From: Emrah Demir <ed@abdsec.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Freeman Zhang <freeman.zhang1992@gmail.com>,
linus971@gmail.com, kexec@lists.infradead.org
Subject: Re: Removal of the kernel code/data/bss resources does break kexec/kdump
Date: Thu, 14 Apr 2016 16:27:48 -0400 [thread overview]
Message-ID: <f80ca230bf1fab7527d355e535de305f@abdsec.com> (raw)
In-Reply-To: <CA+55aFwprUFh+cjB2fWmkMJ3Zgh6XSan0VO8Vr-80Qh0n0Rx+A@mail.gmail.com>
On 2016-04-14 13:40, Linus Torvalds wrote:
>
> Actually, %pK is horrible in /proc and /sys files, and does the wrong
> thing.
>
I agree with that, but for now there is no way to make things right in
/proc or /sys.
>
> A file access should use "file->f_cred", but the seq_file interface
> sadly doesn't expose any way to do that.
>
> I'll take a look, but it's non-trivial to get right. %pK turns out to
> have been seriously mis-designed, and is basically almost always a
> bug.
>
> Linus
In another way, maybe it's good to remove code dependencies on /proc
sensitive files like /proc/iomem.
Kees Coook: "it looks like at least Ubuntu's kernel security test suite
expects to find these entries (when it verifies that STRICT_DEVMEM
hasn't regressed)"
Freeman Zhang: "Removal of these information causes 'kexec/kdump' to
fail in the newer
kernel"
Removing such dependencies would make things better and code/bss/data
sections could be removed.
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next prev parent reply other threads:[~2016-04-14 20:28 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-14 10:14 Removal of the kernel code/data/bss resources does break kexec/kdump Freeman Zhang
2016-04-14 11:07 ` Emrah Demir
2016-04-14 17:40 ` Linus Torvalds
2016-04-14 20:27 ` Emrah Demir [this message]
2016-04-15 1:02 ` Linus Torvalds
2016-04-15 4:41 ` Kees Cook
2016-04-15 15:46 ` Emrah Demir
2016-04-15 16:48 ` Linus Torvalds
2016-04-15 17:08 ` Emrah Demir
2016-04-19 9:04 ` Dave Young
2016-04-19 16:20 ` Linus Torvalds
2016-04-20 1:13 ` Dave Young
2016-04-14 11:26 ` Baoquan He
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