93 lines
3.7 KiB
Markdown
93 lines
3.7 KiB
Markdown
Here’s what those two pieces typically look like in a QEMU VNC + TLS + SASL setup.
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# `/etc/pki/qemu` (TLS x509 creds)
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QEMU’s `-object tls-creds-x509,...,dir=/etc/pki/qemu,endpoint=server` expects this directory to hold the server’s cert/key and the CA it should trust for client certs.
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Example layout:
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```
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/etc/pki/qemu/
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├── ca-cert.pem # CA cert used to verify client certificates (if verify-peer=yes)
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├── server-cert.pem # Server certificate (CN should match the host, or use subjectAltName)
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├── server-key.pem # Private key for server-cert.pem (chmod 600, root-only)
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└── crl.pem # (optional) Certificate Revocation List
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```
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Typical QEMU arg:
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```
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-object tls-creds-x509,id=tls0,dir=/etc/pki/qemu,endpoint=server,verify-peer=yes
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-vnc :0,tls-creds=tls0,sasl
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```
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Notes:
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* `verify-peer=yes` means the VNC client must present a client certificate signed by `ca-cert.pem`. Omit or set `no` if you only want encryption without client certs (and rely on SASL for auth).
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* File names above are the conventional ones QEMU looks for in that dir in server mode.
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* Permissions matter: keep `server-key.pem` readable only by the QEMU user (e.g., `chmod 600`).
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(If you wanted the client side for certificate auth, you’d create a *client* bundle with `client-cert.pem` / `client-key.pem` and give the server’s CA to the client.)
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# `/etc/sasl2/qemu.conf` (SASL settings)
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This file tells Cyrus SASL how to authenticate for the “qemu” service. A simple, local-password (sasldb) setup might be:
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```
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# /etc/sasl2/qemu.conf
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mech_list: scram-sha-256 digest-md5
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pwcheck_method: auxprop
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auxprop_plugin: sasldb
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sasldb_path: /etc/sasldb2
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```
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What each line does:
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* `mech_list`: Which SASL mechanisms to allow. (If your build doesn’t have SCRAM, use `digest-md5` and/or `plain`/`login` — but prefer SCRAM or DIGEST over PLAIN.)
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* `pwcheck_method: auxprop` + `auxprop_plugin: sasldb`: use the local SASL database.
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* `sasldb_path`: where the password DB lives (default is `/etc/sasldb2` on many distros).
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Create users in the sasldb:
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```bash
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sudo saslpasswd2 -a qemu -c alice
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# (it will prompt for a password)
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sudo sasldblistusers2 -f /etc/sasldb2 # verify entry exists
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```
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Then run QEMU with both TLS and SASL:
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```bash
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qemu-system-x86_64 \
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-object tls-creds-x509,id=tls0,dir=/etc/pki/qemu,endpoint=server,verify-peer=no \
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-vnc :0,tls-creds=tls0,sasl
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```
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* Client connects over **TLS** (encrypted), then is prompted for **SASL username/password** (“alice” and the password you set).
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* If you set `verify-peer=yes`, the client must also present a valid client cert signed by your CA.
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## Quick OpenSSL one-liners (for testing)
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> For production, use a proper CA workflow and strong key handling.
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```bash
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# CA
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openssl genrsa -out ca.key 4096
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openssl req -x509 -new -nodes -key ca.key -sha256 -days 3650 -out ca-cert.pem -subj "/CN=QEMU Test CA"
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# Server cert
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openssl genrsa -out server-key.pem 2048
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openssl req -new -key server-key.pem -out server.csr -subj "/CN=your.host.name"
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openssl x509 -req -in server.csr -CA ca-cert.pem -CAkey ca.key -CAcreateserial -out server-cert.pem -days 825 -sha256
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install -m 600 server-key.pem /etc/pki/qemu/
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install -m 644 server-cert.pem ca-cert.pem /etc/pki/qemu/
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```
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## Common pitfalls
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* **Wrong filenames/paths** in `/etc/pki/qemu` → QEMU won’t find the certs.
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* **Permissions too open** on `server-key.pem` → QEMU may refuse or it’s a security risk.
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* **SASL mechanism mismatch** → ensure your client supports one from `mech_list`.
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* **No TLS but SASL with PLAIN/LOGIN** → credentials go over the wire unencrypted; always pair PLAIN/LOGIN with TLS.
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If you tell me your distro, I can tailor the exact package names (Cyrus SASL modules) and service paths.
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