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| -rw-r--r-- | docs/system/qemu-block-drivers.rst.inc | 30 |
1 files changed, 26 insertions, 4 deletions
diff --git a/docs/system/qemu-block-drivers.rst.inc b/docs/system/qemu-block-drivers.rst.inc index e313784..dfe5d22 100644 --- a/docs/system/qemu-block-drivers.rst.inc +++ b/docs/system/qemu-block-drivers.rst.inc @@ -778,10 +778,32 @@ The optional *HOST_KEY_CHECK* parameter controls how the remote host's key is checked. The default is ``yes`` which means to use the local ``.ssh/known_hosts`` file. Setting this to ``no`` turns off known-hosts checking. Or you can check that the host key -matches a specific fingerprint: -``host_key_check=md5:78:45:8e:14:57:4f:d5:45:83:0a:0e:f3:49:82:c9:c8`` -(``sha1:`` can also be used as a prefix, but note that OpenSSH -tools only use MD5 to print fingerprints). +matches a specific fingerprint. The fingerprint can be provided in +``md5``, ``sha1``, or ``sha256`` format, however, it is strongly +recommended to only use ``sha256``, since the other options are +considered insecure by modern standards. The fingerprint value +must be given as a hex encoded string:: + + host_key_check=sha256:04ce2ae89ff4295a6b9c4111640bdcb3297858ee55cb434d9dd88796e93aa795 + +The key string may optionally contain ":" separators between +each pair of hex digits. + +The ``$HOME/.ssh/known_hosts`` file contains the base64 encoded +host keys. These can be converted into the format needed for +QEMU using a command such as:: + + $ for key in `grep 10.33.8.112 known_hosts | awk '{print $3}'` + do + echo $key | base64 -d | sha256sum + done + 6c3aa525beda9dc83eadfbd7e5ba7d976ecb59575d1633c87cd06ed2ed6e366f - + 12214fd9ea5b408086f98ecccd9958609bd9ac7c0ea316734006bc7818b45dc8 - + d36420137bcbd101209ef70c3b15dc07362fbe0fa53c5b135eba6e6afa82f0ce - + +Note that there can be multiple keys present per host, each with +different key ciphers. Care is needed to pick the key fingerprint +that matches the cipher QEMU will negotiate with the remote server. Currently authentication must be done using ssh-agent. Other authentication methods may be supported in future. |