[PATCH] qemu: virtiofs: support <sandbox mode='chroot'/>

Peter Krempa pkrempa at redhat.com
Fri Mar 26 15:53:14 UTC 2021


On Fri, Mar 26, 2021 at 11:37:48 -0400, Cole Robinson wrote:
> Add a new XML element
> 
> <filesystem>
>   <binary>
>     <sandbox mode='chroot|namespace'/>
>   </binary>
> </filesystem>
> 
> Which maps to `virtiofsd -o sandbox=chroot|namespace`, which was added
> in qemu 5.2.0:
> 
> https://git.qemu.org/?p=qemu.git;a=commit;h=06844584b62a43384642f7243b0fc01c9fff0fc7
> 
> Signed-off-by: Cole Robinson <crobinso at redhat.com>
> ---
>  docs/formatdomain.rst                         |  4 ++++
>  docs/schemas/domaincommon.rng                 | 12 ++++++++++
>  src/conf/domain_conf.c                        | 23 +++++++++++++++++++
>  src/conf/domain_conf.h                        | 10 ++++++++
>  src/libvirt_private.syms                      |  1 +
>  src/qemu/qemu_virtiofs.c                      |  2 ++
>  .../vhost-user-fs-fd-memory.xml               |  1 +
>  7 files changed, 53 insertions(+)

Please split the commit as it's usual for libvirt patches.

Also a test case modifying any of the .args files in qemuxml2argv test
is missing.

> 
> diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst
> index 9392c80113..9dda39dbcb 100644
> --- a/docs/formatdomain.rst
> +++ b/docs/formatdomain.rst
> @@ -3234,6 +3234,7 @@ A directory on the host that can be accessed directly from the guest.
>           <driver type='virtiofs' queue='1024'/>
>           <binary path='/usr/libexec/virtiofsd' xattr='on'>
>              <cache mode='always'/>
> +            <sandbox mode='namespace'/>
>              <lock posix='on' flock='on'/>
>           </binary>
>           <source dir='/path'/>
> @@ -3358,6 +3359,9 @@ A directory on the host that can be accessed directly from the guest.
>     ``cache`` element, possible ``mode`` values being ``none`` and ``always``.
>     Locking can be controlled via the ``lock`` element - attributes ``posix`` and
>     ``flock`` both accepting values ``on`` or ``off``. ( :since:`Since 6.2.0` )
> +   The sandboxing method used by virtiofsd can be configured with the ``sandbox``
> +   element, possible ``mode`` values being ``namespace`` and
> +   ``chroot``. ( :since:`Since 7.2.0` )

Is there any reasonable short explanation of differences? Or perhaps
link to virtiofs docs to clarify what that the modes do?


>  ``source``
>     The resource on the host that is being accessed in the guest. The ``name``
>     attribute must be used with ``type='template'``, and the ``dir`` attribute
> diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
> index 1dbfc68f18..6404ebf210 100644
> --- a/docs/schemas/domaincommon.rng
> +++ b/docs/schemas/domaincommon.rng
> @@ -2960,6 +2960,18 @@
>              </optional>
>            </element>
>          </optional>
> +        <optional>
> +          <element name="sandbox">
> +            <optional>
> +              <attribute name="mode">
> +                <choice>
> +                  <value>namespace</value>
> +                  <value>chroot</value>
> +                </choice>
> +              </attribute>
> +            </optional>
> +          </element>
> +        </optional>
>          <optional>
>            <element name="lock">
>              <optional>
> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
> index b0eba9f7bd..70a900ee25 100644
> --- a/src/conf/domain_conf.c
> +++ b/src/conf/domain_conf.c
> @@ -538,6 +538,13 @@ VIR_ENUM_IMPL(virDomainFSCacheMode,
>                "always",
>  );
>  
> +VIR_ENUM_IMPL(virDomainFSSandboxMode,
> +              VIR_DOMAIN_FS_SANDBOX_MODE_LAST,
> +              "default",
> +              "namespace",
> +              "chroot",
> +);
> +
>  
>  VIR_ENUM_IMPL(virDomainNet,
>                VIR_DOMAIN_NET_TYPE_LAST,
> @@ -10373,6 +10380,7 @@ virDomainFSDefParseXML(virDomainXMLOptionPtr xmlopt,
>          g_autofree char *binary = virXPathString("string(./binary/@path)", ctxt);
>          g_autofree char *xattr = virXPathString("string(./binary/@xattr)", ctxt);
>          g_autofree char *cache = virXPathString("string(./binary/cache/@mode)", ctxt);
> +        g_autofree char *sandbox = virXPathString("string(./binary/sandbox/@mode)", ctxt);
>          g_autofree char *posix_lock = virXPathString("string(./binary/lock/@posix)", ctxt);
>          g_autofree char *flock = virXPathString("string(./binary/lock/@flock)", ctxt);
>          int val;
> @@ -10406,6 +10414,16 @@ virDomainFSDefParseXML(virDomainXMLOptionPtr xmlopt,
>              def->cache = val;
>          }
>  
> +        if (sandbox) {
> +            if ((val = virDomainFSSandboxModeTypeFromString(sandbox)) <= 0) {
> +                virReportError(VIR_ERR_XML_ERROR,
> +                               _("cannot parse sandbox mode '%s' for virtiofs"),
> +                               sandbox);
> +                goto error;
> +            }
> +            def->sandbox = val;
> +        }
> +
>          if (posix_lock) {
>              if ((val = virTristateSwitchTypeFromString(posix_lock)) <= 0) {
>                  virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
> @@ -25483,6 +25501,11 @@ virDomainFSDefFormat(virBufferPtr buf,
>                                virDomainFSCacheModeTypeToString(def->cache));
>          }
>  
> +        if (def->sandbox != VIR_DOMAIN_FS_SANDBOX_MODE_DEFAULT) {
> +            virBufferAsprintf(&binaryBuf, "<sandbox mode='%s'/>\n",
> +                              virDomainFSSandboxModeTypeToString(def->sandbox));
> +        }
> +
>          if (def->posix_lock != VIR_TRISTATE_SWITCH_ABSENT) {
>              virBufferAsprintf(&lockAttrBuf, " posix='%s'",
>                                virTristateSwitchTypeToString(def->posix_lock));
> diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
> index 0b8895bbdf..d77b04847b 100644
> --- a/src/conf/domain_conf.h
> +++ b/src/conf/domain_conf.h
> @@ -846,6 +846,14 @@ typedef enum {
>      VIR_DOMAIN_FS_CACHE_MODE_LAST
>  } virDomainFSCacheMode;
>  
> +typedef enum {
> +    VIR_DOMAIN_FS_SANDBOX_MODE_DEFAULT = 0,
> +    VIR_DOMAIN_FS_SANDBOX_MODE_NAMESPACE,
> +    VIR_DOMAIN_FS_SANDBOX_MODE_CHROOT,
> +
> +    VIR_DOMAIN_FS_SANDBOX_MODE_LAST
> +} virDomainFSSandboxMode;
> +
>  struct _virDomainFSDef {
>      int type;
>      int fsdriver; /* enum virDomainFSDriverType */
> @@ -870,6 +878,7 @@ struct _virDomainFSDef {
>      virDomainFSCacheMode cache;
>      virTristateSwitch posix_lock;
>      virTristateSwitch flock;
> +    virDomainFSSandboxMode sandbox;

validation check rejecting sandbox modes for 9p fs is missing

>      virDomainVirtioOptionsPtr virtio;
>      virObjectPtr privateData;
>  };




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