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samba-mirror/source4/smb_server/smb/request.c
2007-10-10 14:05:08 -05:00

646 lines
18 KiB
C

/*
Unix SMB/CIFS implementation.
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 2 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, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/*
this file implements functions for manipulating the 'struct smbsrv_request' structure in smbd
*/
#include "includes.h"
#include "smb_server/smb_server.h"
#include "smb_server/service_smb_proto.h"
#include "smbd/service_stream.h"
#include "lib/stream/packet.h"
#include "ntvfs/ntvfs.h"
/* we over allocate the data buffer to prevent too many realloc calls */
#define REQ_OVER_ALLOCATION 0
/****************************************************************************
construct a basic request packet, mostly used to construct async packets
such as change notify and oplock break requests
****************************************************************************/
struct smbsrv_request *smbsrv_init_request(struct smbsrv_connection *smb_conn)
{
struct smbsrv_request *req;
req = talloc_zero(smb_conn, struct smbsrv_request);
if (!req) {
return NULL;
}
/* setup the request context */
req->smb_conn = smb_conn;
return req;
}
/*
setup a chained reply in req->out with the given word count and initial data buffer size.
*/
static void req_setup_chain_reply(struct smbsrv_request *req, uint_t wct, uint_t buflen)
{
uint32_t chain_base_size = req->out.size;
/* we need room for the wct value, the words, the buffer length and the buffer */
req->out.size += 1 + VWV(wct) + 2 + buflen;
/* over allocate by a small amount */
req->out.allocated = req->out.size + REQ_OVER_ALLOCATION;
req->out.buffer = talloc_realloc(req, req->out.buffer,
uint8_t, req->out.allocated);
if (!req->out.buffer) {
smbsrv_terminate_connection(req->smb_conn, "allocation failed");
return;
}
req->out.hdr = req->out.buffer + NBT_HDR_SIZE;
req->out.vwv = req->out.buffer + chain_base_size + 1;
req->out.wct = wct;
req->out.data = req->out.vwv + VWV(wct) + 2;
req->out.data_size = buflen;
req->out.ptr = req->out.data;
SCVAL(req->out.buffer, chain_base_size, wct);
SSVAL(req->out.vwv, VWV(wct), buflen);
}
/*
setup a reply in req->out with the given word count and initial data buffer size.
the caller will then fill in the command words and data before calling req_send_reply() to
send the reply on its way
*/
void smbsrv_setup_reply(struct smbsrv_request *req, uint_t wct, size_t buflen)
{
uint16_t flags2;
if (req->chain_count != 0) {
req_setup_chain_reply(req, wct, buflen);
return;
}
req->out.size = NBT_HDR_SIZE + MIN_SMB_SIZE + VWV(wct) + buflen;
/* over allocate by a small amount */
req->out.allocated = req->out.size + REQ_OVER_ALLOCATION;
req->out.buffer = talloc_size(req, req->out.allocated);
if (!req->out.buffer) {
smbsrv_terminate_connection(req->smb_conn, "allocation failed");
return;
}
flags2 = FLAGS2_LONG_PATH_COMPONENTS |
FLAGS2_EXTENDED_ATTRIBUTES |
FLAGS2_IS_LONG_NAME;
flags2 |= (req->flags2 & (FLAGS2_UNICODE_STRINGS|FLAGS2_EXTENDED_SECURITY));
if (req->smb_conn->negotiate.client_caps & CAP_STATUS32) {
flags2 |= FLAGS2_32_BIT_ERROR_CODES;
}
req->out.hdr = req->out.buffer + NBT_HDR_SIZE;
req->out.vwv = req->out.hdr + HDR_VWV;
req->out.wct = wct;
req->out.data = req->out.vwv + VWV(wct) + 2;
req->out.data_size = buflen;
req->out.ptr = req->out.data;
SIVAL(req->out.hdr, HDR_RCLS, 0);
SCVAL(req->out.hdr, HDR_WCT, wct);
SSVAL(req->out.vwv, VWV(wct), buflen);
memcpy(req->out.hdr, "\377SMB", 4);
SCVAL(req->out.hdr,HDR_FLG, FLAG_REPLY | FLAG_CASELESS_PATHNAMES);
SSVAL(req->out.hdr,HDR_FLG2, flags2);
SSVAL(req->out.hdr,HDR_PIDHIGH,0);
memset(req->out.hdr + HDR_SS_FIELD, 0, 10);
if (req->in.hdr) {
/* copy the cmd, tid, pid, uid and mid from the request */
SCVAL(req->out.hdr,HDR_COM,CVAL(req->in.hdr,HDR_COM));
SSVAL(req->out.hdr,HDR_TID,SVAL(req->in.hdr,HDR_TID));
SSVAL(req->out.hdr,HDR_PID,SVAL(req->in.hdr,HDR_PID));
SSVAL(req->out.hdr,HDR_UID,SVAL(req->in.hdr,HDR_UID));
SSVAL(req->out.hdr,HDR_MID,SVAL(req->in.hdr,HDR_MID));
} else {
SCVAL(req->out.hdr,HDR_COM,0);
SSVAL(req->out.hdr,HDR_TID,0);
SSVAL(req->out.hdr,HDR_PID,0);
SSVAL(req->out.hdr,HDR_UID,0);
SSVAL(req->out.hdr,HDR_MID,0);
}
}
/*
setup a copy of a request, used when the server needs to send
more than one reply for a single request packet
*/
struct smbsrv_request *smbsrv_setup_secondary_request(struct smbsrv_request *old_req)
{
struct smbsrv_request *req;
ptrdiff_t diff;
req = talloc_memdup(old_req, old_req, sizeof(struct smbsrv_request));
if (req == NULL) {
return NULL;
}
req->out.buffer = talloc_memdup(req, req->out.buffer, req->out.allocated);
if (req->out.buffer == NULL) {
talloc_free(req);
return NULL;
}
diff = req->out.buffer - old_req->out.buffer;
req->out.hdr += diff;
req->out.vwv += diff;
req->out.data += diff;
req->out.ptr += diff;
return req;
}
/*
work out the maximum data size we will allow for this reply, given
the negotiated max_xmit. The basic reply packet must be setup before
this call
note that this is deliberately a signed integer reply
*/
int req_max_data(struct smbsrv_request *req)
{
int ret;
ret = req->smb_conn->negotiate.max_send;
ret -= PTR_DIFF(req->out.data, req->out.hdr);
if (ret < 0) ret = 0;
return ret;
}
/*
grow the allocation of the data buffer portion of a reply
packet. Note that as this can reallocate the packet buffer this
invalidates any local pointers into the packet.
To cope with this req->out.ptr is supplied. This will be updated to
point at the same offset into the packet as before this call
*/
static void req_grow_allocation(struct smbsrv_request *req, uint_t new_size)
{
int delta;
uint8_t *buf2;
delta = new_size - req->out.data_size;
if (delta + req->out.size <= req->out.allocated) {
/* it fits in the preallocation */
return;
}
/* we need to realloc */
req->out.allocated = req->out.size + delta + REQ_OVER_ALLOCATION;
buf2 = talloc_realloc(req, req->out.buffer, uint8_t, req->out.allocated);
if (buf2 == NULL) {
smb_panic("out of memory in req_grow_allocation");
}
if (buf2 == req->out.buffer) {
/* the malloc library gave us the same pointer */
return;
}
/* update the pointers into the packet */
req->out.data = buf2 + PTR_DIFF(req->out.data, req->out.buffer);
req->out.ptr = buf2 + PTR_DIFF(req->out.ptr, req->out.buffer);
req->out.vwv = buf2 + PTR_DIFF(req->out.vwv, req->out.buffer);
req->out.hdr = buf2 + PTR_DIFF(req->out.hdr, req->out.buffer);
req->out.buffer = buf2;
}
/*
grow the data buffer portion of a reply packet. Note that as this
can reallocate the packet buffer this invalidates any local pointers
into the packet.
To cope with this req->out.ptr is supplied. This will be updated to
point at the same offset into the packet as before this call
*/
void req_grow_data(struct smbsrv_request *req, size_t new_size)
{
int delta;
if (!(req->control_flags & SMBSRV_REQ_CONTROL_LARGE) && new_size > req_max_data(req)) {
smb_panic("reply buffer too large!");
}
req_grow_allocation(req, new_size);
delta = new_size - req->out.data_size;
req->out.size += delta;
req->out.data_size += delta;
/* set the BCC to the new data size */
SSVAL(req->out.vwv, VWV(req->out.wct), new_size);
}
/*
send a reply and destroy the request buffer
note that this only looks at req->out.buffer and req->out.size, allowing manually
constructed packets to be sent
*/
void smbsrv_send_reply_nosign(struct smbsrv_request *req)
{
DATA_BLOB blob;
NTSTATUS status;
if (req->smb_conn->connection->event.fde == NULL) {
/* we are in the process of shutting down this connection */
return;
}
if (req->out.size > NBT_HDR_SIZE) {
_smb_setlen(req->out.buffer, req->out.size - NBT_HDR_SIZE);
}
blob = data_blob_const(req->out.buffer, req->out.size);
status = packet_send(req->smb_conn->packet, blob);
if (!NT_STATUS_IS_OK(status)) {
smbsrv_terminate_connection(req->smb_conn, nt_errstr(status));
}
talloc_free(req);
}
/*
possibly sign a message then send a reply and destroy the request buffer
note that this only looks at req->out.buffer and req->out.size, allowing manually
constructed packets to be sent
*/
void smbsrv_send_reply(struct smbsrv_request *req)
{
smbsrv_sign_packet(req);
smbsrv_send_reply_nosign(req);
}
/*
setup the header of a reply to include an NTSTATUS code
*/
void smbsrv_setup_error(struct smbsrv_request *req, NTSTATUS status)
{
if (!req->smb_conn->config.nt_status_support || !(req->smb_conn->negotiate.client_caps & CAP_STATUS32)) {
/* convert to DOS error codes */
uint8_t eclass;
uint32_t ecode;
ntstatus_to_dos(status, &eclass, &ecode);
SCVAL(req->out.hdr, HDR_RCLS, eclass);
SSVAL(req->out.hdr, HDR_ERR, ecode);
SSVAL(req->out.hdr, HDR_FLG2, SVAL(req->out.hdr, HDR_FLG2) & ~FLAGS2_32_BIT_ERROR_CODES);
return;
}
if (NT_STATUS_IS_DOS(status)) {
/* its a encoded DOS error, using the reserved range */
SSVAL(req->out.hdr, HDR_RCLS, NT_STATUS_DOS_CLASS(status));
SSVAL(req->out.hdr, HDR_ERR, NT_STATUS_DOS_CODE(status));
SSVAL(req->out.hdr, HDR_FLG2, SVAL(req->out.hdr, HDR_FLG2) & ~FLAGS2_32_BIT_ERROR_CODES);
} else {
SIVAL(req->out.hdr, HDR_RCLS, NT_STATUS_V(status));
SSVAL(req->out.hdr, HDR_FLG2, SVAL(req->out.hdr, HDR_FLG2) | FLAGS2_32_BIT_ERROR_CODES);
}
}
/*
construct and send an error packet, then destroy the request
auto-converts to DOS error format when appropriate
*/
void smbsrv_send_error(struct smbsrv_request *req, NTSTATUS status)
{
if (req->smb_conn->connection->event.fde == NULL) {
/* the socket has been destroyed - no point trying to send an error! */
talloc_free(req);
return;
}
smbsrv_setup_reply(req, 0, 0);
/* error returns never have any data */
req_grow_data(req, 0);
smbsrv_setup_error(req, status);
smbsrv_send_reply(req);
}
/*
push a string into the data portion of the request packet, growing it if necessary
this gets quite tricky - please be very careful to cover all cases when modifying this
if dest is NULL, then put the string at the end of the data portion of the packet
if dest_len is -1 then no limit applies
*/
size_t req_push_str(struct smbsrv_request *req, uint8_t *dest, const char *str, int dest_len, size_t flags)
{
size_t len;
uint_t grow_size;
uint8_t *buf0;
const int max_bytes_per_char = 3;
if (!(flags & (STR_ASCII|STR_UNICODE))) {
flags |= (req->flags2 & FLAGS2_UNICODE_STRINGS) ? STR_UNICODE : STR_ASCII;
}
if (dest == NULL) {
dest = req->out.data + req->out.data_size;
}
if (dest_len != -1) {
len = dest_len;
} else {
len = (strlen(str)+2) * max_bytes_per_char;
}
grow_size = len + PTR_DIFF(dest, req->out.data);
buf0 = req->out.buffer;
req_grow_allocation(req, grow_size);
if (buf0 != req->out.buffer) {
dest = req->out.buffer + PTR_DIFF(dest, buf0);
}
len = push_string(dest, str, len, flags);
grow_size = len + PTR_DIFF(dest, req->out.data);
if (grow_size > req->out.data_size) {
req_grow_data(req, grow_size);
}
return len;
}
/*
append raw bytes into the data portion of the request packet
return the number of bytes added
*/
size_t req_append_bytes(struct smbsrv_request *req,
const uint8_t *bytes, size_t byte_len)
{
req_grow_allocation(req, byte_len + req->out.data_size);
memcpy(req->out.data + req->out.data_size, bytes, byte_len);
req_grow_data(req, byte_len + req->out.data_size);
return byte_len;
}
/*
append variable block (type 5 buffer) into the data portion of the request packet
return the number of bytes added
*/
size_t req_append_var_block(struct smbsrv_request *req,
const uint8_t *bytes, uint16_t byte_len)
{
req_grow_allocation(req, byte_len + 3 + req->out.data_size);
SCVAL(req->out.data + req->out.data_size, 0, 5);
SSVAL(req->out.data + req->out.data_size, 1, byte_len); /* add field length */
if (byte_len > 0) {
memcpy(req->out.data + req->out.data_size + 3, bytes, byte_len);
}
req_grow_data(req, byte_len + 3 + req->out.data_size);
return byte_len + 3;
}
/*
pull a UCS2 string from a request packet, returning a talloced unix string
the string length is limited by the 3 things:
- the data size in the request (end of packet)
- the passed 'byte_len' if it is not -1
- the end of string (null termination)
Note that 'byte_len' is the number of bytes in the packet
on failure zero is returned and *dest is set to NULL, otherwise the number
of bytes consumed in the packet is returned
*/
static size_t req_pull_ucs2(struct smbsrv_request *req, const char **dest, const uint8_t *src, int byte_len, uint_t flags)
{
int src_len, src_len2, alignment=0;
ssize_t ret;
char *dest2;
if (!(flags & STR_NOALIGN) && ucs2_align(req->in.buffer, src, flags)) {
src++;
alignment=1;
if (byte_len != -1) {
byte_len--;
}
}
if (flags & STR_NO_RANGE_CHECK) {
src_len = byte_len;
} else {
src_len = req->in.data_size - PTR_DIFF(src, req->in.data);
if (byte_len != -1 && src_len > byte_len) {
src_len = byte_len;
}
}
if (src_len < 0) {
*dest = NULL;
return 0;
}
src_len2 = utf16_len_n(src, src_len);
if (src_len2 == 0) {
*dest = talloc_strdup(req, "");
return src_len2 + alignment;
}
ret = convert_string_talloc(req, CH_UTF16, CH_UNIX, src, src_len2, (void **)&dest2);
if (ret == -1) {
*dest = NULL;
return 0;
}
*dest = dest2;
return src_len2 + alignment;
}
/*
pull a ascii string from a request packet, returning a talloced string
the string length is limited by the 3 things:
- the data size in the request (end of packet)
- the passed 'byte_len' if it is not -1
- the end of string (null termination)
Note that 'byte_len' is the number of bytes in the packet
on failure zero is returned and *dest is set to NULL, otherwise the number
of bytes consumed in the packet is returned
*/
static size_t req_pull_ascii(struct smbsrv_request *req, const char **dest, const uint8_t *src, int byte_len, uint_t flags)
{
int src_len, src_len2;
ssize_t ret;
char *dest2;
if (flags & STR_NO_RANGE_CHECK) {
src_len = byte_len;
} else {
src_len = req->in.data_size - PTR_DIFF(src, req->in.data);
if (src_len < 0) {
*dest = NULL;
return 0;
}
if (byte_len != -1 && src_len > byte_len) {
src_len = byte_len;
}
}
src_len2 = strnlen((const char *)src, src_len);
if (src_len2 <= src_len - 1) {
/* include the termination if we didn't reach the end of the packet */
src_len2++;
}
ret = convert_string_talloc(req, CH_DOS, CH_UNIX, src, src_len2, (void **)&dest2);
if (ret == -1) {
*dest = NULL;
return 0;
}
*dest = dest2;
return src_len2;
}
/*
pull a string from a request packet, returning a talloced string
the string length is limited by the 3 things:
- the data size in the request (end of packet)
- the passed 'byte_len' if it is not -1
- the end of string (null termination)
Note that 'byte_len' is the number of bytes in the packet
on failure zero is returned and *dest is set to NULL, otherwise the number
of bytes consumed in the packet is returned
*/
size_t req_pull_string(struct smbsrv_request *req, const char **dest, const uint8_t *src, int byte_len, uint_t flags)
{
if (!(flags & STR_ASCII) &&
(((flags & STR_UNICODE) || (req->flags2 & FLAGS2_UNICODE_STRINGS)))) {
return req_pull_ucs2(req, dest, src, byte_len, flags);
}
return req_pull_ascii(req, dest, src, byte_len, flags);
}
/*
pull a ASCII4 string buffer from a request packet, returning a talloced string
an ASCII4 buffer is a null terminated string that has a prefix
of the character 0x4. It tends to be used in older parts of the protocol.
on failure *dest is set to the zero length string. This seems to
match win2000 behaviour
*/
size_t req_pull_ascii4(struct smbsrv_request *req, const char **dest, const uint8_t *src, uint_t flags)
{
ssize_t ret;
if (PTR_DIFF(src, req->in.data) + 1 > req->in.data_size) {
/* win2000 treats this as the empty string! */
(*dest) = talloc_strdup(req, "");
return 0;
}
/* this consumes the 0x4 byte. We don't check whether the byte
is actually 0x4 or not. This matches win2000 server
behaviour */
src++;
ret = req_pull_string(req, dest, src, -1, flags);
if (ret == -1) {
(*dest) = talloc_strdup(req, "");
return 1;
}
return ret + 1;
}
/*
pull a DATA_BLOB from a request packet, returning a talloced blob
return False if any part is outside the data portion of the packet
*/
BOOL req_pull_blob(struct smbsrv_request *req, const uint8_t *src, int len, DATA_BLOB *blob)
{
if (len != 0 && req_data_oob(req, src, len)) {
return False;
}
(*blob) = data_blob_talloc(req, src, len);
return True;
}
/* check that a lump of data in a request is within the bounds of the data section of
the packet */
BOOL req_data_oob(struct smbsrv_request *req, const uint8_t *ptr, uint32_t count)
{
if (count == 0) {
return False;
}
/* be careful with wraparound! */
if (ptr < req->in.data ||
ptr >= req->in.data + req->in.data_size ||
count > req->in.data_size ||
ptr + count > req->in.data + req->in.data_size) {
return True;
}
return False;
}
/*
pull an open file handle from a packet, taking account of the chained_fnum
*/
uint16_t req_fnum(struct smbsrv_request *req, const uint8_t *base, uint_t offset)
{
if (req->chained_fnum != -1) {
return req->chained_fnum;
}
return SVAL(base, offset);
}