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]>
---
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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