Date: Sat, 8 May 2004 06:40:41 +0000 (UTC) From: "Bjoern A. Zeeb" <bzeeb-lists@lists.zabbadoz.net> To: Eugene Grosbein <eugen@grosbein.pp.ru> Cc: net@freebsd.org Subject: Re: bin/65928: [PATCH] stock ftpd uses superuser credentials for active mode sockets Message-ID: <Pine.BSF.4.53.0405080636010.66978@e0-0.zab2.int.zabbadoz.net> In-Reply-To: <20040508034514.GA937@grosbein.pp.ru> References: <20040508034514.GA937@grosbein.pp.ru>
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On Sat, 8 May 2004, Eugene Grosbein wrote: Hi, > When an active IPv4 TCP connection between > localIP:localport and remoteIP1:remoteport1 exists, > it is not possible for local non-root user to create outgoing > TCP connection from localIP:localport to remoteIP2:remoteport2. > > Why? It prevents http://www.freebsd.org/cgi/query-pr.cgi?pr=bin/65928 > from resolving. to do it with other wording: if in active mode data is send to remote, the server uses ftp-data as port (which is 20 [ftp(21)-1]) and you are running into creating a socket in the privileged port range: net.inet.ip.portrange.reservedlow to net.inet.ip.portrange.reservedhigh which "only may be opened by root-owned processes" [ip(4)]. -- Bjoern A. Zeeb bzeeb at Zabbadoz dot NeT 56 69 73 69 74 http://www.zabbadoz.net/
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