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    SubjectRe: sys_chroot+sys_fchdir Fix
    On Thu, Sep 27, 2007 at 02:01:37AM +0200, Adrian Bunk wrote:
    > <-- snip -->
    > Look, when chroot was being designed, I think they intended that even root
    > should be unable to get out. They went so far as to say that dot-dot
    > wouldn't let you out; and it doesn't.
    > <-- snip -->
    > You were clearly saying that whom you call "they" were the people who
    > designed chroot. And it was you who was claiming in this statement that
    > "they" said it.
    > The OpenBSD manpage you quoted in this thread states chroot() was added
    > in 4.2BSD, and 4.2BSD was released in 1983.
    > You should therefore either bring a source where the people who designed
    > chroot() in 1983 or earlier are stating what you claim they said or
    > admit that you were talking utter bullshit.

    chroot() is present in v7, thank you very much. /usr/sys/sys/sys4.c has


    if (suser())

    and back then it didn't stop lookups by .. at all - u_rdir is only used
    in the beginning of namei() (when pathname starts with /), plus the obvious
    refcounting in exit()/newproc(). So give me a break - back when it had
    been introduced, it didn't do anything jail-like _at_ _all_.

    That check appears only in BSD:
    @@ -1,4 +1,4 @@
    -/* vfs_lookup.c 4.4 03/06/81 */
    +/* vfs_lookup.c 4.5 81/03/09 */

    #include "../h/param.h"
    #include "../h/systm.h"
    @@ -107,6 +107,9 @@
    u.u_segflg = 1;
    eo = 0;
    bp = NULL;
    + if (dp == u.u_rdir && u.u_dent.d_name[0] == '.' &&
    + u.u_dent.d_name[1] == '.' && u.u_dent.d_name[2] == 0)
    + goto cloop;


    with spectaculary lousy commit message ("lint and a minor fixed") by
    wnj. Feel free to ask Bill Joy WTF he had intended. At a guess,
    more consistent behaviour in chrooted environment (i.e. pathname
    resolution looking as if the subtree had been everything).
    To talk about root-safety of _anything_ at that point is bloody ridiculous.
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      Last update: 2007-09-27 06:03    [W:0.031 / U:1.656 seconds]
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