Messages in this thread | | | Date | Mon, 27 Jul 2015 12:18:52 -0400 | From | Boris Ostrovsky <> | Subject | Re: [PATCH v4 0/3] x86: modify_ldt improvement, test, and config option |
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On 07/27/2015 11:53 AM, Andy Lutomirski wrote: > On Mon, Jul 27, 2015 at 8:36 AM, Boris Ostrovsky > <boris.ostrovsky@oracle.com> wrote: >> On 07/25/2015 01:36 AM, Andy Lutomirski wrote: >>> Here's v3. It fixes the "dazed and confused" issue, I hope. It's also >>> probably a good general attack surface reduction, and it replaces some >>> scary code with IMO less scary code. >>> >>> Also, servers and embedded systems should probably turn off modify_ldt. >>> This makes that possible. >>> >>> Xen people, can you take a look at this? >>> >>> Willy and Kees: I left the config option alone. The -tiny people will >>> like it, and we can always add a sysctl of some sort later. >>> >>> Changes from v3: >>> - Hopefully fixed Xen. >> >> 32b-on-32b fails in the same manner. (but non-zero LDT is taken care of) >> >>> - Fixed 32-bit test case on 32-bit native kernel. >> >> I am not sure I see what changed. > I misplaced the fix in the wrong git commit, so I failed to sent it. Oops. > > I just sent v4.1 of patch 3. Can you try that?
I am hitting BUG() in Xen code (returning from a hypercall) when freeing LDT in destroy_context(). Interestingly though when I run the test in the debugger I get SIGILL (just like before) but no BUG().
Let me get back to you on that later today.
-boris
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