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dnsserver: add dns name checking

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This may also prevent deletion of existing corrupted records through
DNS, but should be resolvable through RPC, or at worst LDAP.

Signed-off-by: Bob Campbell <bobcampbell@catalyst.net.nz>
Pair-programmed-with: Garming Sam <garming@catalyst.net.nz>
Reviewed-by: Garming Sam <garming@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
This commit is contained in:
Bob Campbell 2016-12-06 15:34:23 +13:00 committed by Garming Sam
parent 3ba40f6eb1
commit 4408df2493
7 changed files with 289 additions and 50 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
selftest/knownfail
View File

@ -309,5 +309,3 @@
^samba.tests.dcerpc.dnsserver.samba.tests.dcerpc.dnsserver.DnsserverTests.test_add_duplicate_different_type.*
^samba.tests.dcerpc.dnsserver.samba.tests.dcerpc.dnsserver.DnsserverTests.test_rank_none.*
^samba.tests.dcerpc.dnsserver.samba.tests.dcerpc.dnsserver.DnsserverTests.test_security_descriptor.*
^samba.tests.dcerpc.dnsserver.samba.tests.dcerpc.dnsserver.DnsserverTests.test_reject_invalid_commands
^samba.tests.samba_tool.dnscmd.samba.tests.samba_tool.dnscmd.DnsCmdTestCase.test_reject_invalid_commands

91
source4/dns_server/dnsserver_common.c
View File

@ -214,6 +214,91 @@ static int rec_cmp(const struct dnsp_DnssrvRpcRecord *r1,
return r1->dwTimeStamp - r2->dwTimeStamp;
}
/*
* Check for valid DNS names. These are names which are non-empty, do not
* start with a dot and do not have any empty segments.
*/
WERROR dns_name_check(TALLOC_CTX *mem_ctx, size_t len, const char *name)
{
size_t i;
if (len == 0) {
return WERR_DS_INVALID_DN_SYNTAX;
}
for (i = 0; i < len - 1; i++) {
if (name[i] == '.' && name[i+1] == '.') {
return WERR_DS_INVALID_DN_SYNTAX;
}
}
if (len > 1 && name[0] == '.') {
return WERR_DS_INVALID_DN_SYNTAX;
}
return WERR_OK;
}
static WERROR check_name_list(TALLOC_CTX *mem_ctx, uint16_t rec_count,
struct dnsp_DnssrvRpcRecord *records)
{
WERROR werr;
uint16_t i;
size_t len;
struct dnsp_DnssrvRpcRecord record;
werr = WERR_OK;
for (i = 0; i < rec_count; i++) {
record = records[i];
switch (record.wType) {
case DNS_TYPE_NS:
len = strlen(record.data.ns);
werr = dns_name_check(mem_ctx, len, record.data.ns);
break;
case DNS_TYPE_CNAME:
len = strlen(record.data.cname);
werr = dns_name_check(mem_ctx, len, record.data.cname);
break;
case DNS_TYPE_SOA:
len = strlen(record.data.soa.mname);
werr = dns_name_check(mem_ctx, len, record.data.soa.mname);
if (!W_ERROR_IS_OK(werr)) {
break;
}
len = strlen(record.data.soa.rname);
werr = dns_name_check(mem_ctx, len, record.data.soa.rname);
break;
case DNS_TYPE_PTR:
len = strlen(record.data.ptr);
werr = dns_name_check(mem_ctx, len, record.data.ptr);
break;
case DNS_TYPE_MX:
len = strlen(record.data.mx.nameTarget);
werr = dns_name_check(mem_ctx, len, record.data.mx.nameTarget);
break;
case DNS_TYPE_SRV:
len = strlen(record.data.srv.nameTarget);
werr = dns_name_check(mem_ctx, len,
record.data.srv.nameTarget);
break;
/*
* In the default case, the record doesn't have a DN, so it
* must be ok.
*/
default:
break;
}
if (!W_ERROR_IS_OK(werr)) {
return werr;
}
}
return WERR_OK;
}
WERROR dns_common_replace(struct ldb_context *samdb,
TALLOC_CTX *mem_ctx,
struct ldb_dn *dn,
@ -225,6 +310,7 @@ WERROR dns_common_replace(struct ldb_context *samdb,
struct ldb_message_element *el;
uint16_t i;
int ret;
WERROR werr;
struct ldb_message *msg = NULL;
bool was_tombstoned = false;
bool become_tombstoned = false;
@ -234,6 +320,11 @@ WERROR dns_common_replace(struct ldb_context *samdb,
msg->dn = dn;
werr = check_name_list(mem_ctx, rec_count, records);
if (!W_ERROR_IS_OK(werr)) {
return werr;
}
ret = ldb_msg_add_empty(msg, "dnsRecord", LDB_FLAG_MOD_REPLACE, &el);
if (ret != LDB_SUCCESS) {
return DNS_ERR(SERVER_FAILURE);

4
source4/dns_server/dnsserver_common.h
View File

@ -46,7 +46,9 @@ WERROR dns_common_lookup(struct ldb_context *samdb,
struct dnsp_DnssrvRpcRecord **records,
uint16_t *num_records,
bool *tombstoned);
WERROR dns_name_check(TALLOC_CTX *mem_ctx,
size_t len,
const char *name);
WERROR dns_common_replace(struct ldb_context *samdb,
TALLOC_CTX *mem_ctx,
struct ldb_dn *dn,

203
source4/rpc_server/dnsserver/dnsdata.c
View File

@ -21,6 +21,7 @@
#include "includes.h"
#include "dnsserver.h"
#include "dns_server/dnsserver_common.h"
#include "lib/replace/system/network.h"
#include "librpc/gen_ndr/ndr_dnsp.h"
#include "librpc/gen_ndr/ndr_dnsserver.h"
@ -412,15 +413,18 @@ void dnsp_to_dns_copy(TALLOC_CTX *mem_ctx, struct dnsp_DnssrvRpcRecord *dnsp,
}
struct dnsp_DnssrvRpcRecord *dns_to_dnsp_copy(TALLOC_CTX *mem_ctx, struct DNS_RPC_RECORD *dns)
WERROR dns_to_dnsp_convert(TALLOC_CTX *mem_ctx, struct DNS_RPC_RECORD *dns,
struct dnsp_DnssrvRpcRecord **out_dnsp, bool check_name)
{
WERROR res;
int i, len;
struct dnsp_DnssrvRpcRecord *dnsp;
const char *name;
char *talloc_res = NULL;
struct dnsp_DnssrvRpcRecord *dnsp = NULL;
dnsp = talloc_zero(mem_ctx, struct dnsp_DnssrvRpcRecord);
if (dnsp == NULL) {
return NULL;
return WERR_NOT_ENOUGH_MEMORY;
}
dnsp->wDataLength = dns->wDataLength;
@ -438,25 +442,65 @@ struct dnsp_DnssrvRpcRecord *dns_to_dnsp_copy(TALLOC_CTX *mem_ctx, struct DNS_RP
break;
case DNS_TYPE_A:
dnsp->data.ipv4 = talloc_strdup(mem_ctx, dns->data.ipv4);
talloc_res = talloc_strdup(mem_ctx, dns->data.ipv4);
if (talloc_res == NULL) {
goto fail_nomemory;
}
dnsp->data.ipv4 = talloc_res;
break;
case DNS_TYPE_NS:
name = dns->data.name.str;
len = dns->data.name.len;
if (dns->data.name.str[len-1] == '.') {
dnsp->data.ns = talloc_strndup(mem_ctx, dns->data.name.str, len-1);
} else {
dnsp->data.ns = talloc_strdup(mem_ctx, dns->data.name.str);
if (check_name) {
res = dns_name_check(mem_ctx, len, name);
if (!W_ERROR_IS_OK(res)) {
return res;
}
}
if (len > 0 && name[len-1] == '.') {
talloc_res = talloc_strndup(mem_ctx, name, len-1);
if (talloc_res == NULL) {
goto fail_nomemory;
}
dnsp->data.ns = talloc_res;
} else {
talloc_res = talloc_strdup(mem_ctx, name);
if (talloc_res == NULL) {
goto fail_nomemory;
}
dnsp->data.ns = talloc_res;
}
break;
case DNS_TYPE_CNAME:
name = dns->data.name.str;
len = dns->data.name.len;
if (dns->data.name.str[len-1] == '.') {
dnsp->data.cname = talloc_strndup(mem_ctx, dns->data.name.str, len-1);
} else {
dnsp->data.cname = talloc_strdup(mem_ctx, dns->data.name.str);
if (check_name) {
res = dns_name_check(mem_ctx, len, name);
if (!W_ERROR_IS_OK(res)) {
return res;
}
}
if (len > 0 && name[len-1] == '.') {
talloc_res = talloc_strndup(mem_ctx, name, len-1);
if (talloc_res == NULL) {
goto fail_nomemory;
}
dnsp->data.cname = talloc_res;
} else {
talloc_res = talloc_strdup(mem_ctx, name);
if (talloc_res == NULL) {
goto fail_nomemory;
}
dnsp->data.cname = talloc_res;
}
break;
case DNS_TYPE_SOA:
@ -466,40 +510,111 @@ struct dnsp_DnssrvRpcRecord *dns_to_dnsp_copy(TALLOC_CTX *mem_ctx, struct DNS_RP
dnsp->data.soa.expire = dns->data.soa.dwExpire;
dnsp->data.soa.minimum = dns->data.soa.dwMinimumTtl;
name = dns->data.soa.NamePrimaryServer.str;
len = dns->data.soa.NamePrimaryServer.len;
if (dns->data.soa.NamePrimaryServer.str[len-1] == '.') {
dnsp->data.soa.mname = talloc_strndup(mem_ctx, dns->data.soa.NamePrimaryServer.str, len-1);
} else {
dnsp->data.soa.mname = talloc_strdup(mem_ctx, dns->data.soa.NamePrimaryServer.str);
if (check_name) {
res = dns_name_check(mem_ctx, len, name);
if (!W_ERROR_IS_OK(res)) {
return res;
}
}
len = dns->data.soa.ZoneAdministratorEmail.len;
if (dns->data.soa.ZoneAdministratorEmail.str[len-1] == '.') {
dnsp->data.soa.rname = talloc_strndup(mem_ctx, dns->data.soa.ZoneAdministratorEmail.str, len-1);
if (len > 0 && name[len-1] == '.') {
talloc_res = talloc_strndup(mem_ctx, name, len-1);
if (talloc_res == NULL) {
goto fail_nomemory;
}
dnsp->data.soa.mname = talloc_res;
} else {
dnsp->data.soa.rname = talloc_strdup(mem_ctx, dns->data.soa.ZoneAdministratorEmail.str);
talloc_res = talloc_strdup(mem_ctx, name);
if (talloc_res == NULL) {
goto fail_nomemory;
}
dnsp->data.soa.mname = talloc_res;
}
name = dns->data.soa.ZoneAdministratorEmail.str;
len = dns->data.soa.ZoneAdministratorEmail.len;
res = dns_name_check(mem_ctx, len, name);
if (!W_ERROR_IS_OK(res)) {
return res;
}
if (len > 0 && name[len-1] == '.') {
talloc_res = talloc_strndup(mem_ctx, name, len-1);
if (talloc_res == NULL) {
goto fail_nomemory;
}
dnsp->data.soa.rname = talloc_res;
} else {
talloc_res = talloc_strdup(mem_ctx, name);
if (talloc_res == NULL) {
goto fail_nomemory;
}
dnsp->data.soa.rname = talloc_res;
}
break;
case DNS_TYPE_PTR:
dnsp->data.ptr = talloc_strdup(mem_ctx, dns->data.ptr.str);
name = dns->data.ptr.str;
len = dns->data.ptr.len;
if (check_name) {
res = dns_name_check(mem_ctx, len, name);
if (!W_ERROR_IS_OK(res)) {
return res;
}
}
talloc_res = talloc_strdup(mem_ctx, name);
if (talloc_res == NULL) {
goto fail_nomemory;
}
dnsp->data.ptr = talloc_res;
break;
case DNS_TYPE_MX:
dnsp->data.mx.wPriority = dns->data.mx.wPreference;
name = dns->data.mx.nameExchange.str;
len = dns->data.mx.nameExchange.len;
if (dns->data.mx.nameExchange.str[len-1] == '.') {
dnsp->data.mx.nameTarget = talloc_strndup(mem_ctx, dns->data.mx.nameExchange.str, len-1);
} else {
dnsp->data.mx.nameTarget = talloc_strdup(mem_ctx, dns->data.mx.nameExchange.str);
if (check_name) {
res = dns_name_check(mem_ctx, len, name);
if (!W_ERROR_IS_OK(res)) {
return res;
}
}
if (len > 0 && name[len-1] == '.') {
talloc_res = talloc_strndup(mem_ctx, name, len-1);
if (talloc_res == NULL) {
goto fail_nomemory;
}
dnsp->data.mx.nameTarget = talloc_res;
} else {
talloc_res = talloc_strdup(mem_ctx, name);
if (talloc_res == NULL) {
goto fail_nomemory;
}
dnsp->data.mx.nameTarget = talloc_res;
}
break;
case DNS_TYPE_TXT:
dnsp->data.txt.count = dns->data.txt.count;
dnsp->data.txt.str = talloc_array(mem_ctx, const char *, dns->data.txt.count);
for (i=0; i<dns->data.txt.count; i++) {
dnsp->data.txt.str[i] = talloc_strdup(mem_ctx, dns->data.txt.str[i].str);
talloc_res = talloc_strdup(mem_ctx, dns->data.txt.str[i].str);
if (talloc_res == NULL) {
goto fail_nomemory;
}
dnsp->data.txt.str[i] = talloc_res;
}
break;
@ -512,23 +627,43 @@ struct dnsp_DnssrvRpcRecord *dns_to_dnsp_copy(TALLOC_CTX *mem_ctx, struct DNS_RP
dnsp->data.srv.wWeight = dns->data.srv.wWeight;
dnsp->data.srv.wPort = dns->data.srv.wPort;
name = dns->data.srv.nameTarget.str;
len = dns->data.srv.nameTarget.len;
if (dns->data.srv.nameTarget.str[len-1] == '.') {
dnsp->data.srv.nameTarget = talloc_strndup(mem_ctx, dns->data.srv.nameTarget.str, len-1);
} else {
dnsp->data.srv.nameTarget = talloc_strdup(mem_ctx, dns->data.srv.nameTarget.str);
if (check_name) {
res = dns_name_check(mem_ctx, len, name);
if (!W_ERROR_IS_OK(res)) {
return res;
}
}
if (len > 0 && name[len-1] == '.') {
talloc_res = talloc_strndup(mem_ctx, name, len-1);
if (talloc_res == NULL) {
goto fail_nomemory;
}
dnsp->data.srv.nameTarget = talloc_res;
} else {
talloc_res = talloc_strdup(mem_ctx, name);
if (talloc_res == NULL) {
goto fail_nomemory;
}
dnsp->data.srv.nameTarget = talloc_res;
}
break;
default:
memcpy(&dnsp->data, &dns->data, sizeof(union dnsRecordData));
DEBUG(0, ("dnsserver: Found Unhandled DNS record type=%d", dns->wType));
}
return dnsp;
}
*out_dnsp = dnsp;
return WERR_OK;
fail_nomemory:
return WERR_NOT_ENOUGH_MEMORY;
}
/* Intialize tree with given name as the root */
static struct dns_tree *dns_tree_init(TALLOC_CTX *mem_ctx, const char *name, void *data)

33
source4/rpc_server/dnsserver/dnsdb.c
View File

@ -397,17 +397,20 @@ WERROR dnsserver_db_add_record(TALLOC_CTX *mem_ctx,
{
const char * const attrs[] = { "dnsRecord", "dNSTombstoned", NULL };
struct ldb_result *res;
struct dnsp_DnssrvRpcRecord *rec;
struct dnsp_DnssrvRpcRecord *rec = NULL;
struct ldb_message_element *el;
struct ldb_dn *dn;
enum ndr_err_code ndr_err;
NTTIME t;
int ret, i;
int serial;
WERROR werr;
bool was_tombstoned = false;
rec = dns_to_dnsp_copy(mem_ctx, add_record);
W_ERROR_HAVE_NO_MEMORY(rec);
werr = dns_to_dnsp_convert(mem_ctx, add_record, &rec, true);
if (!W_ERROR_IS_OK(werr)) {
return werr;
}
/* Set the correct rank for the record. */
if (z->zoneinfo->dwZoneType == DNS_ZONE_TYPE_PRIMARY) {
@ -514,18 +517,23 @@ WERROR dnsserver_db_update_record(TALLOC_CTX *mem_ctx,
{
const char * const attrs[] = { "dnsRecord", NULL };
struct ldb_result *res;
struct dnsp_DnssrvRpcRecord *arec, *drec;
struct dnsp_DnssrvRpcRecord *arec = NULL, *drec = NULL;
struct ldb_message_element *el;
enum ndr_err_code ndr_err;
NTTIME t;
int ret, i;
int serial;
WERROR werr;
arec = dns_to_dnsp_copy(mem_ctx, add_record);
W_ERROR_HAVE_NO_MEMORY(arec);
werr = dns_to_dnsp_convert(mem_ctx, add_record, &arec, true);
if (!W_ERROR_IS_OK(werr)) {
return werr;
}
drec = dns_to_dnsp_copy(mem_ctx, del_record);
W_ERROR_HAVE_NO_MEMORY(drec);
werr = dns_to_dnsp_convert(mem_ctx, del_record, &drec, true);
if (!W_ERROR_IS_OK(werr)) {
return werr;
}
unix_to_nt_time(&t, time(NULL));
t /= 10*1000*1000;
@ -616,19 +624,22 @@ WERROR dnsserver_db_delete_record(TALLOC_CTX *mem_ctx,
{
const char * const attrs[] = { "dnsRecord", NULL };
struct ldb_result *res;
struct dnsp_DnssrvRpcRecord *rec;
struct dnsp_DnssrvRpcRecord *rec = NULL;
struct ldb_message_element *el;
enum ndr_err_code ndr_err;
int ret, i;
int serial;
WERROR werr;
serial = dnsserver_update_soa(mem_ctx, samdb, z);
if (serial < 0) {
return WERR_INTERNAL_DB_ERROR;
}
rec = dns_to_dnsp_copy(mem_ctx, del_record);
W_ERROR_HAVE_NO_MEMORY(rec);
werr = dns_to_dnsp_convert(mem_ctx, del_record, &rec, false);
if (!W_ERROR_IS_OK(werr)) {
return werr;
}
ret = ldb_search(samdb, mem_ctx, &res, z->zone_dn, LDB_SCOPE_ONELEVEL, attrs,
"(&(objectClass=dnsNode)(name=%s))", name);

4
source4/rpc_server/dnsserver/dnsserver.h
View File

@ -193,7 +193,9 @@ bool dns_record_match(struct dnsp_DnssrvRpcRecord *rec1, struct dnsp_DnssrvRpcRe
void dnsp_to_dns_copy(TALLOC_CTX *mem_ctx, struct dnsp_DnssrvRpcRecord *dnsp,
struct DNS_RPC_RECORD *dns);
struct dnsp_DnssrvRpcRecord *dns_to_dnsp_copy(TALLOC_CTX *mem_ctx, struct DNS_RPC_RECORD *dns);
WERROR dns_to_dnsp_convert(TALLOC_CTX *mem_ctx, struct DNS_RPC_RECORD *dns,
struct dnsp_DnssrvRpcRecord **out_dnsp,
bool check_name);
struct dns_tree *dns_build_tree(TALLOC_CTX *mem_ctx, const char *name, struct ldb_result *res);
WERROR dns_fill_records_array(TALLOC_CTX *mem_ctx, struct dnsserver_zone *z,

2
source4/rpc_server/wscript_build
View File

@ -155,7 +155,7 @@ bld.SAMBA_MODULE('dcerpc_dnsserver',
source='dnsserver/dcerpc_dnsserver.c dnsserver/dnsutils.c dnsserver/dnsdata.c dnsserver/dnsdb.c',
subsystem='dcerpc_server',
init_function='dcerpc_server_dnsserver_init',
deps='DCERPC_COMMON'
deps='DCERPC_COMMON dnsserver_common'
)