[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]

[libvirt] [PATCH v3] Added new attribute mount_security to filesystem element



This patch introduces new attribute to filesystem element
to support customizable security for mount type.
Valid mount_security are: passthrough and mapped.

Usage:
	<filesystem type='mount' mount_security='passthrough'>
	<source dir='/export/to/guest'/>
	<target dir='mount_tag'/>
	</filesystem>

Here is the detailed explanation on these security models:

Security model: mapped
----------------------

Fileserver intercepts and maps all the file object create requests.
Files on the fileserver will be created with Fileserver's user credentials
and the
client-user's credentials are stored in extended attributes.
During getattr() server extracts the client-user's credentials from extended
attributes and sends to the client.

This adds a great deal of security in the cloud environments where the
guest's(client) user space is kept completely isolated from host's user
space.


Security model : passthrough
----------------------------

In this security model, Fileserver passes down all requests to the
underlying filesystem. File system objects on the fileserver will be created
with client-user's credentials. This is done by setting setuid()/setgid()
during creation or chmod/chown after file creation. At the end of create
protocol
request, files on the fileserver will be owned by cleint-user's uid/gid.
This model mimic's current NFSv3 level of security.

Note: This patch is based on Daniel's patch to support 9pfs.
It shall be applied after applying Daniel's patch to support 9pfs.

v3:
- QEMU cmdline still uses security_model, changes done by mistake reverted.

Signed-off-by: Harsh Prateek Bora <harsh linux vnet ibm com>
---
 docs/schemas/domain.rng |    6 ++++++
 src/conf/domain_conf.c  |   29 +++++++++++++++++++++++++++--
 src/conf/domain_conf.h  |   10 ++++++++++
 src/qemu/qemu_conf.c    |    9 +++++++--
 4 files changed, 50 insertions(+), 4 deletions(-)

diff --git a/docs/schemas/domain.rng b/docs/schemas/domain.rng
index ccb8cf3..36eec63 100644
--- a/docs/schemas/domain.rng
+++ b/docs/schemas/domain.rng
@@ -761,6 +761,12 @@
       </choice>
       <optional>
         <ref name="address"/>
+        <attribute name="mount_security">
+        <choice>
+          <value>passthrough</value>
+          <value>mapped</value>
+        </choice>
+        </attribute>
       </optional>
     </element>
   </define>
diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index e05d5d7..ece6937 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -161,6 +161,11 @@ VIR_ENUM_IMPL(virDomainFS, VIR_DOMAIN_FS_TYPE_LAST,
               "file",
               "template")
 
+VIR_ENUM_IMPL(virDomainFSMountSecurity, VIR_DOMAIN_FS_SECURITY_LAST,
+              "passthrough",
+              "mapped")
+
+
 VIR_ENUM_IMPL(virDomainNet, VIR_DOMAIN_NET_TYPE_LAST,
               "user",
               "ethernet",
@@ -1847,6 +1852,7 @@ virDomainFSDefParseXML(xmlNodePtr node,
     char *type = NULL;
     char *source = NULL;
     char *target = NULL;
+    char *mount_security = NULL;
 
     if (VIR_ALLOC(def) < 0) {
         virReportOOMError();
@@ -1864,6 +1870,17 @@ virDomainFSDefParseXML(xmlNodePtr node,
         def->type = VIR_DOMAIN_FS_TYPE_MOUNT;
     }
 
+    mount_security = virXMLPropString(node, "mount_security");
+    if (mount_security) {
+        if ((def->mount_security = virDomainFSMountSecurityTypeFromString(mount_security)) < 0) {
+            virDomainReportError(VIR_ERR_INTERNAL_ERROR,
+                                 _("unknown mount security '%s'"), mount_security);
+            goto error;
+        }
+    } else {
+        def->mount_security = VIR_DOMAIN_FS_SECURITY_PASSTHROUGH;
+    }
+
     cur = node->children;
     while (cur != NULL) {
         if (cur->type == XML_ELEMENT_NODE) {
@@ -5602,6 +5619,7 @@ virDomainFSDefFormat(virBufferPtr buf,
                      int flags)
 {
     const char *type = virDomainFSTypeToString(def->type);
+    const char *mount_sec = virDomainFSMountSecurityTypeToString(def->mount_security);
 
     if (!type) {
         virDomainReportError(VIR_ERR_INTERNAL_ERROR,
@@ -5609,9 +5627,16 @@ virDomainFSDefFormat(virBufferPtr buf,
         return -1;
     }
 
+   if (!mount_sec) {
+        virDomainReportError(VIR_ERR_INTERNAL_ERROR,
+                             _("unexpected mount security %d"), def->mount_security);
+        return -1;
+    }
+
+
     virBufferVSprintf(buf,
-                      "    <filesystem type='%s'>\n",
-                      type);
+                      "    <filesystem type='%s' mount_security='%s'>\n",
+                      type, mount_sec);
 
     if (def->src) {
         switch (def->type) {
diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index 7195c04..3463942 100644
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -236,10 +236,19 @@ enum virDomainFSType {
     VIR_DOMAIN_FS_TYPE_LAST
 };
 
+/* Filesystem mount security model  */
+enum virDomainFSMountSecurity {
+    VIR_DOMAIN_FS_SECURITY_PASSTHROUGH,
+    VIR_DOMAIN_FS_SECURITY_MAPPED,
+
+    VIR_DOMAIN_FS_SECURITY_LAST
+};
+
 typedef struct _virDomainFSDef virDomainFSDef;
 typedef virDomainFSDef *virDomainFSDefPtr;
 struct _virDomainFSDef {
     int type;
+    int mount_security;
     char *src;
     char *dst;
     unsigned int readonly : 1;
@@ -1167,6 +1176,7 @@ VIR_ENUM_DECL(virDomainDiskErrorPolicy)
 VIR_ENUM_DECL(virDomainController)
 VIR_ENUM_DECL(virDomainControllerModel)
 VIR_ENUM_DECL(virDomainFS)
+VIR_ENUM_DECL(virDomainFSMountSecurity)
 VIR_ENUM_DECL(virDomainNet)
 VIR_ENUM_DECL(virDomainChrDevice)
 VIR_ENUM_DECL(virDomainChrChannelTarget)
diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c
index 18a302a..53ebe5a 100644
--- a/src/qemu/qemu_conf.c
+++ b/src/qemu/qemu_conf.c
@@ -2014,6 +2014,7 @@ qemuAssignDeviceAliases(virDomainDefPtr def, unsigned long long qemuCmdFlags)
         if (virAsprintf(&def->fss[i]->info.alias, "fs%d", i) < 0)
             goto no_memory;
     }
+
     for (i = 0; i < def->nsounds ; i++) {
         if (virAsprintf(&def->sounds[i]->info.alias, "sound%d", i) < 0)
             goto no_memory;
@@ -2783,11 +2784,15 @@ char *qemuBuildFSStr(virDomainFSDefPtr fs,
 
     if (fs->type != VIR_DOMAIN_FS_TYPE_MOUNT) {
         qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
-                        _("can only passthrough directories"));
+                        _("only supports mount filesystem type"));
         goto error;
     }
 
-    virBufferAddLit(&opt, "local,security_model=passthrough");
+    virBufferAddLit(&opt, "local");
+    if (fs->mount_security == VIR_DOMAIN_FS_SECURITY_PASSTHROUGH)
+        virBufferAddLit(&opt, ",security_model=passthrough");
+    else if (fs->mount_security == VIR_DOMAIN_FS_SECURITY_MAPPED)
+        virBufferAddLit(&opt, ",security_model=mapped");
     virBufferVSprintf(&opt, ",id=%s%s", QEMU_FSDEV_HOST_PREFIX, fs->info.alias);
     virBufferVSprintf(&opt, ",path=%s", fs->src);
 
-- 
1.7.1.1


[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]