[lkml]   [2005]   [Jan]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: thoughts on kernel security issues

    On Thu, 13 Jan 2005, Alan Cox wrote:
    > On Iau, 2005-01-13 at 16:38, Linus Torvalds wrote:
    > > It wouldn't be a global flag. It's a per-process flag. For example, many
    > > people _do_ need to execute binaries in their home directory. I do it all
    > > the time. I know what a compiler is.
    > noexec has never been worth anything because of scripts. Kernel won't
    > load that binary, I can write a script to do it.

    Scripts can only do what the interpreter does. And it's often a lot harder
    to get the interpreter to do certain things. For example, you simply
    _cannot_ get any thread race conditions with most scripts out there, nor
    can you generally use magic mmap patterns.

    Am I claiming that disallowing self-written ELF binaries gets rid of all
    security holes? Obviously not. I'm claiming that there are things that
    people can do that make it harder, and that _real_ security is not about
    trusting one subsystem, but in making it hard enough in many independent
    ways that it's just too effort-intensive to attack.

    It's the same thing with passwords. Clearly any password protected system
    can be broken into: you just have to guess the password. It then becomes a
    matter of how hard it is to "guess" - at some point you say a password is
    secure not because it is a password, but because it's too _expensive_ to

    So all security issues are about balancing cost vs gain. I'm convinced
    that the gain from openness is higher than the cost. Others will disagree.

    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to
    More majordomo info at
    Please read the FAQ at

     \ /
      Last update: 2009-11-18 23:46    [W:0.019 / U:46.668 seconds]
    ©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site