[Bug 597702] [NEW] Kernel ignores noexec=off parameter

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Hello everybody,

I'm running Ubuntu 10.04 32-bit 2.6.32-22-generic-pae kernel.

I need to boot into Ubuntu having the NX bit set forced OFF since even
if i disabled execution protection from BIOS Ubuntu emulates it. (ref @
https://wiki.ubuntu.com/Security/Features#Non-Exec%20Memory)

As such, according to the kernel parameters from kernel.org (ref @
http://www.kernel.org/doc/Documentation/kernel-parameters.txt search for
noexec) i am appending the following to parameters to my grub.cfg:
noexec=off and noexec32=off

<grub.cfg snip>
menuentry 'Ubuntu, with Linux 2.6.32-22-generic-pae' --class ubuntu --class gnu-linux --class gnu --class os {
	recordfail
	insmod ext2
	set root='(hd0,1)'
	search --no-floppy --fs-uuid --set de69abbd-bd5d-455e-b4c0-be9ab0ed6037
	linux	/boot/vmlinuz-2.6.32-22-generic-pae root=UUID=de69abbd-bd5d-455e-b4c0-be9ab0ed6037 ro   crashkernel=384M-2G:64M,2G-:128M noexec=off noexec32=off
	initrd	/boot/initrd.img-2.6.32-22-generic-pae
}
</grub.cfg snip>

However, the kernel seems to ignore those parameters and still boots
with execution prevention enabled,

<var/log/syslog snip>
Jun 22 16:36:00 EL kernel: [    0.000000] Using x86 segment limits to approximate NX protection
</var/log/syslog snip>

this is verified by running the NX regression test from
http://bazaar.launchpad.net/~ubuntu-bugcontrol/qa-regression-
testing/master/files/head%3A/scripts/kernel-security/nx/

./nx-test stack
data:  0x804a050
bss:   0x805a080
brk:   0x9edc008
rw:    0xb7827000
rwx:   0x60c000
stack: 0xbfec9fd8
Dump of /proc/self/maps:
0035f000-004b2000 r-xp 00000000 08:01 145283     /lib/tls/i686/cmov/libc-2.11.1.so
004b2000-004b3000 ---p 00153000 08:01 145283     /lib/tls/i686/cmov/libc-2.11.1.so
004b3000-004b5000 r--p 00153000 08:01 145283     /lib/tls/i686/cmov/libc-2.11.1.so
004b5000-004b6000 rw-p 00155000 08:01 145283     /lib/tls/i686/cmov/libc-2.11.1.so
004b6000-004b9000 rw-p 00000000 00:00 0 
0060c000-0060d000 rwxp 00000000 00:00 0 
008f1000-008f2000 r-xp 00000000 00:00 0          [vdso]
00a62000-00a7d000 r-xp 00000000 08:01 2350       /lib/ld-2.11.1.so
00a7d000-00a7e000 r--p 0001a000 08:01 2350       /lib/ld-2.11.1.so
00a7e000-00a7f000 rw-p 0001b000 08:01 2350       /lib/ld-2.11.1.so
08048000-08049000 r-xp 00000000 08:01 1443777    /home/vasilis/Downloads/nx/nx-test
08049000-0804a000 r--p 00000000 08:01 1443777    /home/vasilis/Downloads/nx/nx-test
0804a000-0804b000 rw-p 00001000 08:01 1443777    /home/vasilis/Downloads/nx/nx-test
0804b000-0805b000 rw-p 00000000 00:00 0 
09edc000-09efe000 rw-p 00000000 00:00 0          [heap]
b7815000-b7816000 rw-p 00000000 00:00 0 
b7826000-b782b000 rw-p 00000000 00:00 0 
bfeb6000-bfecb000 rw-p 00000000 00:00 0          [stack]
Attempting to execute function at 0xbfec9fe4
If this program seg-faults, the region was enforced as non-executable...
Segmentation fault
...

Any help will be seriously appreciated !!!
Thanks
V.

** Affects: linux (Ubuntu)
     Importance: Undecided
         Status: New

-- 
Kernel ignores noexec=off parameter
https://bugs.edge.launchpad.net/bugs/597702
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