r20640: Commit part 2/2

Update Heimdal to match current lorikeet-heimdal.  This includes
integrated PAC hooks, so Samba doesn't have to handle this any more.

This also brings in the PKINIT code, hence so many new files.

Andrew Bartlett
(This used to be commit 351f7040f7bb73b9a60b22b564686f7c2f98a729)

1 files changed, 1034 insertions, 0 deletions

diff --git a/source4/heimdal/lib/krb5/pac.c b/source4/heimdal/lib/krb5/pac.c
new file mode 100644
index 0000000000..5bc7235459
--- /dev/null
+++ b/source4/heimdal/lib/krb5/pac.c
@@ -0,0 +1,1034 @@
+/*
+ * 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"
+
+RCSID("$Id: pac.c,v 1.13 2007/01/09 11:22:56 lha Exp $");
+
+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 {
+    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 CHECK(r,f,l)						\
+	do {							\
+		if (((r) = f ) != 0) {				\
+			krb5_clear_error_string(context);	\
+			goto l;					\
+		}						\
+	} while(0)
+
+static const char zeros[PAC_ALIGNMENT] = { 0 };
+
+/*
+ *
+ */
+
+krb5_error_code
+krb5_pac_parse(krb5_context context, const void *ptr, size_t len,
+	       struct krb5_pac **pac)
+{
+    krb5_error_code ret;
+    struct krb5_pac *p;
+    krb5_storage *sp = NULL;
+    uint32_t i, tmp, tmp2, header_end;
+
+    p = calloc(1, sizeof(*p));
+    if (p == NULL) {
+	ret = ENOMEM;
+	krb5_set_error_string(context, "out of memory");
+	goto out;
+    }
+
+    sp = krb5_storage_from_readonly_mem(ptr, len);
+    if (sp == NULL) {
+	ret = ENOMEM;
+	krb5_set_error_string(context, "out of memory");
+	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) {
+	krb5_set_error_string(context, "PAC have too few buffer");
+	ret = EINVAL; /* Too few buffers */
+	goto out;
+    }
+    if (tmp2 != 0) {
+	krb5_set_error_string(context, "PAC have wrong version");
+	ret = EINVAL; /* Wrong version */
+	goto out;
+    }
+
+    p->pac = calloc(1, 
+		    sizeof(*p->pac) + (sizeof(p->pac->buffers[0]) * (tmp - 1)));
+    if (p->pac == NULL) {
+	krb5_set_error_string(context, "out of memory");
+	ret = ENOMEM;
+	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)) {
+	    krb5_set_error_string(context, "PAC out of allignment");
+	    ret = EINVAL;
+	    goto out;
+	}
+	if (p->pac->buffers[i].offset_hi) {
+	    krb5_set_error_string(context, "PAC high offset set");
+	    ret = EINVAL;
+	    goto out;
+	}
+	if (p->pac->buffers[i].offset_lo > len) {
+	    krb5_set_error_string(context, "PAC offset off end");
+	    ret = EINVAL;
+	    goto out;
+	}
+	if (p->pac->buffers[i].offset_lo < header_end) {
+	    krb5_set_error_string(context, "PAC offset inside header: %d %d",
+				  p->pac->buffers[i].offset_lo, header_end);
+	    ret = EINVAL;
+	    goto out;
+	}
+	if (p->pac->buffers[i].buffersize > len - p->pac->buffers[i].offset_lo){
+	    krb5_set_error_string(context, "PAC length off end");
+	    ret = EINVAL;
+	    goto out;
+	}
+
+	/* let save pointer to data we need later */
+	if (p->pac->buffers[i].type == PAC_SERVER_CHECKSUM) {
+	    if (p->server_checksum) {
+		krb5_set_error_string(context, "PAC have two server checksums");
+		ret = EINVAL;
+		goto out;
+	    }
+	    p->server_checksum = &p->pac->buffers[i];
+	} else if (p->pac->buffers[i].type == PAC_PRIVSVR_CHECKSUM) {
+	    if (p->privsvr_checksum) {
+		krb5_set_error_string(context, "PAC have two KDC checksums");
+		ret = EINVAL;
+		goto out;
+	    }
+	    p->privsvr_checksum = &p->pac->buffers[i];
+	} else if (p->pac->buffers[i].type == PAC_LOGON_NAME) {
+	    if (p->logon_name) {
+		krb5_set_error_string(context, "PAC have two logon names");
+		ret = EINVAL;
+		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_error_code
+krb5_pac_init(krb5_context context, struct krb5_pac **pac)
+{
+    krb5_error_code ret;
+    struct krb5_pac *p;
+
+    p = calloc(1, sizeof(*p));
+    if (p == NULL) {
+	krb5_set_error_string(context, "out of memory");
+	return ENOMEM;
+    }
+
+    p->pac = calloc(1, sizeof(*p->pac));
+    if (p->pac == NULL) {
+	free(p);
+	krb5_set_error_string(context, "out of memory");
+	return ENOMEM;
+    }
+
+    ret = krb5_data_alloc(&p->data, PACTYPE_SIZE);
+    if (ret) {
+	free (p->pac);
+	free(p);
+	krb5_set_error_string(context, "out of memory");
+	return ret;
+    }
+
+
+    *pac = p;
+    return 0;
+}
+
+krb5_error_code
+krb5_pac_add_buffer(krb5_context context, struct krb5_pac *p,
+		    uint32_t type, const krb5_data *data)
+{
+    krb5_error_code ret;
+    void *ptr;
+    size_t len, offset, header_end;
+    uint32_t i;
+
+    len = p->pac->numbuffers + 1;
+    if (len < p->pac->numbuffers)
+	return EINVAL;
+
+    ptr = realloc(p->pac,
+		  sizeof(*p->pac) + (sizeof(p->pac->buffers[0]) * len));
+    if (ptr == NULL) {
+	krb5_set_error_string(context, "out of memory");
+	return ENOMEM;
+    }
+    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 - 1].type = type;
+    p->pac->buffers[len - 1].buffersize = data->length;
+    p->pac->buffers[len - 1].offset_lo = offset;
+    p->pac->buffers[len - 1].offset_hi = 0;
+
+    len = p->data.length + data->length + PAC_INFO_BUFFER_SIZE;
+    if (len < p->data.length) {
+	krb5_set_error_string(context, "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_string(context, "out of memory");
+	return ret;
+    }
+
+    /* make place for PAC INFO BUFFER header */
+    header_end = PACTYPE_SIZE + (PAC_INFO_BUFFER_SIZE * p->pac->numbuffers);
+    memmove((unsigned char *)p->data.data + header_end,
+	    (unsigned char *)p->data.data + header_end + PAC_INFO_BUFFER_SIZE,
+	    PAC_INFO_BUFFER_SIZE);
+
+    /*
+     *
+     */
+
+    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;
+}
+
+krb5_error_code
+krb5_pac_get_buffer(krb5_context context, struct krb5_pac *p,
+		    uint32_t type, krb5_data *data)
+{
+    krb5_error_code ret;
+    uint32_t i;
+
+    /*
+     * Hide the checksums from external consumers
+     */
+
+    if (type == PAC_PRIVSVR_CHECKSUM || type == PAC_SERVER_CHECKSUM) {
+	ret = krb5_data_alloc(data, 16);
+	if (ret) {
+	    krb5_set_error_string(context, "out of memory");
+	    return ret;
+	}
+	memset(data->data, 0, data->length);
+	return 0;
+    }
+
+    for (i = 0; i < p->pac->numbuffers; i++) {
+	size_t len = p->pac->buffers[i].buffersize;
+	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_string(context, "Out of memory");
+	    return ret;
+	}
+	return 0;
+    }
+    krb5_set_error_string(context, "No PAC buffer of type %lu was found",
+			  (unsigned long)type);
+    return ENOENT;
+}
+
+/*
+ *
+ */
+
+krb5_error_code
+krb5_pac_get_types(krb5_context context,
+		   struct krb5_pac *p,
+		   size_t *len,
+		   uint32_t **types)
+{
+    size_t i;
+
+    *types = calloc(p->pac->numbuffers, sizeof(*types));
+    if (*types == NULL) {
+	*len = 0;
+	krb5_set_error_string(context, "out of memory");
+	return ENOMEM;
+    }
+    for (i = 0; i < p->pac->numbuffers; i++)
+	(*types)[i] = p->pac->buffers[i].type;
+    *len = p->pac->numbuffers;
+
+    return 0;
+}
+
+/*
+ *
+ */
+
+void
+krb5_pac_free(krb5_context context, struct 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_crypto crypto = NULL;
+    krb5_storage *sp = NULL;
+    uint32_t type;
+    krb5_error_code ret;
+    Checksum cksum;
+
+    sp = krb5_storage_from_mem((char *)data->data + sig->offset_lo,
+			       sig->buffersize);
+    if (sp == NULL) {
+	krb5_set_error_string(context, "out of memory");
+	return ENOMEM;
+    }
+    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) {
+	krb5_set_error_string(context, "out of memory");
+	ret = ENOMEM;
+	goto out;
+    }
+    ret = krb5_storage_read(sp, cksum.checksum.data, cksum.checksum.length);
+    if (ret != cksum.checksum.length) {
+	krb5_set_error_string(context, "PAC checksum missing checksum");
+	ret = EINVAL;
+	goto out;
+    }
+
+    if (!krb5_checksum_is_keyed(context, cksum.cksumtype)) {
+	krb5_set_error_string (context, "Checksum type %d not keyed",
+			       cksum.cksumtype);
+	ret = EINVAL;
+	goto out;
+    }
+
+    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);
+    krb5_storage_free(sp);
+
+    return ret;
+
+out:
+    if (sp)
+	krb5_storage_free(sp);
+    if (crypto)
+	krb5_crypto_destroy(context, crypto);
+    return ret;
+}
+
+static krb5_error_code
+create_checksum(krb5_context context,
+		const krb5_keyblock *key,
+		void *data, size_t datalen,
+		void *sig, size_t siglen)
+{
+    krb5_crypto crypto = NULL;
+    krb5_error_code ret;
+    Checksum cksum;
+
+    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_string(context, "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;
+    krb5_principal p2;
+    uint32_t time1, time2;
+    krb5_storage *sp;
+    uint16_t len;
+    char *s;
+
+    sp = krb5_storage_from_readonly_mem((const char *)data->data + logon_name->offset_lo,
+					logon_name->buffersize);
+    if (sp == NULL) {
+	krb5_set_error_string(context, "Out of memory");
+	return ENOMEM;
+    }
+
+    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;
+	if (t1 != t2) {
+	    krb5_storage_free(sp);
+	    krb5_set_error_string(context, "PAC timestamp mismatch");
+	    return EINVAL;
+	}
+    }
+    CHECK(ret, krb5_ret_uint16(sp, &len), out);
+    if (len == 0) {
+	krb5_storage_free(sp);
+	krb5_set_error_string(context, "PAC logon name length missing");
+	return EINVAL;
+    }
+
+    s = malloc(len);
+    if (s == NULL) {
+	krb5_storage_free(sp);
+	krb5_set_error_string(context, "Out of memory");
+	return ENOMEM;
+    }
+    ret = krb5_storage_read(sp, s, len);
+    if (ret != len) {
+	krb5_storage_free(sp);
+	krb5_set_error_string(context, "Failed to read pac logon name");
+	return EINVAL;
+    }
+    krb5_storage_free(sp);
+#if 1 /* cheat for now */
+    {
+	size_t i;
+
+	if (len & 1) {
+	    krb5_set_error_string(context, "PAC logon name malformed");
+	    return EINVAL;
+	}
+
+	for (i = 0; i < len / 2; i++) {
+	    if (s[(i * 2) + 1]) {
+		krb5_set_error_string(context, "PAC logon name not ASCII");
+		return EINVAL;
+	    }
+	    s[i] = s[i * 2];
+	}
+	s[i] = '\0';
+    }
+#else
+    {
+	uint16_t *ucs2;
+	ssize_t ucs2len;
+	size_t u8len;
+
+	ucs2 = malloc(sizeof(ucs2[0]) * len / 2);
+	if (ucs2)
+	    abort();
+	ucs2len = wind_ucs2read(s, len / 2, ucs2);
+	free(s);
+	if (len < 0)
+	    return -1;
+	ret = wind_ucs2toutf8(ucs2, ucs2len, NULL, &u8len);
+	if (ret < 0)
+	    abort();
+	s = malloc(u8len + 1);
+	if (s == NULL)
+	    abort();
+	wind_ucs2toutf8(ucs2, ucs2len, s, &u8len);
+	free(ucs2);
+    }
+#endif
+    ret = krb5_parse_name_flags(context, s, KRB5_PRINCIPAL_PARSE_NO_REALM, &p2);
+    free(s);
+    if (ret)
+	return ret;
+    
+    if (krb5_principal_compare_any_realm(context, principal, p2) != TRUE) {
+	krb5_set_error_string(context, "PAC logon name mismatch");
+	ret = EINVAL;
+    }
+    krb5_free_principal(context, p2);
+    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 i, len;
+
+    t = unix2nttime(authtime);
+
+    krb5_data_zero(logon);
+
+    sp = krb5_storage_emem();
+    if (sp == NULL) {
+	krb5_set_error_string(context, "out of memory");
+	return ENOMEM;
+    }
+    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, &s);
+    if (ret)
+	goto out;
+
+    len = strlen(s);
+    
+    CHECK(ret, krb5_store_uint16(sp, len * 2), out);
+
+#if 1 /* cheat for now */
+    s2 = malloc(len * 2);
+    if (s2 == NULL) {
+	ret = ENOMEM;
+	free(s);
+	goto out;
+    }
+    for (i = 0; i < len; i++) {
+	s2[i * 2] = s[i];
+	s2[i * 2 + 1] = 0;
+    }
+    free(s);
+#else
+    /* write libwind code here */
+#endif
+
+    ret = krb5_storage_write(sp, s2, len * 2);
+    free(s2);
+    if (ret != len * 2) {
+	ret = ENOMEM;
+	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;
+}
+
+
+/*
+ *
+ */
+
+krb5_error_code
+krb5_pac_verify(krb5_context context, 
+		const struct 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_string(context, "PAC missing server checksum");
+	return EINVAL;
+    }
+    if (pac->privsvr_checksum == NULL) {
+	krb5_set_error_string(context, "PAC missing kdc checksum");
+	return EINVAL;
+    }
+    if (pac->logon_name == NULL) {
+	krb5_set_error_string(context, "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;
+
+	ret = krb5_copy_data(context, &pac->data, &copy);
+	if (ret)
+	    return ret;
+
+	if (pac->server_checksum->buffersize < 4)
+	    return EINVAL;
+	if (pac->privsvr_checksum->buffersize < 4)
+	    return EINVAL;
+
+	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) {
+	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) {
+	    krb5_set_error_string(context, "out of memory");
+	    return ENOMEM;
+	}
+	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);
+    ret = krb5_crypto_destroy(context, crypto);
+    if (ret)
+	return ret;
+
+    if (krb5_checksum_is_keyed(context, cktype) == FALSE) {
+	krb5_set_error_string(context, "PAC checksum type is not keyed");
+	return EINVAL;
+    }
+
+    ret = krb5_checksumsize(context, cktype, cksumsize);
+    if (ret)
+	return ret;
+    
+    *cksumtype = (uint32_t)cktype;
+
+    return 0;
+}
+
+krb5_error_code
+_krb5_pac_sign(krb5_context context,
+	       struct 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 i, num = 0;
+    krb5_data logon, d;
+
+    krb5_data_zero(&logon);
+
+    if (p->server_checksum == NULL)
+	num++;
+    if (p->privsvr_checksum == NULL)
+	num++;
+    if (p->logon_name == 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) {
+	    krb5_set_error_string(context, "out of memory");
+	    return ENOMEM;
+	}
+	p->pac = ptr;
+
+	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;
+	}
+	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;
+	}
+    }
+
+    /* 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) {
+	krb5_set_error_string(context, "out of memory");
+	return ENOMEM;
+    }
+    krb5_storage_set_flags(sp, KRB5_STORAGE_BYTEORDER_LE);
+
+    spdata = krb5_storage_emem();
+    if (spdata == NULL) {
+	krb5_storage_free(sp);
+	krb5_set_error_string(context, "out of memory");
+	return ENOMEM;
+    }
+    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) {
+		krb5_set_error_string(context, "out of memory");
+		ret = ENOMEM;
+		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 (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_string(context, "out of memory");
+	goto out;
+    }
+    ret = krb5_storage_write(sp, d.data, d.length);
+    if (ret != d.length) {
+	krb5_data_free(&d);
+	krb5_set_error_string(context, "out of memory");
+	ret = ENOMEM;
+	goto out;
+    }
+    krb5_data_free(&d);
+
+    ret = krb5_storage_to_data(sp, &d);
+    if (ret) {
+	krb5_set_error_string(context, "out of memory");
+	goto out;
+    }
+
+    /* sign */
+
+    ret = create_checksum(context, server_key,
+			  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,
+			  (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;
+}