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/*
* Expand msdfs targets based on client IP
*
* Copyright (C) Volker Lendecke, 2004
*
* 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/>.
*/
#include "includes.h"
#include "system/filesys.h"
#include "smbd/smbd.h"
#include "../librpc/gen_ndr/ndr_netlogon.h"
#include "smbd/globals.h"
#include "auth.h"
#include "../lib/tsocket/tsocket.h"
#undef DBGC_CLASS
#define DBGC_CLASS DBGC_VFS
/**********************************************************
Under mapfile we expect a table of the following format:
IP-Prefix whitespace expansion
For example:
192.168.234 local.samba.org
192.168 remote.samba.org
default.samba.org
This is to redirect a DFS client to a host close to it.
***********************************************************/
static char *read_target_host(TALLOC_CTX *ctx, const char *mapfile,
const char *clientaddr)
{
FILE *f;
char buf[1024];
char *space = buf;
bool found = false;
f = fopen(mapfile, "r");
if (f == NULL) {
DEBUG(0,("can't open IP map %s. Error %s\n",
mapfile, strerror(errno) ));
return NULL;
}
DEBUG(10, ("Scanning mapfile [%s]\n", mapfile));
while (fgets(buf, sizeof(buf), f) != NULL) {
if ((strlen(buf) > 0) && (buf[strlen(buf)-1] == '\n'))
buf[strlen(buf)-1] = '\0';
DEBUG(10, ("Scanning line [%s]\n", buf));
space = strchr_m(buf, ' ');
if (space == NULL) {
DEBUG(0, ("Ignoring invalid line %s\n", buf));
continue;
}
*space = '\0';
if (strncmp(clientaddr, buf, strlen(buf)) == 0) {
found = true;
break;
}
}
fclose(f);
if (!found) {
return NULL;
}
space += 1;
while (isspace(*space))
space += 1;
return talloc_strdup(ctx, space);
}
/**********************************************************
Expand the msdfs target host using read_target_host
explained above. The syntax used in the msdfs link is
msdfs:@table-filename@/share
Everything between and including the two @-signs is
replaced by the substitution string found in the table
described above.
***********************************************************/
static char *expand_msdfs_target(TALLOC_CTX *ctx,
connection_struct *conn,
char *target)
{
char *mapfilename = NULL;
char *filename_start = strchr_m(target, '@');
char *filename_end = NULL;
int filename_len = 0;
char *targethost = NULL;
char *new_target = NULL;
char *raddr;
if (filename_start == NULL) {
DEBUG(10, ("No filename start in %s\n", target));
return NULL;
}
filename_end = strchr_m(filename_start+1, '@');
if (filename_end == NULL) {
DEBUG(10, ("No filename end in %s\n", target));
return NULL;
}
filename_len = PTR_DIFF(filename_end, filename_start+1);
mapfilename = talloc_strdup(ctx, filename_start+1);
if (!mapfilename) {
return NULL;
}
mapfilename[filename_len] = '\0';
DEBUG(10, ("Expanding from table [%s]\n", mapfilename));
raddr = tsocket_address_inet_addr_string(conn->sconn->remote_address,
ctx);
if (raddr == NULL) {
return NULL;
}
targethost = read_target_host(ctx, mapfilename, raddr);
if (targethost == NULL) {
DEBUG(1, ("Could not expand target host from file %s\n",
mapfilename));
return NULL;
}
targethost = talloc_sub_full(ctx,
lp_servicename(talloc_tos(), SNUM(conn)),
conn->session_info->unix_info->unix_name,
conn->connectpath,
conn->session_info->unix_token->gid,
conn->session_info->unix_info->sanitized_username,
conn->session_info->info->domain_name,
targethost);
DEBUG(10, ("Expanded targethost to %s\n", targethost));
/* Replace the part between '@...@' */
*filename_start = '\0';
new_target = talloc_asprintf(ctx,
"%s%s%s",
target,
targethost,
filename_end+1);
if (!new_target) {
return NULL;
}
DEBUG(10, ("New DFS target: %s\n", new_target));
return new_target;
}
static int expand_msdfs_readlinkat(struct vfs_handle_struct *handle,
files_struct *dirfsp,
const struct smb_filename *smb_fname,
char *buf,
size_t bufsiz)
{
TALLOC_CTX *ctx = talloc_tos();
int result;
char *target = talloc_array(ctx, char, PATH_MAX+1);
size_t len;
if (!target) {
errno = ENOMEM;
return -1;
}
if (bufsiz == 0) {
errno = EINVAL;
return -1;
}
result = SMB_VFS_NEXT_READLINKAT(handle,
dirfsp,
smb_fname,
target,
PATH_MAX);
if (result <= 0)
return result;
target[result] = '\0';
if ((strncmp(target, "msdfs:", 6) == 0) &&
(strchr_m(target, '@') != NULL)) {
target = expand_msdfs_target(ctx, handle->conn, target);
if (!target) {
errno = ENOENT;
return -1;
}
}
len = MIN(bufsiz, strlen(target));
memcpy(buf, target, len);
TALLOC_FREE(target);
return len;
}
static struct vfs_fn_pointers vfs_expand_msdfs_fns = {
.readlinkat_fn = expand_msdfs_readlinkat
};
static_decl_vfs;
NTSTATUS vfs_expand_msdfs_init(TALLOC_CTX *ctx)
{
return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "expand_msdfs",
&vfs_expand_msdfs_fns);
}
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