svn commit: samba r10174 - in
branches/SAMBA_4_0/source/auth/kerberos: .
abartlet at samba.org
abartlet at samba.org
Mon Sep 12 14:19:05 GMT 2005
Author: abartlet
Date: 2005-09-12 14:19:05 +0000 (Mon, 12 Sep 2005)
New Revision: 10174
WebSVN: http://websvn.samba.org/cgi-bin/viewcvs.cgi?view=rev&root=samba&rev=10174
Log:
This patch implements generic PAC verification, without assumptions
about the size of the signature. In particular, this works with AES,
which was previously broken Samba4/Samba4.
Reviewed by metze (and thanks for help with the previous IDL commit).
Modified:
branches/SAMBA_4_0/source/auth/kerberos/kerberos_pac.c
Changeset:
Modified: branches/SAMBA_4_0/source/auth/kerberos/kerberos_pac.c
===================================================================
--- branches/SAMBA_4_0/source/auth/kerberos/kerberos_pac.c 2005-09-12 13:52:15 UTC (rev 10173)
+++ branches/SAMBA_4_0/source/auth/kerberos/kerberos_pac.c 2005-09-12 14:19:05 UTC (rev 10174)
@@ -78,38 +78,70 @@
{
krb5_error_code ret;
NTSTATUS status;
- struct PAC_SIGNATURE_DATA srv_sig;
struct PAC_SIGNATURE_DATA *srv_sig_ptr = NULL;
- struct PAC_SIGNATURE_DATA kdc_sig;
struct PAC_SIGNATURE_DATA *kdc_sig_ptr = NULL;
+ struct PAC_SIGNATURE_DATA *srv_sig_wipe = NULL;
+ struct PAC_SIGNATURE_DATA *kdc_sig_wipe = NULL;
struct PAC_LOGON_INFO *logon_info = NULL;
struct PAC_LOGON_NAME *logon_name = NULL;
struct PAC_DATA *pac_data;
+ struct PAC_DATA_RAW *pac_data_raw;
- DATA_BLOB modified_pac_blob = data_blob_talloc(mem_ctx, blob.data, blob.length);
+ DATA_BLOB *srv_sig_blob;
+ DATA_BLOB *kdc_sig_blob;
+
+ DATA_BLOB modified_pac_blob;
NTTIME tgs_authtime_nttime;
krb5_principal client_principal_pac;
int i;
pac_data = talloc(mem_ctx, struct PAC_DATA);
- if (!pac_data) {
+ pac_data_raw = talloc(mem_ctx, struct PAC_DATA_RAW);
+ kdc_sig_wipe = talloc(mem_ctx, struct PAC_SIGNATURE_DATA);
+ srv_sig_wipe = talloc(mem_ctx, struct PAC_SIGNATURE_DATA);
+ if (!pac_data_raw || !pac_data || !kdc_sig_wipe || !srv_sig_wipe) {
return NT_STATUS_NO_MEMORY;
}
- status = ndr_pull_struct_blob(&blob, mem_ctx, pac_data,
+ status = ndr_pull_struct_blob(&blob, pac_data, pac_data,
(ndr_pull_flags_fn_t)ndr_pull_PAC_DATA);
if (!NT_STATUS_IS_OK(status)) {
DEBUG(0,("can't parse the PAC\n"));
return status;
}
- if (pac_data->num_buffers < 3) {
+ if (pac_data->num_buffers < 4) {
/* we need logon_ingo, service_key and kdc_key */
- DEBUG(0,("less than 3 PAC buffers\n"));
- return NT_STATUS_FOOBAR;
+ DEBUG(0,("less than 4 PAC buffers\n"));
+ return NT_STATUS_INVALID_PARAMETER;
}
+ status = ndr_pull_struct_blob(&blob, pac_data_raw, pac_data_raw,
+ (ndr_pull_flags_fn_t)ndr_pull_PAC_DATA_RAW);
+ if (!NT_STATUS_IS_OK(status)) {
+ DEBUG(0,("can't parse the PAC\n"));
+ return status;
+ }
+
+ if (pac_data_raw->num_buffers < 4) {
+ /* we need logon_ingo, service_key and kdc_key */
+ DEBUG(0,("less than 4 PAC buffers\n"));
+ return NT_STATUS_INVALID_PARAMETER;
+ }
+
+ if (pac_data->num_buffers != pac_data_raw->num_buffers) {
+ /* we need logon_ingo, service_key and kdc_key */
+ DEBUG(0,("misparse! PAC_DATA has %d buffers while PAC_DATA_RAW has %d\n",
+ pac_data->num_buffers, pac_data_raw->num_buffers));
+ return NT_STATUS_INVALID_PARAMETER;
+ }
+
for (i=0; i < pac_data->num_buffers; i++) {
+ if (pac_data->buffers[i].type != pac_data_raw->buffers[i].type) {
+ DEBUG(0,("misparse! PAC_DATA buffer %d has type %d while PAC_DATA_RAW has %d\n",
+ i, pac_data->buffers[i].type, pac_data->buffers[i].type));
+ return NT_STATUS_INVALID_PARAMETER;
+ }
switch (pac_data->buffers[i].type) {
case PAC_TYPE_LOGON_INFO:
if (!pac_data->buffers[i].info) {
@@ -122,14 +154,14 @@
break;
}
srv_sig_ptr = &pac_data->buffers[i].info->srv_cksum;
- srv_sig = pac_data->buffers[i].info->srv_cksum;
+ srv_sig_blob = &pac_data_raw->buffers[i].info->remaining;
break;
case PAC_TYPE_KDC_CHECKSUM:
if (!pac_data->buffers[i].info) {
break;
}
kdc_sig_ptr = &pac_data->buffers[i].info->kdc_cksum;
- kdc_sig = pac_data->buffers[i].info->kdc_cksum;
+ kdc_sig_blob = &pac_data_raw->buffers[i].info->remaining;
break;
case PAC_TYPE_LOGON_NAME:
logon_name = &pac_data->buffers[i].info->logon_name;
@@ -141,29 +173,72 @@
if (!logon_info) {
DEBUG(0,("PAC no logon_info\n"));
- return NT_STATUS_FOOBAR;
+ return NT_STATUS_INVALID_PARAMETER;
}
- if (!srv_sig_ptr) {
+ if (!logon_name) {
+ DEBUG(0,("PAC no logon_name\n"));
+ return NT_STATUS_INVALID_PARAMETER;
+ }
+
+ if (!srv_sig_ptr || !srv_sig_blob) {
DEBUG(0,("PAC no srv_key\n"));
- return NT_STATUS_FOOBAR;
+ return NT_STATUS_INVALID_PARAMETER;
}
- if (!kdc_sig_ptr) {
+ if (!kdc_sig_ptr || !kdc_sig_blob) {
DEBUG(0,("PAC no kdc_key\n"));
- return NT_STATUS_FOOBAR;
+ return NT_STATUS_INVALID_PARAMETER;
}
- memset(&modified_pac_blob.data[modified_pac_blob.length - 20],
- '\0', 16);
- memset(&modified_pac_blob.data[modified_pac_blob.length - 44],
- '\0', 16);
+ /* Find and zero out the signatures, as required by the signing algorithm */
+ /* We find the data blobs above, now we parse them to get at the exact portion we should zero */
+ status = ndr_pull_struct_blob(kdc_sig_blob, kdc_sig_wipe, kdc_sig_wipe,
+ (ndr_pull_flags_fn_t)ndr_pull_PAC_SIGNATURE_DATA);
+ if (!NT_STATUS_IS_OK(status)) {
+ DEBUG(0,("can't parse the KDC signature\n"));
+ return status;
+ }
+
+ status = ndr_pull_struct_blob(srv_sig_blob, srv_sig_wipe, srv_sig_wipe,
+ (ndr_pull_flags_fn_t)ndr_pull_PAC_SIGNATURE_DATA);
+ if (!NT_STATUS_IS_OK(status)) {
+ DEBUG(0,("can't parse the SRV signature\n"));
+ return status;
+ }
+
+ /* Now zero the decoded structure */
+ memset(kdc_sig_wipe->signature.data, '\0', kdc_sig_wipe->signature.length);
+ memset(srv_sig_wipe->signature.data, '\0', srv_sig_wipe->signature.length);
+
+ /* and reencode, back into the same place it came from */
+ status = ndr_push_struct_blob(kdc_sig_blob, pac_data_raw, kdc_sig_wipe,
+ (ndr_push_flags_fn_t)ndr_push_PAC_SIGNATURE_DATA);
+ if (!NT_STATUS_IS_OK(status)) {
+ DEBUG(0,("can't repack the KDC signature\n"));
+ return status;
+ }
+ status = ndr_push_struct_blob(srv_sig_blob, pac_data_raw, srv_sig_wipe,
+ (ndr_push_flags_fn_t)ndr_push_PAC_SIGNATURE_DATA);
+ if (!NT_STATUS_IS_OK(status)) {
+ DEBUG(0,("can't repack the SRV signature\n"));
+ return status;
+ }
+
+ /* push out the whole structure, but now with zero'ed signatures */
+ status = ndr_push_struct_blob(&modified_pac_blob, pac_data_raw, pac_data_raw,
+ (ndr_push_flags_fn_t)ndr_push_PAC_DATA_RAW);
+ if (!NT_STATUS_IS_OK(status)) {
+ DEBUG(0,("can't repack the RAW PAC\n"));
+ return status;
+ }
+
/* verify by service_key */
ret = check_pac_checksum(mem_ctx,
- modified_pac_blob, &srv_sig,
- context,
- service_keyblock);
+ modified_pac_blob, srv_sig_ptr,
+ context,
+ service_keyblock);
if (ret) {
DEBUG(1, ("PAC Decode: Failed to verify the service signature: %s\n",
smb_get_krb5_error_message(context, ret, mem_ctx)));
@@ -172,7 +247,7 @@
if (krbtgt_keyblock) {
ret = check_pac_checksum(mem_ctx,
- srv_sig_ptr->signature, &kdc_sig,
+ srv_sig_ptr->signature, kdc_sig_ptr,
context, krbtgt_keyblock);
if (ret) {
DEBUG(1, ("PAC Decode: Failed to verify the KDC signature: %s\n",
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