On 12/12/22 02:35, Mark Hatle wrote:
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In the kernel is the jitter entropy system.  It should work on all platforms that have high res timers available.  (This is the same mechanism that haveged was using before as well.  So no change in the RNG quality, just now built into
the kernel itself.)

The only place we've observed an issue with the new approach is on a qemu
machine that was moderately loaned.  The jitter was apparently too large (our theory) and caused the crng init to happen VERY slowly.  (This would not have
been resolved using rngd.)

All-in-all, I thought this change had already been made, and think it should go in.

(We tested this on microblaze, and performance with and without haveged was the same.  I don't have number, but I expect the same behaviors on any architecture.)

--Mark

On 12/9/22 11:02 AM, Khem Raj wrote:
would be good to know some numbers on non-arm/non-x86 systems too.

On Thu, Dec 8, 2022 at 11:05 PM Xiangyu Chen
<[email protected]> wrote:

It appears that rngd is not needed as of linux-5.6 and later[1]
and should not be installed by default since the purpose of rngd
is to provide additional trusted sources of entropy.

We did some testing on real hardware, the result seems to support that
we no longer need rngd by default on kernel v5.6 and later.

Testing result as below:

1. observing the crng init stage.
  the "random: crng init done" always available before fs being mounted.

2. generating random number without rngd.
  testing command: dd if=/dev/random of=/dev/null status=progress
    on Marvell CN96xx RDB board, speed almost 20.4 MB/s without block
    on NXP i.mx6q board, speed almost 31.9 MB/s without block
    on qemu x86-64, speed almost 2.6MB/s without block

3. using rngtest command without rngd
  testing command: rngtest -c 1000 </dev/random
    on Marvell CN96xx RDB board:
       rngtest: input channel speed: (min=4.340; avg=135.364; max=146.719)Mibits/s        rngtest: FIPS tests speed: (min=8.197; avg=69.020; max=72.800)Mibits/s
       rngtest: Program run time: 418771 microseconds

    on NXP i.mx6q board:
       rngtest: input channel speed: (min=96.820; avg=326.769; max=340.598)Mibits/s        rngtest: FIPS tests speed: (min=15.090; avg=37.543; max=40.324)Mibits/s
       rngtest: Program run time: 570229 microseconds

    on qemu x86-64:
       rngtest: input channel speed: (min=37.769; avg=101.136; max=136.239)Mibits/s        rngtest: FIPS tests speed: (min=10.288; avg=30.682; max=40.155)Mibits/s
       rngtest: Program run time: 836800 microseconds

4. observing sshd service.
   using "systemctl disable rng-tools" disable service and reboot system.    system boot up normal, sshd service also start in normal time without
   block.

Reference:
[1] https://github.com/torvalds/linux/commit/30c08efec8884fb106b8e57094baa51bb4c44e32

Signed-off-by: Xiangyu Chen <[email protected]>

Hello Steve,

According to oe release kernel version(https://wiki.yoctoproject.org/wiki/Linux_Yocto), the kirkstone and langdale is also using linux v5.6 later version kernel, so could you help to cherry pick this commit on master to kirkstone and langdale branch? Thanks!

The commit now on master:

commit: 868dfb46d96a27ec9041cb902fb769330277257d

https://git.openembedded.org/openembedded-core/commit/?id=868dfb46d96a27ec9041cb902fb769330277257d


Thanks,

Xiangyu

---
  meta/recipes-connectivity/openssh/openssh_9.1p1.bb | 9 +--------
  1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/meta/recipes-connectivity/openssh/openssh_9.1p1.bb b/meta/recipes-connectivity/openssh/openssh_9.1p1.bb
index 85f97b1bbb..23ae8d5b0c 100644
--- a/meta/recipes-connectivity/openssh/openssh_9.1p1.bb
+++ b/meta/recipes-connectivity/openssh/openssh_9.1p1.bb
@@ -52,15 +52,12 @@ SYSTEMD_SERVICE:${PN}-sshd = "sshd.socket"

  inherit autotools-brokensep ptest

-PACKAGECONFIG ??= "rng-tools"
+PACKAGECONFIG ??= ""
  PACKAGECONFIG[kerberos] = "--with-kerberos5,--without-kerberos5,krb5"
  PACKAGECONFIG[ldns] = "--with-ldns,--without-ldns,ldns"
  PACKAGECONFIG[libedit] = "--with-libedit,--without-libedit,libedit"
  PACKAGECONFIG[manpages] = "--with-mantype=man,--with-mantype=cat"

-# Add RRECOMMENDS to rng-tools for sshd package
-PACKAGECONFIG[rng-tools] = ""
-
  EXTRA_AUTORECONF += "--exclude=aclocal"

  # login path is hardcoded in sshd
@@ -160,10 +157,6 @@ FILES:${PN}-keygen = "${bindir}/ssh-keygen"

  RDEPENDS:${PN} += "${PN}-scp ${PN}-ssh ${PN}-sshd ${PN}-keygen ${PN}-sftp-server"   RDEPENDS:${PN}-sshd += "${PN}-keygen ${@bb.utils.contains('DISTRO_FEATURES', 'pam', 'pam-plugin-keyinit pam-plugin-loginuid', '', d)}"
-RRECOMMENDS:${PN}-sshd:append:class-target = "\
-    ${@bb.utils.filter('PACKAGECONFIG', 'rng-tools', d)} \
-"
-
  # gdb would make attach-ptrace test pass rather than skip but not worth the build dependencies   RDEPENDS:${PN}-ptest += "${PN}-sftp ${PN}-misc ${PN}-sftp-server make sed sudo coreutils"

--
2.34.1











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