FS#67925 - [linux] [linux-hardened] /dev/random is "too fast"

Attached to Project: Community Packages
Opened by Alex (Loader009) - Thursday, 17 September 2020, 21:02 GMT
Last edited by freswa (frederik) - Thursday, 17 September 2020, 21:24 GMT
Task Type Bug Report
Category Security
Status Closed
Assigned To No-one
Architecture x86_64
Severity High
Priority Normal
Reported Version
Due in Version Undecided
Due Date Undecided
Percent Complete 100%
Votes 0
Private No

Details

Description:
Using /dev/random is too fast in mainline and hardened kernel.
This is however not the case for the lts kernel.

Additional info:
Name : linux
Version : 5.8.9.arch2-1

Name : linux-hardened
Version : 5.8.9.a-1

Name : linux-lts
Version : 5.4.65-1

What it looks like in kernel-lts:
$ dd if=/dev/random of=/dev/null iflag=fullblock bs=512 count=20
20+0 records in
20+0 records out
10240 bytes (10 kB, 10 KiB) copied, 2,26001 s, 4,5 kB/s

Steps to reproduce:
Run the command below and check if the speed is slow or several MB/s.

$ dd if=/dev/random of=/dev/null iflag=fullblock bs=512 count=20
This task depends upon

Closed by  freswa (frederik)
Thursday, 17 September 2020, 21:24 GMT
Reason for closing:  Not a bug
Comment by Alex (Loader009) - Thursday, 17 September 2020, 21:06 GMT
I please you to test this, I do not know if this is a hardware issue.
However, I noticed the same issue on fedora on an Atom-server, thus I think it's an upstream issue.

I also stopped using [linux] and [linux-hardened] after I noticed this issue a few weeks ago.
And (if I remember correctly) the last time I checked was about 2 weeks ago.

I do not have the knowledge to find the issue, I tried and I have no idea where to look at.
I also consider this as a serious issue for any encryption but I do not know where the random data is being taken from.
Comment by freswa (frederik) - Thursday, 17 September 2020, 21:23 GMT

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