Nagaraj wrote: > > > No, you could not crash the kernel this way. Your > > userland program would be the one traversing the symlinks, > > in -user space-. Each call into the kernel would > > traverse one link, sure, but that's certainly not > > going to be a problem for the kernel. > > > > plz have a look at: > http://lwn.net/Articles/2995/ > > I think user process can still do it. Er... no, the article you cite says the same thing I said: the kernel limits symlink traversals on any given path. Any attempt by a user to exploit the recursive nature of symlink lookups will simply fail, without damaging the kernel in any way. > > I also suspect (though I do not know this for certain) > > that the kernel is smart enough to detect kernel-stack > > overflow and kill the offending process. It would be > > trivial: just keep a read-only PTE at the end of the > > kernel stack, and if anything tries to write > > there, take a page fault, notice that it's adjacent > > to the task stack, and kill the process. > > http://van-dijk.net/linuxkernel/200206/1235.html > By reading that, i think it wont ! ( i may be wrong here ) > I donno abt latest kernels. That article doesn't seem to address this issue. It describes a patch for configurable stack size, but does not say anything about the means by which the kernel handles (or fails to handle) a stack overflow. If I get a chance, I'll look at the 2.5.33 code tomorrow and see if it does anything smart in that case. -- Joe "I'd rather chew my leg off than maintain Java code, which sucks, 'cause I have a lot of Java code to maintain and the leg surgery is starting to get expensive." - Me -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
