context *ctx __unused, struct snmp_value *val,
uint32_t sub, uint32_t iidx __unused, enum snmp_op op)
{
if (val->var.subs[sub - 1] != LEAF_usmUserSpinLock)
return (SNMP_ERR_NOSUCHNAME);
switch (op) {
case SNMP_OP_GET:
if (++usm_lock == INT32_MAX)
usm_lock = 0;
val->v.integer = usm_lock;
break;
case SNMP_OP_GETNEXT:
abort();
case SNMP_OP_SET:
if (val->v.integer != usm_lock)
return (SNMP_ERR_INCONS_VALUE);
break;
case SNMP_OP_ROLLBACK:
/* FALLTHROUGH */
case SNMP_OP_COMMIT:
break;
}
return (SNMP_ERR_NOERROR);
}
int
op_usm_users(struct snmp_context *ctx, struct snmp_value *val,
uint32_t sub, uint32_t iidx __unused, enum snmp_op op)
{
uint32_t elen;
struct usm_user *uuser, *clone;
char uname[SNMP_ADM_STR32_SIZ];
uint8_t eid[SNMP_ENGINE_ID_SIZ];
switch (op) {
case SNMP_OP_GET:
if ((uuser = usm_get_user(&val->var, sub)) == NULL)
return (SNMP_ERR_NOSUCHNAME);
break;
case SNMP_OP_GETNEXT:
if ((uuser = usm_get_next_user(&val->var, sub)) == NULL)
return (SNMP_ERR_NOSUCHNAME);
usm_append_userindex(&val->var, sub, uuser);
break;
case SNMP_OP_SET:
if ((uuser = usm_get_user(&val->var, sub)) == NULL &&
val->var.subs[sub - 1] != LEAF_usmUserStatus &&
val->var.subs[sub - 1] != LEAF_usmUserCloneFrom)
return (SNMP_ERR_NOSUCHNAME);
/*
* XXX (ngie): need to investigate the MIB to determine how
* this is possible given some of the transitions below.
*/
if (community != COMM_INITIALIZE &&
uuser != NULL && uuser->type == StorageType_readOnly)
return (SNMP_ERR_NOT_WRITEABLE);
switch (val->var.subs[sub - 1]) {
case LEAF_usmUserSecurityName:
return (SNMP_ERR_NOT_WRITEABLE);
case LEAF_usmUserCloneFrom:
if (uuser != NULL || usm_user_index_decode(&val->var,
sub, eid, &elen, uname) < 0 ||
!(asn_is_suboid(&oid_usmUserSecurityName, &val->v.oid)))
return (SNMP_ERR_WRONG_VALUE);
if ((clone = usm_get_user(&val->v.oid, sub)) == NULL)
return (SNMP_ERR_INCONS_VALUE);
if ((uuser = usm_new_user(eid, elen, uname)) == NULL)
return (SNMP_ERR_GENERR);
uuser->status = RowStatus_notReady;
if (community != COMM_INITIALIZE)
uuser->type = StorageType_volatile;
else
uuser->type = StorageType_readOnly;
uuser->suser.auth_proto = clone->suser.auth_proto;
uuser->suser.priv_proto = clone->suser.priv_proto;
memcpy(uuser->suser.auth_key, clone->suser.auth_key,
sizeof(uuser->suser.auth_key));
memcpy(uuser->suser.priv_key, clone->suser.priv_key,
sizeof(uuser->suser.priv_key));
ctx->scratch->int1 = RowStatus_createAndWait;
break;
case LEAF_usmUserAuthProtocol:
ctx->scratch->int1 = uuser->suser.auth_proto;
if (asn_compare_oid(&oid_usmNoAuthProtocol,
&val->v.oid) == 0)
uuser->suser.auth_proto = SNMP_AUTH_NOAUTH;
else if (asn_compare_oid(&oid_usmHMACMD5AuthProtocol,
&val->v.oid) == 0)
uuser->suser.auth_proto = SNMP_AUTH_HMAC_MD5;
else if (asn_compare_oid(&oid_usmHMACSHAAuthProtocol,
&val->v.oid) == 0)
uuser->suser.auth_proto = SNMP_AUTH_HMAC_SHA;
else
return (SNMP_ERR_WRONG_VALUE);
break;
case LEAF_usmUserAuthKeyChange:
case LEAF_usmUserOwnAuthKeyChange:
if (val->var.subs[sub - 1] ==
LEAF_usmUserOwnAuthKeyChange &&
(usm_user == NULL || strcmp(uuser->suser.sec_name,
usm_user->suser.sec_name) != 0))
return (SNMP_ERR_NO_ACCESS);
if (val->v.octetstring.len > SNMP_AUTH_KEY_SIZ)
return (SNMP_ERR_INCONS_VALUE);
ctx->scratch->ptr1 = malloc(SNMP_AUTH_KEY_SIZ);
if (ctx->scratch->ptr1 == NULL)
return (SNMP_ERR_GENERR);
memcpy(ctx->scratch->ptr1, uuser->suser.auth_key,
SNMP_AUTH_KEY_SIZ);
memcpy(uuser->suser.auth_key, val->v.octetstring.octets,
val->v.octetstring.len);
break;
case LEAF_usmUserPrivProtocol:
ctx->scratch->int1 = uuser->suser.priv_proto;
if (asn_compare_oid(&oid_usmNoPrivProtocol,
&val->v.oid) == 0)
uuser->suser.priv_proto = SNMP_PRIV_NOPRIV;
else if (asn_compare_oid(&oid_usmDESPrivProtocol,
&val->v.oid) == 0)
uuser->suser.priv_proto = SNMP_PRIV_DES;
else if (asn_compare_oid(&oid_usmAesCfb128Protocol,
&val->v.oid) == 0)
uuser->suser.priv_proto = SNMP_PRIV_AES;
else
return (SNMP_ERR_WRONG_VALUE);
break;
case LEAF_usmUserPrivKeyChange:
case LEAF_usmUserOwnPrivKeyChange:
if (val->var.subs[sub - 1] ==
LEAF_usmUserOwnPrivKeyChange &&
(usm_user == NULL || strcmp(uuser->suser.sec_name,
usm_user->suser.sec_name) != 0))
return (SNMP_ERR_NO_ACCESS);
if (val->v.octetstring.len > SNMP_PRIV_KEY_SIZ)
return (SNMP_ERR_INCONS_VALUE);
ctx->scratch->ptr1 = malloc(SNMP_PRIV_KEY_SIZ);
if (ctx->scratch->ptr1 == NULL)
return (SNMP_ERR_GENERR);
memcpy(ctx->scratch->ptr1, uuser->suser.priv_key,
sizeof(uuser->suser.priv_key));
memcpy(uuser->suser.priv_key, val->v.octetstring.octets,
val->v.octetstring.len);
break;
case LEAF_usmUserPublic:
if (val->v.octetstring.len > SNMP_ADM_STR32_SIZ)
return (SNMP_ERR_INCONS_VALUE);
if (uuser->user_public_len > 0) {
ctx->scratch->ptr2 =
malloc(uuser->user_public_len);
if (ctx->scratch->ptr2 == NULL)
return (SNMP_ERR_GENERR);
memcpy(ctx->scratch->ptr2, uuser->user_public,
uuser->user_public_len);
ctx->scratch->int2 = uuser->user_public_len;
}
if (val->v.octetstring.len > 0) {
memcpy(uuser->user_public,
val->v.octetstring.octets,
val->v.octetstring.len);
uuser->user_public_len = val->v.octetstring.len;
} else {
memset(uuser->user_public, 0,
sizeof(uuser->user_public));
uuser->user_public_len = 0;
}
break;
case LEAF_usmUserStorageType:
return (SNMP_ERR_INCONS_VALUE);
case LEAF_usmUserStatus:
if (uuser == NULL) {
if (val->v.integer != RowStatus_createAndWait ||
usm_user_index_decode(&val->var, sub, eid,
&elen, uname) < 0)
return (SNMP_ERR_INCONS_VALUE);
uuser = usm_new_user(eid, elen, uname);
if (uuser == NULL)
return (SNMP_ERR_GENERR);
uuser->status = RowStatus_notReady;
if (community != COMM_INITIALIZE)
uuser->type = StorageType_volatile;
else
uuser->type = StorageType_readOnly;
} else if (val->v.integer != RowStatus_active &&
val->v.integer != RowStatus_destroy)
return (SNMP_ERR_INCONS_VALUE);
uuser->status = val->v.integer;
break;
}
return (SNMP_ERR_NOERROR);
case SNMP_OP_COMMIT:
switch (val->var.subs[sub - 1]) {
case LEAF_usmUserAuthKeyChange:
case LEAF_usmUserOwnAuthKeyChange:
case LEAF_usmUserPrivKeyChange:
case LEAF_usmUserOwnPrivKeyChange:
free(ctx->scratch->ptr1);
break;
case LEAF_usmUserPublic:
if (ctx->scratch->ptr2 != NULL)
free(ctx->scratch->ptr2);
break;
case LEAF_usmUserStatus:
if (val->v.integer != RowStatus_destroy)
break;
if ((uuser = usm_get_user(&val->var, sub)) == NULL)
return (SNMP_ERR_GENERR);
usm_delete_user(uuser);
break;
default:
break;
}
return (SNMP_ERR_NOERROR);
case SNMP_OP_ROLLBACK:
if ((uuser = usm_get_user(&val->var, sub)) == NULL)
return (SNMP_ERR_GENERR);
switch (val->var.subs[sub - 1]) {
case LEAF_usmUserAuthProtocol:
uuser->suser.auth_proto = ctx->scratch->int1;
break;
case LEAF_usmUserAuthKeyChange:
case LEAF_usmUserOwnAuthKeyChange:
memcpy(uuser->suser.auth_key, ctx->scratch->ptr1,
sizeof(uuser->suser.auth_key));
free(ctx->scratch->ptr1);
break;
case LEAF_usmUserPrivProtocol:
uuser->suser.priv_proto = ctx->scratch->int1;
break;
case LEAF_usmUserPrivKeyChange:
case LEAF_usmUserOwnPrivKeyChange:
memcpy(uuser->suser.priv_key, ctx->scratch->ptr1,
sizeof(uuser->suser.priv_key));
free(ctx->scratch->ptr1);
break;
case LEAF_usmUserPublic:
if (ctx->scratch->ptr2 != NULL) {
memcpy(uuser->user_public, ctx->scratch->ptr2,
ctx->scratch->int2);
uuser->user_public_len = ctx->scratch->int2;
free(ctx->scratch->ptr2);
} else {
memset(uuser->user_public, 0,
sizeof(uuser->user_public));
uuser->user_public_len = 0;
}
break;
case LEAF_usmUserCloneFrom:
case LEAF_usmUserStatus:
if (ctx->scratch->int1 == RowStatus_createAndWait)
usm_delete_user(uuser);
break;
default:
break;
}
return (SNMP_ERR_NOERROR);
default:
abort();
}
switch (val->var.subs[sub - 1]) {
case LEAF_usmUserSecurityName:
return (string_get(val, uuser->suser.sec_name, -1));
case LEAF_usmUserCloneFrom:
memcpy(&val->v.oid, &oid_zeroDotZero, sizeof(oid_zeroDotZero));
break;
case LEAF_usmUserAuthProtocol:
switch (uuser->suser.auth_proto) {
case SNMP_AUTH_HMAC_MD5:
memcpy(&val->v.oid, &oid_usmHMACMD5AuthProtocol,
sizeof(oid_usmHMACMD5AuthProtocol));
break;
case SNMP_AUTH_HMAC_SHA:
memcpy(&val->v.oid, &oid_usmHMACSHAAuthProtocol,
sizeof(oid_usmHMACSHAAuthProtocol));
break;
default:
memcpy(&val->v.oid, &oid_usmNoAuthProtocol,
sizeof(oid_usmNoAuthProtocol));
break;
}
break;
case LEAF_usmUserAuthKeyChange:
case LEAF_usmUserOwnAuthKeyChange:
return (string_get(val, (char *)uuser->suser.auth_key, 0));
case LEAF_usmUserPrivProtocol:
switch (uuser->suser.priv_proto) {
case SNMP_PRIV_DES:
memcpy(&val->v.oid, &oid_usmDESPrivProtocol,
sizeof(oid_usmDESPrivProtocol));
break;
case SNMP_PRIV_AES:
memcpy(&val->v.oid, &oid_usmAesCfb128Protocol,
sizeof(oid_usmAesCfb128Protocol));
break;
default:
memcpy(&val->v.oid, &oid_usmNoPrivProtocol,
sizeof(oid_usmNoPrivProtocol));
break;
}
break;
case LEAF_usmUserPrivKeyChange:
case LEAF_usmUserOwnPrivKeyChange:
return (string_get(val, (char *)uuser->suser.priv_key, 0));
case LEAF_usmUserPublic:
return (string_get(val, uuser->user_public,
uuser->user_public_len));
case LEAF_usmUserStorageType:
val->v.integer = uuser->type;
break;
case LEAF_usmUserStatus:
val->v.integer = uuser->status;
break;
}
return (SNMP_ERR_NOERROR);
}
static int
usm_user_index_decode(const struct asn_oid *oid, uint sub, uint8_t *engine,
uint32_t *elen, char *uname)
{
uint32_t i, nlen;
int uname_off;
if (oid->subs[sub] > SNMP_ENGINE_ID_SIZ)
return (-1);
for (i = 0; i < oid->subs[sub]; i++)
engine[i] = oid->subs[sub + i + 1];
*elen = i;
uname_off = sub + oid->subs[sub] + 1;
if ((nlen = oid->subs[uname_off]) >= SNMP_ADM_STR32_SIZ)
return (-1);
for (i = 0; i < nlen; i++)
uname[i] = oid->subs[uname_off + i + 1];
uname[nlen] = '\0';
return (0);
}
static void
usm_append_userindex(struct asn_oid *oid, uint sub,
const struct usm_user *uuser)
{
uint32_t i;
oid->len = sub + uuser->user_engine_len + strlen(uuser->suser.sec_name);
oid->len += 2;
oid->subs[sub] = uuser->user_engine_len;
for (i = 1; i < uuser->user_engine_len + 1; i++)
oid->subs[sub + i] = uuser->user_engine_id[i - 1];
sub += uuser->user_engine_len + 1;
oid->subs[sub] = strlen(uuser->suser.sec_name);
for (i = 1; i <= oid->subs[sub]; i++)
oid->subs[sub + i] = uuser->suser.sec_name[i - 1];
}
static struct usm_user *
usm_get_user(const struct asn_oid *oid, uint sub)
{
uint32_t enginelen;
char username[SNMP_ADM_STR32_SIZ];
uint8_t engineid[SNMP_ENGINE_ID_SIZ];
if (usm_user_index_decode(oid, sub, engineid, &enginelen, username) < 0)
return (NULL);
return (usm_find_user(engineid, enginelen, username));
}
static struct usm_user *
usm_get_next_user(const struct asn_oid *oid, uint sub)
{
uint32_t enginelen;
char username[SNMP_ADM_STR32_SIZ];
uint8_t engineid[SNMP_ENGINE_ID_SIZ];
struct usm_user *uuser;
if (oid->len - sub == 0)
return (usm_first_user());
if (usm_user_index_decode(oid, sub, engineid, &enginelen, username) < 0)
return (NULL);
if ((uuser = usm_find_user(engineid, enginelen, username)) != NULL)
return (usm_next_user(uuser));
return (NULL);
}
/*
* USM snmp module initialization hook.
* Returns 0 on success, < 0 on error.
*/
static int
usm_init(struct lmodule * mod, int argc __unused, char *argv[] __unused)
{
usm_module = mod;
usm_lock = random();
bsnmpd_reset_usm_stats();
return (0);
}
/*
* USM snmp module finalization hook.
*/
static int
usm_fini(void)
{
usm_flush_users();
or_unregister(reg_usm);
return (0);
}
/*
* USM snmp module start operation.
*/
static void
usm_start(void)
{
reg_usm = or_register(&oid_usm,
"The MIB module for managing SNMP User-Based Security Model.",
usm_module);
}
static void
usm_dump(void)
{
struct usm_user *uuser;
struct snmpd_usmstat *usmstats;
const char *const authstr[] = {
"noauth",
"md5",
"sha",
NULL
};
const char *const privstr[] = {
"nopriv",
"des",
"aes",
NULL
};
if ((usmstats = bsnmpd_get_usm_stats()) != NULL) {
syslog(LOG_ERR, "UnsupportedSecLevels\t\t%u",
usmstats->unsupported_seclevels);
syslog(LOG_ERR, "NotInTimeWindows\t\t%u",
usmstats->not_in_time_windows);
syslog(LOG_ERR, "UnknownUserNames\t\t%u",
usmstats->unknown_users);
syslog(LOG_ERR, "UnknownEngineIDs\t\t%u",
usmstats->unknown_engine_ids);
syslog(LOG_ERR, "WrongDigests\t\t%u",
usmstats->wrong_digests);
syslog(LOG_ERR, "DecryptionErrors\t\t%u",
usmstats->decrypt_errors);
}
syslog(LOG_ERR, "USM users");
for (uuser = usm_first_user(); uuser != NULL;
(uuser = usm_next_user(uuser)))
syslog(LOG_ERR, "user %s\t\t%s, %s", uuser->suser.sec_name,
authstr[uuser->suser.auth_proto],
privstr[uuser->suser.priv_proto]);
}
static const char usm_comment[] = \
"This module implements SNMP User-based Security Model defined in RFC 3414.";
extern const struct snmp_module config;
const struct snmp_module config = {
.comment = usm_comment,
.init = usm_init,
.fini = usm_fini,
.start = usm_start,
.tree = usm_ctree,
.dump = usm_dump,
.tree_size = usm_CTREE_SIZE,
};