3 # This file SHOULD NOT be executable! It is sourced by jailsetup.sh and
4 # SHOULD NOT be executed directly!
6 # On entry the current directory will be set to the top of the chroot
7 # This script must perform platform-specific chroot setup which includes
8 # creating any dev device entries, setting up proc (if needed), setting
9 # up lib64 (if needed) as well as installing a basic set of whatever libraries
10 # are needed for a chroot to function on this platform.
12 # This script must also define a pull_in_bin function that may be called to
13 # install an executable together with any libraries it depends on into the
16 # Finally this script must install a suitable nc.openbsd compatible version of
17 # netcat into the chroot jail that's available as nc.openbsd and which supports
18 # connects to unix sockets.
20 # We are designed to set up the chroot based on binaries from
21 # amd64 Debian lenny; some things may need slight modifications if
22 # being run on a different distribution.
24 mkdir
-p dev proc selinux
25 chown
0:0 proc selinux
30 rm -f dev
/null dev
/zero dev
/random dev
/urandom
33 mknod dev
/random c
1 8
34 mknod dev
/urandom c
1 9
35 chmod a
+rw dev
/null dev
/zero dev
/random dev
/urandom
38 mkdir
-p var
/run
/sshd var
/tmp
40 # Bring in basic libraries:
43 cp -p -t lib
/lib
/ld-linux
*.so
*
44 [ ! -d /lib64
] ||
cp -p -t lib
/lib64
/ld-linux
*64.so
*
46 # Besides '=>' libs, attempt to pick up absolute path libs and create a symlink for upto one level deep
48 ldd
"$1" |
grep -v -e linux-gate
-e linux-vdso
-e ld-linux |
awk '{print $1 " " $2 " " $3}' | \
49 while read -r _f1 _f2 _f3
; do
55 case "$_f1" in /*.so
*)
56 _basedir
="$(dirname "$_f1")"
57 _basedir
="${_basedir#/}"
58 _basedir
="${_basedir#usr/}"
64 _basedir
="${_basedir#lib/}"
65 case "$_basedir" in */*) :;; *)
66 if [ ! -e "lib/$_basedir" ]; then
67 ln -s .
"lib/$_basedir"
79 dst
="${2%/}/$(basename "$1")"
80 if [ ! -e "$dst" ] ||
[ "$1" -nt "$dst" ]; then
82 for llib
in $
(extract_libs
"$1"); do
83 (pull_in_lib
"$llib" lib
)
86 case "$(basename "$1")" in libc.
*)
87 # grab libnss_compat.so* from libc location
88 for nlib
in "$(dirname "$1")/libnss_compat."so
*; do
89 (pull_in_lib
"$nlib" "$2")
94 # pull_in_bin takes two arguments:
95 # 1: the full path to a binary to pull in (together with any library dependencies)
96 # 2: the destination directory relative to the current directory to copy it to
97 # 3: optional name of binary that if already in $2 and the same as $1 hard link to instead
98 # for example, "pull_in_bin /bin/sh bin" will install the shell into the chroot bin directory
99 # IMPORTANT: argument 1 must be a machine binary, NOT a shell script or other interpreted text
100 # IMPORTANT: text scripts can simply be copied in or installed as they don't have libraries to copy
101 # NOTE: it's expected that calling this function on a running chroot may cause temporary disruption
102 # In order to avoid a busy error while replacing binaries we first copy the binary to the
103 # var/tmp directory and then force move it into place after the libs have been brought in.
106 if [ -n "$3" ] && [ "$3" != "$(basename "$bin")" ] && \
107 [ -r "${bdst%/}/$3" ] && cmp -s "$bin" "${bdst%/}/$3"; then
108 ln -f "${bdst%/}/$3" "${bdst%/}/$(basename "$bin")"
111 cp -p -t var
/tmp
"$bin"
112 # ...and all the dependencies.
113 for lib
in $
(extract_libs
"$bin"); do
114 pull_in_lib
"$lib" lib
116 mv -f "var/tmp/$(basename "$bin")" "${bdst%/}/"
119 # A catch all that needs to be called after everything's been pulled in
120 chroot_update_permissions
() {
122 chown
-R 0:0 bin dev lib sbin var
125 # nothing special here, the nc.openbsd compatible utility is nc.openbsd
126 pull_in_bin
/bin
/nc.openbsd bin