In article <firstname.lastname@example.org>,
Rob Landley <email@example.com> wrote:
>I.E. it seems like they go out of their way to ALLOW writing to the libaries.
> (I assume they KNOW the difference between MAP_DENYWRITE, MAP_COPY, and
Note that the kernel will refuse to honour MAP_DENYWRITE from user
space, so I'm afraid that changing ld.so won't do a thing.
The reason the kernel refuses to honour it, is that MAP_DENYWRITE is an
excellent DoS-vehicle - you just mmap("/etc/passwd") with MAP_DENYWRITE,
and even root cannot write to it.. Vary nasty.
Which is why the kernel only allows it when the binary loader itself
sets the flag, because security-conscious application writers are
already aware of the "oh, a running binary may not be writable" issues.
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This archive was generated by hypermail 2b29 : Sun Oct 07 2001 - 21:00:30 EST