Негентушный способ для гентушников. Получилось закрыть дырку. Правда, сделал немного тупо, но ничего, работает.
1. # cd /usr/src/linux
2. nano 2100_proc-mem-handling-fix.patch
3. Копипастинг текста отсюда: http://sources.gentoo.org/viewcvs.py/gentoo-x86/sys-kernel/p...

4. ctrl + o
5. # cd fs/proc/
6. # patch ../../2100_proc-mem-handling-fix.patch
7. # make && make modules_install
8. cp arch/<arch>/boot/bzImage /boot/kernel-<version>-gentoo
9. # reboot

ksodete@dev-tester ~ $ ./in
===============================
=          Mempodipper        =
=           by zx2c4          =
=         Jan 21, 2012        =
===============================

[+] Opening socketpair.
[+] Waiting for transferred fd in parent.
[+] Executing child from child fork.
[+] Opening parent mem /proc/4157/mem in child.
[+] Sending fd 5 to parent.
[+] Received fd at 5.
[+] Assigning fd 5 to stderr.
[+] Ptracing su to find next instruction without reading binary.
[+] Resolved exit@plt to 0x402298.
[+] Calculating su padding.
[+] Seeking to offset 0x40227d.
[+] Executing su with shellcode.
ksodete@dev-tester ~ $ whoami
ksodete
ksodete@dev-tester ~ $