Messages in this thread | | | Date | Mon, 8 Apr 2002 01:31:22 +0200 | Subject | Re: Two fixes for 2.4.19-pre5-ac3 | From | (Erik Tews) |
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On Sun, Apr 07, 2002 at 06:42:05PM +0100, Alan Cox wrote: > > And, unless this is reversed the OpenAFS kernel module won't load (it > > needs sys_call_table.): > > Correct. There was agreement a very long time ago that code should not patch > the syscall table (for one its not safe). AFS probably needs fixing so the > AFS syscall hook is exported portably and nicely in the syscall code.
I am really not an expert on kernel-programming but I remember that there was a security-hole in the ptrace-code with which one a local user could gain root access. And there was a little kernel-modul with a wrapper-function for the ptrace-syscall that made traces only possible if the user who was calling this syscall was root. So if I understand right if we don't export the syscall-table it is impossible to write such syscall-wrapper-functions and it requires to recompile the kernel and reboot the machiene to fix such an security-hole.
So wouldn't it be better to export the syscall-table and just write into the documentation that it is not a good idea to manipulate syscalls or write a compiler-makro that gives out a warning when such a module is beeing compiled. - 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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