diff --git a/meta/recipes-connectivity/openssh/openssh/sshd_check_keys b/meta/recipes-connectivity/openssh/openssh/sshd_check_keys index f5bba53ca3..5463b1a4cb 100644 --- a/meta/recipes-connectivity/openssh/openssh/sshd_check_keys +++ b/meta/recipes-connectivity/openssh/openssh/sshd_check_keys @@ -1,5 +1,35 @@ #! /bin/sh +generate_key() { + local FILE=$1 + local TYPE=$2 + local DIR="$(dirname "$FILE")" + + mkdir -p "$DIR" + ssh-keygen -q -f "${FILE}.tmp" -N '' -t $TYPE + + # Atomically rename file public key + mv -f "${FILE}.tmp.pub" "${FILE}.pub" + + # This sync does double duty: Ensuring that the data in the temporary + # private key file is on disk before the rename, and ensuring that the + # public key rename is completed before the private key rename, since we + # switch on the existence of the private key to trigger key generation. + # This does mean it is possible for the public key to exist, but be garbage + # but this is OK because in that case the private key won't exist and the + # keys will be regenerated. + # + # In the event that sync understands arguments that limit what it tries to + # fsync(), we provided them. If it does not, it will simply call sync() + # which is just as well + sync "${FILE}.pub" "$DIR" "${FILE}.tmp" + + mv "${FILE}.tmp" "$FILE" + + # sync to ensure the atomic rename is committed + sync "$DIR" +} + # /etc/default/ssh may set SYSCONFDIR and SSHD_OPTS if test -f /etc/default/ssh; then . /etc/default/ssh @@ -43,22 +73,18 @@ HOST_KEY_ED25519=$(grep ^HostKey "${sshd_config}" | grep _ed25519_ | tail -1 | a # create keys if necessary if [ ! -f $HOST_KEY_RSA ]; then echo " generating ssh RSA key..." - mkdir -p $(dirname $HOST_KEY_RSA) - ssh-keygen -q -f $HOST_KEY_RSA -N '' -t rsa + generate_key $HOST_KEY_RSA rsa fi if [ ! -f $HOST_KEY_ECDSA ]; then echo " generating ssh ECDSA key..." - mkdir -p $(dirname $HOST_KEY_ECDSA) - ssh-keygen -q -f $HOST_KEY_ECDSA -N '' -t ecdsa + generate_key $HOST_KEY_ECDSA ecdsa fi if [ ! -f $HOST_KEY_DSA ]; then echo " generating ssh DSA key..." - mkdir -p $(dirname $HOST_KEY_DSA) - ssh-keygen -q -f $HOST_KEY_DSA -N '' -t dsa + generate_key $HOST_KEY_DSA dsa fi if [ ! -f $HOST_KEY_ED25519 ]; then echo " generating ssh ED25519 key..." - mkdir -p $(dirname $HOST_KEY_ED25519) - ssh-keygen -q -f $HOST_KEY_ED25519 -N '' -t ed25519 + generate_key $HOST_KEY_ED25519 ed25519 fi