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Ingo Molnar <mingo@elte.hu> wrote: > * Jeff Dike <jdike@addtoit.com> wrote: >> Now, there were a couple of ways to legitimately escape from UML, and >> they *did* involve ptrace. Things like single-stepping a system call >> instruction or putting a breakpoint on a system call instruction and >> single-stepping from the breakpoint. As far as I know, these were >> discovered and fixed by UML developers before there was any outside >> awareness of these bugs. > > also, UML 'ptrace clients' are allowed alot more leeway than what a > seccomp-alike ptrace/utrace based syscall filter would allow. It would > clearly exclude activities like 'setting a breakpoint' or > 'single-stepping' - valid syscalls would be limited to > read/write/sigreturn/exit. So instead of breakpointing (using int3), you'd have to write 'mv flag I_AM_HERE;self:jmp self' and resort to polling? This would not prevent (ab)use except for some corner cases. -- Ich danke GMX dafür, die Verwendung meiner Adressen mittels per SPF verbreiteten Lügen zu sabotieren. http://david.woodhou.se/why-not-spf.html - 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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