On 08/06/19 at 03:29am, Jun Wang wrote:
We use customized known-hosts file and distribute various host keys
to it in our operation environment. Adding the option allows mkdumprd package the
corresponding/effective known-hosts file and use it during kdump capture. The default
know-host file isn’t sufficient.
I got your point, replied to Lianbo about some question about the
implementation.
> Thanks,Jun
>
> Sent from Yahoo Mail for iPhone
>
>
> On Monday, August 5, 2019, 8:01 PM, Dave Young <dyoung(a)redhat.com> wrote:
>
> On 08/05/19 at 08:56pm, Lianbo Jiang wrote:
> > When using the ssh kdump, the ssh client will use the '-o
StrictHostKeyChecking=yes'
> > option to connect the kdump server. To ensure the dump file is going to be sent
to
> > a true kdump server as opposed to any fake one, the ssh client needs to
authenticate
> > the server as well. A known_hosts file with server hostkey can be provisioned on
the
> > client side in advance to facilitate the authentication(which is added by
ssh-client
> > module in mkdumprd).
> >
> > Add a configuration in '/etc/kdump.conf' to specify the location of the
known_hosts
> > file to be used in the 'ssh -o UserKnownHostsFile' option.
>
> When add a new option, we need carefully check if this is really
> necessary. In this case, this is only useful for the case one want to
> use ssh -o UserKnownHostsFile, but why this is necessiry, why we can
> not use the global Knownhosts?
>
> >
> > Suggested-by: Jun Wang <junw99(a)yahoo.com>
> > Signed-off-by: Lianbo Jiang <lijiang(a)redhat.com>
> > ---
> > dracut-kdump.sh | 4 ++--
> > kdump-lib-initramfs.sh | 6 ++++++
> > kdump.conf | 4 ++++
> > kdumpctl | 12 ++++++++++--
> > mkdumprd | 11 +++++++++--
> > 5 files changed, 31 insertions(+), 6 deletions(-)
> >
> > diff --git a/dracut-kdump.sh b/dracut-kdump.sh
> > index ce56459ed088..0eafe6458530 100755
> > --- a/dracut-kdump.sh
> > +++ b/dracut-kdump.sh
> > @@ -71,7 +71,7 @@ dump_raw()
> >
> > dump_ssh()
> > {
> > - local _opt="-i $1 -o BatchMode=yes -o StrictHostKeyChecking=yes"
> > + local _opt="-i $1 -o BatchMode=yes -o StrictHostKeyChecking=yes -i $3
-o UserKnownHostsFile"
> > local _dir="$KDUMP_PATH/$HOST_IP-$DATEDIR"
> > local _host=$2
> >
> > @@ -156,7 +156,7 @@ read_kdump_conf()
> > add_dump_code "dump_raw $config_val"
> > ;;
> > ssh)
> > - add_dump_code "dump_ssh $SSH_KEY_LOCATION $config_val"
> > + add_dump_code "dump_ssh $SSH_KEY_LOCATION $config_val
$SSH_KNOWN_HOSTS"
> > ;;
> > esac
> > done <<< "$(read_strip_comments $KDUMP_CONF)"
> > diff --git a/kdump-lib-initramfs.sh b/kdump-lib-initramfs.sh
> > index 608dc6efc07e..7d595d5b7d06 100755
> > --- a/kdump-lib-initramfs.sh
> > +++ b/kdump-lib-initramfs.sh
> > @@ -11,6 +11,7 @@ DATEDIR=`date +%Y-%m-%d-%T`
> > HOST_IP='127.0.0.1'
> > DUMP_INSTRUCTION=""
> > SSH_KEY_LOCATION="/root/.ssh/kdump_id_rsa"
> > +SSH_KNOWN_HOSTS="/root/.ssh/known_hosts"
> > KDUMP_SCRIPT_DIR="/kdumpscripts"
> > DD_BLKSIZE=512
> > FINAL_ACTION="systemctl reboot -f"
> > @@ -38,6 +39,11 @@ get_kdump_confs()
> > SSH_KEY_LOCATION=$config_val
> > fi
> > ;;
> > + known_hosts)
> > + if [ -f "$config_val" ];then
> > + SSH_KNOWN_HOSTS="$config_val"
> > + fi
> > + ;;
> > kdump_pre)
> > KDUMP_PRE="$config_val"
> > ;;
> > diff --git a/kdump.conf b/kdump.conf
> > index 1f0fc2ddc40b..2b10d57ac561 100644
> > --- a/kdump.conf
> > +++ b/kdump.conf
> > @@ -152,6 +152,9 @@
> > # to send fence_kdump notifications to.
> > # (this option is mandatory to enable fence_kdump).
> > #
> > +# known_hosts <path>
> > +# - The "path" represents the path of know_hosts, the
default value
> > +# is /root/.ssh/known_hosts.
> >
> > #raw /dev/vg/lv_kdump
> > #ext4 /dev/vg/lv_kdump
> > @@ -173,3 +176,4 @@ core_collector makedumpfile -l --message-level 1 -d 31
> > #dracut_args --omit-drivers "cfg80211 snd" --add-drivers "ext2
ext3"
> > #fence_kdump_args -p 7410 -f auto -c 0 -i 10
> > #fence_kdump_nodes node1 node2
> > +#known_hosts /root/.ssh/known_hosts
> > diff --git a/kdumpctl b/kdumpctl
> > index a1a6ee24b768..7ba7e8cf2685 100755
> > --- a/kdumpctl
> > +++ b/kdumpctl
> > @@ -9,6 +9,7 @@ MKDUMPRD="/sbin/mkdumprd -f"
> > DRACUT_MODULES_FILE="/usr/lib/dracut/modules.txt"
> > SAVE_PATH=/var/crash
> > SSH_KEY_LOCATION="/root/.ssh/kdump_id_rsa"
> > +SSH_KNOWN_HOSTS="/root/.ssh/known_hosts"
> > INITRD_CHECKSUM_LOCATION="/boot/.fadump_initrd_checksum"
> > DUMP_TARGET=""
> > DEFAULT_INITRD=""
> > @@ -243,7 +244,7 @@ check_config()
> > case "$config_opt" in
> > \#* | "")
> > ;;
> > -
raw|ext2|ext3|ext4|minix|btrfs|xfs|nfs|ssh|sshkey|path|core_collector|kdump_post|kdump_pre|extra_bins|extra_modules|failure_action|default|final_action|force_rebuild|force_no_rebuild|dracut_args|fence_kdump_args|fence_kdump_nodes)
> > +
raw|ext2|ext3|ext4|minix|btrfs|xfs|nfs|ssh|sshkey|known_hosts|path|core_collector|kdump_post|kdump_pre|extra_bins|extra_modules|failure_action|default|final_action|force_rebuild|force_no_rebuild|dracut_args|fence_kdump_args|fence_kdump_nodes)
> > # remove inline comments after the end of a directive.
> > [ -z "$config_val" ] && {
> > echo "Invalid kdump config value for option
$config_opt."
> > @@ -711,6 +712,13 @@ check_ssh_config()
> > echo "WARNING: '$config_val' doesn't exist,
using default value '$SSH_KEY_LOCATION'"
> > fi
> > ;;
> > + known_hosts)
> > + if [ -f "$config_val" ];then
> > + SSH_KNOWN_HOSTS=$(/usr/bin/readlink -m $config_val)
> > + else
> > + echo "WARNING: '$config_val' doesn't exist,
using default value '$SSH_KNOWN_HOSTS'"
> > + fi
> > + ;;
> > path)
> > SAVE_PATH=$config_val
> > ;;
> > @@ -733,7 +741,7 @@ check_ssh_config()
> > check_ssh_target()
> > {
> > local _ret
> > - ssh -q -i $SSH_KEY_LOCATION -o BatchMode=yes $DUMP_TARGET mkdir -p
$SAVE_PATH
> > + ssh -q -i $SSH_KEY_LOCATION -i $SSH_KNOWN_HOSTS -o BatchMode=yes
$DUMP_TARGET mkdir -p $SAVE_PATH
> > _ret=$?
> > if [ $_ret -ne 0 ]; then
> > echo "Could not create $DUMP_TARGET:$SAVE_PATH, you probably need
to run \"kdumpctl propagate\"" >&2
> > diff --git a/mkdumprd b/mkdumprd
> > index cf3533fe2be9..c4e2f8ba4c31 100644
> > --- a/mkdumprd
> > +++ b/mkdumprd
> > @@ -13,6 +13,7 @@ export IN_KDUMP=1
> >
> > conf_file="/etc/kdump.conf"
> > SSH_KEY_LOCATION="/root/.ssh/kdump_id_rsa"
> > +SSH_KNOWN_HOSTS="/root/.ssh/known_hosts"
> > SAVE_PATH=$(awk '/^path/ {print $2}' $conf_file)
> > [ -z "$SAVE_PATH" ] && SAVE_PATH=$DEFAULT_PATH
> > # strip the duplicated "/"
> > @@ -144,7 +145,7 @@ is_readonly_mount() {
> > #called from while loop and shouldn't read from stdin, so we're using
"ssh -n"
> > get_ssh_size() {
> > local _opt _out _size
> > - _opt="-i $SSH_KEY_LOCATION -o BatchMode=yes -o
StrictHostKeyChecking=yes"
> > + _opt="-i $SSH_KEY_LOCATION -o BatchMode=yes -o
StrictHostKeyChecking=yes -i $SSH_KNOWN_HOSTS -o UserKnownHostsFile"
> > _out=$(ssh -q -n $_opt $1 "df -P $SAVE_PATH")
> > [ $? -ne 0 ] && {
> > perror_exit "checking remote ssh server available size
failed."
> > @@ -162,7 +163,7 @@ get_ssh_size() {
> > mkdir_save_path_ssh()
> > {
> > local _opt _dir
> > - _opt="-i $SSH_KEY_LOCATION -o BatchMode=yes -o
StrictHostKeyChecking=yes"
> > + _opt="-i $SSH_KEY_LOCATION -o BatchMode=yes -o
StrictHostKeyChecking=yes -i $SSH_KNOWN_HOSTS -o UserKnownHostsFile"
> > ssh -qn $_opt $1 mkdir -p $SAVE_PATH 2>&1 > /dev/null
> > _ret=$?
> > if [ $_ret -ne 0 ]; then
> > @@ -385,6 +386,12 @@ if [ -f "$keyfile" ]; then
> > SSH_KEY_LOCATION=$(/usr/bin/readlink -m $keyfile)
> > fi
> >
> > +# if specified, get the known_hosts
> > +known_hosts=$(awk '/^known_hosts/ {print $2}' $conf_file)
> > +if [ -f "$known_hosts" ];then
> > + SSH_KNOWN_HOSTS=$(/usr/bin/readlink -m $known_hosts)
> > +fi
> > +
> > if [ "$(uname -m)" = "s390x" ]; then
> > add_dracut_module "znet"
> > fi
> > --
> > 2.17.1
> >
>
>
>