[PATCH v4 0/6] cover: RFE libvirt secret encryption on disk
Libvirt secrets are stored unencrypted on the disk. With this series we want to start encrypting the secrets. 1. Introduce the GnuTLS decryption wrapper functions that work exact opposite to the encryption wrappers. 2. Add a new service called virt-secrets-init-encryption, that is linked to the virtsecretd service. virtsecretd service only starts after the new service generates a random encryption key. 3. Add a new secrets.conf configuration file that helps user to set a. secrets_encryption_key - allows the user to specify the encryption key file path, in case the default key is not to be used. b. encrypt_data - set to 0 or 1. If set to 1, then the newly added secrets will be encrypted. 4. Add encryption scheme or cipher attribute that will allow us to choose the last used cipher. 5. Once we have the encryption key, and a reliable way to tell the daemon what encryption scheme the secret object is using, we can encrypt the secrets on disk and store them in <uuid>.<encryption_scheme> format. It is important to note that if the encryption key is changed between restarts, then the respective secret will not be loaded by the driver. 6. Add documentation. This is a sincere attempt to improve upon the already submitted patch https://lists.libvirt.org/archives/list/devel@lists.libvirt.org/thread/KE6GV... Resolves: https://issues.redhat.com/browse/RHEL-7125 --- Changes in v3: - Fix the regression of loading unencrypted secrets after an upgrade. Previously the .base64 unencrypted secrets were not being loaded. - Add documentation on encrypted secrets. Changes in v3: - Secrets xml configuration no longer stores the encryption scheme, therefore not allowing the user to toggle between ciphers. - Removed unnecessary socket files of the new service. It now has a general configuration with which it starts. - Addressed review comments from Peter on coding style and design. - Loading of secrets is dependent on the file extension. Most recent cipher is used while saving the secrets. Changes in v2: - Corrected the encryption key length check. It should be 32. - Added a new patch that introduces the encryption scheme attribute. This will help us identify which secrets are encrypted. - A new systemd unit service file added that starts before virtsecretd, helping us to construct a random encryption key and pass it to the virtsecretd service. - Parsing logic of secrets.conf moved to a separate file. - Spec file changes, augeas. Arun Menon (6): util: Add support for GnuTLS decryption secret: Set up default encryption secret key for the virtsecretd service secret: Add secret.conf configuration file and parse it secret: Rename virSecretObj structure attribute from base64File to secretValueFile secret: Add functionality to load and save secrets in encrypted format docs: secret: Add documentation of secret encryption feature docs/drvsecret.rst | 4 + docs/meson.build | 1 + docs/secretencryption.rst | 86 ++++++++ include/libvirt/virterror.h | 1 + libvirt.spec.in | 8 + po/POTFILES | 1 + src/conf/virsecretobj.c | 193 ++++++++++++++---- src/conf/virsecretobj.h | 18 +- src/libvirt_private.syms | 1 + src/meson.build | 1 + src/remote/libvirtd.service.in | 4 + src/secret/libvirt_secrets.aug | 40 ++++ src/secret/meson.build | 32 +++ src/secret/secret.conf.in | 14 ++ src/secret/secret_config.c | 179 ++++++++++++++++ src/secret/secret_config.h | 40 ++++ src/secret/secret_driver.c | 34 ++- src/secret/test_libvirt_secrets.aug.in | 6 + .../virt-secret-init-encryption.service.in | 8 + src/secret/virtsecretd.service.extra.in | 8 + src/util/vircrypto.c | 126 +++++++++++- src/util/vircrypto.h | 8 + src/util/virerror.c | 3 + tests/vircryptotest.c | 65 ++++++ 24 files changed, 831 insertions(+), 50 deletions(-) create mode 100644 docs/secretencryption.rst create mode 100644 src/secret/libvirt_secrets.aug create mode 100644 src/secret/secret.conf.in create mode 100644 src/secret/secret_config.c create mode 100644 src/secret/secret_config.h create mode 100644 src/secret/test_libvirt_secrets.aug.in create mode 100644 src/secret/virt-secret-init-encryption.service.in -- 2.51.1
Adds `virCryptoDecryptDataAESgnutls` and `virCryptoDecryptData` as wrapper functions for GnuTLS decryption. These functions are the inverse of the existing GnuTLS encryption wrappers. This commit also includes a corresponding test case to validate data decryption. Signed-off-by: Arun Menon <armenon@redhat.com> Reviewed-by: Peter Krempa <pkrempa@redhat.com> --- src/libvirt_private.syms | 1 + src/util/vircrypto.c | 126 ++++++++++++++++++++++++++++++++++++++- src/util/vircrypto.h | 8 +++ tests/vircryptotest.c | 65 ++++++++++++++++++++ 4 files changed, 199 insertions(+), 1 deletion(-) diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms index 4e57e4a8f6..63a1ae4c70 100644 --- a/src/libvirt_private.syms +++ b/src/libvirt_private.syms @@ -2254,6 +2254,7 @@ virConfWriteMem; # util/vircrypto.h +virCryptoDecryptData; virCryptoEncryptData; virCryptoHashBuf; virCryptoHashString; diff --git a/src/util/vircrypto.c b/src/util/vircrypto.c index 3ce23264ca..00f723bb75 100644 --- a/src/util/vircrypto.c +++ b/src/util/vircrypto.c @@ -98,7 +98,7 @@ virCryptoHashString(virCryptoHash hash, } -/* virCryptoEncryptDataAESgntuls: +/* virCryptoEncryptDataAESgnutls: * * Performs the AES gnutls encryption * @@ -233,3 +233,127 @@ virCryptoEncryptData(virCryptoCipher algorithm, _("algorithm=%1$d is not supported"), algorithm); return -1; } + +/* virCryptoDecryptDataAESgnutls: + * + * Performs the AES gnutls decryption + * + * Same input as virCryptoDecryptData, except the algorithm is replaced + * by the specific gnutls algorithm. + * + * Decrypts the @data buffer using the @deckey and if available the @iv + * + * Returns 0 on success with the plaintext being filled. It is the + * caller's responsibility to clear and free it. Returns -1 on failure + * w/ error set. + */ +static int +virCryptoDecryptDataAESgnutls(gnutls_cipher_algorithm_t gnutls_dec_alg, + uint8_t *deckey, + size_t deckeylen, + uint8_t *iv, + size_t ivlen, + uint8_t *data, + size_t datalen, + uint8_t **plaintextret, + size_t *plaintextlenret) +{ + int rc; + uint8_t padding_length; + gnutls_cipher_hd_t handle = NULL; + gnutls_datum_t dec_key = { .data = deckey, .size = deckeylen }; + gnutls_datum_t iv_buf = { .data = iv, .size = ivlen }; + g_autofree uint8_t *plaintext = NULL; + size_t plaintextlen; + + if ((rc = gnutls_cipher_init(&handle, gnutls_dec_alg, + &dec_key, &iv_buf)) < 0) { + virReportError(VIR_ERR_INTERNAL_ERROR, + _("failed to initialize cipher: '%1$s'"), + gnutls_strerror(rc)); + return -1; + } + + plaintext = g_memdup2(data, datalen); + plaintextlen = datalen; + if (plaintextlen == 0) { + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("decrypted data has zero length")); + goto error; + } + rc = gnutls_cipher_decrypt(handle, plaintext, plaintextlen); + gnutls_cipher_deinit(handle); + if (rc < 0) { + virReportError(VIR_ERR_INTERNAL_ERROR, + _("failed to decrypt the data: '%1$s'"), + gnutls_strerror(rc)); + goto error; + } + /* Before encryption, padding is added to the data. + * The last byte indicates the padding length, because in PKCS#7, all + * padding bytes are set to the padding length value. + */ + padding_length = plaintext[plaintextlen - 1]; + if (padding_length > plaintextlen) { + virReportError(VIR_ERR_INVALID_SECRET, "%s", + _("decrypted data has invalid padding")); + goto error; + } + *plaintextlenret = plaintextlen - padding_length; + *plaintextret = g_steal_pointer(&plaintext); + return 0; + error: + virSecureErase(plaintext, plaintextlen); + return -1; +} + +/* virCryptoDecryptData: + * @algorithm: algorithm desired for decryption + * @deckey: decryption key + * @deckeylen: decryption key length + * @iv: initialization vector + * @ivlen: length of initialization vector + * @data: data to decrypt + * @datalen: length of data + * @plaintext: stream of bytes allocated to store plaintext + * @plaintextlen: size of the stream of bytes + * Returns 0 on success, -1 on failure with error set + */ +int +virCryptoDecryptData(virCryptoCipher algorithm, + uint8_t *deckey, + size_t deckeylen, + uint8_t *iv, + size_t ivlen, + uint8_t *data, + size_t datalen, + uint8_t **plaintext, + size_t *plaintextlen) +{ + switch (algorithm) { + case VIR_CRYPTO_CIPHER_AES256CBC: + if (deckeylen != 32) { + virReportError(VIR_ERR_INVALID_ARG, + _("AES256CBC decryption invalid keylen=%1$zu"), + deckeylen); + return -1; + } + if (ivlen != 16) { + virReportError(VIR_ERR_INVALID_ARG, + _("AES256CBC initialization vector invalid len=%1$zu"), + ivlen); + return -1; + } + return virCryptoDecryptDataAESgnutls(GNUTLS_CIPHER_AES_256_CBC, + deckey, deckeylen, iv, ivlen, + data, datalen, + plaintext, plaintextlen); + case VIR_CRYPTO_CIPHER_NONE: + case VIR_CRYPTO_CIPHER_LAST: + break; + } + + virReportError(VIR_ERR_INVALID_ARG, + _("algorithm=%1$d is not supported"), algorithm); + return -1; +} diff --git a/src/util/vircrypto.h b/src/util/vircrypto.h index 5f079ac335..2e8557839d 100644 --- a/src/util/vircrypto.h +++ b/src/util/vircrypto.h @@ -61,3 +61,11 @@ int virCryptoEncryptData(virCryptoCipher algorithm, uint8_t **ciphertext, size_t *ciphertextlen) ATTRIBUTE_NONNULL(2) ATTRIBUTE_NONNULL(6) ATTRIBUTE_NONNULL(8) ATTRIBUTE_NONNULL(9) G_GNUC_WARN_UNUSED_RESULT; + +int virCryptoDecryptData(virCryptoCipher algorithm, + uint8_t *deckey, size_t deckeylen, + uint8_t *iv, size_t ivlen, + uint8_t *data, size_t datalen, + uint8_t **plaintext, size_t *plaintextlen) + ATTRIBUTE_NONNULL(2) ATTRIBUTE_NONNULL(6) + ATTRIBUTE_NONNULL(8) ATTRIBUTE_NONNULL(9) G_GNUC_WARN_UNUSED_RESULT; diff --git a/tests/vircryptotest.c b/tests/vircryptotest.c index 9ffe70756e..864fa8838d 100644 --- a/tests/vircryptotest.c +++ b/tests/vircryptotest.c @@ -62,6 +62,14 @@ struct testCryptoEncryptData { size_t ciphertextlen; }; +struct testCryptoDecryptData { + virCryptoCipher algorithm; + uint8_t *input; + size_t inputlen; + uint8_t *plaintext; + size_t plaintextlen; +}; + static int testCryptoEncrypt(const void *opaque) { @@ -101,6 +109,44 @@ testCryptoEncrypt(const void *opaque) return 0; } +static int +testCryptoDecrypt(const void *opaque) +{ + const struct testCryptoDecryptData *data = opaque; + g_autofree uint8_t *deckey = NULL; + size_t deckeylen = 32; + g_autofree uint8_t *iv = NULL; + size_t ivlen = 16; + g_autofree uint8_t *plaintext = NULL; + size_t plaintextlen = 0; + + deckey = g_new0(uint8_t, deckeylen); + iv = g_new0(uint8_t, ivlen); + + if (virRandomBytes(deckey, deckeylen) < 0 || + virRandomBytes(iv, ivlen) < 0) { + fprintf(stderr, "Failed to generate random bytes\n"); + return -1; + } + + if (virCryptoDecryptData(data->algorithm, deckey, deckeylen, iv, ivlen, + data->input, data->inputlen, + &plaintext, &plaintextlen) < 0) + return -1; + + if (data->plaintextlen != plaintextlen) { + fprintf(stderr, "Expected plaintexlen(%zu) doesn't match (%zu)\n", + data->plaintextlen, plaintextlen); + return -1; + } + + if (memcmp(data->plaintext, plaintext, plaintextlen)) { + fprintf(stderr, "Expected plaintext doesn't match\n"); + return -1; + } + + return 0; +} static int mymain(void) @@ -155,7 +201,26 @@ mymain(void) #undef VIR_CRYPTO_ENCRYPT +#define VIR_CRYPTO_DECRYPT(a, n, i, il, c, cl) \ + do { \ + struct testCryptoDecryptData data = { \ + .algorithm = a, \ + .input = i, \ + .inputlen = il, \ + .plaintext = c, \ + .plaintextlen = cl, \ + }; \ + if (virTestRun("Decrypt " n, testCryptoDecrypt, &data) < 0) \ + ret = -1; \ + } while (0) + + VIR_CRYPTO_DECRYPT(VIR_CRYPTO_CIPHER_AES256CBC, "aes256cbc", + expected_ciphertext, 16, secretdata, 7); + +#undef VIR_CRYPTO_DECRYPT + return ret == 0 ? EXIT_SUCCESS : EXIT_FAILURE; + } /* Forces usage of not so random virRandomBytes */ -- 2.51.1
This commit sets the foundation for encrypting the libvirt secrets by providing a secure way to pass a secret encryption key to the virtsecretd service. A random secret key is generated using the new virt-secret-init-encryption service. This key can be consumed by the virtsecretd service. By using the "Before=" directive in the new virt-secret-init-encryption service and using "Requires=" directive in the virtsecretd service, we make sure that the daemon is run only after we have an encrypted secret key file generated and placed in /var/lib/libvirt/secrets. The virtsecretd service can then read the key from CREDENTIALS_DIRECTORY. [1] This setup therefore provides a default key out-of-the-box for initial use. A subsequent commit will introduce the logic for virtsecretd to access and use this key via the $CREDENTIALS_DIRECTORY environment variable. [2] [1] https://www.freedesktop.org/software/systemd/man/latest/systemd-creds.html [2] https://systemd.io/CREDENTIALS/ Signed-off-by: Arun Menon <armenon@redhat.com> --- libvirt.spec.in | 5 +++++ src/meson.build | 1 + src/remote/libvirtd.service.in | 4 ++++ src/secret/meson.build | 13 +++++++++++++ src/secret/virt-secret-init-encryption.service.in | 8 ++++++++ src/secret/virtsecretd.service.extra.in | 8 ++++++++ 6 files changed, 39 insertions(+) create mode 100644 src/secret/virt-secret-init-encryption.service.in diff --git a/libvirt.spec.in b/libvirt.spec.in index ccfe75135b..6a497bfecd 100644 --- a/libvirt.spec.in +++ b/libvirt.spec.in @@ -1890,13 +1890,16 @@ exit 0 %pre daemon-driver-secret %libvirt_sysconfig_pre virtsecretd %libvirt_systemd_unix_pre virtsecretd +%libvirt_systemd_oneshot_pre virt-secret-init-encryption %posttrans daemon-driver-secret %libvirt_sysconfig_posttrans virtsecretd %libvirt_systemd_unix_posttrans virtsecretd +%libvirt_systemd_unix_posttrans virt-secret-init-encryption %preun daemon-driver-secret %libvirt_systemd_unix_preun virtsecretd +%libvirt_systemd_unix_preun virt-secret-init-encryption %pre daemon-driver-storage-core %libvirt_sysconfig_pre virtstoraged @@ -2248,11 +2251,13 @@ exit 0 %{_datadir}/augeas/lenses/virtsecretd.aug %{_datadir}/augeas/lenses/tests/test_virtsecretd.aug %{_unitdir}/virtsecretd.service +%{_unitdir}/virt-secret-init-encryption.service %{_unitdir}/virtsecretd.socket %{_unitdir}/virtsecretd-ro.socket %{_unitdir}/virtsecretd-admin.socket %attr(0755, root, root) %{_sbindir}/virtsecretd %dir %attr(0700, root, root) %{_sysconfdir}/libvirt/secrets/ +%dir %attr(0700, root, root) %{_localstatedir}/lib/libvirt/secrets/ %ghost %dir %attr(0700, root, root) %{_rundir}/libvirt/secrets/ %{_libdir}/libvirt/connection-driver/libvirt_driver_secret.so %{_mandir}/man8/virtsecretd.8* diff --git a/src/meson.build b/src/meson.build index 47c978cc1f..f18f562fd9 100644 --- a/src/meson.build +++ b/src/meson.build @@ -837,6 +837,7 @@ if conf.has('WITH_LIBVIRTD') 'sbindir': sbindir, 'sysconfdir': sysconfdir, 'initconfdir': initconfdir, + 'localstatedir': localstatedir, 'name': unit['name'], 'service': unit['service'], 'SERVICE': unit['service'].to_upper(), diff --git a/src/remote/libvirtd.service.in b/src/remote/libvirtd.service.in index b0a062e885..7965010a0a 100644 --- a/src/remote/libvirtd.service.in +++ b/src/remote/libvirtd.service.in @@ -12,6 +12,8 @@ After=libvirtd.socket After=libvirtd-ro.socket After=libvirtd-admin.socket Requires=virtlogd.socket +Requires=virt-secret-init-encryption.service +After=virt-secret-init-encryption.service Wants=virtlockd.socket After=virtlogd.socket After=virtlockd.socket @@ -29,6 +31,8 @@ Conflicts=xendomains.service Type=notify-reload Environment=LIBVIRTD_ARGS="--timeout 120" EnvironmentFile=-@initconfdir@/libvirtd +Environment=SECRETS_ENCRYPTION_KEY=%d/secrets-encryption-key +LoadCredentialEncrypted=secrets-encryption-key:@localstatedir@/lib/libvirt/secrets/secrets-encryption-key ExecStart=@sbindir@/libvirtd $LIBVIRTD_ARGS ExecReload=/bin/kill -HUP $MAINPID KillMode=process diff --git a/src/secret/meson.build b/src/secret/meson.build index 3b859ea7b4..b69abe32ab 100644 --- a/src/secret/meson.build +++ b/src/secret/meson.build @@ -31,6 +31,18 @@ if conf.has('WITH_SECRETS') 'name': 'virtsecretd', } + virt_secret_init_encryption_conf = configuration_data() + + virt_secret_init_encryption_conf.set('localstatedir', localstatedir) + + configure_file( + input: 'virt-secret-init-encryption.service.in', + output: '@0@.service'.format('virt-secret-init-encryption'), + configuration: virt_secret_init_encryption_conf, + install: true, + install_dir: unitdir, + ) + virt_daemon_units += { 'service': 'virtsecretd', 'name': 'secret', @@ -50,5 +62,6 @@ if conf.has('WITH_SECRETS') virt_install_dirs += [ confdir / 'secrets', runstatedir / 'libvirt' / 'secrets', + localstatedir / 'lib' / 'libvirt' / 'secrets', ] endif diff --git a/src/secret/virt-secret-init-encryption.service.in b/src/secret/virt-secret-init-encryption.service.in new file mode 100644 index 0000000000..44940bd72b --- /dev/null +++ b/src/secret/virt-secret-init-encryption.service.in @@ -0,0 +1,8 @@ +[Unit] +Before=virtsecretd.service +Before=libvirtd.service +ConditionPathExists=!@localstatedir@/lib/libvirt/secrets/secrets-encryption-key + +[Service] +Type=oneshot +ExecStart=/usr/bin/sh -c 'umask 0066 && (dd if=/dev/urandom status=none bs=32 count=1 | systemd-creds encrypt --name=secrets-encryption-key - @localstatedir@/lib/libvirt/secrets/secrets-encryption-key)' diff --git a/src/secret/virtsecretd.service.extra.in b/src/secret/virtsecretd.service.extra.in index 1fc8c672f7..116458b22a 100644 --- a/src/secret/virtsecretd.service.extra.in +++ b/src/secret/virtsecretd.service.extra.in @@ -1,2 +1,10 @@ # The contents of this unit will be merged into a base template. # Additional units might be merged as well. See meson.build for details. +# +[Unit] +Requires=virt-secret-init-encryption.service +After=virt-secret-init-encryption.service + +[Service] +LoadCredentialEncrypted=secrets-encryption-key:@localstatedir@/lib/libvirt/secrets/secrets-encryption-key +Environment=SECRETS_ENCRYPTION_KEY=%d/secrets-encryption-key -- 2.51.1
On Fri, Jan 09, 2026 at 23:39:32 +0530, Arun Menon via Devel wrote:
This commit sets the foundation for encrypting the libvirt secrets by providing a secure way to pass a secret encryption key to the virtsecretd service.
A random secret key is generated using the new virt-secret-init-encryption service. This key can be consumed by the virtsecretd service.
By using the "Before=" directive in the new virt-secret-init-encryption service and using "Requires=" directive in the virtsecretd service, we make sure that the daemon is run only after we have an encrypted secret key file generated and placed in /var/lib/libvirt/secrets. The virtsecretd service can then read the key from CREDENTIALS_DIRECTORY. [1]
This setup therefore provides a default key out-of-the-box for initial use. A subsequent commit will introduce the logic for virtsecretd to access and use this key via the $CREDENTIALS_DIRECTORY environment variable. [2]
[1] https://www.freedesktop.org/software/systemd/man/latest/systemd-creds.html [2] https://systemd.io/CREDENTIALS/
Signed-off-by: Arun Menon <armenon@redhat.com> --- libvirt.spec.in | 5 +++++ src/meson.build | 1 + src/remote/libvirtd.service.in | 4 ++++ src/secret/meson.build | 13 +++++++++++++ src/secret/virt-secret-init-encryption.service.in | 8 ++++++++ src/secret/virtsecretd.service.extra.in | 8 ++++++++ 6 files changed, 39 insertions(+) create mode 100644 src/secret/virt-secret-init-encryption.service.in
[...]
diff --git a/src/secret/virt-secret-init-encryption.service.in b/src/secret/virt-secret-init-encryption.service.in new file mode 100644 index 0000000000..44940bd72b --- /dev/null +++ b/src/secret/virt-secret-init-encryption.service.in @@ -0,0 +1,8 @@ +[Unit] +Before=virtsecretd.service +Before=libvirtd.service +ConditionPathExists=!@localstatedir@/lib/libvirt/secrets/secrets-encryption-key + +[Service] +Type=oneshot +ExecStart=/usr/bin/sh -c 'umask 0066 && (dd if=/dev/urandom status=none bs=32 count=1 | systemd-creds encrypt --name=secrets-encryption-key - @localstatedir@/lib/libvirt/secrets/secrets-encryption-key)'
While dealing with the fix in a379327d8abcde8ac8d3e16fe5e4ba6f790d767a I've discovered that 0077 is the more common setting in such case. Not that it'd really change anything here. (If it turns out there'll be only minor changes needed I'll do this change before pushing. This applies to any other comment I'll have). Reviewed-by: Peter Krempa <pkrempa@redhat.com>
On Fri, Jan 09, 2026 at 23:39:32 +0530, Arun Menon via Devel wrote:
This commit sets the foundation for encrypting the libvirt secrets by providing a secure way to pass a secret encryption key to the virtsecretd service.
A random secret key is generated using the new virt-secret-init-encryption service. This key can be consumed by the virtsecretd service.
By using the "Before=" directive in the new virt-secret-init-encryption service and using "Requires=" directive in the virtsecretd service, we make sure that the daemon is run only after we have an encrypted secret key file generated and placed in /var/lib/libvirt/secrets. The virtsecretd service can then read the key from CREDENTIALS_DIRECTORY. [1]
This setup therefore provides a default key out-of-the-box for initial use. A subsequent commit will introduce the logic for virtsecretd to access and use this key via the $CREDENTIALS_DIRECTORY environment variable. [2]
[1] https://www.freedesktop.org/software/systemd/man/latest/systemd-creds.html [2] https://systemd.io/CREDENTIALS/
Signed-off-by: Arun Menon <armenon@redhat.com> --- libvirt.spec.in | 5 +++++ src/meson.build | 1 + src/remote/libvirtd.service.in | 4 ++++ src/secret/meson.build | 13 +++++++++++++ src/secret/virt-secret-init-encryption.service.in | 8 ++++++++ src/secret/virtsecretd.service.extra.in | 8 ++++++++ 6 files changed, 39 insertions(+) create mode 100644 src/secret/virt-secret-init-encryption.service.in
[...]
diff --git a/src/secret/virt-secret-init-encryption.service.in b/src/secret/virt-secret-init-encryption.service.in new file mode 100644 index 0000000000..44940bd72b --- /dev/null +++ b/src/secret/virt-secret-init-encryption.service.in @@ -0,0 +1,8 @@ +[Unit] +Before=virtsecretd.service +Before=libvirtd.service +ConditionPathExists=!@localstatedir@/lib/libvirt/secrets/secrets-encryption-key + +[Service] +Type=oneshot +ExecStart=/usr/bin/sh -c 'umask 0066 && (dd if=/dev/urandom status=none bs=32 count=1 | systemd-creds encrypt --name=secrets-encryption-key - @localstatedir@/lib/libvirt/secrets/secrets-encryption-key)'
AFAIU /dev/random should be used for any crypto-related stuff. /dev/urandom was discouraged e.g. when we've used it as the default backing for the RNG device.
A new configuration file called secret.conf is introduced to let the user configure the path to the secrets encryption key. This key will be used to encrypt/decrypt the secrets in libvirt. By default the path is set to the runtime directory /run/libvirt/secrets, and it is commented in the config file. After parsing the file, the virtsecretd driver checks if an encryption key is present in the path and is valid. If no encryption key is present in the path, then the service will by default use the encryption key stored in the CREDENTIALS_DIRECTORY. Add logic to parse the encryption key file and store the key. It also checks for the encrypt_data attribute in the config file. The encryption and decryption logic will be added in the subsequent patches. Signed-off-by: Arun Menon <armenon@redhat.com> --- include/libvirt/virterror.h | 1 + libvirt.spec.in | 3 + po/POTFILES | 1 + src/secret/libvirt_secrets.aug | 40 ++++++ src/secret/meson.build | 19 +++ src/secret/secret.conf.in | 14 ++ src/secret/secret_config.c | 179 +++++++++++++++++++++++++ src/secret/secret_config.h | 40 ++++++ src/secret/secret_driver.c | 11 ++ src/secret/test_libvirt_secrets.aug.in | 6 + src/util/virerror.c | 3 + 11 files changed, 317 insertions(+) create mode 100644 src/secret/libvirt_secrets.aug create mode 100644 src/secret/secret.conf.in create mode 100644 src/secret/secret_config.c create mode 100644 src/secret/secret_config.h create mode 100644 src/secret/test_libvirt_secrets.aug.in diff --git a/include/libvirt/virterror.h b/include/libvirt/virterror.h index f02da046a3..fa07c36ceb 100644 --- a/include/libvirt/virterror.h +++ b/include/libvirt/virterror.h @@ -353,6 +353,7 @@ typedef enum { command within timeout (Since: 11.2.0) */ VIR_ERR_AGENT_COMMAND_FAILED = 113, /* guest agent responded with failure to a command (Since: 11.2.0) */ + VIR_ERR_INVALID_ENCR_KEY_SECRET = 114, /* encryption key is invalid (Since: 12.0.0) */ # ifdef VIR_ENUM_SENTINELS VIR_ERR_NUMBER_LAST /* (Since: 5.0.0) */ diff --git a/libvirt.spec.in b/libvirt.spec.in index 6a497bfecd..50159e7461 100644 --- a/libvirt.spec.in +++ b/libvirt.spec.in @@ -2250,6 +2250,9 @@ exit 0 %config(noreplace) %{_sysconfdir}/libvirt/virtsecretd.conf %{_datadir}/augeas/lenses/virtsecretd.aug %{_datadir}/augeas/lenses/tests/test_virtsecretd.aug +%{_datadir}/augeas/lenses/libvirt_secrets.aug +%{_datadir}/augeas/lenses/tests/test_libvirt_secrets.aug +%config(noreplace) %{_sysconfdir}/libvirt/secret.conf %{_unitdir}/virtsecretd.service %{_unitdir}/virt-secret-init-encryption.service %{_unitdir}/virtsecretd.socket diff --git a/po/POTFILES b/po/POTFILES index f0aad35c8c..ede667cfaf 100644 --- a/po/POTFILES +++ b/po/POTFILES @@ -232,6 +232,7 @@ src/rpc/virnetsshsession.c src/rpc/virnettlscert.c src/rpc/virnettlsconfig.c src/rpc/virnettlscontext.c +src/secret/secret_config.c src/secret/secret_driver.c src/security/security_apparmor.c src/security/security_dac.c diff --git a/src/secret/libvirt_secrets.aug b/src/secret/libvirt_secrets.aug new file mode 100644 index 0000000000..8dda373e62 --- /dev/null +++ b/src/secret/libvirt_secrets.aug @@ -0,0 +1,40 @@ +(* /etc/libvirt/secret.conf *) + +module Libvirt_secrets = + autoload xfm + + let eol = del /[ \t]*\n/ "\n" + let value_sep = del /[ \t]*=[ \t]*/ " = " + let indent = del /[ \t]*/ "" + + let array_sep = del /,[ \t\n]*/ ", " + let array_start = del /\[[ \t\n]*/ "[ " + let array_end = del /\]/ "]" + + let str_val = del /\"/ "\"" . store /[^\"]*/ . del /\"/ "\"" + let bool_val = store /0|1/ + let int_val = store /[0-9]+/ + let str_array_element = [ seq "el" . str_val ] . del /[ \t\n]*/ "" + let str_array_val = counter "el" . array_start . ( str_array_element . ( array_sep . str_array_element ) * ) ? . array_end + + let str_entry (kw:string) = [ key kw . value_sep . str_val ] + let bool_entry (kw:string) = [ key kw . value_sep . bool_val ] + let int_entry (kw:string) = [ key kw . value_sep . int_val ] + let str_array_entry (kw:string) = [ key kw . value_sep . str_array_val ] + + let secrets_entry = str_entry "secrets_encryption_key" + | bool_entry "encrypt_data" + + (* Each entry in the config is one of the following three ... *) + let entry = secrets_entry + let comment = [ label "#comment" . del /#[ \t]*/ "# " . store /([^ \t\n][^\n]*)?/ . del /\n/ "\n" ] + let empty = [ label "#empty" . eol ] + + let record = indent . entry . eol + + let lns = ( record | comment | empty ) * + + let filter = incl "/etc/libvirt/secret.conf" + . Util.stdexcl + + let xfm = transform lns filter diff --git a/src/secret/meson.build b/src/secret/meson.build index b69abe32ab..cfcc861f4f 100644 --- a/src/secret/meson.build +++ b/src/secret/meson.build @@ -1,5 +1,6 @@ secret_driver_sources = [ 'secret_driver.c', + 'secret_config.c', ] driver_source_files += files(secret_driver_sources) @@ -27,6 +28,24 @@ if conf.has('WITH_SECRETS') ], } + secret_conf = configure_file( + input: 'secret.conf.in', + output: 'secret.conf', + copy: true + ) + virt_conf_files += secret_conf + + virt_aug_files += files('libvirt_secrets.aug') + + virt_test_aug_files += { + 'name': 'test_libvirt_secrets.aug', + 'aug': files('test_libvirt_secrets.aug.in'), + 'conf': files('secret.conf.in'), + 'test_name': 'libvirt_secrets', + 'test_srcdir': meson.current_source_dir(), + 'test_builddir': meson.current_build_dir(), + } + virt_daemon_confs += { 'name': 'virtsecretd', } diff --git a/src/secret/secret.conf.in b/src/secret/secret.conf.in new file mode 100644 index 0000000000..a231c48f8d --- /dev/null +++ b/src/secret/secret.conf.in @@ -0,0 +1,14 @@ +# +# Configuration file for the secrets driver. +# +# The secret encryption key is used to override default encryption +# key path. The user can create an encryption key and set the secret_encryption_key +# to the path on which it resides. +# The key must be 32-bytes long. +#secrets_encryption_key = "/run/libvirt/secrets/secret-encryption-key" + +# The encrypt_data setting is used to indicate if the encryption is on or off. +# 0 indicates off and 1 indicates on. By default it is on +# if secrets_encryption_key is set to a non-NULL +# path, or if a systemd credential named "secrets-encryption-key" exists. +#encrypt_data = 1 diff --git a/src/secret/secret_config.c b/src/secret/secret_config.c new file mode 100644 index 0000000000..4e11bca1b6 --- /dev/null +++ b/src/secret/secret_config.c @@ -0,0 +1,179 @@ +/* + * secret_config.c: secret.conf config file handling + * + * SPDX-License-Identifier: LGPL-2.1-or-later + */ + +#include <config.h> +#include <fcntl.h> +#include "configmake.h" +#include "datatypes.h" +#include "virlog.h" +#include "virerror.h" +#include "virfile.h" +#include "virutil.h" +#include "virsecureerase.h" +#include "secret_config.h" + + +#define VIR_FROM_THIS VIR_FROM_SECRET + +VIR_LOG_INIT("secret.secret_config"); + +static virClass *virSecretDaemonConfigClass; +static void virSecretDaemonConfigDispose(void *obj); + +static int +virSecretConfigOnceInit(void) +{ + if (!VIR_CLASS_NEW(virSecretDaemonConfig, virClassForObject())) + return -1; + + return 0; +} + + +VIR_ONCE_GLOBAL_INIT(virSecretConfig); + + +int +virSecretDaemonConfigFilePath(bool privileged, char **configfile) +{ + if (privileged) { + *configfile = g_strdup(SYSCONFDIR "/libvirt/secret.conf"); + } else { + g_autofree char *configdir = NULL; + + configdir = virGetUserConfigDirectory(); + + *configfile = g_strdup_printf("%s/secret.conf", configdir); + } + + return 0; +} + + +static int +virSecretLoadDaemonConfig(virSecretDaemonConfig *cfg, + const char *filename) +{ + g_autoptr(virConf) conf = NULL; + int res; + + if (virFileExists(filename)) { + conf = virConfReadFile(filename, 0); + if (!conf) + return -1; + res = virConfGetValueBool(conf, "encrypt_data", &cfg->encryptData); + if (res < 0) { + return -1; + } else if (res == 1) { + cfg->encryptDataWasSet = true; + } else { + cfg->encryptDataWasSet = false; + } + + if (virConfGetValueString(conf, "secrets_encryption_key", + &cfg->secretsEncryptionKeyPath) < 0) { + return -1; + } + } + return 0; +} + + +static int +virGetSecretsEncryptionKey(virSecretDaemonConfig *cfg, + uint8_t **secretsEncryptionKey, + size_t *secretsKeyLen) +{ + VIR_AUTOCLOSE fd = -1; + int encryptionKeyLength; + + if ((encryptionKeyLength = virFileReadAll(cfg->secretsEncryptionKeyPath, + VIR_SECRETS_ENCRYPTION_KEY_LEN, + (char**)secretsEncryptionKey)) < 0) { + return -1; + } + if (encryptionKeyLength != VIR_SECRETS_ENCRYPTION_KEY_LEN) { + virReportError(VIR_ERR_INVALID_ENCR_KEY_SECRET, + _("Encryption key length must be '%1$d' '%2$s'"), + VIR_SECRETS_ENCRYPTION_KEY_LEN, + cfg->secretsEncryptionKeyPath); + return -1; + } + + *secretsKeyLen = (size_t)encryptionKeyLength; + return 0; +} + + +virSecretDaemonConfig * +virSecretDaemonConfigNew(bool privileged) +{ + g_autoptr(virSecretDaemonConfig) cfg = NULL; + g_autofree char *configdir = NULL; + g_autofree char *configfile = NULL; + g_autofree char *rundir = NULL; + const char *credentialsDirectory; + + if (virSecretConfigInitialize() < 0) + return NULL; + + if (!(cfg = virObjectNew(virSecretDaemonConfigClass))) + return NULL; + + if (virSecretDaemonConfigFilePath(privileged, &configfile) < 0) + return NULL; + + if (virSecretLoadDaemonConfig(cfg, configfile) < 0) + return NULL; + + credentialsDirectory = getenv("CREDENTIALS_DIRECTORY"); + + if (!cfg->secretsEncryptionKeyPath && credentialsDirectory) { + cfg->secretsEncryptionKeyPath = g_strdup_printf("%s/secrets-encryption-key", + credentialsDirectory); + if (!virFileExists(cfg->secretsEncryptionKeyPath)) { + g_clear_pointer(&cfg->secretsEncryptionKeyPath, g_free); + } + } + + if (!cfg->encryptDataWasSet) { + if (!cfg->secretsEncryptionKeyPath) { + /* No path specified by user or environment, disable encryption */ + cfg->encryptData = false; + } else { + cfg->encryptData = true; + } + } else { + if (cfg->encryptData) { + if (!cfg->secretsEncryptionKeyPath) { + /* Built-in default path must be used */ + rundir = virGetUserRuntimeDirectory(); + cfg->secretsEncryptionKeyPath = g_strdup_printf("%s/secrets/encryption-key", + rundir); + } + } + } + VIR_DEBUG("Secrets encryption key path: %s", NULLSTR(cfg->secretsEncryptionKeyPath)); + + if (cfg->encryptData) { + if (virGetSecretsEncryptionKey(cfg, + &cfg->secretsEncryptionKey, + &cfg->secretsKeyLen) < 0) { + return NULL; + } + } + return g_steal_pointer(&cfg); +} + + +static void +virSecretDaemonConfigDispose(void *obj) +{ + virSecretDaemonConfig *cfg = obj; + + virSecureErase(cfg->secretsEncryptionKey, cfg->secretsKeyLen); + g_free(cfg->secretsEncryptionKeyPath); +} diff --git a/src/secret/secret_config.h b/src/secret/secret_config.h new file mode 100644 index 0000000000..888acf272b --- /dev/null +++ b/src/secret/secret_config.h @@ -0,0 +1,40 @@ +/* + * secret_config.h: secret.conf config file handling + * + * SPDX-License-Identifier: LGPL-2.1-or-later + */ + +#pragma once + +#include "internal.h" +#include "virinhibitor.h" +#include "secret_event.h" +#define VIR_SECRETS_ENCRYPTION_KEY_LEN 32 + +typedef struct _virSecretDaemonConfig virSecretDaemonConfig; +struct _virSecretDaemonConfig { + virObject parent; + /* secrets encryption key path from secret.conf file */ + char *secretsEncryptionKeyPath; + + /* Store the key to encrypt secrets on the disk */ + unsigned char *secretsEncryptionKey; + + size_t secretsKeyLen; + + /* Indicates if the newly written secrets are encrypted or not. + */ + bool encryptData; + + /* Indicates if the config file has encrypt_data set or not. + */ + bool encryptDataWasSet; +}; + +G_DEFINE_AUTOPTR_CLEANUP_FUNC(virSecretDaemonConfig, virObjectUnref); + +int virSecretDaemonConfigFilePath(bool privileged, char **configfile); +virSecretDaemonConfig *virSecretDaemonConfigNew(bool privileged); +int virSecretDaemonConfigLoadFile(virSecretDaemonConfig *data, + const char *filename, + bool allow_missing); diff --git a/src/secret/secret_driver.c b/src/secret/secret_driver.c index 04c3ca49f1..9b13772ad3 100644 --- a/src/secret/secret_driver.c +++ b/src/secret/secret_driver.c @@ -42,6 +42,7 @@ #include "secret_event.h" #include "virutil.h" #include "virinhibitor.h" +#include "secret_config.h" #define VIR_FROM_THIS VIR_FROM_SECRET @@ -70,6 +71,10 @@ struct _virSecretDriverState { /* Immutable pointer, self-locking APIs */ virInhibitor *inhibitor; + + /* Require lock to get reference on 'config', + * then lockless thereafter */ + virSecretDaemonConfig *config; }; static virSecretDriverState *driver; @@ -454,6 +459,7 @@ secretStateCleanupLocked(void) VIR_FREE(driver->configDir); virObjectUnref(driver->secretEventState); + virObjectUnref(driver->config); virInhibitorFree(driver->inhibitor); if (driver->lockFD != -1) @@ -518,6 +524,8 @@ secretStateInitialize(bool privileged, driver->stateDir); goto error; } + if (!(driver->config = virSecretDaemonConfigNew(driver->privileged))) + goto error; driver->inhibitor = virInhibitorNew( VIR_INHIBITOR_WHAT_NONE, @@ -553,6 +561,9 @@ secretStateReload(void) if (!driver) return -1; + if (!(driver->config = virSecretDaemonConfigNew(driver->privileged))) + return -1; + ignore_value(virSecretLoadAllConfigs(driver->secrets, driver->configDir)); return 0; diff --git a/src/secret/test_libvirt_secrets.aug.in b/src/secret/test_libvirt_secrets.aug.in new file mode 100644 index 0000000000..1bb205e0f2 --- /dev/null +++ b/src/secret/test_libvirt_secrets.aug.in @@ -0,0 +1,6 @@ +module Test_libvirt_secrets = + @CONFIG@ + + test Libvirt_secrets.lns get conf = +{ "secrets_encryption_key" = "/run/libvirt/secrets/secret-encryption-key" } +{ "encrypt_data" = "1" } diff --git a/src/util/virerror.c b/src/util/virerror.c index abb014b522..b7d23f81c7 100644 --- a/src/util/virerror.c +++ b/src/util/virerror.c @@ -1296,6 +1296,9 @@ static const virErrorMsgTuple virErrorMsgStrings[] = { [VIR_ERR_AGENT_COMMAND_FAILED] = { N_("guest agent command failed"), N_("guest agent command failed: %1$s") }, + [VIR_ERR_INVALID_ENCR_KEY_SECRET] = { + N_("Invalid encryption key for the secret"), + N_("Invalid encryption key for the secret: %1$s") }, }; G_STATIC_ASSERT(G_N_ELEMENTS(virErrorMsgStrings) == VIR_ERR_NUMBER_LAST); -- 2.51.1
On Fri, Jan 09, 2026 at 23:39:33 +0530, Arun Menon via Devel wrote:
A new configuration file called secret.conf is introduced to let the user configure the path to the secrets encryption key. This key will be used to encrypt/decrypt the secrets in libvirt.
By default the path is set to the runtime directory /run/libvirt/secrets, and it is commented in the config file. After parsing the file, the virtsecretd driver checks if an encryption key is present in the path and is valid.
If no encryption key is present in the path, then the service will by default use the encryption key stored in the CREDENTIALS_DIRECTORY.
Add logic to parse the encryption key file and store the key. It also checks for the encrypt_data attribute in the config file. The encryption and decryption logic will be added in the subsequent patches.
Signed-off-by: Arun Menon <armenon@redhat.com> --- include/libvirt/virterror.h | 1 + libvirt.spec.in | 3 + po/POTFILES | 1 + src/secret/libvirt_secrets.aug | 40 ++++++ src/secret/meson.build | 19 +++ src/secret/secret.conf.in | 14 ++ src/secret/secret_config.c | 179 +++++++++++++++++++++++++ src/secret/secret_config.h | 40 ++++++ src/secret/secret_driver.c | 11 ++ src/secret/test_libvirt_secrets.aug.in | 6 + src/util/virerror.c | 3 + 11 files changed, 317 insertions(+) create mode 100644 src/secret/libvirt_secrets.aug create mode 100644 src/secret/secret.conf.in create mode 100644 src/secret/secret_config.c create mode 100644 src/secret/secret_config.h create mode 100644 src/secret/test_libvirt_secrets.aug.in
diff --git a/include/libvirt/virterror.h b/include/libvirt/virterror.h index f02da046a3..fa07c36ceb 100644 --- a/include/libvirt/virterror.h +++ b/include/libvirt/virterror.h @@ -353,6 +353,7 @@ typedef enum { command within timeout (Since: 11.2.0) */ VIR_ERR_AGENT_COMMAND_FAILED = 113, /* guest agent responded with failure to a command (Since: 11.2.0) */ + VIR_ERR_INVALID_ENCR_KEY_SECRET = 114, /* encryption key is invalid (Since: 12.0.0) */
This needs to be updated to 12.1.0 now. Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Change the attribute name of _virSecretObj because we want it to have a generic name to indicate that secret values can be stored in it in both base64 and encrypted formats. Signed-off-by: Arun Menon <armenon@redhat.com> --- src/conf/virsecretobj.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/src/conf/virsecretobj.c b/src/conf/virsecretobj.c index 66270e2751..a3dd7983bb 100644 --- a/src/conf/virsecretobj.c +++ b/src/conf/virsecretobj.c @@ -39,7 +39,7 @@ VIR_LOG_INIT("conf.virsecretobj"); struct _virSecretObj { virObjectLockable parent; char *configFile; - char *base64File; + char *secretValueFile; virSecretDef *def; unsigned char *value; /* May be NULL */ size_t value_size; @@ -139,7 +139,7 @@ virSecretObjDispose(void *opaque) g_free(obj->value); } g_free(obj->configFile); - g_free(obj->base64File); + g_free(obj->secretValueFile); } @@ -378,11 +378,11 @@ virSecretObjListAdd(virSecretObjList *secrets, if (!(obj = virSecretObjNew())) goto cleanup; - /* Generate the possible configFile and base64File strings + /* Generate the possible configFile and secretValueFile strings * using the configDir, uuidstr, and appropriate suffix */ if (!(obj->configFile = virFileBuildPath(configDir, uuidstr, ".xml")) || - !(obj->base64File = virFileBuildPath(configDir, uuidstr, ".base64"))) + !(obj->secretValueFile = virFileBuildPath(configDir, uuidstr, ".base64"))) goto cleanup; if (virHashAddEntry(secrets->objs, uuidstr, obj) < 0) @@ -656,7 +656,7 @@ virSecretObjDeleteData(virSecretObj *obj) { /* The configFile will already be removed, so secret won't be * loaded again if this fails */ - unlink(obj->base64File); + unlink(obj->secretValueFile); } @@ -691,7 +691,7 @@ virSecretObjSaveData(virSecretObj *obj) base64 = g_base64_encode(obj->value, obj->value_size); - if (virFileRewriteStr(obj->base64File, S_IRUSR | S_IWUSR, base64) < 0) + if (virFileRewriteStr(obj->secretValueFile, S_IRUSR | S_IWUSR, base64) < 0) return -1; return 0; @@ -813,26 +813,26 @@ virSecretLoadValue(virSecretObj *obj) struct stat st; g_autofree char *contents = NULL; - if ((fd = open(obj->base64File, O_RDONLY)) == -1) { + if ((fd = open(obj->secretValueFile, O_RDONLY)) == -1) { if (errno == ENOENT) { ret = 0; goto cleanup; } virReportSystemError(errno, _("cannot open '%1$s'"), - obj->base64File); + obj->secretValueFile); goto cleanup; } if (fstat(fd, &st) < 0) { virReportSystemError(errno, _("cannot stat '%1$s'"), - obj->base64File); + obj->secretValueFile); goto cleanup; } if ((size_t)st.st_size != st.st_size) { virReportError(VIR_ERR_INTERNAL_ERROR, _("'%1$s' file does not fit in memory"), - obj->base64File); + obj->secretValueFile); goto cleanup; } @@ -845,7 +845,7 @@ virSecretLoadValue(virSecretObj *obj) if (saferead(fd, contents, st.st_size) != st.st_size) { virReportSystemError(errno, _("cannot read '%1$s'"), - obj->base64File); + obj->secretValueFile); goto cleanup; } contents[st.st_size] = '\0'; -- 2.51.1
On Fri, Jan 09, 2026 at 23:39:34 +0530, Arun Menon via Devel wrote:
Change the attribute name of _virSecretObj because we want it to have a generic name to indicate that secret values can be stored in it in both base64 and encrypted formats.
Signed-off-by: Arun Menon <armenon@redhat.com> --- src/conf/virsecretobj.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-)
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Now that we have the functionality to provide the secrets driver with an encryption key through a configuration file or using system credentials, and the newly introduced array to iterate over the encryption schemes, we can use the key to save and load secrets. Encrypt all secrets that are going to be saved on the disk if the 'secrets_encryption_key' path is set in the secret.conf file OR if a valid systemd generated credential exists. While loading secrets, identify the decryption method by matching the file extension of the stored secret against the known array values. If no matching scheme is found, the secret is skipped. If the encryption key is changed across restarts, then also the secret driver will fail to load the secrets from the disk that were encrypted with the former key. Signed-off-by: Arun Menon <armenon@redhat.com> --- src/conf/virsecretobj.c | 175 ++++++++++++++++++++++++++++++------- src/conf/virsecretobj.h | 18 +++- src/secret/secret_driver.c | 23 +++-- 3 files changed, 176 insertions(+), 40 deletions(-) diff --git a/src/conf/virsecretobj.c b/src/conf/virsecretobj.c index a3dd7983bb..4dcb32f69a 100644 --- a/src/conf/virsecretobj.c +++ b/src/conf/virsecretobj.c @@ -31,6 +31,10 @@ #include "virhash.h" #include "virlog.h" #include "virstring.h" +#include "virsecret.h" +#include "virrandom.h" +#include "vircrypto.h" +#include "virsecureerase.h" #define VIR_FROM_THIS VIR_FROM_SECRET @@ -45,6 +49,16 @@ struct _virSecretObj { size_t value_size; }; +typedef struct _virSecretSchemeInfo { + const char *suffix; + virCryptoCipher cipher; +} virSecretSchemeInfo; + +virSecretSchemeInfo schemeInfo[] = { + { ".aes256cbc", VIR_CRYPTO_CIPHER_AES256CBC }, + { ".base64", -1 }, +}; + static virClass *virSecretObjClass; static virClass *virSecretObjListClass; static void virSecretObjDispose(void *obj); @@ -323,7 +337,8 @@ virSecretObj * virSecretObjListAdd(virSecretObjList *secrets, virSecretDef **newdef, const char *configDir, - virSecretDef **oldDef) + virSecretDef **oldDef, + bool encryptData) { virSecretObj *obj; virSecretDef *objdef; @@ -363,6 +378,11 @@ virSecretObjListAdd(virSecretObjList *secrets, } else { /* No existing secret with same UUID, * try look for matching usage instead */ + const char *secretSuffix = ".base64"; + g_autofree char *encryptionSchemeSuffix = NULL; + g_autofree char *oldSecretValueFile = virFileBuildPath(configDir, + uuidstr, + secretSuffix); if ((obj = virSecretObjListFindByUsageLocked(secrets, (*newdef)->usage_type, (*newdef)->usage_id))) { @@ -379,10 +399,24 @@ virSecretObjListAdd(virSecretObjList *secrets, goto cleanup; /* Generate the possible configFile and secretValueFile strings - * using the configDir, uuidstr, and appropriate suffix + * using the configDir, uuidstr, and appropriate suffix. + * By default, the latest encryption cipher will be used to encrypt secrets. */ + if (encryptData) { + /* The virSecretObjListAdd() function is called during both + * loading a secret and creating a new one. Check if there is an unencrypted + * .base64 secret present on the disk. + */ + if (virFileExists(oldSecretValueFile)) { + encryptionSchemeSuffix = g_strdup(secretSuffix); + } else { + encryptionSchemeSuffix = g_strdup(schemeInfo[0].suffix); + } + } else { + encryptionSchemeSuffix = g_strdup(secretSuffix); + } if (!(obj->configFile = virFileBuildPath(configDir, uuidstr, ".xml")) || - !(obj->secretValueFile = virFileBuildPath(configDir, uuidstr, ".base64"))) + !(obj->secretValueFile = virFileBuildPath(configDir, uuidstr, encryptionSchemeSuffix))) goto cleanup; if (virHashAddEntry(secrets->objs, uuidstr, obj) < 0) @@ -682,15 +716,40 @@ virSecretObjSaveConfig(virSecretObj *obj) int -virSecretObjSaveData(virSecretObj *obj) +virSecretObjSaveData(virSecretObj *obj, + bool encryptData, + uint8_t *secretsEncryptionKey, + size_t secretsKeyLen) { g_autofree char *base64 = NULL; + g_autofree uint8_t *secret = NULL; + g_autofree uint8_t *encryptedValue = NULL; + size_t encryptedValueLen = 0; + size_t secretLen = 0; + uint8_t iv[16] = { 0 }; if (!obj->value) return 0; - base64 = g_base64_encode(obj->value, obj->value_size); - + if (encryptData && secretsEncryptionKey) { + if (virRandomBytes(iv, sizeof(iv)) < 0) { + return -1; + } + if (virCryptoEncryptData(schemeInfo[0].cipher, + secretsEncryptionKey, secretsKeyLen, + iv, sizeof(iv), + (uint8_t *)obj->value, obj->value_size, + &encryptedValue, &encryptedValueLen) < 0) { + return -1; + } + secretLen = sizeof(iv) + encryptedValueLen; + secret = g_new0(uint8_t, secretLen); + memcpy(secret, iv, sizeof(iv)); + memcpy(secret + sizeof(iv), encryptedValue, encryptedValueLen); + base64 = g_base64_encode(secret, secretLen); + } else { + base64 = g_base64_encode(obj->value, obj->value_size); + } if (virFileRewriteStr(obj->secretValueFile, S_IRUSR | S_IWUSR, base64) < 0) return -1; @@ -737,7 +796,10 @@ virSecretObjGetValue(virSecretObj *obj) int virSecretObjSetValue(virSecretObj *obj, const unsigned char *value, - size_t value_size) + size_t value_size, + bool encryptData, + uint8_t *secretsEncryptionKey, + size_t secretsKeyLen) { virSecretDef *def = obj->def; g_autofree unsigned char *old_value = NULL; @@ -753,7 +815,10 @@ virSecretObjSetValue(virSecretObj *obj, obj->value = g_steal_pointer(&new_value); obj->value_size = value_size; - if (!def->isephemeral && virSecretObjSaveData(obj) < 0) + if (!def->isephemeral && virSecretObjSaveData(obj, + encryptData, + secretsEncryptionKey, + secretsKeyLen) < 0) goto error; /* Saved successfully - drop old value */ @@ -807,11 +872,23 @@ virSecretLoadValidateUUID(virSecretDef *def, static int -virSecretLoadValue(virSecretObj *obj) +virSecretLoadValue(virSecretObj *obj, + uint8_t *secretsEncryptionKey, + size_t secretsKeyLen) { - int ret = -1, fd = -1; + int ret = -1; + VIR_AUTOCLOSE fd = -1; struct stat st; + size_t i; + g_autofree char *contents = NULL; + g_autofree uint8_t *contentsEncrypted = NULL; + g_autofree uint8_t *decryptedValue = NULL; + + size_t decryptedValueLen = 0; + uint8_t iv[16] = { 0 }; + uint8_t *ciphertext = NULL; + size_t ciphertextLen = 0; if ((fd = open(obj->secretValueFile, O_RDONLY)) == -1) { if (errno == ENOENT) { @@ -841,25 +918,52 @@ virSecretLoadValue(virSecretObj *obj) goto cleanup; } - contents = g_new0(char, st.st_size + 1); - - if (saferead(fd, contents, st.st_size) != st.st_size) { - virReportSystemError(errno, _("cannot read '%1$s'"), - obj->secretValueFile); - goto cleanup; + /* Iterate over the encryption schemes and decrypt the contents + * of the file on the disk, by matching the file extension with the encryption + * scheme. + * If there is no scheme matching the file extension, then that secret is not loaded. */ + + for (i = 0; i < G_N_ELEMENTS(schemeInfo); i++) { + if (virStringHasSuffix(obj->secretValueFile, schemeInfo[i].suffix)) { + contents = g_new0(char, st.st_size + 1); + if (saferead(fd, contents, st.st_size) != st.st_size) { + virReportSystemError(errno, _("cannot read '%1$s'"), + obj->secretValueFile); + goto cleanup; + } + contents[st.st_size] = '\0'; + if (schemeInfo[i].cipher != -1) { + contentsEncrypted = g_base64_decode(contents, &obj->value_size); + if (sizeof(iv) > obj->value_size) { + virReportError(VIR_ERR_INVALID_SECRET, + _("Encrypted secret size '%1$zu' is invalid"), + obj->value_size); + goto cleanup; + } + memcpy(iv, contentsEncrypted, sizeof(iv)); + ciphertext = contentsEncrypted + sizeof(iv); + ciphertextLen = obj->value_size - sizeof(iv); + if (virCryptoDecryptData(schemeInfo[i].cipher, + secretsEncryptionKey, secretsKeyLen, + iv, sizeof(iv), + ciphertext, ciphertextLen, + &decryptedValue, &decryptedValueLen) < 0) { + goto cleanup; + } + g_free(obj->value); + obj->value = g_steal_pointer(&decryptedValue); + obj->value_size = decryptedValueLen; + } else { + obj->value = g_base64_decode(contents, &obj->value_size); + } + break; + } } - contents[st.st_size] = '\0'; - - VIR_FORCE_CLOSE(fd); - - obj->value = g_base64_decode(contents, &obj->value_size); - ret = 0; - cleanup: - if (contents != NULL) - memset(contents, 0, st.st_size); - VIR_FORCE_CLOSE(fd); + virSecureErase(contentsEncrypted, obj->value_size); + virSecureErase(contents, st.st_size); + virSecureErase(iv, sizeof(iv)); return ret; } @@ -868,7 +972,10 @@ static virSecretObj * virSecretLoad(virSecretObjList *secrets, const char *file, const char *path, - const char *configDir) + const char *configDir, + bool encryptData, + uint8_t *secretsEncryptionKey, + size_t secretsKeyLen) { g_autoptr(virSecretDef) def = NULL; virSecretObj *obj = NULL; @@ -879,10 +986,10 @@ virSecretLoad(virSecretObjList *secrets, if (virSecretLoadValidateUUID(def, file) < 0) return NULL; - if (!(obj = virSecretObjListAdd(secrets, &def, configDir, NULL))) + if (!(obj = virSecretObjListAdd(secrets, &def, configDir, NULL, encryptData))) return NULL; - if (virSecretLoadValue(obj) < 0) { + if (virSecretLoadValue(obj, secretsEncryptionKey, secretsKeyLen) < 0) { virSecretObjListRemove(secrets, obj); g_clear_pointer(&obj, virObjectUnref); return NULL; @@ -894,7 +1001,10 @@ virSecretLoad(virSecretObjList *secrets, int virSecretLoadAllConfigs(virSecretObjList *secrets, - const char *configDir) + const char *configDir, + bool encryptData, + uint8_t *secretsEncryptionKey, + size_t secretsKeyLen) { g_autoptr(DIR) dir = NULL; struct dirent *de; @@ -915,7 +1025,10 @@ virSecretLoadAllConfigs(virSecretObjList *secrets, if (!(path = virFileBuildPath(configDir, de->d_name, NULL))) continue; - if (!(obj = virSecretLoad(secrets, de->d_name, path, configDir))) { + if (!(obj = virSecretLoad(secrets, de->d_name, path, configDir, + encryptData, + secretsEncryptionKey, + secretsKeyLen))) { VIR_ERROR(_("Error reading secret: %1$s"), virGetLastErrorMessage()); continue; diff --git a/src/conf/virsecretobj.h b/src/conf/virsecretobj.h index 17897c5513..2e4d980988 100644 --- a/src/conf/virsecretobj.h +++ b/src/conf/virsecretobj.h @@ -51,7 +51,8 @@ virSecretObj * virSecretObjListAdd(virSecretObjList *secrets, virSecretDef **newdef, const char *configDir, - virSecretDef **oldDef); + virSecretDef **oldDef, + bool encryptData); typedef bool (*virSecretObjListACLFilter)(virConnectPtr conn, @@ -86,7 +87,10 @@ int virSecretObjSaveConfig(virSecretObj *obj); int -virSecretObjSaveData(virSecretObj *obj); +virSecretObjSaveData(virSecretObj *obj, + bool encryptData, + uint8_t *secretsEncryptionKey, + size_t secretsKeyLen); virSecretDef * virSecretObjGetDef(virSecretObj *obj); @@ -101,7 +105,10 @@ virSecretObjGetValue(virSecretObj *obj); int virSecretObjSetValue(virSecretObj *obj, const unsigned char *value, - size_t value_size); + size_t value_size, + bool encryptData, + uint8_t *secretsEncryptionKey, + size_t secretsKeyLen); size_t virSecretObjGetValueSize(virSecretObj *obj); @@ -112,4 +119,7 @@ virSecretObjSetValueSize(virSecretObj *obj, int virSecretLoadAllConfigs(virSecretObjList *secrets, - const char *configDir); + const char *configDir, + bool encryptData, + uint8_t *secretsEncryptionKey, + size_t secretsKeyLen); diff --git a/src/secret/secret_driver.c b/src/secret/secret_driver.c index 9b13772ad3..f25b9ba73f 100644 --- a/src/secret/secret_driver.c +++ b/src/secret/secret_driver.c @@ -223,13 +223,17 @@ secretDefineXML(virConnectPtr conn, goto cleanup; if (!(obj = virSecretObjListAdd(driver->secrets, &def, - driver->configDir, &backup))) + driver->configDir, &backup, + driver->config->encryptData))) goto cleanup; objDef = virSecretObjGetDef(obj); if (!objDef->isephemeral) { if (backup && backup->isephemeral) { - if (virSecretObjSaveData(obj) < 0) + if (virSecretObjSaveData(obj, + driver->config->encryptData, + driver->config->secretsEncryptionKey, + driver->config->secretsKeyLen) < 0) goto restore_backup; } @@ -333,7 +337,10 @@ secretSetValue(virSecretPtr secret, if (virSecretSetValueEnsureACL(secret->conn, def) < 0) goto cleanup; - if (virSecretObjSetValue(obj, value, value_size) < 0) + if (virSecretObjSetValue(obj, value, value_size, + driver->config->encryptData, + driver->config->secretsEncryptionKey, + driver->config->secretsKeyLen) < 0) goto cleanup; event = virSecretEventValueChangedNew(def->uuid, @@ -542,7 +549,10 @@ secretStateInitialize(bool privileged, if (!(driver->secrets = virSecretObjListNew())) goto error; - if (virSecretLoadAllConfigs(driver->secrets, driver->configDir) < 0) + if (virSecretLoadAllConfigs(driver->secrets, driver->configDir, + driver->config->encryptData, + driver->config->secretsEncryptionKey, + driver->config->secretsKeyLen) < 0) goto error; return VIR_DRV_STATE_INIT_COMPLETE; @@ -564,7 +574,10 @@ secretStateReload(void) if (!(driver->config = virSecretDaemonConfigNew(driver->privileged))) return -1; - ignore_value(virSecretLoadAllConfigs(driver->secrets, driver->configDir)); + ignore_value(virSecretLoadAllConfigs(driver->secrets, driver->configDir, + driver->config->encryptData, + driver->config->secretsEncryptionKey, + driver->config->secretsKeyLen)); return 0; } -- 2.51.1
On Fri, Jan 09, 2026 at 23:39:35 +0530, Arun Menon via Devel wrote:
Now that we have the functionality to provide the secrets driver with an encryption key through a configuration file or using system credentials, and the newly introduced array to iterate over the encryption schemes, we can use the key to save and load secrets.
Encrypt all secrets that are going to be saved on the disk if the 'secrets_encryption_key' path is set in the secret.conf file OR if a valid systemd generated credential exists.
While loading secrets, identify the decryption method by matching the file extension of the stored secret against the known array values. If no matching scheme is found, the secret is skipped. If the encryption key is changed across restarts, then also the secret driver will fail to load the secrets from the disk that were encrypted with the former key.
Signed-off-by: Arun Menon <armenon@redhat.com> --- src/conf/virsecretobj.c | 175 ++++++++++++++++++++++++++++++------- src/conf/virsecretobj.h | 18 +++- src/secret/secret_driver.c | 23 +++-- 3 files changed, 176 insertions(+), 40 deletions(-)
diff --git a/src/conf/virsecretobj.c b/src/conf/virsecretobj.c index a3dd7983bb..4dcb32f69a 100644 --- a/src/conf/virsecretobj.c +++ b/src/conf/virsecretobj.c @@ -31,6 +31,10 @@ #include "virhash.h" #include "virlog.h" #include "virstring.h" +#include "virsecret.h" +#include "virrandom.h" +#include "vircrypto.h" +#include "virsecureerase.h"
#define VIR_FROM_THIS VIR_FROM_SECRET
@@ -45,6 +49,16 @@ struct _virSecretObj { size_t value_size; };
+typedef struct _virSecretSchemeInfo { + const char *suffix; + virCryptoCipher cipher; +} virSecretSchemeInfo; + +virSecretSchemeInfo schemeInfo[] = { + { ".aes256cbc", VIR_CRYPTO_CIPHER_AES256CBC }, + { ".base64", -1 }, +}; + static virClass *virSecretObjClass; static virClass *virSecretObjListClass; static void virSecretObjDispose(void *obj); @@ -323,7 +337,8 @@ virSecretObj * virSecretObjListAdd(virSecretObjList *secrets, virSecretDef **newdef, const char *configDir, - virSecretDef **oldDef) + virSecretDef **oldDef, + bool encryptData) { virSecretObj *obj; virSecretDef *objdef; @@ -363,6 +378,11 @@ virSecretObjListAdd(virSecretObjList *secrets, } else { /* No existing secret with same UUID, * try look for matching usage instead */ + const char *secretSuffix = ".base64"; + g_autofree char *encryptionSchemeSuffix = NULL; + g_autofree char *oldSecretValueFile = virFileBuildPath(configDir, + uuidstr, + secretSuffix); if ((obj = virSecretObjListFindByUsageLocked(secrets, (*newdef)->usage_type, (*newdef)->usage_id))) { @@ -379,10 +399,24 @@ virSecretObjListAdd(virSecretObjList *secrets, goto cleanup;
/* Generate the possible configFile and secretValueFile strings - * using the configDir, uuidstr, and appropriate suffix + * using the configDir, uuidstr, and appropriate suffix. + * By default, the latest encryption cipher will be used to encrypt secrets. */ + if (encryptData) { + /* The virSecretObjListAdd() function is called during both + * loading a secret and creating a new one. Check if there is an unencrypted + * .base64 secret present on the disk. + */ + if (virFileExists(oldSecretValueFile)) { + encryptionSchemeSuffix = g_strdup(secretSuffix); + } else { + encryptionSchemeSuffix = g_strdup(schemeInfo[0].suffix); + } + } else { + encryptionSchemeSuffix = g_strdup(secretSuffix); + } if (!(obj->configFile = virFileBuildPath(configDir, uuidstr, ".xml")) || - !(obj->secretValueFile = virFileBuildPath(configDir, uuidstr, ".base64"))) + !(obj->secretValueFile = virFileBuildPath(configDir, uuidstr, encryptionSchemeSuffix))) goto cleanup;
So as-written this doesn't work properly. First I'll demonstrate the bug the bug. 1) Assume you have an existing secret prior to running this version: ~ # ls -1 /etc/libvirt/secrets/c021dc3e-8227-4bfa-8f1c-ebd0356fb872* /etc/libvirt/secrets/c021dc3e-8227-4bfa-8f1c-ebd0356fb872.base64 /etc/libvirt/secrets/c021dc3e-8227-4bfa-8f1c-ebd0356fb872.xml ~ # virsh -q secret-get-value --plain c021dc3e-8227-4bfa-8f1c-ebd0356fb872 ble ~ # base64 -d /etc/libvirt/secrets/c021dc3e-8227-4bfa-8f1c-ebd0356fb872.base64 ble ~ # cat /etc/libvirt/secrets/c021dc3e-8227-4bfa-8f1c-ebd0356fb872.base64; echo YmxlCg== 2) update secret (set the same thing) ~ # virsh secret-set-value --secret c021dc3e-8227-4bfa-8f1c-ebd0356fb872 --base64 YmxlCg== warning: Passing secret value as command-line argument is insecure! Secret value set ~ # ls -1 /etc/libvirt/secrets/c021dc3e-8227-4bfa-8f1c-ebd0356fb872* /etc/libvirt/secrets/c021dc3e-8227-4bfa-8f1c-ebd0356fb872.base64 /etc/libvirt/secrets/c021dc3e-8227-4bfa-8f1c-ebd0356fb872.xml ~ # cat /etc/libvirt/secrets/c021dc3e-8227-4bfa-8f1c-ebd0356fb872.base64; echo 3gInXNNABHGXFK64pFkH4AfxTc5HzSLiZnyXm+7h+ms= ~ # base64 -d /etc/libvirt/secrets/c021dc3e-8227-4bfa-8f1c-ebd0356fb872.base64 Þ'\Ó@q®¸¤YàñMÎGÍ"âf|îáúki 3) after daemon restart this obviously corrupts further: ~ # virsh secret-get-value c021dc3e-8227-4bfa-8f1c-ebd0356fb872 --plain Þ'\Ó@q®¸¤YàñMÎGÍ"âf|îáúk As you can see the old filename is used but the value is saved using the new encryption scheme. For this to work properly we must either A) Store the format based on the file where we loaded it from and on subsequent updates on the secret use the saved format or B) On any update use the newer format but nuke the old file too. In addition I don't like that virSecretObjListAdd() is looking at files in the host in the first place. In addition it also duplicates the format checking which is then done in virSecretLoadValue Thus I think that: 1) virSecretObjListAdd ought to only generate the file name prefix, not the actual full filename 2) virSecretLoadValue will concatenate the prefix with the suffix based on the list of supported schemes/formats, check if given file exists and load it if yes, otherwise continue down the list 3) virSecretObjSetValue will (if we go with option B) save using the most recent format, then go down the list and unlink any other files with the same prefix using the older formats/schemes (or in case of option A first check if any existing variant exists, if yes use that, otherwise pick the one from top of the list.) The rest of the patch looks good to me. Since this will require another version don't forget to apply the other things I've pointed out.
Document the new encryption of secrets feature in secretencryption.rst. Signed-off-by: Arun Menon <armenon@redhat.com> --- docs/drvsecret.rst | 4 ++ docs/meson.build | 1 + docs/secretencryption.rst | 86 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 91 insertions(+) create mode 100644 docs/secretencryption.rst diff --git a/docs/drvsecret.rst b/docs/drvsecret.rst index 76a9097d2b..234551d5ae 100644 --- a/docs/drvsecret.rst +++ b/docs/drvsecret.rst @@ -63,3 +63,7 @@ the traditional system or session libvirt connections to QEMU. Normal practice would be to open the secret driver in embedded mode any time one of the other drivers is opened in embedded mode so that the two drivers can interact in-process. + +Further reading +---------------------------- +- `Secret Encryption <secretencryption.html>`__ diff --git a/docs/meson.build b/docs/meson.build index 21e0b19c25..0e74f9c4bf 100644 --- a/docs/meson.build +++ b/docs/meson.build @@ -97,6 +97,7 @@ docs_rst_files = [ 'programming-languages', 'python', 'remote', + 'secretencryption', 'securityprocess', 'ssh-proxy', 'storage', diff --git a/docs/secretencryption.rst b/docs/secretencryption.rst new file mode 100644 index 0000000000..0762fec685 --- /dev/null +++ b/docs/secretencryption.rst @@ -0,0 +1,86 @@ +.. role:: since + +Secret storage and encryption +----------------------------- + +The secret objects can either be ephemeral or persistent. +Ephemeral secrets are only kept in memory, never stored persistently on the disk. +See `Secrets <formatsecret.html>`__ + +:since:`Since 12.0.0` if a secret is defined as persistent, then it is stored **encrypted** on the disk. + + +Systemd Credentials Sealing +--------------------------- + +Out of the box, secrets are sealed using systemd credentials. This ties the +encrypted secret files to the specific host. + +The `virt-secret-init-encryption` service automatically generates a random +32-byte key and encrypts it using `systemd-creds`, storing the result in +`/var/lib/libvirt/secrets/secrets-encryption-key`. The `virtsecretd` service +then automatically loads this key securely via the systemd `LoadCredentialEncrypted` +mechanism. + +Disabling Systemd Credentials +----------------------------- + +You can control encryption behavior by editing the `secret.conf` configuration +file located in ``@SYSCONFDIR@/libvirt/secret.conf`` or ``$XDG_CONFIG_HOME/libvirt/secret.conf`` +depending on how the daemon was started (system mode or session mode respectively). + +To **disable encryption entirely** (which effectively disables the use of any +systemd credentials for this purpose): + +:: + + encrypt_data = 0 + +Setting ``encrypt_data = 0`` takes precedence over any available systemd +credentials. If you have existing encrypted secrets, this setting will prevent +the secret driver from loading the encryption key, making those secrets +inaccessible. New or updated secrets will be stored in plain base64 format. + +To **use a custom encryption key** instead of the systemd credential. +Defining a custom key path takes precedence over the systemd credential + +:: + + secrets_encryption_key = "/path/to/custom/key" + +Configuring Encryption on Non-Systemd Hosts +------------------------------------------- + +On hosts without systemd, or if you prefer to manage the key manually, you can +create a raw encryption key and configure libvirt to use it. + +Generate a random 32-byte key: + +:: + + dd if=/dev/urandom of=/path/to/key/file bs=32 count=1 + +Update `secret.conf` to point to this key: + +:: + + secrets_encryption_key = "/path/to/key/file" + +Manual Systemd Credential Creation +---------------------------------- + +If you want to use systemd credentials but need to customize the encryption parameters +(for example, to specify which TPM PCRs to bind to), you can generate the +credential file manually. + +To create the default `/var/lib/libvirt/secrets/secrets-encryption-key` manually +using `systemd-creds` (adjusting arguments to `systemd-creds encrypt` as needed): + +:: + + dd if=/dev/urandom bs=32 count=1 | \ + systemd-creds encrypt --name=secrets-encryption-key - \ + /var/lib/libvirt/secrets/secrets-encryption-key + +You can pass extra arguments to `systemd-creds encrypt <https://www.freedesktop.org/software/systemd/man/latest/systemd-creds.html?__goaway_challenge=meta-refresh&__goaway_id=54a57e2fe25ce44179e75746c9531063&__goaway_referer=https%3A%2F%2Fwww.google.com%2F#encrypt%20input%7C-%20output%7C->`__, +such as ``--tpm2-device=...`` or ``--tpm2-pcrs=...``, to customize the sealing policy. -- 2.51.1
On Fri, Jan 09, 2026 at 23:39:36 +0530, Arun Menon via Devel wrote:
Document the new encryption of secrets feature in secretencryption.rst.
Signed-off-by: Arun Menon <armenon@redhat.com> --- docs/drvsecret.rst | 4 ++ docs/meson.build | 1 + docs/secretencryption.rst | 86 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 91 insertions(+) create mode 100644 docs/secretencryption.rst
diff --git a/docs/drvsecret.rst b/docs/drvsecret.rst index 76a9097d2b..234551d5ae 100644 --- a/docs/drvsecret.rst +++ b/docs/drvsecret.rst @@ -63,3 +63,7 @@ the traditional system or session libvirt connections to QEMU. Normal practice would be to open the secret driver in embedded mode any time one of the other drivers is opened in embedded mode so that the two drivers can interact in-process. + +Further reading +---------------------------- +- `Secret Encryption <secretencryption.html>`__ diff --git a/docs/meson.build b/docs/meson.build index 21e0b19c25..0e74f9c4bf 100644 --- a/docs/meson.build +++ b/docs/meson.build @@ -97,6 +97,7 @@ docs_rst_files = [ 'programming-languages', 'python', 'remote', + 'secretencryption', 'securityprocess', 'ssh-proxy', 'storage', diff --git a/docs/secretencryption.rst b/docs/secretencryption.rst new file mode 100644 index 0000000000..0762fec685 --- /dev/null +++ b/docs/secretencryption.rst @@ -0,0 +1,86 @@ +.. role:: since + +Secret storage and encryption +-----------------------------
This document is missing a main headline, all others you have in this file are at the same level based on the underline.
+ +The secret objects can either be ephemeral or persistent. +Ephemeral secrets are only kept in memory, never stored persistently on the disk. +See `Secrets <formatsecret.html>`__ + +:since:`Since 12.0.0` if a secret is defined as persistent, then it is stored **encrypted** on the disk.
12.1.0 Since you are describing how secrets are stored please also outline how upgrades work. E.g. if we upgrade to newer format or preserve existing one whichever you choose to implement.
+Systemd Credentials Sealing +--------------------------- + +Out of the box, secrets are sealed using systemd credentials. This ties the +encrypted secret files to the specific host. + +The `virt-secret-init-encryption` service automatically generates a random +32-byte key and encrypts it using `systemd-creds`, storing the result in +`/var/lib/libvirt/secrets/secrets-encryption-key`. The `virtsecretd` service +then automatically loads this key securely via the systemd `LoadCredentialEncrypted` +mechanism. + +Disabling Systemd Credentials +----------------------------- + +You can control encryption behavior by editing the `secret.conf` configuration +file located in ``@SYSCONFDIR@/libvirt/secret.conf`` or ``$XDG_CONFIG_HOME/libvirt/secret.conf`` +depending on how the daemon was started (system mode or session mode respectively). + +To **disable encryption entirely** (which effectively disables the use of any +systemd credentials for this purpose): + +:: + + encrypt_data = 0 + +Setting ``encrypt_data = 0`` takes precedence over any available systemd +credentials. If you have existing encrypted secrets, this setting will prevent +the secret driver from loading the encryption key, making those secrets +inaccessible. New or updated secrets will be stored in plain base64 format. + +To **use a custom encryption key** instead of the systemd credential. +Defining a custom key path takes precedence over the systemd credential + +:: + + secrets_encryption_key = "/path/to/custom/key" + +Configuring Encryption on Non-Systemd Hosts +------------------------------------------- + +On hosts without systemd, or if you prefer to manage the key manually, you can +create a raw encryption key and configure libvirt to use it. + +Generate a random 32-byte key: + +:: + + dd if=/dev/urandom of=/path/to/key/file bs=32 count=1
/dev/random
+ +Update `secret.conf` to point to this key: + +:: + + secrets_encryption_key = "/path/to/key/file" + +Manual Systemd Credential Creation +---------------------------------- + +If you want to use systemd credentials but need to customize the encryption parameters +(for example, to specify which TPM PCRs to bind to), you can generate the +credential file manually. + +To create the default `/var/lib/libvirt/secrets/secrets-encryption-key` manually +using `systemd-creds` (adjusting arguments to `systemd-creds encrypt` as needed): + +:: + + dd if=/dev/urandom bs=32 count=1 | \
/dev/random
+ systemd-creds encrypt --name=secrets-encryption-key - \ + /var/lib/libvirt/secrets/secrets-encryption-key + +You can pass extra arguments to `systemd-creds encrypt <https://www.freedesktop.org/software/systemd/man/latest/systemd-creds.html?__goaway_challenge=meta-refresh&__goaway_id=54a57e2fe25ce44179e75746c9531063&__goaway_referer=https%3A%2F%2Fwww.google.com%2F#encrypt%20input%7C-%20output%7C->`__,
Clean up the URL from the arguments used to bypass robot validation.
+such as ``--tpm2-device=...`` or ``--tpm2-pcrs=...``, to customize the sealing policy. -- 2.51.1
On Fri, Jan 09, 2026 at 11:39:30PM +0530, Arun Menon wrote:
Libvirt secrets are stored unencrypted on the disk. With this series we want to start encrypting the secrets.
1. Introduce the GnuTLS decryption wrapper functions that work exact opposite to the encryption wrappers.
2. Add a new service called virt-secrets-init-encryption, that is linked to the virtsecretd service. virtsecretd service only starts after the new service generates a random encryption key.
3. Add a new secrets.conf configuration file that helps user to set a. secrets_encryption_key - allows the user to specify the encryption key file path, in case the default key is not to be used. b. encrypt_data - set to 0 or 1. If set to 1, then the newly added secrets will be encrypted.
4. Add encryption scheme or cipher attribute that will allow us to choose the last used cipher.
5. Once we have the encryption key, and a reliable way to tell the daemon what encryption scheme the secret object is using, we can encrypt the secrets on disk and store them in <uuid>.<encryption_scheme> format. It is important to note that if the encryption key is changed between restarts, then the respective secret will not be loaded by the driver.
6. Add documentation.
This is a sincere attempt to improve upon the already submitted patch https://lists.libvirt.org/archives/list/devel@lists.libvirt.org/thread/KE6GV...
Resolves: https://issues.redhat.com/browse/RHEL-7125
---
Changes in v3: v4 - Fix the regression of loading unencrypted secrets after an upgrade. Previously the .base64 unencrypted secrets were not being loaded. - Add documentation on encrypted secrets.
Changes in v3: - Secrets xml configuration no longer stores the encryption scheme, therefore not allowing the user to toggle between ciphers. - Removed unnecessary socket files of the new service. It now has a general configuration with which it starts. - Addressed review comments from Peter on coding style and design. - Loading of secrets is dependent on the file extension. Most recent cipher is used while saving the secrets.
Changes in v2: - Corrected the encryption key length check. It should be 32. - Added a new patch that introduces the encryption scheme attribute. This will help us identify which secrets are encrypted. - A new systemd unit service file added that starts before virtsecretd, helping us to construct a random encryption key and pass it to the virtsecretd service. - Parsing logic of secrets.conf moved to a separate file. - Spec file changes, augeas.
Arun Menon (6): util: Add support for GnuTLS decryption secret: Set up default encryption secret key for the virtsecretd service secret: Add secret.conf configuration file and parse it secret: Rename virSecretObj structure attribute from base64File to secretValueFile secret: Add functionality to load and save secrets in encrypted format docs: secret: Add documentation of secret encryption feature
docs/drvsecret.rst | 4 + docs/meson.build | 1 + docs/secretencryption.rst | 86 ++++++++ include/libvirt/virterror.h | 1 + libvirt.spec.in | 8 + po/POTFILES | 1 + src/conf/virsecretobj.c | 193 ++++++++++++++---- src/conf/virsecretobj.h | 18 +- src/libvirt_private.syms | 1 + src/meson.build | 1 + src/remote/libvirtd.service.in | 4 + src/secret/libvirt_secrets.aug | 40 ++++ src/secret/meson.build | 32 +++ src/secret/secret.conf.in | 14 ++ src/secret/secret_config.c | 179 ++++++++++++++++ src/secret/secret_config.h | 40 ++++ src/secret/secret_driver.c | 34 ++- src/secret/test_libvirt_secrets.aug.in | 6 + .../virt-secret-init-encryption.service.in | 8 + src/secret/virtsecretd.service.extra.in | 8 + src/util/vircrypto.c | 126 +++++++++++- src/util/vircrypto.h | 8 + src/util/virerror.c | 3 + tests/vircryptotest.c | 65 ++++++ 24 files changed, 831 insertions(+), 50 deletions(-) create mode 100644 docs/secretencryption.rst create mode 100644 src/secret/libvirt_secrets.aug create mode 100644 src/secret/secret.conf.in create mode 100644 src/secret/secret_config.c create mode 100644 src/secret/secret_config.h create mode 100644 src/secret/test_libvirt_secrets.aug.in create mode 100644 src/secret/virt-secret-init-encryption.service.in
-- 2.51.1
Hello, A gentle ping on this series. Any further suggestion is appreciated. Regards, Arun Menon
On 21/01/26 16:23, Arun Menon wrote:
On Fri, Jan 09, 2026 at 11:39:30PM +0530, Arun Menon wrote:
Libvirt secrets are stored unencrypted on the disk. With this series we want to start encrypting the secrets.
1. Introduce the GnuTLS decryption wrapper functions that work exact opposite to the encryption wrappers.
2. Add a new service called virt-secrets-init-encryption, that is linked to the virtsecretd service. virtsecretd service only starts after the new service generates a random encryption key.
3. Add a new secrets.conf configuration file that helps user to set a. secrets_encryption_key - allows the user to specify the encryption key file path, in case the default key is not to be used. b. encrypt_data - set to 0 or 1. If set to 1, then the newly added secrets will be encrypted.
4. Add encryption scheme or cipher attribute that will allow us to choose the last used cipher.
5. Once we have the encryption key, and a reliable way to tell the daemon what encryption scheme the secret object is using, we can encrypt the secrets on disk and store them in <uuid>.<encryption_scheme> format. It is important to note that if the encryption key is changed between restarts, then the respective secret will not be loaded by the driver.
6. Add documentation.
This is a sincere attempt to improve upon the already submitted patch https://lists.libvirt.org/archives/list/devel@lists.libvirt.org/thread/KE6GV...
Resolves:https://issues.redhat.com/browse/RHEL-7125
---
Changes in v3: v4 - Fix the regression of loading unencrypted secrets after an upgrade. Previously the .base64 unencrypted secrets were not being loaded. - Add documentation on encrypted secrets.
Changes in v3: - Secrets xml configuration no longer stores the encryption scheme, therefore not allowing the user to toggle between ciphers. - Removed unnecessary socket files of the new service. It now has a general configuration with which it starts. - Addressed review comments from Peter on coding style and design. - Loading of secrets is dependent on the file extension. Most recent cipher is used while saving the secrets.
Changes in v2: - Corrected the encryption key length check. It should be 32. - Added a new patch that introduces the encryption scheme attribute. This will help us identify which secrets are encrypted. - A new systemd unit service file added that starts before virtsecretd, helping us to construct a random encryption key and pass it to the virtsecretd service. - Parsing logic of secrets.conf moved to a separate file. - Spec file changes, augeas.
Arun Menon (6): util: Add support for GnuTLS decryption secret: Set up default encryption secret key for the virtsecretd service secret: Add secret.conf configuration file and parse it secret: Rename virSecretObj structure attribute from base64File to secretValueFile secret: Add functionality to load and save secrets in encrypted format docs: secret: Add documentation of secret encryption feature
docs/drvsecret.rst | 4 + docs/meson.build | 1 + docs/secretencryption.rst | 86 ++++++++ include/libvirt/virterror.h | 1 + libvirt.spec.in | 8 + po/POTFILES | 1 + src/conf/virsecretobj.c | 193 ++++++++++++++---- src/conf/virsecretobj.h | 18 +- src/libvirt_private.syms | 1 + src/meson.build | 1 + src/remote/libvirtd.service.in | 4 + src/secret/libvirt_secrets.aug | 40 ++++ src/secret/meson.build | 32 +++ src/secret/secret.conf.in | 14 ++ src/secret/secret_config.c | 179 ++++++++++++++++ src/secret/secret_config.h | 40 ++++ src/secret/secret_driver.c | 34 ++- src/secret/test_libvirt_secrets.aug.in | 6 + .../virt-secret-init-encryption.service.in | 8 + src/secret/virtsecretd.service.extra.in | 8 + src/util/vircrypto.c | 126 +++++++++++- src/util/vircrypto.h | 8 + src/util/virerror.c | 3 + tests/vircryptotest.c | 65 ++++++ 24 files changed, 831 insertions(+), 50 deletions(-) create mode 100644 docs/secretencryption.rst create mode 100644 src/secret/libvirt_secrets.aug create mode 100644 src/secret/secret.conf.in create mode 100644 src/secret/secret_config.c create mode 100644 src/secret/secret_config.h create mode 100644 src/secret/test_libvirt_secrets.aug.in create mode 100644 src/secret/virt-secret-init-encryption.service.in
-- 2.51.1
Hello,
A gentle ping on this series. Any further suggestion is appreciated.
Regards, Arun Menon
Hi, Friendly ping on this series. Please let me know if there is any additional feedback. -- Regards, Arun Menon
participants (2)
-
Arun Menon -
Peter Krempa