Here's a screenshot of SUBTERFUGUE using the SimplePathSandbox trick. This trick restricts read and write access to the specified directory trees. In this example, we're specifying that all files may be read, but that only /tmp/abc (and the files it contains, recursively, since it's a directory here) and /dev/tty may be written. (The 'net=1' means that network access is enabled.)
The copy of bash and other commands used here are the unmodified Debian versions. All filesystems are ext2, mounted read/write from ordinary disks, with no special file attributes set. Nothing up our sleeves, as it were.
bash-2.03$ sf --trick=SimplePathSandbox:"read=['/'];write=['/tmp/abc', '/dev/tty'];net=1" bash bash-2.03$ cd /tmp bash-2.03$ ls -l foo -rw-rw-r-- 1 mkc mkc 11664 Feb 3 01:26 foo bash-2.03$ touch foo write deny (open): 'foo' bash-2.03$ ls -l foo -rw-rw-r-- 1 mkc mkc 11664 Feb 3 01:26 foo bash-2.03$ rm -f foo write deny (unlink): 'foo' rm: cannot unlink `foo': Permission denied bash-2.03$ ls -l foo -rw-rw-r-- 1 mkc mkc 11664 Feb 3 01:26 foo bash-2.03$ cd /tmp/abc bash-2.03$ ls -al total 44 drwxr-xr-x 2 mkc mkc 1024 Feb 3 01:12 . drwxrwxrwt 13 root root 39936 Feb 3 01:26 .. -rw-r--r-- 1 mkc mkc 4 Feb 3 01:12 a -rw-r--r-- 1 mkc mkc 4 Feb 3 01:12 b -rw-r--r-- 1 mkc mkc 4 Feb 3 01:12 c bash-2.03$ echo foobar > d bash-2.03$ ls -al total 45 drwxr-xr-x 2 mkc mkc 1024 Feb 3 01:27 . drwxrwxrwt 13 root root 39936 Feb 3 01:26 .. -rw-r--r-- 1 mkc mkc 4 Feb 3 01:12 a -rw-r--r-- 1 mkc mkc 4 Feb 3 01:12 b -rw-r--r-- 1 mkc mkc 4 Feb 3 01:12 c -rw-r--r-- 1 mkc mkc 7 Feb 3 01:27 d bash-2.03$ cp a .. write deny (open): '../a' cp: cannot create regular file `../a': Permission denied bash-2.03$ exit exit write deny (open): '/usr/local/home/mkc/.bash_history'
You are strongly advised not to try anything like this yourself (yet), unless you're using a scratch system that you don't mind losing.
bash-2.03$ su Password: microdog# sf --trick=SimplePathSandbox:"read=['/'];write=['/tmp/abc', '/dev/tty'];net=1" bash microdog# cd /tmp microdog# ls -l foo -rw-rw-r-- 1 mkc mkc 11664 Feb 3 01:26 foo microdog# rm -f foo write deny (unlink): 'foo' rm: cannot unlink `foo': Permission denied microdog# ls -l foo -rw-rw-r-- 1 mkc mkc 11664 Feb 3 01:26 foo microdog# touch /arf write deny (open): '/arf' touch: /arf: Permission deniedThe file 'redinstall' is an imaginary install script for Redmond Pandemic, Inc. It has a couple of bugs.
microdog# cat /tmp/redinstall #!/bin/sh set -x rm -f /etc/passwd cat <<'EOF' > /etc/passwd billg::0:0:That's *Mr* Third to you!:/:/command.com EOF cp /dev/null /usr/bin/passwd microdog# /tmp/redinstall + rm -f /etc/passwd write deny (unlink): '/etc/passwd' rm: cannot unlink `/etc/passwd': Permission denied + cat write deny (open): '/tmp/t.HHMckb' /tmp/redinstall: cannot create temp file for here document: Permission denied + cp /dev/null /usr/bin/passwd write deny (open): '/usr/bin/passwd' cp: cannot create regular file `/usr/bin/passwd': Permission denied microdog# exit exit write deny (open): '/root/.bash_history'We see now that /usr/bin/passwd is unscathed, and that it can be altered by root again once we have exited sf.
microdog# cd /usr/bin microdog# ls -l passwd -rwsr-xr-x 1 root root 28896 Jul 17 1998 passwd microdog# mv passwd passwd.tmp microdog# ls -l passwd ls: passwd: No such file or directory microdog# mv passwd.tmp passwd microdog# ls -l passwd -rwsr-xr-x 1 root root 28896 Jul 17 1998 passwd microdog# exit
This shows the Trace trick, which basically does what 'strace' does. (The output is very unpolished compared to strace, and very little argument decoding has yet been implemented.)
bash-2.03$ sf --trick=Trace date
[16433] brk(0) =
[16433] brk() = 134538648
[16433] open('/etc/ld.so.preload', 0, 1073818004) =
[16433] open() = -2 ENOENT (No such file or directory)
[16433] open('/etc/ld.so.cache', 0, 0) =
[16433] open() = 4
[16433] fstat(4, -1073744172) =
[16433] fstat() = 0
[16433] mmap(-1073744116, -1073744172, 1073815716, 1073817392, 4, -1073743964) =
[16433] mmap() = 1073819648
[16433] close(4) =
[16433] close() = 0
[16433] open('/lib/libc.so.6', 0, 1) =
[16433] open() = 4
[16433] fstat(4, -1073744220) =
[16433] fstat() = 0
[16433] read(4, -1073748228, 4096) =
[16433] read() = 4096 '\177ELF\001\001\001\000\000\000\000\000\000\000\000\000\003\000\003\000\001\000\000\000\344\210\001\0004\000\000\000'
[16433] mmap(-1073748388, 3, 1073815716, -1073748016, -1073748356, -1073743916) =
[16433] mmap() = 1073840128
[16433] mprotect(1074716672, 27900, 0) =
[16433] mprotect() = 0
[16433] mmap(-1073748388, 16384, 1073815716, -1073748016, -1073748332, -1073743916) =
[16433] mmap() = 1074716672
[16433] mmap(-1073748388, 0, 1073815716, 1074733056, -1073748332, -1073743916) =
[16433] mmap() = 1074733056
[16433] close(4) =
[16433] close() = 0
[16433] munmap(1073819648, 19819) =
[16433] munmap() = 0
[16433] personality(0) =
[16433] personality() = 0
[16433] getpid() =
[16433] getpid() = 16433
[16433] brk(0) =
[16433] brk() = 134538648
[16433] brk(134539064) =
[16433] brk() = 134539064
[16433] brk(134541312) =
[16433] brk() = 134541312
[16433] time(-1073742676) =
[16433] time() = 949639556
[16433] open('/etc/localtime', 0, 438) =
[16433] open() = 4
[16433] read(4, -1073742988, 44) =
[16433] read() = 44 'TZif\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\004\000\000\000\004\000\000\000\000'
[16433] read(4, 134539312, 1170) =
[16433] read() = 1170 '\236\246,\200\237\272\371p\240\206\016\200\241\232\333p\242\313t\000\243\203\367\360\244E\322\200\245c\331\360'
[16433] fstat(4, -1073743536) =
[16433] fstat() = 0
[16433] mmap(-1073743432, -1073743536, 1074727000, 4096, 134539128, -1073743280) =
[16433] mmap() = 1073819648
[16433] read(4, 1073819648, 4096) =
[16433] read() = 48 '\377\377\271\260\001\000\377\377\253\240\000\004\377\377\271\260\001\010\377\377\271\260\000\014CWT\000CST\000'
[16433] close(4) =
[16433] close() = 0
[16433] munmap(1073819648, 4096) =
[16433] munmap() = 0
[16433] fstat(1, -1073744788) =
[16433] fstat() = 0
[16433] mmap(-1073744684, -1073744788, 1074727000, 4096, 134538080, -1073744532) =
[16433] mmap() = 1073819648
[16433] ioctl(1, 21505, -1073744808) =
[16433] ioctl() = 0
[16433] write(1, 'Thu Feb 3 22:45:56 CST 2000\012', 29) =
Thu Feb 3 22:45:56 CST 2000
[16433] write() = 29
[16433] close(1) =
[16433] close() = 0
[16433] munmap(1073819648, 4096) =
[16433] munmap() = 0
[16433] _exit(0) =
[16433] exited (status = 0)
Here's a shot of the NetThrottle trick, which limits network bandwith. It has a GTK interface to allow the bandwidth limit to be interactively modified.
In this example, NetThrottle is being used to keep a kernel download from swamping the network connection.
The TimeWarp trick can be used to control the application's experience of passing time. In this screenshot, we see several independent SUBTERFUGUE sessions being used to run xclock with differing warp factors.
