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Date:      Sat,  6 Apr 2002 23:29:11 +1000 (EST)
From:      Joshua Goodall <joshua@roughtrade.ent>
To:        FreeBSD-gnats-submit@FreeBSD.org
Subject:   kern/36813: un-bzero'd sin_zero causes bind() in PF_INET to fail
Message-ID:  <20020406132911.BFC9D3EAA@green.shallow.net>

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>Number:         36813
>Category:       kern
>Synopsis:       un-bzero'd sin_zero causes bind() in PF_INET to fail
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sat Apr 06 07:00:05 PST 2002
>Closed-Date:
>Last-Modified:
>Originator:     Joshua Goodall
>Release:        FreeBSD 4.5-STABLE i386
>Organization:
>Environment:
System: FreeBSD green.shallow.net 4.5-STABLE FreeBSD 4.5-STABLE #2: Sat Mar 30 12:55:07 EST 2002 joshua@green.shallow.net:/usr/obj/usr/src/sys/GREEN i386

>Description:
ifa_ifwithaddr compares rather more than is desirable; that is, the
sin_zero struct element is also considered. As a result, bind() to
addresses other that INADDR_ANY or multicast addresses fails if the
struct was not bzero'd first, which although advisable, is not
always the case (particularly in some third-party software).

This is fixed in -current but not MFC'd.

>How-To-Repeat:

On an unfixed -stable kernel, this program only succeeded if invoked
as "dobz":

#include <stdio.h>
#include <errno.h>
#include <libgen.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>

int
main(int ac, char **av)
{
	struct sockaddr_in sin;
	int on = 1, port = 2345, fd;
	u_long interface_address = 0x7f000001;
	
        if ((fd = socket(PF_INET, SOCK_DGRAM, 0)) == -1) {
		perror("socket()"); exit(1);
	}
	sin.sin_family	= AF_INET;
	sin.sin_port	= htons(port);
	sin.sin_addr.s_addr= htonl(interface_address);

	if (strcmp(basename(*av), "dobz") == 0)
		bzero(sin.sin_zero, sizeof(sin.sin_zero));

	if (bind(fd, (struct sockaddr *) &sin, sizeof(sin)) == -1) {
		fprintf(stderr,
			"bind() fd %d fam %d port %d addr %s errno %d %s\n",
			fd, sin.sin_family, (int)ntohs(sin.sin_port),
			inet_ntoa(sin.sin_addr.s_addr), errno, strerror(errno));
		exit(1);
	}
	printf("succeeded!\n");
}

>Fix:


Index: sys/netinet/in_pcb.c
===================================================================
RCS file: /cvs/src/sys/netinet/in_pcb.c,v
retrieving revision 1.59.2.21
diff -u -r1.59.2.21 in_pcb.c
--- sys/netinet/in_pcb.c	26 Feb 2002 18:11:24 -0000	1.59.2.21
+++ sys/netinet/in_pcb.c	6 Apr 2002 12:52:45 -0000
@@ -220,6 +220,7 @@
 				reuseport = SO_REUSEADDR|SO_REUSEPORT;
 		} else if (sin->sin_addr.s_addr != INADDR_ANY) {
 			sin->sin_port = 0;		/* yech... */
+			bzero(&sin->sin_zero, sizeof(sin->sin_zero));
 			if (ifa_ifwithaddr((struct sockaddr *)sin) == 0)
 				return (EADDRNOTAVAIL);
 		}

>Release-Note:
>Audit-Trail:
>Unformatted:

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