Messages in this thread | | | Date | Sat, 6 Aug 2011 16:18:38 -0400 | Subject | Re: [PATCH v3 10/10] x86-64: Add CONFIG_UNSAFE_VSYSCALLS to feature-removal-schedule | From | Andrew Lutomirski <> |
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On Tuesday, May 31, 2011, Ingo Molnar <mingo@elte.hu> wrote: > > * Ingo Molnar <mingo@elte.hu> wrote: > >> [...] solution that filters the caller RIP at the generic syscall >> entry point and checks RCX against the 'expected' SYSCALL >> instruction address, which is the (per task) vdso-address + >> constant-offset. > > Note that this solution would allow the vsyscall page to be > 'filtered' to the 3 allowed system calls rather efficiently, via a > second level check. > > This second check does not affect the fastpath, and it could be put > behind a CONFIG_COMPAT_VSYSCALL deprecation define once glibc does > not put vsyscall references anywhere - but we could even keep it > around forever, as this way it's defanged permanently.
I'm confused. Are you thinking about the 32-bit vDSO? I think that 64-bit code puts syscall instructions all over the place.
--Andy
> > Thanks, > > Ingo > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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