[libvirt] [PATCH 3/3] Create storage volumes directly with desired uid/gid.
Laine Stump
laine at laine.org
Wed Jan 13 06:25:07 UTC 2010
In order to avoid problems trying to chown files that were created by
root on a root-squashing nfs server, fork a new process that setuid's
to the desired uid before creating the file. (It's only done this way
if the pool containing the new volume is of type 'netfs', otherwise
the old method of creating the file followed by chown() is used.)
This changes the semantics of the "create_func" slightly - previously
it was assumed that this function just created the file, then the
caller would chown it to the desired uid. Now, create_func does both
operations.
There are multiple functions that can take on the role of create_func:
createFileDir - previously called mkdir(), now calls virDirCreate().
virStorageBackendCreateRaw - previously called open(),
now calls virFileCreate().
virStorageBackendCreateQemuImg - use virRunWithHook() to setuid/gid.
virStorageBackendCreateQcowCreate - same.
virStorageBackendCreateBlockFrom - preserve old behavior.
---
src/storage/storage_backend.c | 115 ++++++++++++++++++++++++++++----
src/storage/storage_backend.h | 8 ++-
src/storage/storage_backend_disk.c | 3 +-
src/storage/storage_backend_fs.c | 25 +++----
src/storage/storage_backend_logical.c | 3 +-
src/storage/storage_driver.c | 4 +-
6 files changed, 123 insertions(+), 35 deletions(-)
diff --git a/src/storage/storage_backend.c b/src/storage/storage_backend.c
index 9dc801c..1a39a55 100644
--- a/src/storage/storage_backend.c
+++ b/src/storage/storage_backend.c
@@ -205,6 +205,7 @@ cleanup:
static int
virStorageBackendCreateBlockFrom(virConnectPtr conn,
+ virStoragePoolObjPtr pool ATTRIBUTE_UNUSED,
virStorageVolDefPtr vol,
virStorageVolDefPtr inputvol,
unsigned int flags ATTRIBUTE_UNUSED)
@@ -229,6 +230,15 @@ virStorageBackendCreateBlockFrom(virConnectPtr conn,
goto cleanup;
}
+ if (getuid() == 0) {
+ if (fchown(fd, vol->target.perms.uid, vol->target.perms.gid) < 0) {
+ virReportSystemError(conn, errno,
+ _("cannot chown %s to (%u, %u)"),
+ vol->target.path, vol->target.perms.uid,
+ vol->target.perms.gid);
+ goto cleanup;
+ }
+ }
if (close(fd) < 0) {
virReportSystemError(conn, errno,
_("cannot close file '%s'"),
@@ -247,12 +257,14 @@ cleanup:
int
virStorageBackendCreateRaw(virConnectPtr conn,
+ virStoragePoolObjPtr pool,
virStorageVolDefPtr vol,
virStorageVolDefPtr inputvol,
unsigned int flags ATTRIBUTE_UNUSED)
{
int fd = -1;
int ret = -1;
+ int createstat;
unsigned long long remain;
char *buf = NULL;
@@ -263,14 +275,23 @@ virStorageBackendCreateRaw(virConnectPtr conn,
return -1;
}
- if ((fd = open(vol->target.path, O_RDWR | O_CREAT | O_EXCL,
- vol->target.perms.mode)) < 0) {
- virReportSystemError(conn, errno,
+ if ((createstat = virFileCreate(vol->target.path, vol->target.perms.mode,
+ vol->target.perms.uid, vol->target.perms.gid,
+ (pool->def->type == VIR_STORAGE_POOL_NETFS
+ ? VIR_FILE_CREATE_AS_UID : 0))) < 0) {
+ virReportSystemError(conn, createstat,
_("cannot create path '%s'"),
vol->target.path);
goto cleanup;
}
+ if ((fd = open(vol->target.path, O_RDWR | O_EXCL)) < 0) {
+ virReportSystemError(conn, errno,
+ _("cannot open new path '%s'"),
+ vol->target.path);
+ goto cleanup;
+ }
+
/* Seek to the final size, so the capacity is available upfront
* for progress reporting */
if (ftruncate(fd, vol->capacity) < 0) {
@@ -453,12 +474,82 @@ cleanup:
return ret;
}
+static int virStorageBuildSetUIDHook(void *data) {
+ virStorageVolDefPtr vol = data;
+
+ if ((vol->target.perms.gid != 0)
+ && (setgid(vol->target.perms.gid) != 0)) {
+ virReportSystemError(NULL, errno,
+ _("Cannot set gid to %u before creating %s"),
+ vol->target.perms.gid, vol->target.path);
+ return -1;
+ }
+ if ((vol->target.perms.uid != 0)
+ && (setuid(vol->target.perms.uid) != 0)) {
+ virReportSystemError(NULL, errno,
+ _("Cannot set uid to %u before creating %s"),
+ vol->target.perms.uid, vol->target.path);
+ return -1;
+ }
+ return 0;
+}
+
+static int virStorageBackendCreateExecCommand(virConnectPtr conn,
+ virStoragePoolObjPtr pool,
+ virStorageVolDefPtr vol,
+ const char **cmdargv) {
+ struct stat st;
+ gid_t gid;
+ uid_t uid;
+ int filecreated = 0;
+
+ if ((pool->def->type == VIR_STORAGE_POOL_NETFS)
+ && (getuid() == 0)
+ && ((vol->target.perms.uid != 0) || (vol->target.perms.gid != 0))) {
+ if (virRunWithHook(conn, cmdargv,
+ virStorageBuildSetUIDHook, vol, NULL) == 0) {
+ /* command was successfully run, check if the file was created */
+ if (stat(vol->target.path, &st) >=0)
+ filecreated = 1;
+ }
+ }
+ if (!filecreated) {
+ if (virRun(conn, cmdargv, NULL) < 0) {
+ virReportSystemError(NULL, errno,
+ _("Cannot run %s to create %s"),
+ cmdargv[0], vol->target.path);
+ return -1;
+ }
+ if (stat(vol->target.path, &st) < 0) {
+ virReportSystemError(NULL, errno,
+ _("%s failed to create %s"),
+ cmdargv[0], vol->target.path);
+ return -1;
+ }
+ }
+
+ gid = (vol->target.perms.gid != 0) ? vol->target.perms.gid : -1;
+ uid = (vol->target.perms.uid != 0) ? vol->target.perms.uid : -1;
+ if (((gid != -1) && (gid != st.st_gid))
+ || ((uid != -1) && (uid != st.st_uid))) {
+ /* either uid or gid wasn't properly set during creation */
+ if (chown(vol->target.path, uid, gid) < 0) {
+ virReportSystemError(NULL, errno, _("cannot chown %s to (%u, %u)"),
+ vol->target.path, uid, gid);
+ return -1;
+ }
+ }
+ return 0;
+}
+
static int
virStorageBackendCreateQemuImg(virConnectPtr conn,
+ virStoragePoolObjPtr pool,
virStorageVolDefPtr vol,
virStorageVolDefPtr inputvol,
unsigned int flags ATTRIBUTE_UNUSED)
{
+ int ret;
char size[100];
char *create_tool;
short use_kvmimg;
@@ -616,14 +707,10 @@ virStorageBackendCreateQemuImg(virConnectPtr conn,
/* Size in KB */
snprintf(size, sizeof(size), "%lluK", vol->capacity/1024);
- if (virRun(conn, imgargv, NULL) < 0) {
- VIR_FREE(imgargv[0]);
- return -1;
- }
-
+ ret = virStorageBackendCreateExecCommand(conn, pool, vol, imgargv);
VIR_FREE(imgargv[0]);
- return 0;
+ return ret;
}
/*
@@ -632,10 +719,12 @@ virStorageBackendCreateQemuImg(virConnectPtr conn,
*/
static int
virStorageBackendCreateQcowCreate(virConnectPtr conn,
+ virStoragePoolObjPtr pool,
virStorageVolDefPtr vol,
virStorageVolDefPtr inputvol,
unsigned int flags ATTRIBUTE_UNUSED)
{
+ int ret;
char size[100];
const char *imgargv[4];
@@ -672,14 +761,10 @@ virStorageBackendCreateQcowCreate(virConnectPtr conn,
imgargv[2] = vol->target.path;
imgargv[3] = NULL;
- if (virRun(conn, imgargv, NULL) < 0) {
- VIR_FREE(imgargv[0]);
- return -1;
- }
-
+ ret = virStorageBackendCreateExecCommand(conn, pool, vol, imgargv);
VIR_FREE(imgargv[0]);
- return 0;
+ return ret;
}
virStorageBackendBuildVolFrom
diff --git a/src/storage/storage_backend.h b/src/storage/storage_backend.h
index 88c6161..fc5d8fb 100644
--- a/src/storage/storage_backend.h
+++ b/src/storage/storage_backend.h
@@ -34,14 +34,18 @@ typedef int (*virStorageBackendRefreshPool)(virConnectPtr conn, virStoragePoolOb
typedef int (*virStorageBackendStopPool)(virConnectPtr conn, virStoragePoolObjPtr pool);
typedef int (*virStorageBackendDeletePool)(virConnectPtr conn, virStoragePoolObjPtr pool, unsigned int flags);
-typedef int (*virStorageBackendBuildVol)(virConnectPtr conn, virStorageVolDefPtr vol);
+typedef int (*virStorageBackendBuildVol)(virConnectPtr conn,
+ virStoragePoolObjPtr pool, virStorageVolDefPtr vol);
typedef int (*virStorageBackendCreateVol)(virConnectPtr conn, virStoragePoolObjPtr pool, virStorageVolDefPtr vol);
typedef int (*virStorageBackendRefreshVol)(virConnectPtr conn, virStoragePoolObjPtr pool, virStorageVolDefPtr vol);
typedef int (*virStorageBackendDeleteVol)(virConnectPtr conn, virStoragePoolObjPtr pool, virStorageVolDefPtr vol, unsigned int flags);
-typedef int (*virStorageBackendBuildVolFrom)(virConnectPtr conn, virStorageVolDefPtr origvol, virStorageVolDefPtr newvol, unsigned int flags);
+typedef int (*virStorageBackendBuildVolFrom)(virConnectPtr conn, virStoragePoolObjPtr pool,
+ virStorageVolDefPtr origvol, virStorageVolDefPtr newvol,
+ unsigned int flags);
/* File creation/cloning functions used for cloning between backends */
int virStorageBackendCreateRaw(virConnectPtr conn,
+ virStoragePoolObjPtr pool,
virStorageVolDefPtr vol,
virStorageVolDefPtr inputvol,
unsigned int flags);
diff --git a/src/storage/storage_backend_disk.c b/src/storage/storage_backend_disk.c
index 72ccd81..5ecf210 100644
--- a/src/storage/storage_backend_disk.c
+++ b/src/storage/storage_backend_disk.c
@@ -599,6 +599,7 @@ virStorageBackendDiskCreateVol(virConnectPtr conn,
static int
virStorageBackendDiskBuildVolFrom(virConnectPtr conn,
+ virStoragePoolObjPtr pool,
virStorageVolDefPtr vol,
virStorageVolDefPtr inputvol,
unsigned int flags)
@@ -609,7 +610,7 @@ virStorageBackendDiskBuildVolFrom(virConnectPtr conn,
if (!build_func)
return -1;
- return build_func(conn, vol, inputvol, flags);
+ return build_func(conn, pool, vol, inputvol, flags);
}
static int
diff --git a/src/storage/storage_backend_fs.c b/src/storage/storage_backend_fs.c
index 4fe40b3..1f98627 100644
--- a/src/storage/storage_backend_fs.c
+++ b/src/storage/storage_backend_fs.c
@@ -737,6 +737,7 @@ virStorageBackendFileSystemVolCreate(virConnectPtr conn,
}
static int createFileDir(virConnectPtr conn,
+ virStoragePoolObjPtr pool,
virStorageVolDefPtr vol,
virStorageVolDefPtr inputvol,
unsigned int flags ATTRIBUTE_UNUSED) {
@@ -747,7 +748,10 @@ static int createFileDir(virConnectPtr conn,
return -1;
}
- if (mkdir(vol->target.path, vol->target.perms.mode) < 0) {
+ if (virDirCreate(vol->target.path, vol->target.perms.mode,
+ vol->target.perms.uid, vol->target.perms.gid,
+ (pool->def->type == VIR_STORAGE_POOL_NETFS
+ ? VIR_FILE_CREATE_AS_UID : 0)) != 0) {
virReportSystemError(conn, errno,
_("cannot create path '%s'"),
vol->target.path);
@@ -759,6 +763,7 @@ static int createFileDir(virConnectPtr conn,
static int
_virStorageBackendFileSystemVolBuild(virConnectPtr conn,
+ virStoragePoolObjPtr pool,
virStorageVolDefPtr vol,
virStorageVolDefPtr inputvol)
{
@@ -794,7 +799,7 @@ _virStorageBackendFileSystemVolBuild(virConnectPtr conn,
return -1;
}
- if (create_func(conn, vol, inputvol, 0) < 0)
+ if (create_func(conn, pool, vol, inputvol, 0) < 0)
return -1;
if ((fd = open(vol->target.path, O_RDONLY)) < 0) {
@@ -804,16 +809,6 @@ _virStorageBackendFileSystemVolBuild(virConnectPtr conn,
return -1;
}
- /* We can only chown/grp if root */
- if (getuid() == 0) {
- if (fchown(fd, vol->target.perms.uid, vol->target.perms.gid) < 0) {
- virReportSystemError(conn, errno,
- _("cannot set file owner '%s'"),
- vol->target.path);
- close(fd);
- return -1;
- }
- }
if (fchmod(fd, vol->target.perms.mode) < 0) {
virReportSystemError(conn, errno,
_("cannot set file mode '%s'"),
@@ -839,8 +834,9 @@ _virStorageBackendFileSystemVolBuild(virConnectPtr conn,
*/
static int
virStorageBackendFileSystemVolBuild(virConnectPtr conn,
+ virStoragePoolObjPtr pool,
virStorageVolDefPtr vol) {
- return _virStorageBackendFileSystemVolBuild(conn, vol, NULL);
+ return _virStorageBackendFileSystemVolBuild(conn, pool, vol, NULL);
}
/*
@@ -848,10 +844,11 @@ virStorageBackendFileSystemVolBuild(virConnectPtr conn,
*/
static int
virStorageBackendFileSystemVolBuildFrom(virConnectPtr conn,
+ virStoragePoolObjPtr pool,
virStorageVolDefPtr vol,
virStorageVolDefPtr inputvol,
unsigned int flags ATTRIBUTE_UNUSED) {
- return _virStorageBackendFileSystemVolBuild(conn, vol, inputvol);
+ return _virStorageBackendFileSystemVolBuild(conn, pool, vol, inputvol);
}
/**
diff --git a/src/storage/storage_backend_logical.c b/src/storage/storage_backend_logical.c
index 5eebfac..c2e74a5 100644
--- a/src/storage/storage_backend_logical.c
+++ b/src/storage/storage_backend_logical.c
@@ -660,6 +660,7 @@ virStorageBackendLogicalCreateVol(virConnectPtr conn,
static int
virStorageBackendLogicalBuildVolFrom(virConnectPtr conn,
+ virStoragePoolObjPtr pool,
virStorageVolDefPtr vol,
virStorageVolDefPtr inputvol,
unsigned int flags)
@@ -670,7 +671,7 @@ virStorageBackendLogicalBuildVolFrom(virConnectPtr conn,
if (!build_func)
return -1;
- return build_func(conn, vol, inputvol, flags);
+ return build_func(conn, pool, vol, inputvol, flags);
}
static int
diff --git a/src/storage/storage_driver.c b/src/storage/storage_driver.c
index c2f7850..50fcbe2 100644
--- a/src/storage/storage_driver.c
+++ b/src/storage/storage_driver.c
@@ -1331,7 +1331,7 @@ storageVolumeCreateXML(virStoragePoolPtr obj,
voldef->building = 1;
virStoragePoolObjUnlock(pool);
- buildret = backend->buildVol(obj->conn, buildvoldef);
+ buildret = backend->buildVol(obj->conn, pool, buildvoldef);
storageDriverLock(driver);
virStoragePoolObjLock(pool);
@@ -1484,7 +1484,7 @@ storageVolumeCreateXMLFrom(virStoragePoolPtr obj,
virStoragePoolObjUnlock(origpool);
}
- buildret = backend->buildVolFrom(obj->conn, newvol, origvol, flags);
+ buildret = backend->buildVolFrom(obj->conn, pool, newvol, origvol, flags);
storageDriverLock(driver);
virStoragePoolObjLock(pool);
--
1.6.6
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