Re: [PATCH] mmap: add sysctl for controlling ~VM_MAYEXEC taint

On Tue, 16 Aug 2011 10:07:46 PDT, Roland McGrath said:

I think the expectation is that the administrator or system builder
who decides to set the (non-default) noexec mount option will also
set the sysctl at the same time.

On the other hand, a design that requires 2 separate actions to be taken in
order to make it work, and which fails unsafe if the second step isn't taken,
is a bad design. If we're talking "expectations", let's not forget that the
mount option is called "noexec", not "only-really-noexec-if-you-set-a-magic-sysctl". 

I'll also point out that we didn't add a sysctl in 2.6.0 to say whether or not
to still allow the old "/lib/ld-linux.so your-binary-here" hack to execute binaries
off a partition mounted noexec - we simply said "this will no longer be permitted".