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