lib/krb5/keytab_file.c

/*
 * Copyright (c) 1997 - 2002 Kungliga Tekniska H�gskolan
 * (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: keytab_file.c,v 1.11 2002/05/28 12:57:27 joda Exp $");

#define KRB5_KT_VNO_1 1
#define KRB5_KT_VNO_2 2
#define KRB5_KT_VNO   KRB5_KT_VNO_2

/* file operations -------------------------------------------- */

struct fkt_data {
    char *filename;
};

static krb5_error_code
krb5_kt_ret_data(krb5_context context,
		 krb5_storage *sp,
		 krb5_data *data)
{
    int ret;
    int16_t size;
    ret = krb5_ret_int16(sp, &size);
    if(ret)
	return ret;
    data->length = size;
    data->data = malloc(size);
    if (data->data == NULL) {
	krb5_set_error_string (context, "malloc: out of memory");
	return ENOMEM;
    }
    ret = krb5_storage_read(sp, data->data, size);
    if(ret != size)
	return (ret < 0)? errno : KRB5_KT_END;
    return 0;
}

static krb5_error_code
krb5_kt_ret_string(krb5_context context,
		   krb5_storage *sp,
		   general_string *data)
{
    int ret;
    int16_t size;
    ret = krb5_ret_int16(sp, &size);
    if(ret)
	return ret;
    *data = malloc(size + 1);
    if (*data == NULL) {
	krb5_set_error_string (context, "malloc: out of memory");
	return ENOMEM;
    }
    ret = krb5_storage_read(sp, *data, size);
    (*data)[size] = '\0';
    if(ret != size)
	return (ret < 0)? errno : KRB5_KT_END;
    return 0;
}

static krb5_error_code
krb5_kt_store_data(krb5_context context,
		   krb5_storage *sp,
		   krb5_data data)
{
    int ret;
    ret = krb5_store_int16(sp, data.length);
    if(ret < 0)
	return ret;
    ret = krb5_storage_write(sp, data.data, data.length);
    if(ret != data.length){
	if(ret < 0)
	    return errno;
	return KRB5_KT_END;
    }
    return 0;
}

static krb5_error_code
krb5_kt_store_string(krb5_storage *sp,
		     general_string data)
{
    int ret;
    size_t len = strlen(data);
    ret = krb5_store_int16(sp, len);
    if(ret < 0)
	return ret;
    ret = krb5_storage_write(sp, data, len);
    if(ret != len){
	if(ret < 0)
	    return errno;
	return KRB5_KT_END;
    }
    return 0;
}

static krb5_error_code
krb5_kt_ret_keyblock(krb5_context context, krb5_storage *sp, krb5_keyblock *p)
{
    int ret;
    int16_t tmp;

    ret = krb5_ret_int16(sp, &tmp); /* keytype + etype */
    if(ret) return ret;
    p->keytype = tmp;
    ret = krb5_kt_ret_data(context, sp, &p->keyvalue);
    return ret;
}

static krb5_error_code
krb5_kt_store_keyblock(krb5_context context,
		       krb5_storage *sp,
		       krb5_keyblock *p)
{
    int ret;

    ret = krb5_store_int16(sp, p->keytype); /* keytype + etype */
    if(ret) return ret;
    ret = krb5_kt_store_data(context, sp, p->keyvalue);
    return ret;
}


static krb5_error_code
krb5_kt_ret_principal(krb5_context context,
		      krb5_storage *sp,
		      krb5_principal *princ)
{
    int i;
    int ret;
    krb5_principal p;
    int16_t tmp;

    ALLOC(p, 1);
    if(p == NULL) {
	krb5_set_error_string (context, "malloc: out of memory");
	return ENOMEM;
    }

    ret = krb5_ret_int16(sp, &tmp);
    if(ret)
	return ret;
    if(krb5_storage_is_flags(sp, KRB5_STORAGE_PRINCIPAL_WRONG_NUM_COMPONENTS))
	tmp--;
    p->name.name_string.len = tmp;
    ret = krb5_kt_ret_string(context, sp, &p->realm);
    if(ret)
	return ret;
    p->name.name_string.val = calloc(p->name.name_string.len,
				     sizeof(*p->name.name_string.val));
    if(p->name.name_string.val == NULL) {
	krb5_set_error_string (context, "malloc: out of memory");
	return ENOMEM;
    }
    for(i = 0; i < p->name.name_string.len; i++){
	ret = krb5_kt_ret_string(context, sp, p->name.name_string.val + i);
	if(ret)
	    return ret;
    }
    if (krb5_storage_is_flags(sp, KRB5_STORAGE_PRINCIPAL_NO_NAME_TYPE))
	p->name.name_type = KRB5_NT_UNKNOWN;
    else {
	int32_t tmp32;
	ret = krb5_ret_int32(sp, &tmp32);
	p->name.name_type = tmp32;
	if (ret)
	    return ret;
    }
    *princ = p;
    return 0;
}

static krb5_error_code
krb5_kt_store_principal(krb5_context context,
			krb5_storage *sp,
			krb5_principal p)
{
    int i;
    int ret;

    if(krb5_storage_is_flags(sp, KRB5_STORAGE_PRINCIPAL_WRONG_NUM_COMPONENTS))
	ret = krb5_store_int16(sp, p->name.name_string.len + 1);
    else
	ret = krb5_store_int16(sp, p->name.name_string.len);
    if(ret) return ret;
    ret = krb5_kt_store_string(sp, p->realm);
    if(ret) return ret;
    for(i = 0; i < p->name.name_string.len; i++){
	ret = krb5_kt_store_string(sp, p->name.name_string.val[i]);
	if(ret)
	    return ret;
    }
    if(!krb5_storage_is_flags(sp, KRB5_STORAGE_PRINCIPAL_NO_NAME_TYPE)) {
	ret = krb5_store_int32(sp, p->name.name_type);
	if(ret)
	    return ret;
    }

    return 0;
}

static krb5_error_code
fkt_resolve(krb5_context context, const char *name, krb5_keytab id)
{
    struct fkt_data *d;

    d = malloc(sizeof(*d));
    if(d == NULL) {
	krb5_set_error_string (context, "malloc: out of memory");
	return ENOMEM;
    }
    d->filename = strdup(name);
    if(d->filename == NULL) {
	free(d);
	krb5_set_error_string (context, "malloc: out of memory");
	return ENOMEM;
    }
    id->data = d;
    return 0;
}

static krb5_error_code
fkt_close(krb5_context context, krb5_keytab id)
{
    struct fkt_data *d = id->data;
    free(d->filename);
    free(d);
    return 0;
}

static krb5_error_code
fkt_get_name(krb5_context context,
	     krb5_keytab id,
	     char *name,
	     size_t namesize)
{
    /* This function is XXX */
    struct fkt_data *d = id->data;
    strlcpy(name, d->filename, namesize);
    return 0;
}

static void
storage_set_flags(krb5_context context, krb5_storage *sp, int vno)
{
    int flags = 0;
    switch(vno) {
    case KRB5_KT_VNO_1:
	flags |= KRB5_STORAGE_PRINCIPAL_WRONG_NUM_COMPONENTS;
	flags |= KRB5_STORAGE_PRINCIPAL_NO_NAME_TYPE;
	flags |= KRB5_STORAGE_HOST_BYTEORDER;
	break;
    case KRB5_KT_VNO_2:
	break;
    default:
	krb5_warnx(context,
		   "storage_set_flags called with bad vno (%d)", vno);
    }
    krb5_storage_set_flags(sp, flags);
}

static krb5_error_code
fkt_start_seq_get_int(krb5_context context,
		      krb5_keytab id,
		      int flags,
		      krb5_kt_cursor *c)
{
    int8_t pvno, tag;
    krb5_error_code ret;
    struct fkt_data *d = id->data;

    c->fd = open (d->filename, flags);
    if (c->fd < 0) {
	ret = errno;
	krb5_set_error_string(context, "open(%s): %s", d->filename,
			      strerror(ret));
	return ret;
    }
    c->sp = krb5_storage_from_fd(c->fd);
    krb5_storage_set_eof_code(c->sp, KRB5_KT_END);
    ret = krb5_ret_int8(c->sp, &pvno);
    if(ret) {
	krb5_storage_free(c->sp);
	close(c->fd);
	return ret;
    }
    if(pvno != 5) {
	krb5_storage_free(c->sp);
	close(c->fd);
	krb5_clear_error_string (context);
	return KRB5_KEYTAB_BADVNO;
    }
    ret = krb5_ret_int8(c->sp, &tag);
    if (ret) {
	krb5_storage_free(c->sp);
	close(c->fd);
	return ret;
    }
    id->version = tag;
    storage_set_flags(context, c->sp, id->version);
    return 0;
}

static krb5_error_code
fkt_start_seq_get(krb5_context context,
		  krb5_keytab id,
		  krb5_kt_cursor *c)
{
    return fkt_start_seq_get_int(context, id, O_RDONLY | O_BINARY, c);
}

static krb5_error_code
fkt_next_entry_int(krb5_context context,
		   krb5_keytab id,
		   krb5_keytab_entry *entry,
		   krb5_kt_cursor *cursor,
		   off_t *start,
		   off_t *end)
{
    int32_t len;
    int ret;
    int8_t tmp8;
    int32_t tmp32;
    off_t pos, curpos;

    pos = krb5_storage_seek(cursor->sp, 0, SEEK_CUR);
loop:
    ret = krb5_ret_int32(cursor->sp, &len);
    if (ret)
	return ret;
    if(len < 0) {
	pos = krb5_storage_seek(cursor->sp, -len, SEEK_CUR);
	goto loop;
    }
    ret = krb5_kt_ret_principal (context, cursor->sp, &entry->principal);
    if (ret)
	goto out;
    ret = krb5_ret_int32(cursor->sp, &tmp32);
    entry->timestamp = tmp32;
    if (ret)
	goto out;
    ret = krb5_ret_int8(cursor->sp, &tmp8);
    if (ret)
	goto out;
    entry->vno = tmp8;
    ret = krb5_kt_ret_keyblock (context, cursor->sp, &entry->keyblock);
    if (ret)
	goto out;
    /* there might be a 32 bit kvno here
     * if it's zero, assume that the 8bit one was right,
     * otherwise trust the new value */
    curpos = krb5_storage_seek(cursor->sp, 0, SEEK_CUR);
    if(len + 4 + pos - curpos == 4) {
	ret = krb5_ret_int32(cursor->sp, &tmp32);
	if (ret == 0 && tmp32 != 0) {
	    entry->vno = tmp32;
	}
    }
    if(start) *start = pos;
    if(end) *end = *start + 4 + len;
 out:
    krb5_storage_seek(cursor->sp, pos + 4 + len, SEEK_SET);
    return ret;
}

static krb5_error_code
fkt_next_entry(krb5_context context,
	       krb5_keytab id,
	       krb5_keytab_entry *entry,
	       krb5_kt_cursor *cursor)
{
    return fkt_next_entry_int(context, id, entry, cursor, NULL, NULL);
}

static krb5_error_code
fkt_end_seq_get(krb5_context context,
		krb5_keytab id,
		krb5_kt_cursor *cursor)
{
    krb5_storage_free(cursor->sp);
    close(cursor->fd);
    return 0;
}

static krb5_error_code
fkt_setup_keytab(krb5_context context,
		 krb5_keytab id,
		 krb5_storage *sp)
{
    krb5_error_code ret;
    ret = krb5_store_int8(sp, 5);
    if(ret)
	return ret;
    if(id->version == 0)
	id->version = KRB5_KT_VNO;
    return krb5_store_int8 (sp, id->version);
}

static krb5_error_code
fkt_add_entry(krb5_context context,
	      krb5_keytab id,
	      krb5_keytab_entry *entry)
{
    int ret;
    int fd;
    krb5_storage *sp;
    struct fkt_data *d = id->data;
    krb5_data keytab;
    int32_t len;

    fd = open (d->filename, O_RDWR | O_BINARY);
    if (fd < 0) {
	fd = open (d->filename, O_RDWR | O_CREAT | O_BINARY, 0600);
	if (fd < 0) {
	    ret = errno;
	    krb5_set_error_string(context, "open(%s): %s", d->filename,
				  strerror(ret));
	    return ret;
	}
	sp = krb5_storage_from_fd(fd);
	krb5_storage_set_eof_code(sp, KRB5_KT_END);
	ret = fkt_setup_keytab(context, id, sp);
	if(ret) {
	    krb5_storage_free(sp);
	    close(fd);
	    return ret;
	}
	storage_set_flags(context, sp, id->version);
    } else {
	int8_t pvno, tag;
	sp = krb5_storage_from_fd(fd);
	krb5_storage_set_eof_code(sp, KRB5_KT_END);
	ret = krb5_ret_int8(sp, &pvno);
	if(ret) {
	    /* we probably have a zero byte file, so try to set it up
               properly */
	    ret = fkt_setup_keytab(context, id, sp);
	    if(ret) {
		krb5_set_error_string(context, "%s: keytab is corrupted: %s",
				      d->filename, strerror(ret));
		krb5_storage_free(sp);
		close(fd);
		return ret;
	    }
	    storage_set_flags(context, sp, id->version);
	} else {
	    if(pvno != 5) {
		krb5_storage_free(sp);
		close(fd);
		krb5_clear_error_string (context);
		ret = KRB5_KEYTAB_BADVNO;
		krb5_set_error_string(context, "%s: %s",
				      d->filename, strerror(ret));
		return ret;
	    }
	    ret = krb5_ret_int8 (sp, &tag);
	    if (ret) {
		krb5_set_error_string(context, "%s: reading tag: %s",
				      d->filename, strerror(ret));
		krb5_storage_free(sp);
		close(fd);
		return ret;
	    }
	    id->version = tag;
	    storage_set_flags(context, sp, id->version);
	}
    }

    {
	krb5_storage *emem;
	emem = krb5_storage_emem();
	if(emem == NULL) {
	    ret = ENOMEM;
	    krb5_set_error_string (context, "malloc: out of memory");
	    goto out;
	}
	ret = krb5_kt_store_principal(context, emem, entry->principal);
	if(ret) {
	    krb5_storage_free(emem);
	    goto out;
	}
	ret = krb5_store_int32 (emem, entry->timestamp);
	if(ret) {
	    krb5_storage_free(emem);
	    goto out;
	}
	ret = krb5_store_int8 (emem, entry->vno % 256);
	if(ret) {
	    krb5_storage_free(emem);
	    goto out;
	}
	ret = krb5_kt_store_keyblock (context, emem, &entry->keyblock);
	if(ret) {
	    krb5_storage_free(emem);
	    goto out;
	}
	ret = krb5_store_int32 (emem, entry->vno);
	if (ret) {
	    krb5_storage_free(emem);
	    goto out;
	}

	ret = krb5_storage_to_data(emem, &keytab);
	krb5_storage_free(emem);
	if(ret)
	    goto out;
    }

    while(1) {
	ret = krb5_ret_int32(sp, &len);
	if(ret == KRB5_KT_END) {
	    len = keytab.length;
	    break;
	}
	if(len < 0) {
	    len = -len;
	    if(len >= keytab.length) {
		krb5_storage_seek(sp, -4, SEEK_CUR);
		break;
	    }
	}
	krb5_storage_seek(sp, len, SEEK_CUR);
    }
    ret = krb5_store_int32(sp, len);
    if(krb5_storage_write(sp, keytab.data, keytab.length) < 0)
	ret = errno;
    memset(keytab.data, 0, keytab.length);
    krb5_data_free(&keytab);
  out:
    krb5_storage_free(sp);
    close(fd);
    return ret;
}

static krb5_error_code
fkt_remove_entry(krb5_context context,
		 krb5_keytab id,
		 krb5_keytab_entry *entry)
{
    krb5_keytab_entry e;
    krb5_kt_cursor cursor;
    off_t pos_start, pos_end;
    int found = 0;

    fkt_start_seq_get_int(context, id, O_RDWR | O_BINARY, &cursor);
    while(fkt_next_entry_int(context, id, &e, &cursor,
			     &pos_start, &pos_end) == 0) {
	if(krb5_kt_compare(context, &e, entry->principal,
			   entry->vno, entry->keyblock.keytype)) {
	    int32_t len;
	    unsigned char buf[128];
	    found = 1;
	    krb5_storage_seek(cursor.sp, pos_start, SEEK_SET);
	    len = pos_end - pos_start - 4;
	    krb5_store_int32(cursor.sp, -len);
	    memset(buf, 0, sizeof(buf));
	    while(len > 0) {
		krb5_storage_write(cursor.sp, buf, min(len, sizeof(buf)));
		len -= min(len, sizeof(buf));
	    }
	}
    }
    krb5_kt_end_seq_get(context, id, &cursor);
    if (!found) {
	krb5_clear_error_string (context);
	return KRB5_KT_NOTFOUND;
    }
    return 0;
}

const krb5_kt_ops krb5_fkt_ops = {
    "FILE",
    fkt_resolve,
    fkt_get_name,
    fkt_close,
    NULL, /* get */
    fkt_start_seq_get,
    fkt_next_entry,
    fkt_end_seq_get,
    fkt_add_entry,
    fkt_remove_entry
};