Files
rsync/connection.c
T
Andrew Tridgell d199b43149 daemon: harden authentication, access, socket and config-hook handling
authenticate.c: seed gen_challenge() from /dev/urandom, add an "auth digest" floor
to refuse weak negotiated digests, and fstat the opened --password-file fd rather
than re-stat the pathname; checksum.c carries auth_digest_rank().  socket.c: reject
control bytes in the daemon host before a proxy CONNECT and bind the stunnel server
cert to the requested hostname.  clientserver/access: warn when proxy-protocol
fail-closes.  loadparm + daemon-parm: only shell-quote %RSYNC_*% for shell-executed
hooks, and add the auth-digest / proxy-protocol-hosts module parameters.
2026-07-20 14:05:31 +10:00

50 lines
1.5 KiB
C

/*
* Support the max connections option.
*
* Copyright (C) 1998 Andrew Tridgell
* Copyright (C) 2006-2020 Wayne Davison
*
* 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, visit the http://fsf.org website.
*/
#include "rsync.h"
/* A simple routine to do connection counting. This returns 1 on success
* and 0 on failure, with errno also being set if the open() failed (errno
* will be 0 if the lock request failed). */
int claim_connection(char *fname, int max_connections)
{
int fd, i;
if (max_connections == 0)
return 1;
/* 'lock file = PATH': refuse symlinks not owned by uid 0 or our euid so
* a planted parent can't redirect the root daemon's O_CREAT open. */
if ((fd = open_no_attacker_symlinks(fname, O_RDWR|O_CREAT, 0600)) < 0)
return 0;
/* Find a free spot. */
for (i = 0; i < max_connections; i++) {
if (lock_range(fd, i*4, 4))
return 1;
}
close(fd);
/* A lock failure needs to return an errno of 0. */
errno = 0;
return 0;
}