Re: [libvirt] [PATCH v3 06/10] storage: Add support to create a luks volume

Partially resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1301021 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 driver state dir path 1a. the file name will include the pool name, the volume name, secret, and XXXXXX for usage in the mkostemp call. 1b. mkostemp 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 2. create a secret object 2a. use an alias combinding the volume name and "_luks0" 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 | 254 ++++++++++++++++++++++++++++++++++++++--- src/storage/storage_backend.h | 3 +- src/util/virqemu.c | 23 ++++ src/util/virqemu.h | 6 + tests/storagevolxml2argvtest.c | 3 +- 6 files changed, 269 insertions(+), 21 deletions(-) diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms index 9ac033d..eea18dd 100644 --- a/src/libvirt_private.syms +++ b/src/libvirt_private.syms @@ -2169,6 +2169,7 @@ virProcessWait; # util/virqemu.h +virQEMUBuildLuksOpts; virQEMUBuildObjectCommandlineFromJSON; diff --git a/src/storage/storage_backend.c b/src/storage/storage_backend.c index 97f6ffe..4fb77fc 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; }

@@ -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->encinfo,

+ &opts, info) < 0) return -1; if (opts) virCommandAddArgList(cmd, "-o", opts, NULL); @@ -1140,6 +1205,43 @@ virStorageBackendCreateQemuImgSetOptions(virCommandPtr cmd, } +/* 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) +{ + char *str = NULL; + virJSONValuePtr props = NULL; + char *commandStr = NULL; + + if (virAsprintf(&info->secretAlias, "%s_luks0", vol->name) < 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 +1252,8 @@ 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 +1265,8 @@ 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 +1297,18 @@ 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 +1324,6 @@ virStorageBackendCreateQemuImgCmdFromVol(virConnectPtr conn, conn, vol) < 0) return NULL; -

/* Size in KB */ info.size_arg = VIR_DIV_UP(vol->target.capacity, 1024); @@ -1226,11 +1342,21 @@ 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); virCommandAddArg(cmd, info.path); @@ -1240,6 +1366,78 @@ virStorageBackendCreateQemuImgCmdFromVol(virConnectPtr conn, return cmd; } + +static char * +virStorageBackendCreateQemuImgSecretPath(virConnectPtr conn, + virStoragePoolObjPtr pool, + virStorageVolDefPtr vol) +{ + virStorageEncryptionPtr enc = vol->target.encryption; + 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; + } +

+ /* Since we don't have a file, just go to cleanup using NULL secretPath */

+ if (!(secretPath = virStoragePoolObjBuildTempFilePath(pool, vol))) + goto cleanup; + + if ((fd = mkostemp(secretPath, O_CLOEXEC)) < 0) { + virReportSystemError(errno, "%s", + _("failed to open luks secret file for write")); + goto error; + } + + if (virSecretGetSecretString(conn, &enc->secrets[0]->seclookupdef, + VIR_SECRET_USAGE_TYPE_PASSPHRASE, + &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 ((vol->target.perms->uid != (uid_t) -1) && + (vol->target.perms->gid != (gid_t) -1)) { + if (chown(secretPath, vol->target.perms->uid, + vol->target.perms->gid) < 0) { + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("failed to chown luks secret file")); + goto error; + } + } + + cleanup: + 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 +1449,7 @@ virStorageBackendCreateQemuImg(virConnectPtr conn, char *create_tool; int imgformat; virCommandPtr cmd; + char *secretPath = NULL; virCheckFlags(VIR_STORAGE_VOL_CREATE_PREALLOC_METADATA, -1); @@ -1266,8 +1465,21 @@ 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 +1487,10 @@ 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..4e4a6dd 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, + virStorageEncryptionInfoDefPtr 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);