Fwd: Linux entropy

Fwd: Linux entropy

[Traian Teodorescu]

Hello,

I've been redirected by  the "friendly bot" to you (I've already looked 
into "kernelnewbies" but I didn't find a linked topic). I would want to 
know more about the subject below. Is there another possibility to read 
the value of current entropy in new versions of kernel ? Are the old 
services (as for instance haveged) still compatible ?

Thank you and have a nice evening,

Traian


-------- Forwarded Message --------
Subject:     Linux entropy
Date:     Tue, 21 Mar 2023 17:03:36 +0100
From:     Traian Teodorescu <traian.teodorescu@bluewin.ch>
To:     gregkh@linuxfoundation.org


Mr Kroah-Hartmann,

I've recently discovered that the value containing the machine's entropy 
(in /proc/sys/kernel/random/entropy_avail ) isn't updated anymore on one 
of my machines. I found some articles on the Internet about this change, 
but nothing very "official".

There is also an explanation at 
"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-5.15.y&id=e7e196e1ae2603a2c5f1894f1868a7a5b5a2c5e0" 
about keeping forward secrecy, etc, that I didn't really understood.

I began using Linux since less than 10 years and I am not what you can 
call an experienced user, but from my point of view this change doesn't 
make sense. If I understand well some basic principles, Linux kernel is 
the only one meant to be accessible to everybody wanting to understand 
deeply how a modern OS works, so what's the gain in this "obfuscation" 
?  From my point of view, a sysadmin should know how much entropy they 
have on their machines.

So, please, can you please make some comments about this change ? (of 
eventually send me a link to an article that I can trust ?)

I really enjoyed Linux a lot those years and I learned to appreciate it, 
so from this point of view I am grateful to the teams maintaining free 
software, so ... thank you !

Thanks for an eventual answer and have a nice evening,

Traian

Fwd: Fwd: Linux entropy

[Traian Teodorescu]

Hello, can you please answer to my question below ? It's about the 
"/proc/sys/kernel/random/entropy_avail" variable which doesn't show 
anymore a credible value.
Thank you,
Traian

-------- Forwarded Message --------
Subject: 	Fwd: Linux entropy
Date: 	Wed, 22 Mar 2023 05:51:10 +0100
From: 	Traian Teodorescu <traian.teodorescu@bluewin.ch>
To: 	linux-kernel@vger.kernel.org



Hello,

I've been redirected by  the "friendly bot" to you (I've already looked 
into "kernelnewbies" but I didn't find a linked topic). I would want to 
know more about the subject below. Is there another possibility to read 
the value of current entropy in new versions of kernel ? Are the old 
services (as for instance haveged) still compatible ?

Thank you and have a nice evening,

Traian


-------- Forwarded Message --------
Subject:     Linux entropy
Date:     Tue, 21 Mar 2023 17:03:36 +0100
From:     Traian Teodorescu <traian.teodorescu@bluewin.ch>
To:     gregkh@linuxfoundation.org


Mr Kroah-Hartmann,

I've recently discovered that the value containing the machine's entropy 
(in /proc/sys/kernel/random/entropy_avail ) isn't updated anymore on one 
of my machines. I found some articles on the Internet about this change, 
but nothing very "official".

There is also an explanation at 
"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-5.15.y&id=e7e196e1ae2603a2c5f1894f1868a7a5b5a2c5e0" 
about keeping forward secrecy, etc, that I didn't really understood.

I began using Linux since less than 10 years and I am not what you can 
call an experienced user, but from my point of view this change doesn't 
make sense. If I understand well some basic principles, Linux kernel is 
the only one meant to be accessible to everybody wanting to understand 
deeply how a modern OS works, so what's the gain in this "obfuscation" 
?  From my point of view, a sysadmin should know how much entropy they 
have on their machines.

So, please, can you please make some comments about this change ? (of 
eventually send me a link to an article that I can trust ?)

I really enjoyed Linux a lot those years and I learned to appreciate it, 
so from this point of view I am grateful to the teams maintaining free 
software, so ... thank you !

Thanks for an eventual answer and have a nice evening,

Traian

Re: Fwd: Fwd: Linux entropy

[Bagas Sanjaya]

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On Sun, Mar 26, 2023 at 12:03:52AM +0100, Traian Teodorescu wrote:
> Hello, can you please answer to my question below ? It's about the
> "/proc/sys/kernel/random/entropy_avail" variable which doesn't show anymore
> a credible value.

Hi and welcome to LKML!

First, when replying, use "Reply all" instead of forwarding and don't
top-post; reply inline with appropriate context instead.

Second, to improve the chance of getting an answer, Cc: relevant
lists and maintainers (see MAINTAINERS).

Last but not least, see catb document on how to ask smart questions [1].

Thanks!

[1]: http://www.catb.org/~esr/faqs/smart-questions.html 

-- 
An old man doll... just what I always wanted! - Clara

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