Signed-off-by: Ján Tomko <jtomko(a)redhat.com&gt; --- src/conf/domain_conf.c | 98 +++++++++++++++++++++--------------------- 1 file changed, 49 insertions(+), 49 deletions(-) diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c index 2c8727de54..dd67e7f21b 100644 --- a/src/conf/domain_conf.c +++ b/src/conf/domain_conf.c @@ -8581,6 +8581,55 @@ virDomainNetGenerateMAC(virDomainXMLOption *xmlopt, } +static int virDomainIdMapEntrySort(const void *a, const void *b) +{ + const virDomainIdMapEntry *entrya = a; + const virDomainIdMapEntry *entryb = b; + + if (entrya->start > entryb->start) + return 1; + else if (entrya->start < entryb->start) + return -1; + else + return 0; +} + +/* Parse the XML definition for user namespace id map. + * + * idmap has the form of + * + * <uid start='0' target='1000' count='10'/> + * <gid start='0' target='1000' count='10'/> + */ +static virDomainIdMapEntry * +virDomainIdmapDefParseXML(xmlXPathContextPtr ctxt, + xmlNodePtr *node, + size_t num) +{ + size_t i; + virDomainIdMapEntry *idmap = NULL; + VIR_XPATH_NODE_AUTORESTORE(ctxt) + + idmap = g_new0(virDomainIdMapEntry, num); + + for (i = 0; i < num; i++) { + ctxt->node = node[i]; + if (virXPathUInt("string(./@start)", ctxt, &idmap[i].start) < 0 || + virXPathUInt("string(./@target)", ctxt, &idmap[i].target) < 0 || + virXPathUInt("string(./@count)", ctxt, &idmap[i].count) < 0) { + virReportError(VIR_ERR_XML_ERROR, "%s", + _("invalid idmap start/target/count settings")); + VIR_FREE(idmap); + return NULL; + } + } + + qsort(idmap, num, sizeof(idmap[0]), virDomainIdMapEntrySort); + + return idmap; +} + + static virDomainFSDef * virDomainFSDefParseXML(virDomainXMLOption *xmlopt, xmlNodePtr node, @@ -15711,55 +15760,6 @@ virDomainDefParseBootXML(xmlXPathContextPtr ctxt, return 0; } - -static int virDomainIdMapEntrySort(const void *a, const void *b) -{ - const virDomainIdMapEntry *entrya = a; - const virDomainIdMapEntry *entryb = b; - - if (entrya->start > entryb->start) - return 1; - else if (entrya->start < entryb->start) - return -1; - else - return 0; -} - -/* Parse the XML definition for user namespace id map. - * - * idmap has the form of - * - * <uid start='0' target='1000' count='10'/> - * <gid start='0' target='1000' count='10'/> - */ -static virDomainIdMapEntry * -virDomainIdmapDefParseXML(xmlXPathContextPtr ctxt, - xmlNodePtr *node, - size_t num) -{ - size_t i; - virDomainIdMapEntry *idmap = NULL; - VIR_XPATH_NODE_AUTORESTORE(ctxt) - - idmap = g_new0(virDomainIdMapEntry, num); - - for (i = 0; i < num; i++) { - ctxt->node = node[i]; - if (virXPathUInt("string(./@start)", ctxt, &idmap[i].start) < 0 || - virXPathUInt("string(./@target)", ctxt, &idmap[i].target) < 0 || - virXPathUInt("string(./@count)", ctxt, &idmap[i].count) < 0) { - virReportError(VIR_ERR_XML_ERROR, "%s", - _("invalid idmap start/target/count settings")); - VIR_FREE(idmap); - return NULL; - } - } - - qsort(idmap, num, sizeof(idmap[0]), virDomainIdMapEntrySort); - - return idmap; -} - /* Parse the XML definition for an IOThread ID * * Format is : -- 2.41.0

Let unprivileged virtiofs use user namespace. Signed-off-by: Ján Tomko <jtomko(a)redhat.com&gt; --- docs/formatdomain.rst | 7 +++ src/conf/domain_conf.c | 51 +++++++++++++++++++ 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 bc469e5f9f..0f10b3043f 100644 --- a/docs/formatdomain.rst +++ b/docs/formatdomain.rst @@ -3501,6 +3501,10 @@ 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'/> @@ -3650,6 +3654,9 @@ 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. ``readonly`` Enables exporting filesystem as a readonly mount for guest, by default read-write access is given (currently only works for QEMU/KVM driver). diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c index dd67e7f21b..2379a9204f 100644 --- a/src/conf/domain_conf.c +++ b/src/conf/domain_conf.c @@ -2585,6 +2585,8 @@ 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); } @@ -8767,6 +8769,8 @@ 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; + xmlNodePtr *nodes = NULL; if (queue_size && virStrToLong_ull(queue_size, NULL, 10, &def->queue_size) < 0) { virReportError(VIR_ERR_XML_ERROR, @@ -8812,6 +8816,30 @@ virDomainFSDefParseXML(virDomainXMLOption *xmlopt, VIR_XML_PROP_NONZERO, &def->sandbox) < 0) goto error; + + if ((n = virXPathNodeSet("./idmap/uid", ctxt, &nodes)) < 0) + return NULL; + + if (n) { + def->idmap.uidmap = virDomainIdmapDefParseXML(ctxt, nodes, n); + if (!def->idmap.uidmap) + return NULL; + + def->idmap.nuidmap = n; + } + VIR_FREE(nodes); + + if ((n = virXPathNodeSet("./idmap/gid", ctxt, &nodes)) < 0) + return NULL; + + if (n) { + def->idmap.gidmap = virDomainIdmapDefParseXML(ctxt, nodes, n); + if (!def->idmap.gidmap) + return NULL; + + def->idmap.ngidmap = n; + } + VIR_FREE(nodes); } if (source == NULL && def->type != VIR_DOMAIN_FS_TYPE_RAM @@ -23164,6 +23192,29 @@ 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 8937968e3b..b84719b01d 100644 --- a/src/conf/domain_conf.h +++ b/src/conf/domain_conf.h @@ -925,6 +925,7 @@ 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 2f9ba31c0a..2ca0e92f00 100644 --- a/src/conf/schemas/domaincommon.rng +++ b/src/conf/schemas/domaincommon.rng @@ -3052,6 +3052,9 @@ </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'/> -- 2.41.0

Pass the ID map to virtiofsd. https://bugzilla.redhat.com/show_bug.cgi?id=2034630 https://gitlab.com/libvirt/libvirt/-/issues/535 Signed-off-by: Ján Tomko <jtomko(a)redhat.com&gt; --- src/qemu/qemu_virtiofs.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/src/qemu/qemu_virtiofs.c b/src/qemu/qemu_virtiofs.c index 230f85c291..94c8b4711e 100644 --- a/src/qemu/qemu_virtiofs.c +++ b/src/qemu/qemu_virtiofs.c @@ -169,6 +169,19 @@ qemuVirtioFSBuildCommandLine(virQEMUDriverConfig *cfg, if (cfg->virtiofsdDebug) virCommandAddArg(cmd, "-d"); + if (fs->idmap.nuidmap > 0) { + virCommandAddArgFormat(cmd, "--uid-map=:%u:%u:%u:", + fs->idmap.uidmap[0].start, + fs->idmap.uidmap[0].target, + fs->idmap.uidmap[0].count); + } + if (fs->idmap.ngidmap > 0) { + virCommandAddArgFormat(cmd, "--gid-map=:%u:%u:%u:", + fs->idmap.gidmap[0].start, + fs->idmap.gidmap[0].target, + fs->idmap.gidmap[0].count); + } + return g_steal_pointer(&cmd); } -- 2.41.0

Signed-off-by: Ján Tomko <jtomko(a)redhat.com&gt; --- docs/kbase/virtiofs.rst | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) diff --git a/docs/kbase/virtiofs.rst b/docs/kbase/virtiofs.rst index 5940092db5..ecfb8e4236 100644 --- a/docs/kbase/virtiofs.rst +++ b/docs/kbase/virtiofs.rst @@ -59,6 +59,35 @@ Sharing a host directory with a guest Note: this requires virtiofs support in the guest kernel (Linux v5.4 or later) +ID mapping +========== + +In unprivileged mode (``qemu:///session``), mapping user/group IDs is available +(since libvirt version TBD). After reserving an ID range from the host for your +regular user + +:: + + $ cat /etc/subuid + jtomko:100000:65536 + $ cat /etc/subgid + jtomko:100000:65536 + +you can let virtiofsd map guest UIDs from 0 to 65535 +to host IDs 100000 to 165535 for example: + +:: + + <filesystem type='mount' accessmode='passthrough'> + <driver type='virtiofs' queue='1024'/> + ... + <idmap> + <uid start='0' target='100000' count='65535'/> + <gid start='0' target='100000' count='65535'/> + </idmap> + </filesystem> + + Optional parameters =================== -- 2.41.0

On a Monday in 2023, Daniel P. Berrangé wrote: In this series, optional. My reasoning was that someone might want to not do it and would prefer to run virtiofsd as their own user. On second thought, that is not what accessmode='passthrough' means, so for non-mapping non-privileged use, a different/new accessmode attribute will be needed. So, by default libvirt would assume that unprivileged accessmode='passthrough' means "use the whole range for my user from /etc/subuid"? Podman treats /etc/subuid as a pool and chooses a 64K range that is (to its knowledge) unused. I'm undecided whether that would also be a reasonable option for a default. Jano