Re: [PATCH] fs: make dumpable=2 only write to a pipe

[Alan Cox]

On Thu, 21 Jun 2012 12:43:19 -0700
Kees Cook <keescook@xxxxxxxxxxxx> wrote:

> When the suid_dumpable sysctl is set to "2", and there is no
> core dump pipe defined in the core_pattern sysctl, a local user
> can cause core files to be written to root-writable directories,
> potentially with user-controlled content. This means an admin
> can unknowningly reintroduce a variation of CVE-2006-2451 (see
> abf75a5033d4da7b8a7e92321d74021d1fcfb502).

Its intended to work the way it does. It's also ABI. I think pipe-only is
a really good idea. Likewise I accept with the pipe feature nowdays there
is a good case to kill off case 2.

However I don't think magically turning one into the other is sensible,
in fact its *stupid* IMHO because it's asking systems to get unexpected
behaviour.

I would much rather see case 2 either left as is, or set to return
-EINVAL (or similar) and a new case 3 for pipe only.

Alan
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