Slashdot Mirror
Hole In Linux Kernel Provides Root Rights
oztiks writes with this excerpt from The H:
"A vulnerability in the 32-bit compatibility mode of the current Linux kernel (and previous versions) for 64-bit systems can be exploited to escalate privileges. For instance, attackers can break into a system and exploit a hole in the web server to get complete root (also known as superuser) rights or permissions for a victim's system. According to a report, the problem occurs because the 32-bit call emulation layer does not check whether the call is truly in the Syscall table. Ben Hawkes, who discovered the problem, says the vulnerability can be exploited to execute arbitrary code with kernel rights. ... Hawkes says the vulnerability was discovered and remedied back in 2007, but at some point in 2008 kernel developers apparently removed the patch, reintroducing the vulnerability. The older exploit apparently only needed slight modifications to work with the new hole."
You're talking about git submodules and I'm gonna go ahead and guess that the answer you'll receive from the kernel folks about that is a big fat "no". Maybe if Git had usable project hierarchies, things might be different.
Also to note: even Git can't fix stupid policy or stupid programming decisions.
He is probably referring to the bout of security fixes for windows 7 with the same wording.. there has been quite a few of them lately.
And that's relevant to this thread how again?
Might as well start posting stuff about Chewbacca.
Maybe Linux' kernel is too big?
Chewbacca lives on Endor wihout any Linux or Windows computers ....
RIP America
July 4, 1776 - September 11, 2001
If you know how to drive git you could try applying these:
x86-64, compat: Retruncate rax after ia32 syscall entry tracing
x86-64, compat: Test %rax for the syscall number, not %eax
there is a workaround of disabling 32bit binaries (I'd paste a link if Google Chrome dev channel would let me... for some reason I can only paste into /.'s comment box before I've typed anything else, I'll follow-up with it), but of course you may need them depending on what your machine does.
There's also a separate issue that also gives local root, fixed by:
compat: Make compat_alloc_user_space() incorporate the access_ok()
I'm running a kernel base don 2.6.35.4 but with all 3 of those commits applied (note the last one tries to modify an arch/tile/ file which doesn't exist in 2.6.35.4, just ignore that) and can confirm that neither exploit works.
Ubuntu, at least, has already released the patch as a kernel upgrade; it was fixed early in the week so I presume most other distros have too.
I've seen far too many rooted servers to agree with you about the deployment issue.
For large sets, this will be our guide even unto death, for the LORD will work for each type of data it is applied to...
A LOT of hosts still get rooted because of weak passwords. A LOT of valuable hosts get rooted through social engineering. Just because you've seen rooted hosts, doesn't mean that there is any wide-scale deployment of anything.
It's also part of the reason behind the slow turnaround time on patches coming out of Redmond. They do regression testing.
It's quite possible to have two independent reasons for doing something.
Those who do study history are doomed to stand helplessly by while everyone else repeats it.
The vulnerability is affecting kernels compiled with 32-bit compatibility support. Enabling this option seems to be the default, even on x64 systems that do not have 32-bit libraries and cannot execute 32-bit binaries. You can say
zcat /proc/config.gz | grep CONFIG_IA32_EMULATION
to see if you have it on. More info, and the origina hack.
Who the fuck calls that superuser?
All I had to do was turn around and reach at the bookshelf behind me:
"But we must warn you: there is a special user on every UNIX system, called the super-user, who can read or modify any file on the system. The special loginm name root carries super-user privledges...."
from page 52, "The UNIX Programming Environment", Brian W. Kernigan & Robert Pike, Prentice Hall, 1984.
The offending patch was authored and committed by a Redhat developer. Since this guy made his own company's product insecure for their clients, I'd say that Redhat could very well fire him. Whether they will or not depends on the company. Besides, do you know of a Microsoft (or any closed source software company) employee being fired based on their coding vulnerable software? How about a CEO being fired for selling vulnerable software to the public? Where's the accountability there?
cd /usr/src/linux &&
grep -ilE 'super.?user' `find . -iname *.[ch]`
arch/avr32/mm/cache.c
arch/h8300/include/asm/cachectl.h
arch/ia64/kernel/unaligned.c
arch/m68k/include/asm/cachectl.h
arch/m68k/kernel/sys_m68k.c
arch/parisc/hpux/sys_hpux.c
arch/x86/kernel/apm_32.c
arch/x86/kernel/ioport.c
drivers/char/apm-emulation.c
drivers/char/rio/errors.h
drivers/char/rio/rioctrl.c
drivers/net/wireless/airo.c
drivers/scsi/megaraid.c
drivers/scsi/megaraid/megaraid_mm.c
drivers/staging/vt6655/iwctl.c
drivers/staging/vt6656/iwctl.c
fs/cachefiles/daemon.c
fs/ext4/mballoc.c
fs/fcntl.c
fs/namei.c
fs/ntfs/super.c
fs/smbfs/file.c
fs/ubifs/budget.c
fs/ufs/ufs_fs.h
fs/unionfs/sioq.c
fs/utimes.c
fs/xfs/quota/xfs_qm.c
fs/xfs/quota/xfs_qm_syscalls.c
fs/xfs/xfs_quota.h
include/linux/acct.h
include/linux/dqblk_xfs.h
include/linux/fd.h
include/linux/keyboard.h
include/linux/random.h
include/linux/sched.h
include/linux/shm.h
include/net/sock.h
kernel/kexec.c
kernel/sys.c
kernel/sysctl.c
kernel/time/ntp.c
mm/mempolicy.c
mm/migrate.c
mm/oom_kill.c
net/core/dev.c
net/core/sock.c
net/netlink/af_netlink.c
net/netrom/af_netrom.c
(full disclosure: I also piped it thru |sed -e 's/^\.\///g' for formatting purposes (slashdot puts it all one one line if they begin with ./ for some reason) and |sort because I'm just like that)
The revolution will not be televised... but it will have a page on Wikipedia