[libvirt] [PATCH RFC 13/16] storage: Add support to create a luks volume

If the volume xml was looking to create a luks volume take the necessary steps in order to make that happen. The processing will be: 1. create a temporary file in the storage pool target path 1a. the file name will either be $volname_$UUID.tmp or $volname_$USAGE.tmp depending on how the encryption xml specified fetching the secret 1b. create/open the file, initially setting mode to 0600 with current effective uid:gid as owner 1c. fetch the secret into a buffer and write that into the file 1d. change file protections to 0400 2. create a secret object 2a. use a similarly crafted alias to the file name 2b. add the file to the object 3. create/add luks options to the commandline 3a. at the very least a "key-secret" using the secret object alias 3b. if found in the XML the various "cipher" and "ivgen" options Signed-off-by: John Ferlan <jferlan(a)redhat.com&gt; --- src/libvirt_private.syms | 1 + src/storage/storage_backend.c | 285 ++++++++++++++++++++++++++++++++++++++--- src/storage/storage_backend.h | 3 +- src/util/virqemu.c | 23 ++++ src/util/virqemu.h | 6 + tests/storagevolxml2argvtest.c | 3 +- 6 files changed, 300 insertions(+), 21 deletions(-) diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms index 3fd042b..ea71037 100644 --- a/src/libvirt_private.syms +++ b/src/libvirt_private.syms @@ -2142,6 +2142,7 @@ virProcessWait; # util/virqemu.h +virQEMUBuildLuksOpts; virQEMUBuildObjectCommandlineFromJSON; diff --git a/src/storage/storage_backend.c b/src/storage/storage_backend.c index 4965c9e..bb4fa2f 100644 --- a/src/storage/storage_backend.c +++ b/src/storage/storage_backend.c @@ -55,11 +55,14 @@ #include "viralloc.h" #include "internal.h" #include "secret_conf.h" +#include "secret_util.h" #include "viruuid.h" #include "virstoragefile.h" #include "storage_backend.h" #include "virlog.h" #include "virfile.h" +#include "virjson.h" +#include "virqemu.h" #include "stat-time.h" #include "virstring.h" #include "virxml.h" @@ -880,6 +883,7 @@ virStoragePloopResize(virStorageVolDefPtr vol, enum { QEMU_IMG_BACKING_FORMAT_OPTIONS = 0, QEMU_IMG_BACKING_FORMAT_OPTIONS_COMPAT, + QEMU_IMG_FORMAT_LUKS, }; static bool @@ -907,6 +911,27 @@ virStorageBackendQemuImgSupportsCompat(const char *qemuimg) return ret; } + +static bool +virStorageBackendQemuImgSupportsLuks(const char *qemuimg) +{ + bool ret = false; + int exitstatus = -1; + virCommandPtr cmd = virCommandNewArgList(qemuimg, "create", "-o", "?", + "-f", "luks", "/dev/null", NULL); + + if (virCommandRun(cmd, &exitstatus) < 0) + goto cleanup; + + if (exitstatus == 0) + ret = true; + + cleanup: + virCommandFree(cmd); + return ret; +} + + static int virStorageBackendQEMUImgBackingFormat(const char *qemuimg) { @@ -915,12 +940,18 @@ virStorageBackendQEMUImgBackingFormat(const char *qemuimg) * out what else we have */ int ret = QEMU_IMG_BACKING_FORMAT_OPTIONS; - /* QEMU 2.0 changed to using a format that only QEMU 1.1 and newer - * understands. Since we still support QEMU 0.12 and newer, we need - * to be able to handle the previous format as can be set via a - * compat=0.10 option. */ - if (virStorageBackendQemuImgSupportsCompat(qemuimg)) - ret = QEMU_IMG_BACKING_FORMAT_OPTIONS_COMPAT; + /* QEMU 2.6 added support for luks - let's check for that. + * If available, then we can also assume OPTIONS_COMPAT is present */ + if (virStorageBackendQemuImgSupportsLuks(qemuimg)) { + ret = QEMU_IMG_FORMAT_LUKS; + } else { + /* QEMU 2.0 changed to using a format that only QEMU 1.1 and newer + * understands. Since we still support QEMU 0.12 and newer, we need + * to be able to handle the previous format as can be set via a + * compat=0.10 option. */ + if (virStorageBackendQemuImgSupportsCompat(qemuimg)) + ret = QEMU_IMG_BACKING_FORMAT_OPTIONS_COMPAT; + } return ret; } @@ -941,21 +972,31 @@ struct _virStorageBackendQemuImgInfo { const char *inputPath; const char *inputFormatStr; int inputFormat; + + char *secretAlias; + const char *secretPath; }; + static int -virStorageBackendCreateQemuImgOpts(char **opts, +virStorageBackendCreateQemuImgOpts(virStorageEncryptionPtr enc, + char **opts, struct _virStorageBackendQemuImgInfo info) { virBuffer buf = VIR_BUFFER_INITIALIZER; - if (info.backingPath) - virBufferAsprintf(&buf, "backing_fmt=%s,", - virStorageFileFormatTypeToString(info.backingFormat)); - if (info.encryption) - virBufferAddLit(&buf, "encryption=on,"); - if (info.preallocate) - virBufferAddLit(&buf, "preallocation=metadata,"); + if (info.format == VIR_STORAGE_FILE_LUKS) { + virQEMUBuildLuksOpts(&buf, enc, info.secretAlias); + } else { + if (info.backingPath) + virBufferAsprintf(&buf, "backing_fmt=%s,", + virStorageFileFormatTypeToString(info.backingFormat)); + if (info.encryption) + virBufferAddLit(&buf, "encryption=on,"); + if (info.preallocate) + virBufferAddLit(&buf, "preallocation=metadata,"); + } + if (info.nocow) virBufferAddLit(&buf, "nocow=on,"); @@ -1025,6 +1066,22 @@ virStorageBackendCreateQemuImgCheckEncryption(int format, if (virStorageGenerateQcowEncryption(conn, vol) < 0) return -1; } + } else if (format == VIR_STORAGE_FILE_LUKS) { + if (enc->format != VIR_STORAGE_ENCRYPTION_FORMAT_LUKS) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, + _("unsupported volume encryption format %d"), + vol->target.encryption->format); + return -1; + } + if (enc->nsecrets > 1) { + virReportError(VIR_ERR_XML_ERROR, "%s", + _("too many secrets for luks encryption")); + return -1; + } + if (enc->nsecrets == 0) { + virReportError(VIR_ERR_XML_ERROR, "%s", + _("no secret provided for luks encryption")); + } } else { virReportError(VIR_ERR_CONFIG_UNSUPPORTED, _("volume encryption unsupported with format %s"), type); @@ -1069,6 +1126,12 @@ virStorageBackendCreateQemuImgSetBacking(virStoragePoolObjPtr pool, int accessRetCode = -1; char *absolutePath = NULL; + if (info->format == VIR_STORAGE_FILE_LUKS) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", + _("cannot set backing store for luks volume")); + return -1; + } + info->backingFormat = vol->target.backingStore->format; info->backingPath = vol->target.backingStore->path; @@ -1121,6 +1184,7 @@ virStorageBackendCreateQemuImgSetBacking(virStoragePoolObjPtr pool, static int virStorageBackendCreateQemuImgSetOptions(virCommandPtr cmd, + virStorageVolDefPtr vol, int imgformat, struct _virStorageBackendQemuImgInfo info) { @@ -1130,7 +1194,8 @@ virStorageBackendCreateQemuImgSetOptions(virCommandPtr cmd, imgformat >= QEMU_IMG_BACKING_FORMAT_OPTIONS_COMPAT) info.compat = "0.10"; - if (virStorageBackendCreateQemuImgOpts(&opts, info) < 0) + if (virStorageBackendCreateQemuImgOpts(vol->target.encryption, + &opts, info) < 0) return -1; if (opts) virCommandAddArgList(cmd, "-o", opts, NULL); @@ -1140,6 +1205,66 @@ virStorageBackendCreateQemuImgSetOptions(virCommandPtr cmd, } +/* Create a hopefully unique enough name to be used for both the + * secretPath and secretAlias generation + */ +static char * +virStorageBackendCreateQemuImgLuksName(const char *volname, + virStorageEncryptionPtr enc) +{ + char *ret; + + if (enc->secrets[0]->secdef.type == VIR_SECRET_LOOKUP_TYPE_UUID) + ignore_value(virAsprintf(&ret, "%s_%s", volname, + enc->secrets[0]->secdef.u.uuid)); + else + ignore_value(virAsprintf(&ret, "%s_%s", volname, + enc->secrets[0]->secdef.u.usage)); + return ret; +} + + +/* Add a secret object to the command line: + * --object secret,id=$secretAlias,file=$secretPath + * + * NB: format=raw is assumed + */ +static int +virStorageBackendCreateQemuImgSecretObject(virCommandPtr cmd, + virStorageVolDefPtr vol, + struct _virStorageBackendQemuImgInfo *info) +{ + virStorageEncryptionPtr enc = vol->target.encryption; + char *str = NULL; + virJSONValuePtr props = NULL; + char *commandStr = NULL; + + if (!(str = virStorageBackendCreateQemuImgLuksName(vol->name, enc))) + return -1; + + if (virAsprintf(&info->secretAlias, "%s_luks0", str) < 0) { + VIR_FREE(str); + return -1; + } + VIR_FREE(str); + + if (virJSONValueObjectCreate(&props, "s:file", info->secretPath, NULL) < 0) + return -1; + + if (!(commandStr = virQEMUBuildObjectCommandlineFromJSON("secret", + info->secretAlias, + props))) { + virJSONValueFree(props); + return -1; + } + virJSONValueFree(props); + + virCommandAddArgList(cmd, "--object", commandStr, NULL); + + return 0; +} + + /* Create a qemu-img virCommand from the supplied binary path, * volume definitions and imgformat */ @@ -1150,7 +1275,8 @@ virStorageBackendCreateQemuImgCmdFromVol(virConnectPtr conn, virStorageVolDefPtr inputvol, unsigned int flags, const char *create_tool, - int imgformat) + int imgformat, + const char *secretPath) { virCommandPtr cmd = NULL; const char *type; @@ -1162,6 +1288,8 @@ virStorageBackendCreateQemuImgCmdFromVol(virConnectPtr conn, .compat = vol->target.compat, .features = vol->target.features, .nocow = vol->target.nocow, + .secretPath = secretPath, + .secretAlias = NULL, }; virCheckFlags(VIR_STORAGE_VOL_CREATE_PREALLOC_METADATA, NULL); @@ -1192,6 +1320,18 @@ virStorageBackendCreateQemuImgCmdFromVol(virConnectPtr conn, _("format features only available with qcow2")); return NULL; } + if (info.format == VIR_STORAGE_FILE_LUKS) { + if (inputvol) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", + _("cannot use inputvol with luks volume")); + return NULL; + } + if (!info.encryption) { + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("missing encryption description")); + return NULL; + } + } if (inputvol && virStorageBackendCreateQemuImgSetInput(inputvol, &info) < 0) @@ -1207,7 +1347,6 @@ virStorageBackendCreateQemuImgCmdFromVol(virConnectPtr conn, conn, vol) < 0) return NULL; - /* Size in KB */ info.size_arg = VIR_DIV_UP(vol->target.capacity, 1024); @@ -1226,10 +1365,20 @@ virStorageBackendCreateQemuImgCmdFromVol(virConnectPtr conn, if (info.backingPath) virCommandAddArgList(cmd, "-b", info.backingPath, NULL); - if (virStorageBackendCreateQemuImgSetOptions(cmd, imgformat, info) < 0) { + if (info.format == VIR_STORAGE_FILE_LUKS && + virStorageBackendCreateQemuImgSecretObject(cmd, vol, &info) < 0) { + VIR_FREE(info.secretAlias); + virCommandFree(cmd); + return NULL; + } + + if (virStorageBackendCreateQemuImgSetOptions(cmd, vol, imgformat, + info) < 0) { + VIR_FREE(info.secretAlias); virCommandFree(cmd); return NULL; } + VIR_FREE(info.secretAlias); if (info.inputPath) virCommandAddArg(cmd, info.inputPath); @@ -1240,6 +1389,86 @@ virStorageBackendCreateQemuImgCmdFromVol(virConnectPtr conn, return cmd; } + +static char * +virStorageBackendCreateQemuImgSecretPath(virConnectPtr conn, + virStoragePoolObjPtr pool, + virStorageVolDefPtr vol) +{ + virStorageEncryptionPtr enc = vol->target.encryption; + char *str = NULL; + char *secretPath = NULL; + int fd = -1; + uint8_t *secret = NULL; + size_t secretlen = 0; + + if (!enc) { + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("missing encryption description")); + return NULL; + } + + if (!conn || !conn->secretDriver || + !conn->secretDriver->secretLookupByUUID || + !conn->secretDriver->secretLookupByUsage || + !conn->secretDriver->secretGetValue) { + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("unable to look up encryption secret")); + return NULL; + } + + /* Create a temporary secret file in the pool using */ + if (!(str = virStorageBackendCreateQemuImgLuksName(vol->name, enc))) + return NULL; + + /* Since we don't have a file, just go to cleanup using NULL secretPath */ + if (!(secretPath = virFileBuildPath(pool->def->target.path, str, ".tmp"))) + goto cleanup; + + if ((fd = open(secretPath, O_WRONLY|O_TRUNC|O_CREAT, 0600)) < 0) { + virReportSystemError(errno, "%s", + _("failed to open luks secret file for write")); + goto error; + } + + if (virSecretGetSecretString(conn, &enc->secrets[0]->secdef, + VIR_SECRET_USAGE_TYPE_LUKS, + &secret, &secretlen) < 0) + goto error; + + if (safewrite(fd, secret, secretlen) < 0) { + virReportSystemError(errno, "%s", + _("failed to write luks secret file")); + goto error; + } + VIR_FORCE_CLOSE(fd); + + if (chown(secretPath, geteuid(), getegid()) < 0) { + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("failed to chown luks secret file")); + goto error; + } + + if (chmod(secretPath, 0400) < 0) { + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("failed to chown luks secret file")); + goto error; + } + + cleanup: + VIR_FREE(str); + VIR_DISPOSE_N(secret, secretlen); + VIR_FORCE_CLOSE(fd); + + return secretPath; + + error: + unlink(secretPath); + VIR_FREE(secretPath); + goto cleanup; +} + + int virStorageBackendCreateQemuImg(virConnectPtr conn, virStoragePoolObjPtr pool, @@ -1251,6 +1480,7 @@ virStorageBackendCreateQemuImg(virConnectPtr conn, char *create_tool; int imgformat; virCommandPtr cmd; + char *secretPath = NULL; virCheckFlags(VIR_STORAGE_VOL_CREATE_PREALLOC_METADATA, -1); @@ -1266,8 +1496,21 @@ virStorageBackendCreateQemuImg(virConnectPtr conn, if (imgformat < 0) goto cleanup; + if (vol->target.format == VIR_STORAGE_FILE_LUKS) { + if (imgformat < QEMU_IMG_FORMAT_LUKS) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, + _("this version of '%s' does not support luks"), + create_tool); + goto cleanup; + } + if (!(secretPath = + virStorageBackendCreateQemuImgSecretPath(conn, pool, vol))) + goto cleanup; + } + cmd = virStorageBackendCreateQemuImgCmdFromVol(conn, pool, vol, inputvol, - flags, create_tool, imgformat); + flags, create_tool, + imgformat, secretPath); if (!cmd) goto cleanup; @@ -1275,6 +1518,10 @@ virStorageBackendCreateQemuImg(virConnectPtr conn, virCommandFree(cmd); cleanup: + if (secretPath) { + unlink(secretPath); + VIR_FREE(secretPath); + } VIR_FREE(create_tool); return ret; } diff --git a/src/storage/storage_backend.h b/src/storage/storage_backend.h index 5bc622c..28e1a65 100644 --- a/src/storage/storage_backend.h +++ b/src/storage/storage_backend.h @@ -241,7 +241,8 @@ virStorageBackendCreateQemuImgCmdFromVol(virConnectPtr conn, virStorageVolDefPtr inputvol, unsigned int flags, const char *create_tool, - int imgformat); + int imgformat, + const char *secretPath); /* ------- virStorageFile backends ------------ */ typedef struct _virStorageFileBackend virStorageFileBackend; diff --git a/src/util/virqemu.c b/src/util/virqemu.c index 895168e..a56fb3f 100644 --- a/src/util/virqemu.c +++ b/src/util/virqemu.c @@ -140,3 +140,26 @@ virQEMUBuildObjectCommandlineFromJSON(const char *type, virBufferFreeAndReset(&buf); return ret; } + + +void +virQEMUBuildLuksOpts(virBufferPtr buf, + virStorageEncryptionPtr enc, + const char *alias) +{ + virBufferAsprintf(buf, "key-secret=%s,", alias); + + /* If there's any cipher, then add that to the command line */ + if (enc->cipher.name) { + virBufferAsprintf(buf, "cipher-alg=%s-%u,", + enc->cipher.name, enc->cipher.size); + if (enc->cipher.mode) + virBufferAsprintf(buf, "cipher-mode=%s,", enc->cipher.mode); + if (enc->cipher.hash) + virBufferAsprintf(buf, "hash-alg=%s,", enc->cipher.hash); + if (enc->ivgen.name) + virBufferAsprintf(buf, "ivgen-alg=%s,", enc->ivgen.name); + if (enc->ivgen.hash) + virBufferAsprintf(buf, "ivgen-hash-alg=%s,", enc->ivgen.hash); + } +} diff --git a/src/util/virqemu.h b/src/util/virqemu.h index af4ec1d..dfb79b9 100644 --- a/src/util/virqemu.h +++ b/src/util/virqemu.h @@ -26,9 +26,15 @@ # include "internal.h" # include "virjson.h" +# include "virstorageencryption.h" char *virQEMUBuildObjectCommandlineFromJSON(const char *type, const char *alias, virJSONValuePtr props); +void virQEMUBuildLuksOpts(virBufferPtr buf, + virStorageEncryptionPtr enc, + const char *alias) + ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_NONNULL(3); + #endif /* __VIR_QEMU_H_ */ diff --git a/tests/storagevolxml2argvtest.c b/tests/storagevolxml2argvtest.c index af7de0b..2fd1cbf 100644 --- a/tests/storagevolxml2argvtest.c +++ b/tests/storagevolxml2argvtest.c @@ -83,7 +83,8 @@ testCompareXMLToArgvFiles(bool shouldFail, cmd = virStorageBackendCreateQemuImgCmdFromVol(conn, &poolobj, vol, inputvol, flags, - create_tool, imgformat); + create_tool, imgformat, + NULL); if (!cmd) { if (shouldFail) { virResetLastError(); -- 2.5.5