Date: Fri, 25 May 2007 17:32:27 +0900 (JST) From: Takamichi Tateoka <tate@tateoka.org> To: FreeBSD-gnats-submit@FreeBSD.org Subject: ports/112983: XDMCP login from remote host crashs xdm in xorg 7.2 Message-ID: <20070525083227.E29A8154A16@leaf.mobile.tateoka.org> Resent-Message-ID: <200705250900.l4P90A8D020771@freefall.freebsd.org>
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>Number: 112983
>Category: ports
>Synopsis: XDMCP login from remote host crashs xdm in xorg 7.2
>Confidential: no
>Severity: serious
>Priority: high
>Responsible: freebsd-ports-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Fri May 25 09:00:09 GMT 2007
>Closed-Date:
>Last-Modified:
>Originator: Takamichi Tateoka
>Release: FreeBSD 6.2-RELEASE-p5 i386
>Organization:
private
>Environment:
System: FreeBSD leaf.mobile.tateoka.org 6.2-RELEASE-p5 FreeBSD 6.2-RELEASE-p5 #1: Fri May 25 02:16:41 JST 2007 tate@leaf.mobile.tateoka.org:/usr/src/sys/i386/compile/GENERIC i386
xorg 7.2 upgraded.
>Description:
XDMCP login from remote host crashs xdm.
Xdm is crashed because pam_get_item() in
pam_sm_close_session() makes variable "tty" as NULL.
Following patch makes it clear:
---BEGIN---
*** /usr/src/lib/libpam/modules/pam_lastlog/pam_lastlog.c.orig Fri May 25 15:59:00 2007
--- /usr/src/lib/libpam/modules/pam_lastlog/pam_lastlog.c Fri May 25 16:14:18 2007
***************
*** 173,178 ****
--- 173,183 ----
const void *tty;
pam_get_item(pamh, PAM_TTY, (const void **)&tty);
+ if (tty == NULL){
+ syslog(LOG_ERR, "tty is NULL");
+ return(PAM_SYSTEM_ERR);
+ }
+
if (strncmp(tty, _PATH_DEV, strlen(_PATH_DEV)) == 0)
tty = (const char *)tty + strlen(_PATH_DEV);
if (*(const char *)tty == '\0')
---END---
With this patch, xdm logged to /var/log/messages following lines:
May 25 16:29:53 leaf xdm: tty is NULL
May 25 16:29:53 leaf xdm: in _openpam_check_error_code(): pam_sm_close_session()
: unexpected return value 4
>How-To-Repeat:
- add LISTEN and remote host IP address to Xaccess file on target host.
- comment out DisplayManager.requestPort in xdm-config file on target host.
- start xdm on target host.
- execute "X -query targethost" from remote host.
xdm window appears on remote host, but it cause SEGV if login.
/var/log/messages on target host says like that:
May 25 16:05:35 leaf kernel: pid 88443 (xdm), uid 0: exited on signal 11 (core d umped)
>Fix:
>Release-Note:
>Audit-Trail:
>Unformatted:
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