1 |
In terms of userland, non hardened profile doesn't protect you at all |
2 |
against buffer overflows, you are removing one important security |
3 |
layer. SSP protects you against buffer overflows in terms that the |
4 |
vulnerable application gets killed when the canary is modified before |
5 |
the execution of the arbitrary code. PIE protects you against return |
6 |
into libc attacks that doesn't need an executable stack. PaX is not |
7 |
perfect and needs them as complementary solutions. For example I think |
8 |
that RANDEXEC was removed from PaX time ago, one buffer overflow that |
9 |
uses return into libc attack could be succesfully against one |
10 |
non-hardened binary. Since skype is a network oriented software... |
11 |
|
12 |
2008/12/25 Grant <emailgrant@×××××.com>: |
13 |
>> Hardened profiles: Yes there's a difference, no you should not switch to |
14 |
>> hardened/linux/${ARCH} at this time. |
15 |
> |
16 |
> Is hardened/x86/2.6 still available for new installations? My other |
17 |
> systems are amd64 but none of them list hardened/amd64/2.6. |
18 |
> |
19 |
>> You can get skype working by downloading or building gcc 4.1.x and pointing |
20 |
>> LD_LIBRARY_PATH at the shared object directory when starting skype. skype |
21 |
>> won't be using hardened toolchain but since its closed source and you're |
22 |
>> willing to switch the whole machine to non-hardened I figure you probably |
23 |
>> don't mind. ;) |
24 |
>> |
25 |
>> Example: |
26 |
>> 1. Download |
27 |
>> http://tinderbox.dev.gentoo.org/default-linux/x86/sys-devel/gcc-4.1.2.tbz2 |
28 |
>> 2. unpack the archive to ${HOME}/tinderbox-pkgs/sys-devel/gcc/ |
29 |
>> 3. Run it: |
30 |
>> LD_LIBRARY_PATH="${HOME}/tinderbox-pkgs/sys-devel/gcc/usr/lib/gcc/i686-pc-linux-gnu/4.1.2/" |
31 |
>> skype |
32 |
>> |
33 |
>> If you only require VoIP capability and not skype specifically you might be |
34 |
>> interested net-im/ekiga. |
35 |
> |
36 |
> Thank you very much for that, but I'm trying to simplify. You see, |
37 |
> I'm only a fake sysadmin. Does using a hardened kernel with a |
38 |
> non-hardened profile still offer good protection? |
39 |
> |
40 |
> - Grant |
41 |
> |
42 |
>>> > I've been able to do so; basically I switched over to the standard |
43 |
>>> > profile, disabled selinux in the kernel, and re-emerged system for new |
44 |
>>> > use flags. There were some other details but overall the process was |
45 |
>>> > pretty painless, anyone ambitious enough to configure a hardened system |
46 |
>>> > can probably handle the switch without much problem. Not that I'm |
47 |
>>> > encouraging you to drop hardened (especially on a laptop that could be |
48 |
>>> > exposed to random wifi networks ;-) |
49 |
>>> |
50 |
>>> Is there any difference between 1 and 8 here? Should I switch to 8? |
51 |
>>> |
52 |
>>> # eselect profile list |
53 |
>>> Available profile symlink targets: |
54 |
>>> [1] hardened/x86/2.6 * |
55 |
>>> [2] selinux/2007.0/x86 |
56 |
>>> [3] selinux/2007.0/x86/hardened |
57 |
>>> [4] default/linux/x86/2008.0 |
58 |
>>> [5] default/linux/x86/2008.0/desktop |
59 |
>>> [6] default/linux/x86/2008.0/developer |
60 |
>>> [7] default/linux/x86/2008.0/server |
61 |
>>> [8] hardened/linux/x86 |
62 |
>>> |
63 |
>>> - Grant |
64 |
>>> |
65 |
>>> >> Can I switch my laptop's profile from a hardened one to a non-hardened |
66 |
>>> >> one? I thought this was impossible without a complete reinstall but |
67 |
>>> >> folks on the gentoo-user list seem to think it's not a problem. |
68 |
>>> >> |
69 |
>>> >> - Grant |
70 |
> |
71 |
> |