8:47 a.m.
Allow the user to manually tweak the ID mapping that will allow
virtiofsd to run unprivileged.
Signed-off-by: Ján Tomko <jtomko(a)redhat.com>
---
docs/formatdomain.rst | 8 +++
src/conf/domain_conf.c | 50 +++++++++++++++++++
src/conf/domain_conf.h | 1 +
src/conf/schemas/domaincommon.rng | 3 ++
.../vhost-user-fs-fd-memory.xml | 4 ++
5 files changed, 66 insertions(+)
diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst
index 310d2bc427..96e03a3807 100644
--- a/docs/formatdomain.rst
+++ b/docs/formatdomain.rst
@@ -3548,6 +3548,10 @@ A directory on the host that can be accessed directly from the
guest.
</binary>
<source dir='/path'/>
<target dir='mount_tag'/>
+ <idmap>
+ <uid start='0' target='100000'
count='65535'/>
+ <gid start='0' target='100000'
count='65535'/>
+ </idmap>
</filesystem>
<filesystem type='mount'>
<driver type='virtiofs' queue='1024'/>
@@ -3697,6 +3701,10 @@ A directory on the host that can be accessed directly from the
guest.
Where the ``source`` can be accessed in the guest. For most drivers this is
an automatic mount point, but for QEMU/KVM this is merely an arbitrary string
tag that is exported to the guest as a hint for where to mount.
+``idmap``
+ For ``virtiofs``, an ``idmap`` element can be specified to map IDs in the user
+ namespace. See the `Container boot`_ section for the syntax of the element.
+ :since:`Since 10.0.0`
``readonly``
Enables exporting filesystem as a readonly mount for guest, by default
read-write access is given (currently only works for QEMU/KVM driver; not
diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index a70a1f29f2..58a985fc5d 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -2588,6 +2588,8 @@ void virDomainFSDefFree(virDomainFSDef *def)
virObjectUnref(def->privateData);
g_free(def->binary);
g_free(def->sock);
+ g_free(def->idmap.uidmap);
+ g_free(def->idmap.gidmap);
g_free(def);
}
@@ -8771,6 +8773,9 @@ virDomainFSDefParseXML(virDomainXMLOption *xmlopt,
xmlNodePtr binary_lock_node = virXPathNode("./binary/lock", ctxt);
xmlNodePtr binary_cache_node = virXPathNode("./binary/cache", ctxt);
xmlNodePtr binary_sandbox_node = virXPathNode("./binary/sandbox",
ctxt);
+ ssize_t n;
+ g_autofree xmlNodePtr *uid_nodes = NULL;
+ g_autofree xmlNodePtr *gid_nodes = NULL;
if (queue_size && virStrToLong_ull(queue_size, NULL, 10,
&def->queue_size) < 0) {
virReportError(VIR_ERR_XML_ERROR,
@@ -8816,6 +8821,28 @@ virDomainFSDefParseXML(virDomainXMLOption *xmlopt,
VIR_XML_PROP_NONZERO,
&def->sandbox) < 0)
goto error;
+
+ if ((n = virXPathNodeSet("./idmap/uid", ctxt, &uid_nodes)) < 0)
+ return NULL;
+
+ if (n) {
+ def->idmap.uidmap = virDomainIdmapDefParseXML(ctxt, uid_nodes, n);
+ if (!def->idmap.uidmap)
+ return NULL;
+
+ def->idmap.nuidmap = n;
+ }
+
+ if ((n = virXPathNodeSet("./idmap/gid", ctxt, &gid_nodes)) < 0)
+ return NULL;
+
+ if (n) {
+ def->idmap.gidmap = virDomainIdmapDefParseXML(ctxt, gid_nodes, n);
+ if (!def->idmap.gidmap)
+ return NULL;
+
+ def->idmap.ngidmap = n;
+ }
}
if (source == NULL && def->type != VIR_DOMAIN_FS_TYPE_RAM
@@ -23233,6 +23260,29 @@ virDomainFSDefFormat(virBuffer *buf,
virXMLFormatElement(buf, "driver", &driverAttrBuf, &driverBuf);
virXMLFormatElement(buf, "binary", &binaryAttrBuf, &binaryBuf);
+ if (def->idmap.uidmap) {
+ size_t i;
+
+ virBufferAddLit(buf, "<idmap>\n");
+ virBufferAdjustIndent(buf, 2);
+ for (i = 0; i < def->idmap.nuidmap; i++) {
+ virBufferAsprintf(buf,
+ "<uid start='%u' target='%u'
count='%u'/>\n",
+ def->idmap.uidmap[i].start,
+ def->idmap.uidmap[i].target,
+ def->idmap.uidmap[i].count);
+ }
+ for (i = 0; i < def->idmap.ngidmap; i++) {
+ virBufferAsprintf(buf,
+ "<gid start='%u' target='%u'
count='%u'/>\n",
+ def->idmap.gidmap[i].start,
+ def->idmap.gidmap[i].target,
+ def->idmap.gidmap[i].count);
+ }
+ virBufferAdjustIndent(buf, -2);
+ virBufferAddLit(buf, "</idmap>\n");
+ }
+
switch (def->type) {
case VIR_DOMAIN_FS_TYPE_MOUNT:
case VIR_DOMAIN_FS_TYPE_BIND:
diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index 5a93ee0aee..0c5e2636e1 100644
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -888,6 +888,7 @@ struct _virDomainFSDef {
virTristateSwitch flock;
virDomainFSSandboxMode sandbox;
int thread_pool_size;
+ virDomainIdMapDef idmap;
virDomainVirtioOptions *virtio;
virObject *privateData;
};
diff --git a/src/conf/schemas/domaincommon.rng b/src/conf/schemas/domaincommon.rng
index b98a2ae602..f318c06797 100644
--- a/src/conf/schemas/domaincommon.rng
+++ b/src/conf/schemas/domaincommon.rng
@@ -3120,6 +3120,9 @@
</choice>
<empty/>
</element>
+ <optional>
+ <ref name="idmap"/>
+ </optional>
<ref name="filesystemCommon"/>
</interleave>
</group>
diff --git a/tests/qemuxml2argvdata/vhost-user-fs-fd-memory.xml
b/tests/qemuxml2argvdata/vhost-user-fs-fd-memory.xml
index 81de8c0dd7..1d0bc26c46 100644
--- a/tests/qemuxml2argvdata/vhost-user-fs-fd-memory.xml
+++ b/tests/qemuxml2argvdata/vhost-user-fs-fd-memory.xml
@@ -34,6 +34,10 @@
<lock posix='off' flock='off'/>
<thread_pool size='16'/>
</binary>
+ <idmap>
+ <uid start='0' target='100000' count='65535'/>
+ <gid start='0' target='100000' count='65535'/>
+ </idmap>
<source dir='/path'/>
<target dir='mount_tag'/>
<address type='pci' domain='0x0000' bus='0x00'
slot='0x02' function='0x0'/>
--
2.42.0