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Subject: Re: [PATCH 11/18] maccess: remove strncpy_from_unsafe
To:     David Laight <David.Laight@ACULAB.COM>,
        Al Viro <viro@zeniv.linux.org.uk>
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From:   Daniel Borkmann <daniel@iogearbox.net>
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Date:   Thu, 14 May 2020 12:21:52 +0200
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On 5/14/20 12:01 PM, David Laight wrote:
[...]
> If it's not a stupid question why is a BPF program allowed to get
> into a situation where it might have an invalid kernel address.
> 
> It all stinks of a hole that allows all of kernel memory to be read
> and copied to userspace.
> 
> Now you might want to something special so that BPF programs just
> abort on OOPS instead of possibly paniking the kernel.
> But that is different from a copy that expects to be passed garbage.

I suggest you read up on probe_kernel_read() and its uses in tracing in
general, looks like you haven't done that.