static krb5_error_code
k5_pac_verify_kdc_checksum(krb5_context context,
const krb5_pac pac,
const krb5_keyblock *privsvr)
{
krb5_error_code ret;
krb5_data server_checksum, privsvr_checksum;
krb5_checksum checksum;
krb5_boolean valid;
krb5_octet *p;
ret = k5_pac_locate_buffer(context, pac,
PAC_PRIVSVR_CHECKSUM, &privsvr_checksum);
if (ret != 0)
return ret;
if (privsvr_checksum.length < PAC_SIGNATURE_DATA_LENGTH)
return KRB5_BAD_MSIZE;
ret = k5_pac_locate_buffer(context, pac,
PAC_SERVER_CHECKSUM, &server_checksum);
if (ret != 0)
return ret;
if (server_checksum.length < PAC_SIGNATURE_DATA_LENGTH)
return KRB5_BAD_MSIZE;
p = (krb5_octet *)privsvr_checksum.data;
checksum.checksum_type = load_32_le(p);
checksum.length = privsvr_checksum.length - PAC_SIGNATURE_DATA_LENGTH;
checksum.contents = p + PAC_SIGNATURE_DATA_LENGTH;
if (!krb5_c_is_keyed_cksum(checksum.checksum_type))
return KRB5KRB_AP_ERR_INAPP_CKSUM;
server_checksum.data += PAC_SIGNATURE_DATA_LENGTH;
server_checksum.length -= PAC_SIGNATURE_DATA_LENGTH;
ret = krb5_c_verify_checksum(context, privsvr,
KRB5_KEYUSAGE_APP_DATA_CKSUM,
&server_checksum, &checksum, &valid);
if (ret != 0)
return ret;
if (valid == FALSE)
ret = KRB5KRB_AP_ERR_BAD_INTEGRITY;
return ret;
}
static krb5_error_code
k5_insert_client_info(krb5_context context,
krb5_pac pac,
krb5_timestamp authtime,
krb5_const_principal principal)
{
krb5_error_code ret;
krb5_data client_info;
char *princ_name_utf8 = NULL;
unsigned char *princ_name_ucs2 = NULL, *p;
size_t princ_name_ucs2_len = 0;
krb5_ui_8 nt_authtime;
/* If we already have a CLIENT_INFO buffer, then just validate it */
if (k5_pac_locate_buffer(context, pac, KRB5_PAC_CLIENT_INFO,
&client_info) == 0) {
return k5_pac_validate_client(context, pac, authtime, principal);
}
ret = krb5_unparse_name_flags(context, principal,
KRB5_PRINCIPAL_UNPARSE_NO_REALM,
&princ_name_utf8);
if (ret != 0)
goto cleanup;
ret = krb5int_utf8s_to_ucs2les(princ_name_utf8,
&princ_name_ucs2,
&princ_name_ucs2_len);
if (ret != 0)
goto cleanup;
client_info.length = PAC_CLIENT_INFO_LENGTH + princ_name_ucs2_len;
client_info.data = NULL;
ret = k5_pac_add_buffer(context, pac, KRB5_PAC_CLIENT_INFO,
&client_info, TRUE, &client_info);
if (ret != 0)
goto cleanup;
p = (unsigned char *)client_info.data;
/* copy in authtime converted to a 64-bit NT time */
k5_seconds_since_1970_to_time(authtime, &nt_authtime);
store_64_le(nt_authtime, p);
p += 8;
/* copy in number of UCS-2 characters in principal name */
store_16_le(princ_name_ucs2_len, p);
p += 2;
/* copy in principal name */
memcpy(p, princ_name_ucs2, princ_name_ucs2_len);
cleanup:
if (princ_name_ucs2 != NULL)
free(princ_name_ucs2);
krb5_free_unparsed_name(context, princ_name_utf8);
return ret;
}
krb5_error_code
k5_pac_validate_client(krb5_context context,
const krb5_pac pac,
krb5_timestamp authtime,
krb5_const_principal principal)
{
krb5_error_code ret;
krb5_data client_info;
char *pac_princname;
unsigned char *p;
krb5_timestamp pac_authtime;
krb5_ui_2 pac_princname_length;
krb5_int64 pac_nt_authtime;
krb5_principal pac_principal;
ret = k5_pac_locate_buffer(context, pac, PAC_CLIENT_INFO, &client_info);
if (ret != 0)
return ret;
if (client_info.length < PAC_CLIENT_INFO_LENGTH)
return ERANGE;
p = (unsigned char *)client_info.data;
pac_nt_authtime = load_64_le(p);
p += 8;
pac_princname_length = load_16_le(p);
p += 2;
ret = k5_time_to_seconds_since_1970(pac_nt_authtime, &pac_authtime);
if (ret != 0)
return ret;
if (client_info.length < PAC_CLIENT_INFO_LENGTH + pac_princname_length ||
pac_princname_length % 2)
return ERANGE;
ret = krb5int_ucs2lecs_to_utf8s(p, (size_t)pac_princname_length / 2,
&pac_princname, NULL);
if (ret != 0)
return ret;
ret = krb5_parse_name_flags(context, pac_princname, 0, &pac_principal);
if (ret != 0) {
free(pac_princname);
return ret;
}
free(pac_princname);
if (pac_authtime != authtime ||
!krb5_principal_compare_flags(context,
pac_principal,
principal,
KRB5_PRINCIPAL_COMPARE_IGNORE_REALM))
ret = KRB5KRB_AP_WRONG_PRINC;
krb5_free_principal(context, pac_principal);
return ret;
}
static krb5_error_code
mspac_get_attribute(krb5_context kcontext,
krb5_authdata_context context,
void *plugin_context,
void *request_context,
const krb5_data *attribute,
krb5_boolean *authenticated,
krb5_boolean *complete,
krb5_data *value,
krb5_data *display_value,
int *more)
{
struct mspac_context *pacctx = (struct mspac_context *)request_context;
krb5_error_code code;
krb5_ui_4 type;
if (display_value != NULL) {
display_value->data = NULL;
display_value->length = 0;
}
if (*more != -1 || pacctx->pac == NULL)
return ENOENT;
/* If it didn't verify, pretend it didn't exist. */
if (!pacctx->pac->verified) {
TRACE_MSPAC_DISCARD_UNVERF(kcontext);
return ENOENT;
}
code = mspac_attr2type(attribute, &type);
if (code != 0)
return code;
/* -1 is a magic type that refers to the entire PAC */
if (type == (krb5_ui_4)-1) {
if (value != NULL)
code = krb5int_copy_data_contents(kcontext,
&pacctx->pac->data,
value);
else
code = 0;
} else {
if (value != NULL)
code = krb5_pac_get_buffer(kcontext, pacctx->pac, type, value);
else
code = k5_pac_locate_buffer(kcontext, pacctx->pac, type, NULL);
}
if (code == 0) {
*authenticated = pacctx->pac->verified;
*complete = TRUE;
}
*more = 0;
return code;
}
static krb5_error_code
k5_insert_checksum(krb5_context context,
krb5_pac pac,
krb5_ui_4 type,
const krb5_keyblock *key,
krb5_cksumtype *cksumtype)
{
krb5_error_code ret;
size_t len;
krb5_data cksumdata;
ret = krb5int_c_mandatory_cksumtype(context, key->enctype, cksumtype);
if (ret != 0)
return ret;
ret = krb5_c_checksum_length(context, *cksumtype, &len);
if (ret != 0)
return ret;
ret = k5_pac_locate_buffer(context, pac, type, &cksumdata);
if (ret == 0) {
/*
* If we're resigning PAC, make sure we can fit checksum
* into existing buffer
*/
if (cksumdata.length != PAC_SIGNATURE_DATA_LENGTH + len)
return ERANGE;
memset(cksumdata.data, 0, cksumdata.length);
} else {
/* Add a zero filled buffer */
cksumdata.length = PAC_SIGNATURE_DATA_LENGTH + len;
cksumdata.data = NULL;
ret = k5_pac_add_buffer(context, pac,
type, &cksumdata,
TRUE, &cksumdata);
if (ret != 0)
return ret;
}
/* Encode checksum type into buffer */
store_32_le((krb5_ui_4)*cksumtype, cksumdata.data);
return 0;
}
/*
* Find a buffer and copy data into output
*/
krb5_error_code KRB5_CALLCONV
krb5_pac_get_buffer(krb5_context context,
krb5_pac pac,
krb5_ui_4 type,
krb5_data *data)
{
krb5_data d;
krb5_error_code ret;
ret = k5_pac_locate_buffer(context, pac, type, &d);
if (ret != 0)
return ret;
data->data = malloc(d.length);
if (data->data == NULL)
return ENOMEM;
data->length = d.length;
memcpy(data->data, d.data, d.length);
return 0;
}
krb5_error_code KRB5_CALLCONV
krb5_pac_sign(krb5_context context, krb5_pac pac, krb5_timestamp authtime,
krb5_const_principal principal, const krb5_keyblock *server_key,
const krb5_keyblock *privsvr_key, krb5_data *data)
{
krb5_error_code ret;
krb5_data server_cksum, privsvr_cksum;
krb5_cksumtype server_cksumtype, privsvr_cksumtype;
krb5_crypto_iov iov[2];
data->length = 0;
data->data = NULL;
if (principal != NULL) {
ret = k5_insert_client_info(context, pac, authtime, principal);
if (ret != 0)
return ret;
}
/* Create zeroed buffers for both checksums */
ret = k5_insert_checksum(context, pac, KRB5_PAC_SERVER_CHECKSUM,
server_key, &server_cksumtype);
if (ret != 0)
return ret;
ret = k5_insert_checksum(context, pac, KRB5_PAC_PRIVSVR_CHECKSUM,
privsvr_key, &privsvr_cksumtype);
if (ret != 0)
return ret;
/* Now, encode the PAC header so that the checksums will include it */
ret = k5_pac_encode_header(context, pac);
if (ret != 0)
return ret;
/* Generate the server checksum over the entire PAC */
ret = k5_pac_locate_buffer(context, pac, KRB5_PAC_SERVER_CHECKSUM,
&server_cksum);
if (ret != 0)
return ret;
assert(server_cksum.length > PAC_SIGNATURE_DATA_LENGTH);
iov[0].flags = KRB5_CRYPTO_TYPE_DATA;
iov[0].data = pac->data;
iov[1].flags = KRB5_CRYPTO_TYPE_CHECKSUM;
iov[1].data.data = server_cksum.data + PAC_SIGNATURE_DATA_LENGTH;
iov[1].data.length = server_cksum.length - PAC_SIGNATURE_DATA_LENGTH;
ret = krb5_c_make_checksum_iov(context, server_cksumtype,
server_key, KRB5_KEYUSAGE_APP_DATA_CKSUM,
iov, sizeof(iov)/sizeof(iov[0]));
if (ret != 0)
return ret;
/* Generate the privsvr checksum over the server checksum buffer */
ret = k5_pac_locate_buffer(context, pac, KRB5_PAC_PRIVSVR_CHECKSUM,
&privsvr_cksum);
if (ret != 0)
return ret;
assert(privsvr_cksum.length > PAC_SIGNATURE_DATA_LENGTH);
iov[0].flags = KRB5_CRYPTO_TYPE_DATA;
iov[0].data.data = server_cksum.data + PAC_SIGNATURE_DATA_LENGTH;
iov[0].data.length = server_cksum.length - PAC_SIGNATURE_DATA_LENGTH;
iov[1].flags = KRB5_CRYPTO_TYPE_CHECKSUM;
iov[1].data.data = privsvr_cksum.data + PAC_SIGNATURE_DATA_LENGTH;
iov[1].data.length = privsvr_cksum.length - PAC_SIGNATURE_DATA_LENGTH;
ret = krb5_c_make_checksum_iov(context, privsvr_cksumtype,
privsvr_key, KRB5_KEYUSAGE_APP_DATA_CKSUM,
iov, sizeof(iov)/sizeof(iov[0]));
if (ret != 0)
return ret;
data->data = k5memdup(pac->data.data, pac->data.length, &ret);
if (data->data == NULL)
return ret;
data->length = pac->data.length;
memset(pac->data.data, 0,
PACTYPE_LENGTH + (pac->pac->cBuffers * PAC_INFO_BUFFER_LENGTH));
return 0;
}
static krb5_error_code
k5_pac_verify_server_checksum(krb5_context context,
const krb5_pac pac,
const krb5_keyblock *server)
{
krb5_error_code ret;
krb5_data pac_data; /* PAC with zeroed checksums */
krb5_checksum checksum;
krb5_data checksum_data;
krb5_boolean valid;
krb5_octet *p;
ret = k5_pac_locate_buffer(context, pac,
PAC_SERVER_CHECKSUM, &checksum_data);
if (ret != 0)
return ret;
if (checksum_data.length < PAC_SIGNATURE_DATA_LENGTH)
return KRB5_BAD_MSIZE;
p = (krb5_octet *)checksum_data.data;
checksum.checksum_type = load_32_le(p);
checksum.length = checksum_data.length - PAC_SIGNATURE_DATA_LENGTH;
checksum.contents = p + PAC_SIGNATURE_DATA_LENGTH;
if (!krb5_c_is_keyed_cksum(checksum.checksum_type))
return KRB5KRB_AP_ERR_INAPP_CKSUM;
pac_data.length = pac->data.length;
pac_data.data = malloc(pac->data.length);
if (pac_data.data == NULL)
return ENOMEM;
memcpy(pac_data.data, pac->data.data, pac->data.length);
/* Zero out both checksum buffers */
ret = k5_pac_zero_signature(context, pac,
PAC_SERVER_CHECKSUM, &pac_data);
if (ret != 0) {
free(pac_data.data);
return ret;
}
ret = k5_pac_zero_signature(context, pac,
PAC_PRIVSVR_CHECKSUM, &pac_data);
if (ret != 0) {
free(pac_data.data);
return ret;
}
ret = krb5_c_verify_checksum(context, server,
KRB5_KEYUSAGE_APP_DATA_CKSUM,
&pac_data, &checksum, &valid);
free(pac_data.data);
if (ret != 0) {
return ret;
}
if (valid == FALSE)
ret = KRB5KRB_AP_ERR_BAD_INTEGRITY;
return ret;
}
/*
* Add a buffer to the provided PAC and update header.
*/
krb5_error_code
k5_pac_add_buffer(krb5_context context,
krb5_pac pac,
krb5_ui_4 type,
const krb5_data *data,
krb5_boolean zerofill,
krb5_data *out_data)
{
PACTYPE *header;
size_t header_len, i, pad = 0;
char *pac_data;
assert((data->data == NULL) == zerofill);
/* Check there isn't already a buffer of this type */
if (k5_pac_locate_buffer(context, pac, type, NULL) == 0) {
return EEXIST;
}
header = (PACTYPE *)realloc(pac->pac,
sizeof(PACTYPE) +
(pac->pac->cBuffers * sizeof(PAC_INFO_BUFFER)));
if (header == NULL) {
return ENOMEM;
}
pac->pac = header;
header_len = PACTYPE_LENGTH + (pac->pac->cBuffers * PAC_INFO_BUFFER_LENGTH);
if (data->length % PAC_ALIGNMENT)
pad = PAC_ALIGNMENT - (data->length % PAC_ALIGNMENT);
pac_data = realloc(pac->data.data,
pac->data.length + PAC_INFO_BUFFER_LENGTH + data->length + pad);
if (pac_data == NULL) {
return ENOMEM;
}
pac->data.data = pac_data;
/* Update offsets of existing buffers */
for (i = 0; i < pac->pac->cBuffers; i++)
pac->pac->Buffers[i].Offset += PAC_INFO_BUFFER_LENGTH;
/* Make room for new PAC_INFO_BUFFER */
memmove(pac->data.data + header_len + PAC_INFO_BUFFER_LENGTH,
pac->data.data + header_len,
pac->data.length - header_len);
memset(pac->data.data + header_len, 0, PAC_INFO_BUFFER_LENGTH);
/* Initialise new PAC_INFO_BUFFER */
pac->pac->Buffers[i].ulType = type;
pac->pac->Buffers[i].cbBufferSize = data->length;
pac->pac->Buffers[i].Offset = pac->data.length + PAC_INFO_BUFFER_LENGTH;
assert((pac->pac->Buffers[i].Offset % PAC_ALIGNMENT) == 0);
/* Copy in new PAC data and zero padding bytes */
if (zerofill)
memset(pac->data.data + pac->pac->Buffers[i].Offset, 0, data->length);
else
memcpy(pac->data.data + pac->pac->Buffers[i].Offset, data->data, data->length);
memset(pac->data.data + pac->pac->Buffers[i].Offset + data->length, 0, pad);
pac->pac->cBuffers++;
pac->data.length += PAC_INFO_BUFFER_LENGTH + data->length + pad;
if (out_data != NULL) {
out_data->data = pac->data.data + pac->pac->Buffers[i].Offset;
out_data->length = data->length;
}
pac->verified = FALSE;
return 0;
}
