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https://github.com/samba-team/samba.git
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b947ad3a49
lib/debug.c: Fix for potential null pointer access.
Jeremy.
(This used to be commit 5a4d22dd66
)
227 lines
6.3 KiB
C
227 lines
6.3 KiB
C
/*
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Unix SMB/Netbios implementation.
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Version 3.0
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change notify handling - hash based implementation
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Copyright (C) Jeremy Allison 1994-1998
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Copyright (C) Andrew Tridgell 2000
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include "includes.h"
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struct change_data {
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time_t last_check_time; /* time we last checked this entry */
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time_t modify_time; /* Info from the directory we're monitoring. */
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time_t status_time; /* Info from the directory we're monitoring. */
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time_t total_time; /* Total time of all directory entries - don't care if it wraps. */
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unsigned int num_entries; /* Zero or the number of files in the directory. */
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unsigned int mode_sum;
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unsigned char name_hash[16];
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};
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/****************************************************************************
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Create the hash we will use to determine if the contents changed.
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*****************************************************************************/
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static BOOL notify_hash(connection_struct *conn, char *path, uint32 flags,
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struct change_data *data, struct change_data *old_data)
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{
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SMB_STRUCT_STAT st;
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pstring full_name;
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char *p;
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char *fname;
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size_t remaining_len;
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size_t fullname_len;
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void *dp;
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ZERO_STRUCTP(data);
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if(vfs_stat(conn,path, &st) == -1)
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return False;
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data->modify_time = st.st_mtime;
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data->status_time = st.st_ctime;
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if (old_data) {
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/*
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* Shortcut to avoid directory scan if the time
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* has changed - we always must return true then.
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*/
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if (old_data->modify_time != data->modify_time ||
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old_data->status_time != data->status_time ) {
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return True;
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}
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}
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/*
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* If we are to watch for changes that are only stored
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* in inodes of files, not in the directory inode, we must
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* scan the directory and produce a unique identifier with
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* which we can determine if anything changed. We use the
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* modify and change times from all the files in the
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* directory, added together (ignoring wrapping if it's
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* larger than the max time_t value).
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*/
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dp = OpenDir(conn, path, True);
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if (dp == NULL)
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return False;
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data->num_entries = 0;
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pstrcpy(full_name, path);
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pstrcat(full_name, "/");
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fullname_len = strlen(full_name);
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remaining_len = sizeof(full_name) - fullname_len - 1;
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p = &full_name[fullname_len];
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while ((fname = ReadDirName(dp))) {
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if(strequal(fname, ".") || strequal(fname, ".."))
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continue;
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data->num_entries++;
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safe_strcpy(p, fname, remaining_len);
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ZERO_STRUCT(st);
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/*
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* Do the stat - but ignore errors.
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*/
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vfs_stat(conn,full_name, &st);
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/*
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* Always sum the times.
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*/
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data->total_time += (st.st_mtime + st.st_ctime);
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/*
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* If requested hash the names.
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*/
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if (flags & (FILE_NOTIFY_CHANGE_DIR_NAME|FILE_NOTIFY_CHANGE_FILE_NAME|FILE_NOTIFY_CHANGE_FILE)) {
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int i;
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unsigned char tmp_hash[16];
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mdfour(tmp_hash, (unsigned char *)fname, strlen(fname));
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for (i=0;i<16;i++)
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data->name_hash[i] ^= tmp_hash[i];
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}
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/*
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* If requested sum the mode_t's.
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*/
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if (flags & (FILE_NOTIFY_CHANGE_ATTRIBUTES|FILE_NOTIFY_CHANGE_SECURITY))
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data->mode_sum = st.st_mode;
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}
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CloseDir(dp);
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return True;
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}
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/****************************************************************************
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Register a change notify request.
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*****************************************************************************/
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static void *hash_register_notify(connection_struct *conn, char *path, uint32 flags)
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{
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struct change_data data;
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if (!notify_hash(conn, path, flags, &data, NULL))
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return NULL;
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data.last_check_time = time(NULL);
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return (void *)memdup(&data, sizeof(data));
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}
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/****************************************************************************
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Check if a change notify should be issued.
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A time of zero means instantaneous check - don't modify the last check time.
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*****************************************************************************/
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static BOOL hash_check_notify(connection_struct *conn, uint16 vuid, char *path, uint32 flags, void *datap, time_t t)
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{
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struct change_data *data = (struct change_data *)datap;
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struct change_data data2;
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if (t && t < data->last_check_time + lp_change_notify_timeout())
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return False;
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if (!change_to_user(conn,vuid))
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return True;
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if (!set_current_service(conn,True)) {
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change_to_root_user();
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return True;
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}
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if (!notify_hash(conn, path, flags, &data2, data) ||
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data2.modify_time != data->modify_time ||
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data2.status_time != data->status_time ||
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data2.total_time != data->total_time ||
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data2.num_entries != data->num_entries ||
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data2.mode_sum != data->mode_sum ||
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memcmp(data2.name_hash, data->name_hash, sizeof(data2.name_hash))) {
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change_to_root_user();
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return True;
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}
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if (t)
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data->last_check_time = t;
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change_to_root_user();
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return False;
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}
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/****************************************************************************
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Remove a change notify data structure.
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*****************************************************************************/
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static void hash_remove_notify(void *datap)
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{
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free(datap);
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}
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/****************************************************************************
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Setup hash based change notify.
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****************************************************************************/
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struct cnotify_fns *hash_notify_init(void)
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{
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static struct cnotify_fns cnotify;
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cnotify.register_notify = hash_register_notify;
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cnotify.check_notify = hash_check_notify;
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cnotify.remove_notify = hash_remove_notify;
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cnotify.select_time = lp_change_notify_timeout();
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return &cnotify;
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}
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/*
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change_notify_reply_packet(cnbp->request_buf,ERRSRV,ERRaccess);
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change_notify_reply_packet(cnbp->request_buf,0,NT_STATUS_NOTIFY_ENUM_DIR);
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chain_size = 0;
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file_chain_reset();
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uint16 vuid = (lp_security() == SEC_SHARE) ? UID_FIELD_INVALID :
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SVAL(cnbp->request_buf,smb_uid);
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*/
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