Date: Sun, 2 Feb 1997 04:57:29 +1100 (EST) From: Julian Assange <proff@iq.org> To: FreeBSD-gnats-submit@freebsd.org, rms@gnu.ai.mit.edu, dyson@freebsd.org Subject: bin/2634: <Synopsis of the problem (one line)> rtld patches for easy creation of chroot enviroments Message-ID: <199702011757.EAA07388@profane.iq.org> Resent-Message-ID: <199702011800.KAA02204@freefall.freebsd.org>
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>Number: 2634
>Category: bin
>Synopsis: rtld patches for easy creation of chroot enviroments
>Confidential: no
>Severity: non-critical
>Priority: medium
>Responsible: freebsd-bugs
>State: open
>Class: change-request
>Submitter-Id: current-users
>Arrival-Date: Sat Feb 1 10:00:01 PST 1997
>Last-Modified:
>Originator: Julian Assange
>Organization:
>Release: FreeBSD 3.0-CURRENT i386
>Environment:
>Description:
[note to rms: can you bounce this to whoever is responsible for gnu rtld?
my distribution doesn't have any contact details :(]
Creation of chrooted() enviroments is normally quite a difficult
affair and impossible to do securely without source modification
of the program to be executed [otherwise you have executeables or
shared library images in the chrooted() area].
The following patches allow very easy creation of chrooted areas, without
source modification, or unsafe static linking or copying of library images.
e.g
# export LD_CHROOT=/usr/local/chroot/named
# named
>How-To-Repeat:
>Fix:
--- src/gnu/usr.bin/ld/rtld/rtld.c~ Sun Feb 2 04:29:16 1997
+++ src/gnu/usr.bin/ld/rtld/rtld.c Sun Feb 2 04:21:36 1997
@@ -194,6 +194,7 @@
static char *ld_tracing;
static char *ld_suppress_warnings;
static char *ld_warn_non_pure_code;
+static char *ld_chroot;
struct so_map *link_map_head;
struct so_map *link_map_tail;
@@ -411,6 +412,13 @@
(void)close(crtp->crt_ldfd);
anon_close();
+ if (ld_chroot) {
+ if (chdir(ld_chroot) !=0 ||
+ chroot(ld_chroot) !=0 ||
+ chdir("/") !=0)
+ err(1, "LD_CHROOT(%s) failed", ld_chroot);
+ }
+
return LDSO_VERSION_HAS_DLEXIT;
}
@@ -2037,6 +2045,7 @@
L("LD_BIND_NOW=", 0, &ld_bind_now)
L("LD_SUPPRESS_WARNINGS=", 0, &ld_suppress_warnings)
L("LD_WARN_NON_PURE_CODE=", 0, &ld_warn_non_pure_code)
+ L("LD_CHROOT=", 1, &ld_chroot)
{ NULL, 0, NULL }
};
#undef L
--- src/gnu/usr.bin/ld/rtld/rtld.1~ Sun Feb 2 04:29:10 1997
+++ src/gnu/usr.bin/ld/rtld/rtld.1 Sun Feb 2 04:24:51 1997
@@ -117,6 +117,9 @@
the directories specified by LD_LIBRARY_PATH will be searched first
followed by the set of built-in standard directories.
This is ignored for set-user-ID and set-group-ID programs.
+.It Ev LD_CHROOT
+Directory to chroot() to immediately after linking.
+This is ignored for set-user-ID and set-group-ID programs.
.It Ev LD_BIND_NOW
When set to a nonempty string, causes
.Nm
@@ -219,6 +222,7 @@
.Sh SEE ALSO
.Xr ld 1 ,
.Xr link 5 ,
-.Xr ldconfig 8
+.Xr ldconfig 8 ,
+.Xr chroot 2
.Sh HISTORY
The shared library model employed first appeared in SunOS 4.0
>Audit-Trail:
>Unformatted:
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