1 |
On 3 Apr 2009 at 1:22, Alex Efros wrote: |
2 |
> On Thu, Apr 02, 2009 at 11:17:10PM +0200, pageexec@××××××××.hu wrote: |
3 |
> > can you strace bash/etc to see what happens? probably we'll see what runs |
4 |
> |
5 |
> how do I can strace process N1? |
6 |
|
7 |
you can enable and boot into softmode then turn it off and see what |
8 |
you can reproduce then. that won't let you strace pid=1 but let's |
9 |
you play with the rest while running an MPROTECT kernel. |
10 |
|
11 |
> PaX doesn't kill bash if it executed not as process N1. |
12 |
|
13 |
hmm, i don't get it. are you saying that with MPROTECT enabled in the |
14 |
kernel, bash fails to start when run as init, but works otherwise? |
15 |
|
16 |
> > against the MPROTECT restricions. my guess is either textrels or gnu_stack |
17 |
> > (compare scanelf -lpqRte on your systems). |
18 |
> |
19 |
> it's same on all servers: |
20 |
|
21 |
hmm, so nothing stands out, and only pid=1 is ever affected? i've never seen |
22 |
such a failure mode ;). |
23 |
|
24 |
> > btw, why are you using SEGMEXEC on your core2? |
25 |
> |
26 |
> Hmm. You think I should use PAGEEXEC instead? According to help in linux |
27 |
> kernel SEGMEXEC looks more suitable for Core2Duo and Xeon E5310... |
28 |
> |
29 |
> In help for PAGEEXEC it doesn't recommended for P4 and there is nothing |
30 |
> about newest processors, so I suppose PAGEEXEC may not be a good choice. |
31 |
|
32 |
the help talks about exactly what is problematic, the P4 core. the core2 |
33 |
is different, and it also has hw non-exec support. |
34 |
|
35 |
> After your question I've re-read help, and notice "i386 with hardware |
36 |
> non-executable bit support" item at end of list with less usual archs like |
37 |
> avr32, sparc, etc. If that was said about Core/Xeon too, then there |
38 |
> probably little usability issue with that help. ;-) |
39 |
|
40 |
i can't possibly list every cpuid that has NX support, up to you to determine |
41 |
it ;). besides, you can always enable both non-exec features and the kernel |
42 |
will choose the better one at runtime. |