Messages in this thread | | | Subject | Re: [PATCH v3 10/10] x86-64: Add CONFIG_UNSAFE_VSYSCALLS to feature-removal-schedule | From | Valdis.Kletnieks@vt ... | Date | Wed, 01 Jun 2011 13:35:32 -0400 |
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On Tue, 31 May 2011 09:16:04 EDT, Andy Lutomirski said:
> +What: CONFIG_UNSAFE_VSYSCALLS (x86_64)
Wow. I went nuts trying to find where this was because I couldn't find it in Linus's tree I pulled a little while ago, before I realized you added it in patch 8 and deprecated it in patch 10.
Speaking of which:
+ On a system with recent enough glibc (probably 2.14 or + newer) and no static binaries, you can say N without a + performance penalty to improve security
So I checked my laptop (Fedora 16 Rawhide), and found a bunch of static binaries. The ones that look like people may care:
# file /sbin/* | grep statically /sbin/grub: ELF 32-bit LSB executable, Intel 80386, version 1 (GNU/Linux), statically linked, for GNU/Linux 2.6.18, stripped /sbin/insmod.static: ELF 64-bit LSB executable, x86-64, version 1 (GNU/Linux), statically linked, for GNU/Linux 2.6.32, stripped /sbin/ldconfig: ELF 64-bit LSB executable, x86-64, version 1 (GNU/Linux), statically linked, for GNU/Linux 2.6.32, stripped /sbin/sln: ELF 64-bit LSB executable, x86-64, version 1 (GNU/Linux), statically linked, for GNU/Linux 2.6.32, stripped
Might be a challenge to get rid of them though. Unless we don't care anymore about "use a statically linked ldconfig to fix a corrupted ls.so.cache" and "reboot from a rescue disk" the only choice. I think the insmod.static ends up getting used in initrds to get the root filesystem mounted, we may care about that as well.. ;)
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