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    SubjectRe: Ptrace hole / Linux 2.2.25
    Alan Cox <> writes:

    > A patch for Linux 2.4.20/Linux 2.4.21pre is attached. The patch also
    > subtly changes the PR_SET_DUMPABLE prctl. We believe this is neccessary and
    > that it will not affect any software. The functionality change is specific
    > to unusual debugging situations.

    I am concerned about this change because it will break sandboxing
    software that I have written, which uses prctl() to turn
    dumpability back on so that it can open a file, setuid(), and
    then execve() through the open file via /proc/self/fd/#. Without
    calling prctl(), the ownership of /proc/self/fd/* becomes root,
    so the process cannot exec it after it drops privileges. It uses
    prctl() in other places to get the same effect in /proc, but
    that's one of the most critical.
    <> <> <> <>
    Stanford Ph.D. Student - MSU Alumnus - Debian Maintainer - GNU Developer
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