ndr.c

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/* 
   Unix SMB/CIFS implementation.

   libndr interface

   Copyright (C) Andrew Tridgell 2003
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

/*
  this provides the core routines for NDR parsing functions

  see http://www.opengroup.org/onlinepubs/9629399/chap14.htm for details
  of NDR encoding rules
*/

#include "includes.h"
#include "librpc/ndr/libndr.h"
#include "lib/util/dlinklist.h"
#include "librpc/gen_ndr/dcerpc.h"
#include "param/param.h"

#define NDR_BASE_MARSHALL_SIZE 1024

/* this guid indicates NDR encoding in a protocol tower */
const struct ndr_syntax_id ndr_transfer_syntax = {
  { 0x8a885d04, 0x1ceb, 0x11c9, {0x9f, 0xe8}, {0x08,0x00,0x2b,0x10,0x48,0x60} },
  2
};

const struct ndr_syntax_id ndr64_transfer_syntax = {
  { 0x71710533, 0xbeba, 0x4937, {0x83, 0x19}, {0xb5,0xdb,0xef,0x9c,0xcc,0x36} },
  1
};

/*
  work out the number of bytes needed to align on a n byte boundary
*/
_PUBLIC_ size_t ndr_align_size(uint32_t offset, size_t n)
{
	if ((offset & (n-1)) == 0) return 0;
	return n - (offset & (n-1));
}

/*
  initialise a ndr parse structure from a data blob
*/
_PUBLIC_ struct ndr_pull *ndr_pull_init_blob(const DATA_BLOB *blob, TALLOC_CTX *mem_ctx, struct smb_iconv_convenience *iconv_convenience)
{
	struct ndr_pull *ndr;

	ndr = talloc_zero(mem_ctx, struct ndr_pull);
	if (!ndr) return NULL;
	ndr->current_mem_ctx = mem_ctx;

	ndr->data = blob->data;
	ndr->data_size = blob->length;
	ndr->iconv_convenience = talloc_reference(ndr, iconv_convenience);

	return ndr;
}

/*
  advance by 'size' bytes
*/
_PUBLIC_ enum ndr_err_code ndr_pull_advance(struct ndr_pull *ndr, uint32_t size)
{
	ndr->offset += size;
	if (ndr->offset > ndr->data_size) {
		return ndr_pull_error(ndr, NDR_ERR_BUFSIZE, 
				      "ndr_pull_advance by %u failed",
				      size);
	}
	return NDR_ERR_SUCCESS;
}

/*
  set the parse offset to 'ofs'
*/
static enum ndr_err_code ndr_pull_set_offset(struct ndr_pull *ndr, uint32_t ofs)
{
	ndr->offset = ofs;
	if (ndr->offset > ndr->data_size) {
		return ndr_pull_error(ndr, NDR_ERR_BUFSIZE, 
				      "ndr_pull_set_offset %u failed",
				      ofs);
	}
	return NDR_ERR_SUCCESS;
}

/* create a ndr_push structure, ready for some marshalling */
_PUBLIC_ struct ndr_push *ndr_push_init_ctx(TALLOC_CTX *mem_ctx, struct smb_iconv_convenience *iconv_convenience)
{
	struct ndr_push *ndr;

	ndr = talloc_zero(mem_ctx, struct ndr_push);
	if (!ndr) {
		return NULL;
	}

	ndr->flags = 0;
	ndr->alloc_size = NDR_BASE_MARSHALL_SIZE;
	ndr->data = talloc_array(ndr, uint8_t, ndr->alloc_size);
	if (!ndr->data) {
		return NULL;
	}
	ndr->iconv_convenience = talloc_reference(ndr, iconv_convenience);

	return ndr;
}

/* return a DATA_BLOB structure for the current ndr_push marshalled data */
_PUBLIC_ DATA_BLOB ndr_push_blob(struct ndr_push *ndr)
{
	DATA_BLOB blob;
	blob = data_blob_const(ndr->data, ndr->offset);
	if (ndr->alloc_size > ndr->offset) {
		ndr->data[ndr->offset] = 0;
	}
	return blob;
}


/*
  expand the available space in the buffer to ndr->offset + extra_size
*/
_PUBLIC_ enum ndr_err_code ndr_push_expand(struct ndr_push *ndr, uint32_t extra_size)
{
	uint32_t size = extra_size + ndr->offset;

	if (size < ndr->offset) {
		/* extra_size overflowed the offset */
		return ndr_push_error(ndr, NDR_ERR_BUFSIZE, "Overflow in push_expand to %u",
				      size);
	}

	if (ndr->alloc_size > size) {
		return NDR_ERR_SUCCESS;
	}

	ndr->alloc_size += NDR_BASE_MARSHALL_SIZE;
	if (size+1 > ndr->alloc_size) {
		ndr->alloc_size = size+1;
	}
	ndr->data = talloc_realloc(ndr, ndr->data, uint8_t, ndr->alloc_size);
	if (!ndr->data) {
		return ndr_push_error(ndr, NDR_ERR_ALLOC, "Failed to push_expand to %u",
				      ndr->alloc_size);
	}

	return NDR_ERR_SUCCESS;
}

_PUBLIC_ void ndr_print_debug_helper(struct ndr_print *ndr, const char *format, ...)
{
	va_list ap;
	char *s = NULL;
	int i;

	va_start(ap, format);
	vasprintf(&s, format, ap);
	va_end(ap);

	for (i=0;i<ndr->depth;i++) {
		DEBUGADD(0,("    "));
	}

	DEBUGADD(0,("%s\n", s));
	free(s);
}

_PUBLIC_ void ndr_print_string_helper(struct ndr_print *ndr, const char *format, ...)
{
	va_list ap;
	int i;

	for (i=0;i<ndr->depth;i++) {
		ndr->private_data = talloc_asprintf_append_buffer(
					(char *)ndr->private_data, "    ");
	}

	va_start(ap, format);
	ndr->private_data = talloc_vasprintf_append_buffer((char *)ndr->private_data, 
						    format, ap);
	va_end(ap);
	ndr->private_data = talloc_asprintf_append_buffer((char *)ndr->private_data, 
						   "\n");
}

/*
  a useful helper function for printing idl structures via DEBUG()
*/
_PUBLIC_ void ndr_print_debug(ndr_print_fn_t fn, const char *name, void *ptr)
{
	struct ndr_print *ndr;

	ndr = talloc_zero(NULL, struct ndr_print);
	if (!ndr) return;
	ndr->print = ndr_print_debug_helper;
	ndr->depth = 1;
	ndr->flags = 0;
	fn(ndr, name, ptr);
	talloc_free(ndr);
}

/*
  a useful helper function for printing idl unions via DEBUG()
*/
_PUBLIC_ void ndr_print_union_debug(ndr_print_fn_t fn, const char *name, uint32_t level, void *ptr)
{
	struct ndr_print *ndr;

	ndr = talloc_zero(NULL, struct ndr_print);
	if (!ndr) return;
	ndr->print = ndr_print_debug_helper;
	ndr->depth = 1;
	ndr->flags = 0;
	ndr_print_set_switch_value(ndr, ptr, level);
	fn(ndr, name, ptr);
	talloc_free(ndr);
}

/*
  a useful helper function for printing idl function calls via DEBUG()
*/
_PUBLIC_ void ndr_print_function_debug(ndr_print_function_t fn, const char *name, int flags, void *ptr)
{
	struct ndr_print *ndr;

	ndr = talloc_zero(NULL, struct ndr_print);
	if (!ndr) return;
	ndr->print = ndr_print_debug_helper;
	ndr->depth = 1;
	ndr->flags = 0;
	fn(ndr, name, flags, ptr);
	talloc_free(ndr);
}

/*
  a useful helper function for printing idl structures to a string
*/
_PUBLIC_ char *ndr_print_struct_string(TALLOC_CTX *mem_ctx, ndr_print_fn_t fn, const char *name, void *ptr)
{
	struct ndr_print *ndr;
	char *ret = NULL;

	ndr = talloc_zero(mem_ctx, struct ndr_print);
	if (!ndr) return NULL;
	ndr->private_data = talloc_strdup(ndr, "");
	if (!ndr->private_data) {
		goto failed;
	}
	ndr->print = ndr_print_string_helper;
	ndr->depth = 1;
	ndr->flags = 0;
	fn(ndr, name, ptr);
	ret = talloc_steal(mem_ctx, (char *)ndr->private_data);
failed:
	talloc_free(ndr);
	return ret;
}

/*
  a useful helper function for printing idl unions to a string
*/
_PUBLIC_ char *ndr_print_union_string(TALLOC_CTX *mem_ctx, ndr_print_fn_t fn, const char *name, uint32_t level, void *ptr)
{
	struct ndr_print *ndr;
	char *ret = NULL;

	ndr = talloc_zero(mem_ctx, struct ndr_print);
	if (!ndr) return NULL;
	ndr->private_data = talloc_strdup(ndr, "");
	if (!ndr->private_data) {
		goto failed;
	}
	ndr->print = ndr_print_string_helper;
	ndr->depth = 1;
	ndr->flags = 0;
	ndr_print_set_switch_value(ndr, ptr, level);
	fn(ndr, name, ptr);
	ret = talloc_steal(mem_ctx, (char *)ndr->private_data);
failed:
	talloc_free(ndr);
	return ret;
}

/*
  a useful helper function for printing idl function calls to a string
*/
_PUBLIC_ char *ndr_print_function_string(TALLOC_CTX *mem_ctx,
				ndr_print_function_t fn, const char *name, 
				int flags, void *ptr)
{
	struct ndr_print *ndr;
	char *ret = NULL;

	ndr = talloc_zero(mem_ctx, struct ndr_print);
	if (!ndr) return NULL;
	ndr->private_data = talloc_strdup(ndr, "");
	if (!ndr->private_data) {
		goto failed;
	}
	ndr->print = ndr_print_string_helper;
	ndr->depth = 1;
	ndr->flags = 0;
	fn(ndr, name, flags, ptr);
	ret = talloc_steal(mem_ctx, (char *)ndr->private_data);
failed:
	talloc_free(ndr);
	return ret;
}

_PUBLIC_ void ndr_set_flags(uint32_t *pflags, uint32_t new_flags)
{
	/* the big/little endian flags are inter-dependent */
	if (new_flags & LIBNDR_FLAG_LITTLE_ENDIAN) {
		(*pflags) &= ~LIBNDR_FLAG_BIGENDIAN;
	}
	if (new_flags & LIBNDR_FLAG_BIGENDIAN) {
		(*pflags) &= ~LIBNDR_FLAG_LITTLE_ENDIAN;
	}
	if (new_flags & LIBNDR_FLAG_REMAINING) {
		(*pflags) &= ~LIBNDR_ALIGN_FLAGS;
	}
	if (new_flags & LIBNDR_ALIGN_FLAGS) {
		(*pflags) &= ~LIBNDR_FLAG_REMAINING;
	}
	(*pflags) |= new_flags;
}

/*
  return and possibly log an NDR error
*/
_PUBLIC_ enum ndr_err_code ndr_pull_error(struct ndr_pull *ndr,
				 enum ndr_err_code ndr_err,
				 const char *format, ...)
{
	char *s=NULL;
	va_list ap;

	va_start(ap, format);
	vasprintf(&s, format, ap);
	va_end(ap);

	DEBUG(3,("ndr_pull_error(%u): %s\n", ndr_err, s));

	free(s);

	return ndr_err;
}

/*
  return and possibly log an NDR error
*/
_PUBLIC_ enum ndr_err_code ndr_push_error(struct ndr_push *ndr,
				 enum ndr_err_code ndr_err,
				 const char *format, ...)
{
	char *s=NULL;
	va_list ap;

	va_start(ap, format);
	vasprintf(&s, format, ap);
	va_end(ap);

	DEBUG(3,("ndr_push_error(%u): %s\n", ndr_err, s));

	free(s);

	return ndr_err;
}

/*
  handle subcontext buffers, which in midl land are user-marshalled, but
  we use magic in pidl to make them easier to cope with
*/
_PUBLIC_ enum ndr_err_code ndr_pull_subcontext_start(struct ndr_pull *ndr,
				   struct ndr_pull **_subndr,
				   size_t header_size,
				   ssize_t size_is)
{
	struct ndr_pull *subndr;
	uint32_t r_content_size;

	switch (header_size) {
	case 0: {
		uint32_t content_size = ndr->data_size - ndr->offset;
		if (size_is >= 0) {
			content_size = size_is;
		}
		r_content_size = content_size;
		break;
	}

	case 2: {
		uint16_t content_size;
		NDR_CHECK(ndr_pull_uint16(ndr, NDR_SCALARS, &content_size));
		if (size_is >= 0 && size_is != content_size) {
			return ndr_pull_error(ndr, NDR_ERR_SUBCONTEXT, "Bad subcontext (PULL) size_is(%d) mismatch content_size %d", 
						(int)size_is, (int)content_size);
		}
		r_content_size = content_size;
		break;
	}

	case 4: {
		uint32_t content_size;
		NDR_CHECK(ndr_pull_uint32(ndr, NDR_SCALARS, &content_size));
		if (size_is >= 0 && size_is != content_size) {
			return ndr_pull_error(ndr, NDR_ERR_SUBCONTEXT, "Bad subcontext (PULL) size_is(%d) mismatch content_size %d", 
						(int)size_is, (int)content_size);
		}
		r_content_size = content_size;
		break;
	}
	default:
		return ndr_pull_error(ndr, NDR_ERR_SUBCONTEXT, "Bad subcontext (PULL) header_size %d", 
				      (int)header_size);
	}

	NDR_PULL_NEED_BYTES(ndr, r_content_size);

	subndr = talloc_zero(ndr, struct ndr_pull);
	NDR_ERR_HAVE_NO_MEMORY(subndr);
	subndr->flags		= ndr->flags;
	subndr->current_mem_ctx	= ndr->current_mem_ctx;

	subndr->data = ndr->data + ndr->offset;
	subndr->offset = 0;
	subndr->data_size = r_content_size;
	subndr->iconv_convenience = talloc_reference(subndr, ndr->iconv_convenience);

	*_subndr = subndr;
	return NDR_ERR_SUCCESS;
}

_PUBLIC_ enum ndr_err_code ndr_pull_subcontext_end(struct ndr_pull *ndr,
				 struct ndr_pull *subndr,
				 size_t header_size,
				 ssize_t size_is)
{
	uint32_t advance;
	if (size_is >= 0) {
		advance = size_is;
	} else if (header_size > 0) {
		advance = subndr->data_size;
	} else {
		advance = subndr->offset;
	}
	NDR_CHECK(ndr_pull_advance(ndr, advance));
	return NDR_ERR_SUCCESS;
}

_PUBLIC_ enum ndr_err_code ndr_push_subcontext_start(struct ndr_push *ndr,
				   struct ndr_push **_subndr,
				   size_t header_size,
				   ssize_t size_is)
{
	struct ndr_push *subndr;

	subndr = ndr_push_init_ctx(ndr, ndr->iconv_convenience);
	NDR_ERR_HAVE_NO_MEMORY(subndr);
	subndr->flags	= ndr->flags;

	*_subndr = subndr;
	return NDR_ERR_SUCCESS;
}

/*
  push a subcontext header 
*/
_PUBLIC_ enum ndr_err_code ndr_push_subcontext_end(struct ndr_push *ndr,
				 struct ndr_push *subndr,
				 size_t header_size,
				 ssize_t size_is)
{
	if (size_is >= 0) {
		ssize_t padding_len = size_is - subndr->offset;
		if (padding_len > 0) {
			NDR_CHECK(ndr_push_zero(subndr, padding_len));
		} else if (padding_len < 0) {
			return ndr_push_error(ndr, NDR_ERR_SUBCONTEXT, "Bad subcontext (PUSH) content_size %d is larger than size_is(%d)",
					      (int)subndr->offset, (int)size_is);