Re: [PATCH] fs/proc: Add process text segment md5-summing

[Eric W. Biederman]

Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> writes:

> On Mon, 12 Nov 2012 21:36:17 +0000
> Arvid Brodin <Arvid.Brodin@xxxxxxxx> wrote:
>
>> Adds /proc/<pid>/text_md5sum which, when read, calculates an md5sum over
>> the process' text segment. This can detect some cases where the system RAM
>> has been disturbed by e.g. ESD or cosmic radiation (on systems where ECC
>> is not available). It might also detect some accidental or malicious
>> modifications of executables, where the perpetrator has not bothered to
>> cover up the tracks.
>
> I thought the review comments regarding the earlier patch were rather
> fatal, sorry.

To add another nail in the coffin.

You can do this with ptrace or with /proc/<pid>/mem without a kernel
patch.

To make this safe would need a ptrace_may_acces(PTRACE_MODE_READ)
permission check.  At which point not doing this with ptrace just adds
up to extra kernel maintenance for no real point.

Eric


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