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From: =?utf-8?Q?Dag-Erling_Sm=C3=B8rgrav?= <des@des.no>
To: Bruce Evans <bde@zeta.org.au>
References: <23727599.post@talk.nabble.com> <86prdvipwe.fsf@ds4.des.no>
	<20090527233110.E4243@delplex.bde.org> <86r5yaijef.fsf@ds4.des.no>
	<20090529210855.V1643@besplex.bde.org>
Date: Fri, 29 May 2009 18:53:22 +0200
In-Reply-To: <20090529210855.V1643@besplex.bde.org> (Bruce Evans's message of
	"Sat, 30 May 2009 02:01:47 +1000 (EST)")
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Cc: freebsd-hackers@FreeBSD.org, Jakub Lach <jakub_lach@mailplus.pl>
Subject: Re: FYI Lighttpd 1.4.23 /kernel (trailing '/' on regular file
	symlink) vulnerability
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Bruce Evans <bde@zeta.org.au> writes:
> Dag-Erling Sm=C3=B8rgrav <des@des.no> writes:
> % Index: sys/kern/vfs_lookup.c
> % =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> % --- sys/kern/vfs_lookup.c	(revision 192899)
> % +++ sys/kern/vfs_lookup.c	(working copy)
> % @@ -147,6 +147,9 @@
> %  		cnp->cn_flags &=3D ~LOCKSHARED;
> %  	fdp =3D p->p_fd;
> % % +	/* We will set this ourselves if we need it. */
> % +	cnp->cn_flags &=3D ~TRAILINGSLASH;
> % +
>
> Can TRAILINGSLASH ever be set here?  Is namei() ever called recursively?

"suspenders and a belt"

It is hypothetically possible for the caller to have set it.

> %  	/*
> %  	 * Get a buffer for the name to be translated, and copy the
> %  	 * name into the buffer.
> % @@ -533,6 +536,8 @@
> %  		if (*cp =3D=3D '\0') {
> %  			trailing_slash =3D 1;
>
> I thought at first that this flag can go away.

I intend to remove it later - I just wanted to get the bug fixed first.
I'm happy to hear that removing it will fix the two bugs introduced by
the patch I committed :)

DES
--=20
Dag-Erling Sm=C3=B8rgrav - des@des.no