/* * 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) { XFILE *f; char buf[1024]; char *space = buf; bool found = false; f = x_fopen(mapfile, O_RDONLY, 0); 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 (x_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; } } x_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, raddr, mapfilename); if (targethost == NULL) { DEBUG(1, ("Could not expand target host from file %s\n", mapfilename)); return NULL; } targethost = talloc_sub_advanced(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_readlink(struct vfs_handle_struct *handle, const char *path, 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_READLINK(handle, path, 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 = { .readlink_fn = expand_msdfs_readlink }; NTSTATUS vfs_expand_msdfs_init(void); NTSTATUS vfs_expand_msdfs_init(void) { return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "expand_msdfs", &vfs_expand_msdfs_fns); }