lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Tue, 23 Jan 2007 10:22:41 -0800 From: Rick Jones <rick.jones2@...com> To: Herbert Xu <herbert@...dor.apana.org.au> Cc: dean gaudet <dean@...tic.org>, netdev@...r.kernel.org Subject: Re: why would EPIPE cause socket port to change? Herbert Xu wrote: > dean gaudet <dean@...tic.org> wrote: > >>in the test program below the getsockname result on a TCP socket changes >>across a write which produces EPIPE... here's a fragment of the strace: >> >>getsockname(3, {sa_family=AF_INET, sin_port=htons(37636), sin_addr=inet_addr("127.0.0.1")}, [17863593746633850896]) = 0 >>... >>write(3, "hi!\n", 4) = 4 >>write(3, "hi!\n", 4) = -1 EPIPE (Broken pipe) >>--- SIGPIPE (Broken pipe) @ 0 (0) --- >>getsockname(3, {sa_family=AF_INET, sin_port=htons(59882), sin_addr=inet_addr("127.0.0.1")}, [16927060683038654480]) = 0 >> >>why does the port# change? this is on 2.6.19.1. > > > Prior to the last write, the socket entered the CLOSED state meaning > that the old port is no longer allocated to it. As a result, the > last write operates on an unconnected socket which causes a new local > port to be allocated as an autobind. It then fails because the socket > is still not connected. > > So any attempt to run getsockname after an error on the socket is > simply buggy. But falls within the principle of least surprise doesn't it? Unless the application has called close() or bind(), it does seem like a reasonable expectation that the port assignments are not changed. > (fwiw this is one of two reasons i've found for libnss-ldap to leak > sockets... causing nscd to crash.) Of course, that seems rather odd too - why does libnss-ldap check the socket name on a socket after an EPIPE anyway? rick jones - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists