[krbdev.mit.edu #1770] [Maurice Massar] Bug#206851: krb5-kdc: krb5kdc segfaults on startup

[Sam Hartman via RT]

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Subject: Bug#206851: krb5-kdc: krb5kdc segfaults on startup
Reply-To: Maurice Massar <massar at unix-ag.uni-kl.de>,
	206851 at bugs.debian.org
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From: Maurice Massar <massar at unix-ag.uni-kl.de>
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Package: krb5-kdc
Version: 1.3-2
Severity: important
Tags: sid patch

hi,

on my System krb5kdc segfaults on startup.
syslog shows this:
Aug 23 14:30:21 linux1 krb5kdc[10198]: setting up network...
Aug 23 14:30:21 linux1 krb5kdc[10198]: setting up network...
Aug 23 14:30:21 linux1 krb5kdc[10198]: skipping unrecognized local address family 17
Aug 23 14:30:21 linux1 last message repeated 7 times
(it looks like all messages get logged twice, but I haven't checked yet if
this is not a local config problem on my system)

I debugged this with gdb and found that the problem is in
krb5-1.3/src/include/foreachaddr.c, where foreach_localaddr()
assumes that getifaddrs() never returns an entry with ifp->ifa_addr == NULL

writing a small test program I found that to be not the case on my system:
ifaddr @ 0x0x804a2bc
next: 0x0x804a340
name: `ppp0'
flags: 0x10D1
addr: (null)
netmask: (null)
broadaddr: (null)
dstaddr: (null)
data: 0x0x804a92c

this small patch should solve that

--- krb5-1.3.orig/src/include/foreachaddr.c
+++ krb5-1.3/src/include/foreachaddr.c
@@ -382,6 +382,8 @@
 #endif 
        if ((ifp->ifa_flags & IFF_UP) == 0)
            continue;
+       if (!ifp->ifa_addr)
+           continue;
        if (ifp->ifa_flags & IFF_LOOPBACK) {
            ifp->ifa_flags &= ~IFF_UP;
            continue;
@@ -393,6 +395,8 @@
                continue;
            if (ifp2->ifa_flags & IFF_LOOPBACK)
                continue;
+           if (!ifp2->ifa_addr)
+               continue;
            if (addr_eq (ifp->ifa_addr, ifp2->ifa_addr)) {
                match = 1;
                ifp->ifa_flags &= ~IFF_UP;


-- System Information:
Debian Release: testing/unstable
Architecture: i386
Kernel: Linux linux1 2.4.21-2-686 #1 Sat Jul 5 00:38:35 EST 2003 i686
Locale: LANG=C, LC_CTYPE=C

Versions of packages krb5-kdc depends on:
ii  debconf       1.3.11                     Debian configuration management sy
ii  krb5-user     1.3-2                      Basic programs to authenticate usi
ii  libc6         2.3.2-3                    GNU C Library: Shared libraries an
ii  libcomerr2    1.34+1.35-WIP-2003.08.21-2 The Common Error Description libra
ii  libkadm55     1.3-2                      MIT Kerberos administration runtim
ii  libkrb53      1.3-2                      MIT Kerberos runtime libraries

-- debconf information:
  krb5-kdc/debconf: yes
  krb5-kdc/run-krb524: true
* krb5-kdc/krb4-mode: nopreauth