Date: Tue, 07 Aug 2012 12:30:46 -0500 From: Bryan Drewery <bdrewery@FreeBSD.org> To: FreeBSD-gnats-submit@FreeBSD.org Subject: kern/170460: [kern] uuidgen(2) uses ipfw0 interface for MAC address resulting in zeros Message-ID: <201208071731.q77HVbsB095956@freefall.freebsd.org> Resent-Message-ID: <201208071740.q77He160096998@freefall.freebsd.org>
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>Number: 170460
>Category: kern
>Synopsis: [kern] uuidgen(2) uses ipfw0 interface for MAC address resulting in zeros
>Confidential: no
>Severity: non-critical
>Priority: medium
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: update
>Submitter-Id: current-users
>Arrival-Date: Tue Aug 07 17:40:01 UTC 2012
>Closed-Date:
>Last-Modified:
>Originator: Bryan Drewery
>Release: FreeBSD 8.3-RELEASE i386
>Organization:
>Environment:
>Description:
uuidgen(2) reads the first MAC address it finds. This can result in the ipfw0 interace address being used, which is 0.
# ifconfig
ipfw0: flags=8801<UP,SIMPLEX,MULTICAST> metric 0 mtu 65536
nd6 options=23<PERFORMNUD,ACCEPT_RTADV,AUTO_LINKLOCAL>
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> metric 0 mtu 16384
options=3<RXCSUM,TXCSUM>
inet6 ::1 prefixlen 128
inet6 fe80::1%lo0 prefixlen 64 scopeid 0x2
inet 127.0.0.1 netmask 0xff000000
nd6 options=23<PERFORMNUD,ACCEPT_RTADV,AUTO_LINKLOCAL>
xn0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
options=503<RXCSUM,TXCSUM,TSO4,LRO>
ether 08:00:27:a2:7d:bf
inet6 fe80::a00:27ff:fea2:7dbf%xn0 prefixlen 64 scopeid 0x3
inet 10.10.0.35 netmask 0xffff0000 broadcast 10.10.255.255
inet6 2001:470:1f11:262:a00:27ff:fea2:7dbf prefixlen 64 autoconf
nd6 options=23<PERFORMNUD,ACCEPT_RTADV,AUTO_LINKLOCAL>
media: Ethernet manual
status: active
# uuidgen
102beb5c-e0b5-11e1-9304-000000000000
>How-To-Repeat:
Compile with IPFIREWALL.
I'm also using XEN domU.
Somehow the ipfw0 interface is coming first.
>Fix:
Ignore interfaces with no link address.
With patch, it properly ignores ipfw0:
# uuidgen
7ba3705f-e0b5-11e1-9bf7-080027a27dbf
# uuidgen
7bf8778f-e0b5-11e1-9bf7-080027a27dbf
--- patch-kern_uuid_ipfw0.txt begins here ---
Index: sys/kern/kern_uuid.c
===================================================================
--- sys/kern/kern_uuid.c (revision 239130)
+++ sys/kern/kern_uuid.c (working copy)
@@ -102,7 +102,7 @@
TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
sdl = (struct sockaddr_dl*)ifa->ifa_addr;
if (sdl != NULL && sdl->sdl_family == AF_LINK &&
- sdl->sdl_type == IFT_ETHER) {
+ sdl->sdl_type == IFT_ETHER && sdl->sdl_alen > 0) {
/* Got a MAC address. */
bcopy(LLADDR(sdl), node, UUID_NODE_LEN);
IF_ADDR_RUNLOCK(ifp);
--- patch-kern_uuid_ipfw0.txt ends here ---
>Release-Note:
>Audit-Trail:
>Unformatted:
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