From owner-freebsd-net@FreeBSD.ORG  Mon Apr 14 09:02:15 2008
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From: Marc =?iso-8859-1?q?L=F6rner?= <marc.loerner@hob.de>
Organization: hob
Date: Mon, 14 Apr 2008 10:33:35 +0200
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Subject: problem in if_tap.c
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Hello,
I found the following problem in the if_tap-device code in function tapcreate
when used on 64-bit systems:

       TAPDEBUG("tapcreate(%s%d). minor = %#x\n", name, unit, minor(dev));

        /* generate fake MAC address: 00 bd xx xx xx unit_no */
        macaddr_hi = htons(0x00bd);
        bcopy(&macaddr_hi, eaddr, sizeof(short));

---->
        bcopy(&ticks, &eaddr[2], sizeof(long));
        eaddr[5] = (u_char)unit;

        /* fill the rest and attach interface */

sizeof(long) is not always 4 on any system (e.g. on ia64 it's 8)
=> bytes are copied from undefined memory  into undefined memory

Regards,
Marc

P.S.: On replies please cc me because I'm not on the list.