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bbaae5f43c3743a91cc3cd9833b2126c6e5493ef
heimdal/lib/krb5/pac.c
Nicolas Williams f38089257b Misc fixes (coverity)
2016-11-20 17:43:51 -06:00

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/*
* Copyright (c) 2006 - 2007 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* 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.
*
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE 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 INSTITUTE 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.
*/
#include "krb5_locl.h"
#include <wind.h>
struct PAC_INFO_BUFFER {
uint32_t type;
uint32_t buffersize;
uint32_t offset_hi;
uint32_t offset_lo;
};
struct PACTYPE {
uint32_t numbuffers;
uint32_t version;
struct PAC_INFO_BUFFER buffers[1];
};
struct krb5_pac_data {
struct PACTYPE *pac;
krb5_data data;
struct PAC_INFO_BUFFER *server_checksum;
struct PAC_INFO_BUFFER *privsvr_checksum;
struct PAC_INFO_BUFFER *logon_name;
};
#define PAC_ALIGNMENT 8
#define PACTYPE_SIZE 8
#define PAC_INFO_BUFFER_SIZE 16
#define PAC_SERVER_CHECKSUM 6
#define PAC_PRIVSVR_CHECKSUM 7
#define PAC_LOGON_NAME 10
#define PAC_CONSTRAINED_DELEGATION 11
#define CHECK(r,f,l) \
do { \
if (((r) = f ) != 0) { \
krb5_clear_error_message(context); \
goto l; \
} \
} while(0)
static const char zeros[PAC_ALIGNMENT] = { 0 };
/*
* HMAC-MD5 checksum over any key (needed for the PAC routines)
*/
static krb5_error_code
HMAC_MD5_any_checksum(krb5_context context,
const krb5_keyblock *key,
const void *data,
size_t len,
unsigned usage,
Checksum *result)
{
struct _krb5_key_data local_key;
krb5_error_code ret;
memset(&local_key, 0, sizeof(local_key));
ret = krb5_copy_keyblock(context, key, &local_key.key);
if (ret)
return ret;
ret = krb5_data_alloc (&result->checksum, 16);
if (ret) {
krb5_free_keyblock(context, local_key.key);
return ret;
}
result->cksumtype = CKSUMTYPE_HMAC_MD5;
ret = _krb5_HMAC_MD5_checksum(context, &local_key, data, len, usage, result);
if (ret)
krb5_data_free(&result->checksum);
krb5_free_keyblock(context, local_key.key);
return ret;
}
/*
*
*/
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_pac_parse(krb5_context context, const void *ptr, size_t len,
krb5_pac *pac)
{
krb5_error_code ret;
krb5_pac p;
krb5_storage *sp = NULL;
uint32_t i, tmp, tmp2, header_end;
p = calloc(1, sizeof(*p));
if (p == NULL) {
ret = krb5_enomem(context);
goto out;
}
sp = krb5_storage_from_readonly_mem(ptr, len);
if (sp == NULL) {
ret = krb5_enomem(context);
goto out;
}
krb5_storage_set_flags(sp, KRB5_STORAGE_BYTEORDER_LE);
CHECK(ret, krb5_ret_uint32(sp, &tmp), out);
CHECK(ret, krb5_ret_uint32(sp, &tmp2), out);
if (tmp < 1) {
ret = EINVAL; /* Too few buffers */
krb5_set_error_message(context, ret, N_("PAC have too few buffer", ""));
goto out;
}
if (tmp2 != 0) {
ret = EINVAL; /* Wrong version */
krb5_set_error_message(context, ret,
N_("PAC have wrong version %d", ""),
(int)tmp2);
goto out;
}
p->pac = calloc(1,
sizeof(*p->pac) + (sizeof(p->pac->buffers[0]) * (tmp - 1)));
if (p->pac == NULL) {
ret = krb5_enomem(context);
goto out;
}
p->pac->numbuffers = tmp;
p->pac->version = tmp2;
header_end = PACTYPE_SIZE + (PAC_INFO_BUFFER_SIZE * p->pac->numbuffers);
if (header_end > len) {
ret = EINVAL;
goto out;
}
for (i = 0; i < p->pac->numbuffers; i++) {
CHECK(ret, krb5_ret_uint32(sp, &p->pac->buffers[i].type), out);
CHECK(ret, krb5_ret_uint32(sp, &p->pac->buffers[i].buffersize), out);
CHECK(ret, krb5_ret_uint32(sp, &p->pac->buffers[i].offset_lo), out);
CHECK(ret, krb5_ret_uint32(sp, &p->pac->buffers[i].offset_hi), out);
/* consistency checks */
if (p->pac->buffers[i].offset_lo & (PAC_ALIGNMENT - 1)) {
ret = EINVAL;
krb5_set_error_message(context, ret,
N_("PAC out of allignment", ""));
goto out;
}
if (p->pac->buffers[i].offset_hi) {
ret = EINVAL;
krb5_set_error_message(context, ret,
N_("PAC high offset set", ""));
goto out;
}
if (p->pac->buffers[i].offset_lo > len) {
ret = EINVAL;
krb5_set_error_message(context, ret,
N_("PAC offset off end", ""));
goto out;
}
if (p->pac->buffers[i].offset_lo < header_end) {
ret = EINVAL;
krb5_set_error_message(context, ret,
N_("PAC offset inside header: %lu %lu", ""),
(unsigned long)p->pac->buffers[i].offset_lo,
(unsigned long)header_end);
goto out;
}
if (p->pac->buffers[i].buffersize > len - p->pac->buffers[i].offset_lo){
ret = EINVAL;
krb5_set_error_message(context, ret, N_("PAC length off end", ""));
goto out;
}
/* let save pointer to data we need later */
if (p->pac->buffers[i].type == PAC_SERVER_CHECKSUM) {
if (p->server_checksum) {
ret = EINVAL;
krb5_set_error_message(context, ret,
N_("PAC have two server checksums", ""));
goto out;
}
p->server_checksum = &p->pac->buffers[i];
} else if (p->pac->buffers[i].type == PAC_PRIVSVR_CHECKSUM) {
if (p->privsvr_checksum) {
ret = EINVAL;
krb5_set_error_message(context, ret,
N_("PAC have two KDC checksums", ""));
goto out;
}
p->privsvr_checksum = &p->pac->buffers[i];
} else if (p->pac->buffers[i].type == PAC_LOGON_NAME) {
if (p->logon_name) {
ret = EINVAL;
krb5_set_error_message(context, ret,
N_("PAC have two logon names", ""));
goto out;
}
p->logon_name = &p->pac->buffers[i];
}
}
ret = krb5_data_copy(&p->data, ptr, len);
if (ret)
goto out;
krb5_storage_free(sp);
*pac = p;
return 0;
out:
if (sp)
krb5_storage_free(sp);
if (p) {
if (p->pac)
free(p->pac);
free(p);
}
*pac = NULL;
return ret;
}
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_pac_init(krb5_context context, krb5_pac *pac)
{
krb5_error_code ret;
krb5_pac p;
p = calloc(1, sizeof(*p));
if (p == NULL) {
return krb5_enomem(context);
}
p->pac = calloc(1, sizeof(*p->pac));
if (p->pac == NULL) {
free(p);
return krb5_enomem(context);
}
ret = krb5_data_alloc(&p->data, PACTYPE_SIZE);
if (ret) {
free (p->pac);
free(p);
return krb5_enomem(context);
}
*pac = p;
return 0;
}
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_pac_add_buffer(krb5_context context, krb5_pac p,
uint32_t type, const krb5_data *data)
{
krb5_error_code ret;
void *ptr;
size_t len, offset, header_end, old_end;
uint32_t i;
len = p->pac->numbuffers;
ptr = realloc(p->pac,
sizeof(*p->pac) + (sizeof(p->pac->buffers[0]) * len));
if (ptr == NULL)
return krb5_enomem(context);
p->pac = ptr;
for (i = 0; i < len; i++)
p->pac->buffers[i].offset_lo += PAC_INFO_BUFFER_SIZE;
offset = p->data.length + PAC_INFO_BUFFER_SIZE;
p->pac->buffers[len].type = type;
p->pac->buffers[len].buffersize = data->length;
p->pac->buffers[len].offset_lo = offset;
p->pac->buffers[len].offset_hi = 0;
old_end = p->data.length;
len = p->data.length + data->length + PAC_INFO_BUFFER_SIZE;
if (len < p->data.length) {
krb5_set_error_message(context, EINVAL, "integer overrun");
return EINVAL;
}
/* align to PAC_ALIGNMENT */
len = ((len + PAC_ALIGNMENT - 1) / PAC_ALIGNMENT) * PAC_ALIGNMENT;
ret = krb5_data_realloc(&p->data, len);
if (ret) {
krb5_set_error_message(context, ret, N_("malloc: out of memory", ""));
return ret;
}
/*
* make place for new PAC INFO BUFFER header
*/
header_end = PACTYPE_SIZE + (PAC_INFO_BUFFER_SIZE * p->pac->numbuffers);
memmove((unsigned char *)p->data.data + header_end + PAC_INFO_BUFFER_SIZE,
(unsigned char *)p->data.data + header_end ,
old_end - header_end);
memset((unsigned char *)p->data.data + header_end, 0, PAC_INFO_BUFFER_SIZE);
/*
* copy in new data part
*/
memcpy((unsigned char *)p->data.data + offset,
data->data, data->length);
memset((unsigned char *)p->data.data + offset + data->length,
0, p->data.length - offset - data->length);
p->pac->numbuffers += 1;
return 0;
}
/**
* Get the PAC buffer of specific type from the pac.
*
* @param context Kerberos 5 context.
* @param p the pac structure returned by krb5_pac_parse().
* @param type type of buffer to get
* @param data return data, free with krb5_data_free().
*
* @return Returns 0 to indicate success. Otherwise an kerberos et
* error code is returned, see krb5_get_error_message().
*
* @ingroup krb5_pac
*/
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_pac_get_buffer(krb5_context context, krb5_pac p,
uint32_t type, krb5_data *data)
{
krb5_error_code ret;
uint32_t i;
for (i = 0; i < p->pac->numbuffers; i++) {
const size_t len = p->pac->buffers[i].buffersize;
const size_t offset = p->pac->buffers[i].offset_lo;
if (p->pac->buffers[i].type != type)
continue;
ret = krb5_data_copy(data, (unsigned char *)p->data.data + offset, len);
if (ret) {
krb5_set_error_message(context, ret, N_("malloc: out of memory", ""));
return ret;
}
return 0;
}
krb5_set_error_message(context, ENOENT, "No PAC buffer of type %lu was found",
(unsigned long)type);
return ENOENT;
}
/*
*
*/
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_pac_get_types(krb5_context context,
krb5_pac p,
size_t *len,
uint32_t **types)
{
size_t i;
*types = calloc(p->pac->numbuffers, sizeof(**types));
if (*types == NULL) {
*len = 0;
return krb5_enomem(context);
}
for (i = 0; i < p->pac->numbuffers; i++)
(*types)[i] = p->pac->buffers[i].type;
*len = p->pac->numbuffers;
return 0;
}
/*
*
*/
KRB5_LIB_FUNCTION void KRB5_LIB_CALL
krb5_pac_free(krb5_context context, krb5_pac pac)
{
krb5_data_free(&pac->data);
free(pac->pac);
free(pac);
}
/*
*
*/
static krb5_error_code
verify_checksum(krb5_context context,
const struct PAC_INFO_BUFFER *sig,
const krb5_data *data,
void *ptr, size_t len,
const krb5_keyblock *key)
{
krb5_storage *sp = NULL;
uint32_t type;
krb5_error_code ret;
Checksum cksum;
memset(&cksum, 0, sizeof(cksum));
sp = krb5_storage_from_mem((char *)data->data + sig->offset_lo,
sig->buffersize);
if (sp == NULL)
return krb5_enomem(context);
krb5_storage_set_flags(sp, KRB5_STORAGE_BYTEORDER_LE);
CHECK(ret, krb5_ret_uint32(sp, &type), out);
cksum.cksumtype = type;
cksum.checksum.length =
sig->buffersize - krb5_storage_seek(sp, 0, SEEK_CUR);
cksum.checksum.data = malloc(cksum.checksum.length);
if (cksum.checksum.data == NULL) {
ret = krb5_enomem(context);
goto out;
}
ret = krb5_storage_read(sp, cksum.checksum.data, cksum.checksum.length);
if (ret != (int)cksum.checksum.length) {
ret = EINVAL;
krb5_set_error_message(context, ret, "PAC checksum missing checksum");
goto out;
}
if (!krb5_checksum_is_keyed(context, cksum.cksumtype)) {
ret = EINVAL;
krb5_set_error_message(context, ret, "Checksum type %d not keyed",
cksum.cksumtype);
goto out;
}
/* If the checksum is HMAC-MD5, the checksum type is not tied to
* the key type, instead the HMAC-MD5 checksum is applied blindly
* on whatever key is used for this connection, avoiding issues
* with unkeyed checksums on des-cbc-md5 and des-cbc-crc. See
* http://comments.gmane.org/gmane.comp.encryption.kerberos.devel/8743
* for the same issue in MIT, and
* http://blogs.msdn.com/b/openspecification/archive/2010/01/01/verifying-the-server-signature-in-kerberos-privilege-account-certificate.aspx
* for Microsoft's explaination */
if (cksum.cksumtype == CKSUMTYPE_HMAC_MD5) {
Checksum local_checksum;
memset(&local_checksum, 0, sizeof(local_checksum));
ret = HMAC_MD5_any_checksum(context, key, ptr, len,
KRB5_KU_OTHER_CKSUM, &local_checksum);
if (ret != 0 || krb5_data_ct_cmp(&local_checksum.checksum, &cksum.checksum) != 0) {
ret = KRB5KRB_AP_ERR_BAD_INTEGRITY;
krb5_set_error_message(context, ret,
N_("PAC integrity check failed for "
"hmac-md5 checksum", ""));
}
krb5_data_free(&local_checksum.checksum);
} else {
krb5_crypto crypto = NULL;
ret = krb5_crypto_init(context, key, 0, &crypto);
if (ret)
goto out;
ret = krb5_verify_checksum(context, crypto, KRB5_KU_OTHER_CKSUM,
ptr, len, &cksum);
krb5_crypto_destroy(context, crypto);
}
free(cksum.checksum.data);
krb5_storage_free(sp);
return ret;
out:
if (cksum.checksum.data)
free(cksum.checksum.data);
if (sp)
krb5_storage_free(sp);
return ret;
}
static krb5_error_code
create_checksum(krb5_context context,
const krb5_keyblock *key,
uint32_t cksumtype,
void *data, size_t datalen,
void *sig, size_t siglen)
{
krb5_crypto crypto = NULL;
krb5_error_code ret;
Checksum cksum;
/* If the checksum is HMAC-MD5, the checksum type is not tied to
* the key type, instead the HMAC-MD5 checksum is applied blindly
* on whatever key is used for this connection, avoiding issues
* with unkeyed checksums on des-cbc-md5 and des-cbc-crc. See
* http://comments.gmane.org/gmane.comp.encryption.kerberos.devel/8743
* for the same issue in MIT, and
* http://blogs.msdn.com/b/openspecification/archive/2010/01/01/verifying-the-server-signature-in-kerberos-privilege-account-certificate.aspx
* for Microsoft's explaination */
if (cksumtype == (uint32_t)CKSUMTYPE_HMAC_MD5) {
ret = HMAC_MD5_any_checksum(context, key, data, datalen,
KRB5_KU_OTHER_CKSUM, &cksum);
if (ret)
return ret;
} else {
ret = krb5_crypto_init(context, key, 0, &crypto);
if (ret)
return ret;
ret = krb5_create_checksum(context, crypto, KRB5_KU_OTHER_CKSUM, 0,
data, datalen, &cksum);
krb5_crypto_destroy(context, crypto);
if (ret)
return ret;
}
if (cksum.checksum.length != siglen) {
krb5_set_error_message(context, EINVAL, "pac checksum wrong length");
free_Checksum(&cksum);
return EINVAL;
}
memcpy(sig, cksum.checksum.data, siglen);
free_Checksum(&cksum);
return 0;
}
/*
*
*/
#define NTTIME_EPOCH 0x019DB1DED53E8000LL
static uint64_t
unix2nttime(time_t unix_time)
{
long long wt;
wt = unix_time * (uint64_t)10000000 + (uint64_t)NTTIME_EPOCH;
return wt;
}
static krb5_error_code
verify_logonname(krb5_context context,
const struct PAC_INFO_BUFFER *logon_name,
const krb5_data *data,
time_t authtime,
krb5_const_principal principal)
{
krb5_error_code ret;
uint32_t time1, time2;
krb5_storage *sp;
uint16_t len;
char *s = NULL;
char *principal_string = NULL;
char *logon_string = NULL;
sp = krb5_storage_from_readonly_mem((const char *)data->data + logon_name->offset_lo,
logon_name->buffersize);
if (sp == NULL)
return krb5_enomem(context);
krb5_storage_set_flags(sp, KRB5_STORAGE_BYTEORDER_LE);
CHECK(ret, krb5_ret_uint32(sp, &time1), out);
CHECK(ret, krb5_ret_uint32(sp, &time2), out);
{
uint64_t t1, t2;
t1 = unix2nttime(authtime);
t2 = ((uint64_t)time2 << 32) | time1;
/*
* When neither the ticket nor the PAC set an explicit authtime,
* both times are zero, but relative to different time scales.
* So we must compare "not set" values without converting to a
* common time reference.
*/
if (t1 != t2 && (t2 != 0 && authtime != 0)) {
krb5_storage_free(sp);
krb5_set_error_message(context, EINVAL, "PAC timestamp mismatch");
return EINVAL;
}
}
CHECK(ret, krb5_ret_uint16(sp, &len), out);
if (len == 0) {
krb5_storage_free(sp);
krb5_set_error_message(context, EINVAL, "PAC logon name length missing");
return EINVAL;
}
s = malloc(len);
if (s == NULL) {
krb5_storage_free(sp);
return krb5_enomem(context);
}
ret = krb5_storage_read(sp, s, len);
if (ret != len) {
krb5_storage_free(sp);
krb5_set_error_message(context, EINVAL, "Failed to read PAC logon name");
return EINVAL;
}
krb5_storage_free(sp);
{
size_t ucs2len = len / 2;
uint16_t *ucs2;
size_t u8len;
unsigned int flags = WIND_RW_LE;
ucs2 = malloc(sizeof(ucs2[0]) * ucs2len);
if (ucs2 == NULL)
return krb5_enomem(context);
ret = wind_ucs2read(s, len, &flags, ucs2, &ucs2len);
free(s);
if (ret) {
free(ucs2);
krb5_set_error_message(context, ret, "Failed to convert string to UCS-2");
return ret;
}
ret = wind_ucs2utf8_length(ucs2, ucs2len, &u8len);
if (ret) {
free(ucs2);
krb5_set_error_message(context, ret, "Failed to count length of UCS-2 string");
return ret;
}
u8len += 1; /* Add space for NUL */
logon_string = malloc(u8len);
if (logon_string == NULL) {
free(ucs2);
return krb5_enomem(context);
}
ret = wind_ucs2utf8(ucs2, ucs2len, logon_string, &u8len);
free(ucs2);
if (ret) {
free(logon_string);
krb5_set_error_message(context, ret, "Failed to convert to UTF-8");
return ret;
}
}
ret = krb5_unparse_name_flags(context, principal,
KRB5_PRINCIPAL_UNPARSE_NO_REALM |
KRB5_PRINCIPAL_UNPARSE_DISPLAY,
&principal_string);
if (ret) {
free(logon_string);
return ret;
}
ret = strcmp(logon_string, principal_string);
if (ret != 0) {
ret = EINVAL;
krb5_set_error_message(context, ret, "PAC logon name [%s] mismatch principal name [%s]",
logon_string, principal_string);
}
free(logon_string);
free(principal_string);
return ret;
out:
return ret;
}
/*
*
*/
static krb5_error_code
build_logon_name(krb5_context context,
time_t authtime,
krb5_const_principal principal,
krb5_data *logon)
{
krb5_error_code ret;
krb5_storage *sp;
uint64_t t;
char *s, *s2;
size_t s2_len;
t = unix2nttime(authtime);
krb5_data_zero(logon);
sp = krb5_storage_emem();
if (sp == NULL)
return krb5_enomem(context);
krb5_storage_set_flags(sp, KRB5_STORAGE_BYTEORDER_LE);
CHECK(ret, krb5_store_uint32(sp, t & 0xffffffff), out);
CHECK(ret, krb5_store_uint32(sp, t >> 32), out);
ret = krb5_unparse_name_flags(context, principal,
KRB5_PRINCIPAL_UNPARSE_NO_REALM |
KRB5_PRINCIPAL_UNPARSE_DISPLAY,
&s);
if (ret)
goto out;
{
size_t ucs2_len;
uint16_t *ucs2;
unsigned int flags;
ret = wind_utf8ucs2_length(s, &ucs2_len);
if (ret) {
krb5_set_error_message(context, ret, "Principal %s is not valid UTF-8", s);
free(s);
return ret;
}
ucs2 = malloc(sizeof(ucs2[0]) * ucs2_len);
if (ucs2 == NULL) {
free(s);
return krb5_enomem(context);
}
ret = wind_utf8ucs2(s, ucs2, &ucs2_len);
if (ret) {
free(ucs2);
krb5_set_error_message(context, ret, "Principal %s is not valid UTF-8", s);
free(s);
return ret;
} else
free(s);
s2_len = (ucs2_len + 1) * 2;
s2 = malloc(s2_len);
if (s2 == NULL) {
free(ucs2);
return krb5_enomem(context);
}
flags = WIND_RW_LE;
ret = wind_ucs2write(ucs2, ucs2_len,
&flags, s2, &s2_len);
free(ucs2);
if (ret) {
free(s2);
krb5_set_error_message(context, ret, "Failed to write to UCS-2 buffer");
return ret;
}
/*
* we do not want zero termination
*/
s2_len = ucs2_len * 2;
}
CHECK(ret, krb5_store_uint16(sp, s2_len), out);
ret = krb5_storage_write(sp, s2, s2_len);
free(s2);
if (ret != (int)s2_len) {
ret = krb5_enomem(context);
goto out;
}
ret = krb5_storage_to_data(sp, logon);
if (ret)
goto out;
krb5_storage_free(sp);
return 0;
out:
krb5_storage_free(sp);
return ret;
}
/**
* Verify the PAC.
*
* @param context Kerberos 5 context.
* @param pac the pac structure returned by krb5_pac_parse().
* @param authtime The time of the ticket the PAC belongs to.
* @param principal the principal to verify.
* @param server The service key, most always be given.
* @param privsvr The KDC key, may be given.
* @return Returns 0 to indicate success. Otherwise an kerberos et
* error code is returned, see krb5_get_error_message().
*
* @ingroup krb5_pac
*/
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_pac_verify(krb5_context context,
const krb5_pac pac,
time_t authtime,
krb5_const_principal principal,
const krb5_keyblock *server,
const krb5_keyblock *privsvr)
{
krb5_error_code ret;
if (pac->server_checksum == NULL) {
krb5_set_error_message(context, EINVAL, "PAC missing server checksum");
return EINVAL;
}
if (pac->privsvr_checksum == NULL) {
krb5_set_error_message(context, EINVAL, "PAC missing kdc checksum");
return EINVAL;
}
if (pac->logon_name == NULL) {
krb5_set_error_message(context, EINVAL, "PAC missing logon name");
return EINVAL;
}
ret = verify_logonname(context,
pac->logon_name,
&pac->data,
authtime,
principal);
if (ret)
return ret;
/*
* in the service case, clean out data option of the privsvr and
* server checksum before checking the checksum.
*/
{
krb5_data *copy;
if (pac->server_checksum->buffersize < 4 ||
pac->privsvr_checksum->buffersize < 4)
return EINVAL;
ret = krb5_copy_data(context, &pac->data, &copy);
if (ret)
return ret;
memset((char *)copy->data + pac->server_checksum->offset_lo + 4,
0,
pac->server_checksum->buffersize - 4);
memset((char *)copy->data + pac->privsvr_checksum->offset_lo + 4,
0,
pac->privsvr_checksum->buffersize - 4);
ret = verify_checksum(context,
pac->server_checksum,
&pac->data,
copy->data,
copy->length,
server);
krb5_free_data(context, copy);
if (ret)
return ret;
}
if (privsvr) {
/* The priv checksum covers the server checksum */
ret = verify_checksum(context,
pac->privsvr_checksum,
&pac->data,
(char *)pac->data.data
+ pac->server_checksum->offset_lo + 4,
pac->server_checksum->buffersize - 4,
privsvr);
if (ret)
return ret;
}
return 0;
}
/*
*
*/
static krb5_error_code
fill_zeros(krb5_context context, krb5_storage *sp, size_t len)
{
ssize_t sret;
size_t l;
while (len) {
l = len;
if (l > sizeof(zeros))
l = sizeof(zeros);
sret = krb5_storage_write(sp, zeros, l);
if (sret <= 0)
return krb5_enomem(context);
len -= sret;
}
return 0;
}
static krb5_error_code
pac_checksum(krb5_context context,
const krb5_keyblock *key,
uint32_t *cksumtype,
size_t *cksumsize)
{
krb5_cksumtype cktype;
krb5_error_code ret;
krb5_crypto crypto = NULL;
ret = krb5_crypto_init(context, key, 0, &crypto);
if (ret)
return ret;
ret = krb5_crypto_get_checksum_type(context, crypto, &cktype);
krb5_crypto_destroy(context, crypto);
if (ret)
return ret;
if (krb5_checksum_is_keyed(context, cktype) == FALSE) {
*cksumtype = CKSUMTYPE_HMAC_MD5;
*cksumsize = 16;
}
ret = krb5_checksumsize(context, cktype, cksumsize);
if (ret)
return ret;
*cksumtype = (uint32_t)cktype;
return 0;
}
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
_krb5_pac_sign(krb5_context context,
krb5_pac p,
time_t authtime,
krb5_principal principal,
const krb5_keyblock *server_key,
const krb5_keyblock *priv_key,
krb5_data *data)
{
krb5_error_code ret;
krb5_storage *sp = NULL, *spdata = NULL;
uint32_t end;
size_t server_size, priv_size;
uint32_t server_offset = 0, priv_offset = 0;
uint32_t server_cksumtype = 0, priv_cksumtype = 0;
int num = 0;
size_t i;
krb5_data logon, d;
krb5_data_zero(&logon);
for (i = 0; i < p->pac->numbuffers; i++) {
if (p->pac->buffers[i].type == PAC_SERVER_CHECKSUM) {
if (p->server_checksum == NULL) {
p->server_checksum = &p->pac->buffers[i];
}
if (p->server_checksum != &p->pac->buffers[i]) {
ret = EINVAL;
krb5_set_error_message(context, ret,
N_("PAC have two server checksums", ""));
goto out;
}
} else if (p->pac->buffers[i].type == PAC_PRIVSVR_CHECKSUM) {
if (p->privsvr_checksum == NULL) {
p->privsvr_checksum = &p->pac->buffers[i];
}
if (p->privsvr_checksum != &p->pac->buffers[i]) {
ret = EINVAL;
krb5_set_error_message(context, ret,
N_("PAC have two KDC checksums", ""));
goto out;
}
} else if (p->pac->buffers[i].type == PAC_LOGON_NAME) {
if (p->logon_name == NULL) {
p->logon_name = &p->pac->buffers[i];
}
if (p->logon_name != &p->pac->buffers[i]) {
ret = EINVAL;
krb5_set_error_message(context, ret,
N_("PAC have two logon names", ""));
goto out;
}
}
}
if (p->logon_name == NULL)
num++;
if (p->server_checksum == NULL)
num++;
if (p->privsvr_checksum == NULL)
num++;
if (num) {
void *ptr;
ptr = realloc(p->pac, sizeof(*p->pac) + (sizeof(p->pac->buffers[0]) * (p->pac->numbuffers + num - 1)));
if (ptr == NULL)
return krb5_enomem(context);
p->pac = ptr;
if (p->logon_name == NULL) {
p->logon_name = &p->pac->buffers[p->pac->numbuffers++];
memset(p->logon_name, 0, sizeof(*p->logon_name));
p->logon_name->type = PAC_LOGON_NAME;
}
if (p->server_checksum == NULL) {
p->server_checksum = &p->pac->buffers[p->pac->numbuffers++];
memset(p->server_checksum, 0, sizeof(*p->server_checksum));
p->server_checksum->type = PAC_SERVER_CHECKSUM;
}
if (p->privsvr_checksum == NULL) {
p->privsvr_checksum = &p->pac->buffers[p->pac->numbuffers++];
memset(p->privsvr_checksum, 0, sizeof(*p->privsvr_checksum));
p->privsvr_checksum->type = PAC_PRIVSVR_CHECKSUM;
}
}
/* Calculate LOGON NAME */
ret = build_logon_name(context, authtime, principal, &logon);
if (ret)
goto out;
/* Set lengths for checksum */
ret = pac_checksum(context, server_key, &server_cksumtype, &server_size);
if (ret)
goto out;
ret = pac_checksum(context, priv_key, &priv_cksumtype, &priv_size);
if (ret)
goto out;
/* Encode PAC */
sp = krb5_storage_emem();
if (sp == NULL)
return krb5_enomem(context);
krb5_storage_set_flags(sp, KRB5_STORAGE_BYTEORDER_LE);
spdata = krb5_storage_emem();
if (spdata == NULL) {
krb5_storage_free(sp);
return krb5_enomem(context);
}
krb5_storage_set_flags(spdata, KRB5_STORAGE_BYTEORDER_LE);
CHECK(ret, krb5_store_uint32(sp, p->pac->numbuffers), out);
CHECK(ret, krb5_store_uint32(sp, p->pac->version), out);
end = PACTYPE_SIZE + (PAC_INFO_BUFFER_SIZE * p->pac->numbuffers);
for (i = 0; i < p->pac->numbuffers; i++) {
uint32_t len;
size_t sret;
void *ptr = NULL;
/* store data */
if (p->pac->buffers[i].type == PAC_SERVER_CHECKSUM) {
len = server_size + 4;
server_offset = end + 4;
CHECK(ret, krb5_store_uint32(spdata, server_cksumtype), out);
CHECK(ret, fill_zeros(context, spdata, server_size), out);
} else if (p->pac->buffers[i].type == PAC_PRIVSVR_CHECKSUM) {
len = priv_size + 4;
priv_offset = end + 4;
CHECK(ret, krb5_store_uint32(spdata, priv_cksumtype), out);
CHECK(ret, fill_zeros(context, spdata, priv_size), out);
} else if (p->pac->buffers[i].type == PAC_LOGON_NAME) {
len = krb5_storage_write(spdata, logon.data, logon.length);
if (logon.length != len) {
ret = EINVAL;
goto out;
}
} else {
len = p->pac->buffers[i].buffersize;
ptr = (char *)p->data.data + p->pac->buffers[i].offset_lo;
sret = krb5_storage_write(spdata, ptr, len);
if (sret != len) {
ret = krb5_enomem(context);
goto out;
}
/* XXX if not aligned, fill_zeros */
}
/* write header */
CHECK(ret, krb5_store_uint32(sp, p->pac->buffers[i].type), out);
CHECK(ret, krb5_store_uint32(sp, len), out);
CHECK(ret, krb5_store_uint32(sp, end), out);
CHECK(ret, krb5_store_uint32(sp, 0), out);
/* advance data endpointer and align */
{
int32_t e;
end += len;
e = ((end + PAC_ALIGNMENT - 1) / PAC_ALIGNMENT) * PAC_ALIGNMENT;
if ((int32_t)end != e) {
CHECK(ret, fill_zeros(context, spdata, e - end), out);
}
end = e;
}
}
/* assert (server_offset != 0 && priv_offset != 0); */
/* export PAC */
ret = krb5_storage_to_data(spdata, &d);
if (ret) {
krb5_set_error_message(context, ret, N_("malloc: out of memory", ""));
goto out;
}
ret = krb5_storage_write(sp, d.data, d.length);
if (ret != (int)d.length) {
krb5_data_free(&d);
ret = krb5_enomem(context);
goto out;
}
krb5_data_free(&d);
ret = krb5_storage_to_data(sp, &d);
if (ret) {
ret = krb5_enomem(context);
goto out;
}
/* sign */
ret = create_checksum(context, server_key, server_cksumtype,
d.data, d.length,
(char *)d.data + server_offset, server_size);
if (ret) {
krb5_data_free(&d);
goto out;
}
ret = create_checksum(context, priv_key, priv_cksumtype,
(char *)d.data + server_offset, server_size,
(char *)d.data + priv_offset, priv_size);
if (ret) {
krb5_data_free(&d);
goto out;
}
/* done */
*data = d;
krb5_data_free(&logon);
krb5_storage_free(sp);
krb5_storage_free(spdata);
return 0;
out:
krb5_data_free(&logon);
if (sp)
krb5_storage_free(sp);
if (spdata)
krb5_storage_free(spdata);
return ret;
}
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