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ChrisJumper Advocate
Joined: 12 Mar 2005 Posts: 2390 Location: Germany
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bendlas n00b
Joined: 12 May 2014 Posts: 3
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alex6z Tux's lil' helper
Joined: 20 Jul 2005 Posts: 119
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Posted: Tue May 13, 2014 11:13 am Post subject: |
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Here is the patch that was done to the latest linux. I tried it on 3.0 and it wouldn't compile. 3.2 is in long term support but there is no back port yet. This patch likely doesn't work there either.
The good news is that it appears that this exploit is for SMP systems only. I tried the crash PoC here http://pastebin.com/raw.php?i=yTSFUBgZ and it didn't crash my Pentium III on 3.0.76, and it didn't crash 2.6.32 on my Debian system with a P4 even with hypertheading. Not tried as root in either case.
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--- old/drivers/tty/n_tty.c
+++ new/drivers/tty/n_tty.c
@@ -2353,8 +2353,12 @@
if (tty->ops->flush_chars)
tty->ops->flush_chars(tty);
} else {
+ struct n_tty_data *ldata = tty->disc_data;
+
while (nr > 0) {
+ mutex_lock(&ldata->output_lock);
c = tty->ops->write(tty, b, nr);
+ mutex_unlock(&ldata->output_lock);
if (c < 0) {
retval = c;
goto break_out;
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alex6z Tux's lil' helper
Joined: 20 Jul 2005 Posts: 119
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Posted: Tue May 13, 2014 5:52 pm Post subject: |
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Update: got my 2.6.32 Debian system to crash when logged in over ssh, but it didn't work (or not right away) at the console. Turned off HT and now I can't crash it anymore. |
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e3k Guru
Joined: 01 Oct 2007 Posts: 513 Location: Inner Space
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platojones Veteran
Joined: 23 Oct 2002 Posts: 1602 Location: Just over the horizon
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Posted: Wed May 14, 2014 5:55 pm Post subject: |
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The latest gentoo-sources kernel (3.14.4) contains linux patch 3.14.4, which has the fix in it. |
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e3k Guru
Joined: 01 Oct 2007 Posts: 513 Location: Inner Space
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Posted: Wed May 14, 2014 7:18 pm Post subject: |
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thank you platojones. i could live without nvidia-drivers using vesa. but i cant get that thing booting because i have root on ZFS. if i only would be lazy enough not to experiment with the root filesystem...
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3.10.40 is patched too and works for me. _________________
Flux & Contemplation - Portrait of an Artist in Isolation
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