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Last active September 23, 2024 13:16
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How to install custom SSL certificates on an ASUS RT-N66U running asuswrt-merlin
###########################################
# IMPORTANT NOTE:
#
# As of asuswrt-merlin 380.67 Beta, you
# can now configure SSL certificates from
# the Webui, making these instructions
# unnecessary.
###########################################
# First, enable SSH in the Administration->System tab.
# Then log in to the device.
# Verify that https_crt_save is off
admin@RT-N66U:/tmp/home/root# nvram get https_crt_save
0
# Enable https_crt_save and verify that it was set correctly
admin@RT-N66U:/tmp/home/root# nvram set https_crt_save=1
admin@RT-N66U:/tmp/home/root# nvram get https_crt_save
1
# Write your custom key and certificate to the ephemeral file system.
# Note that these files will not be preserved on restart.
admin@RT-N66U:/tmp/home/root# cat >/etc/key.pem
# paste in key
admin@RT-N66U:/tmp/home/root# cat >/etc/cert.pem
# paste in cert
# Verify https_crt_file is empty
admin@RT-N66U:/tmp/home/root# nvram get https_crt_file
admin@RT-N66U:/tmp/home/root#
# Restart httpd. When httpd starts up with https_crt_save enabled, it does the
# following: If /etc/cert.pem and /etc/key.pem exist, it tars them together and
# saves them in https_crt_file. If they do not exist (this would be the case
# on reboot) and https_crt_file exists, httpd will extract the contents of
# https_crt_file. You can see how this works in the start_ssl function here:
# https://github.com/RMerl/asuswrt-merlin/blob/master/release/src/router/httpd/httpd.c
admin@RT-N66U:/tmp/home/root# service restart_httpd
# Ensure https_crt_file is now full
admin@RT-N66U:/tmp/home/root# nvram get https_crt_file
# ...snip...
# Reboot AP to make sure cert is put back on boot
admin@RT-N66U:/tmp/home/root# reboot
@jmontleon
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jmontleon commented Sep 12, 2024

Maybe extract and retain the other files. The archive looks like this for me, which suggests in december I replaced the key and crt, but kept the rest. Perhaps if other files are missing it regenerates / restores it. I should have kept better notes...

 tar tzvf cert.tgz
-rw-rw-rw- 0/0      1517 2018-05-05 01:05:31 etc/cacert.pem
-rw------- 0/0      1679 2018-05-05 01:05:31 etc/cakey.pem
-rw-rw-rw- 0/0      1838 2023-12-19 22:53:50 etc/cert.pem
-rw------- 0/0      1704 2023-12-19 22:53:51 etc/key.pem
-rw-rw-rw- 0/0      1517 2018-05-05 01:05:31 etc/cacert_gen.pem
-rw------- 0/0      1679 2018-05-05 01:05:31 etc/cakey_gen.pem
-rw-rw-rw- 0/0      1838 2018-05-05 01:05:25 etc/cert_gen.pem
-rw------- 0/0      1675 2018-05-05 01:05:25 etc/key_gen.pem

@stephen-dunne
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Yep, that was the missing piece of the puzzle.

Extracting the existing /jffs/cert.tgz into a temp subdir, overwriting etc/key.pem and etc/cert.pem and recreating /jffs/cert.tgz then running nvram set https_crt_save=1 and service restart_httpd seems to do the trick.

Finally !! Thanks for your help !

@cristit
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cristit commented Sep 21, 2024

Yep, that was the missing piece of the puzzle.

Extracting the existing /jffs/cert.tgz into a temp subdir, overwriting etc/key.pem and etc/cert.pem and recreating /jffs/cert.tgz then running nvram set https_crt_save=1 and service restart_httpd seems to do the trick.

Finally !! Thanks for your help !

I tryed exactly this and checked the md5 sum:
Before copy cert.tgz to /jffs/cert.tgz md5 was: ef7ba5b1ec34074a56c1349653860d82
after copy: 899f0ec767378c8e5a84079d4e6315d3 /jffs/cert.tgz
then I ran following commands:

nvram set https_crt_save=1
service restart_httpd

after last command, the md5 was ef7ba5b1ec34074a56c1349653860d82 (as initial).
I'm using: 3.0.0.4.388_24328-g1e6e634
any idea?

@janedenone
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after last command, the md5 was ef7ba5b1ec34074a56c1349653860d82 (as initial). I'm using: 3.0.0.4.388_24328-g1e6e634 any idea?

Same here. I am happy for everyone who managed to upload and activate their own certificate, but lost hope for myself.

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