hyperv: Escape WQL queries

The code was vulnerable to SQL injection. Likely not a security issue due to
WMI SQL and other constraints but still lame. For example:

  virsh # dominfo \"
  error: failed to get domain '"'
  error: internal error: SOAP fault during enumeration: code 's:Sender', subcode
  'n:CannotProcessFilter', reason 'The data source could not process the filter.
  The filter might be missing or it might be invalid. Change the filter and try
  the request again.  ', detail 'The WS-Management service cannot process the
  request. The WQL query is invalid. '

This commit fixes the Hyper-V driver by escaping all WMI SQL string parameters.

The same command with the fix:

  virsh # dominfo \"
  error: failed to get domain '"'
  error: Domain not found: No domain with name "

Signed-off-by: Ladi Prosek <lprosek@redhat.com>

src/hyperv/hyperv_driver.c

@@ -301,7 +301,7 @@ hypervNodeGetInfo(virConnectPtr conn, virNodeInfoPtr info)
     }
 
     /* Get Win32_Processor list */
-    virBufferAsprintf(&query,
+    virBufferEscapeSQL(&query,
                        "associators of "
                        "{Win32_ComputerSystem.Name=\"%s\"} "
                        "where AssocClass = Win32_ComputerSystemProcessor "
@@ -493,7 +493,7 @@ hypervDomainLookupByUUID(virConnectPtr conn, const unsigned char *uuid)
     virBufferAddLit(&query, MSVM_COMPUTERSYSTEM_WQL_SELECT);
     virBufferAddLit(&query, "where ");
     virBufferAddLit(&query, MSVM_COMPUTERSYSTEM_WQL_VIRTUAL);
-    virBufferAsprintf(&query, "and Name = \"%s\"", uuid_string);
+    virBufferEscapeSQL(&query, "and Name = \"%s\"", uuid_string);
 
     if (hypervGetMsvmComputerSystemList(priv, &query, &computerSystem) < 0)
         goto cleanup;
@@ -525,7 +525,7 @@ hypervDomainLookupByName(virConnectPtr conn, const char *name)
     virBufferAddLit(&query, MSVM_COMPUTERSYSTEM_WQL_SELECT);
     virBufferAddLit(&query, "where ");
     virBufferAddLit(&query, MSVM_COMPUTERSYSTEM_WQL_VIRTUAL);
-    virBufferAsprintf(&query, "and ElementName = \"%s\"", name);
+    virBufferEscapeSQL(&query, "and ElementName = \"%s\"", name);
 
     if (hypervGetMsvmComputerSystemList(priv, &query, &computerSystem) < 0)
         goto cleanup;
@@ -673,7 +673,7 @@ hypervDomainGetInfo(virDomainPtr domain, virDomainInfoPtr info)
         goto cleanup;
 
     /* Get Msvm_VirtualSystemSettingData */
-    virBufferAsprintf(&query,
+    virBufferEscapeSQL(&query,
                        "associators of "
                        "{Msvm_ComputerSystem.CreationClassName=\"Msvm_ComputerSystem\","
                        "Name=\"%s\"} "
@@ -695,7 +695,7 @@ hypervDomainGetInfo(virDomainPtr domain, virDomainInfoPtr info)
     }
 
     /* Get Msvm_ProcessorSettingData */
-    virBufferAsprintf(&query,
+    virBufferEscapeSQL(&query,
                        "associators of "
                        "{Msvm_VirtualSystemSettingData.InstanceID=\"%s\"} "
                        "where AssocClass = Msvm_VirtualSystemSettingDataComponent "
@@ -716,7 +716,7 @@ hypervDomainGetInfo(virDomainPtr domain, virDomainInfoPtr info)
     }
 
     /* Get Msvm_MemorySettingData */
-    virBufferAsprintf(&query,
+    virBufferEscapeSQL(&query,
                        "associators of "
                        "{Msvm_VirtualSystemSettingData.InstanceID=\"%s\"} "
                        "where AssocClass = Msvm_VirtualSystemSettingDataComponent "
@@ -810,7 +810,7 @@ hypervDomainGetXMLDesc(virDomainPtr domain, unsigned int flags)
         goto cleanup;
 
     /* Get Msvm_VirtualSystemSettingData */
-    virBufferAsprintf(&query,
+    virBufferEscapeSQL(&query,
                        "associators of "
                        "{Msvm_ComputerSystem.CreationClassName=\"Msvm_ComputerSystem\","
                        "Name=\"%s\"} "
@@ -832,7 +832,7 @@ hypervDomainGetXMLDesc(virDomainPtr domain, unsigned int flags)
     }
 
     /* Get Msvm_ProcessorSettingData */
-    virBufferAsprintf(&query,
+    virBufferEscapeSQL(&query,
                        "associators of "
                        "{Msvm_VirtualSystemSettingData.InstanceID=\"%s\"} "
                        "where AssocClass = Msvm_VirtualSystemSettingDataComponent "
@@ -853,7 +853,7 @@ hypervDomainGetXMLDesc(virDomainPtr domain, unsigned int flags)
     }
 
     /* Get Msvm_MemorySettingData */
-    virBufferAsprintf(&query,
+    virBufferEscapeSQL(&query,
                        "associators of "
                        "{Msvm_VirtualSystemSettingData.InstanceID=\"%s\"} "
                        "where AssocClass = Msvm_VirtualSystemSettingDataComponent "
@@ -1397,7 +1397,7 @@ hypervDomainSendKey(virDomainPtr domain, unsigned int codeset,
     if (hypervMsvmComputerSystemFromDomain(domain, &computerSystem) < 0)
         goto cleanup;
 
-    virBufferAsprintf(&query,
+    virBufferEscapeSQL(&query,
             "associators of "
             "{Msvm_ComputerSystem.CreationClassName=\"Msvm_ComputerSystem\","
             "Name=\"%s\"} "
@@ -1534,7 +1534,7 @@ hypervDomainSetMemoryFlags(virDomainPtr domain, unsigned long memory,
         }
 
         virBufferAddLit(&eprQuery, MSVM_COMPUTERSYSTEM_WQL_SELECT);
-        virBufferAsprintf(&eprQuery, "where Name = \"%s\"", uuid_string);
+        virBufferEscapeSQL(&eprQuery, "where Name = \"%s\"", uuid_string);
 
         if (hypervAddEprParam(params, "ComputerSystem", priv, &eprQuery,
                     Msvm_ComputerSystem_WmiInfo) < 0)

src/hyperv/hyperv_wmi.c

@@ -895,7 +895,7 @@ hypervInvokeMethod(hypervPrivate *priv, hypervInvokeParamsListPtr params,
          */
         while (!completed && timeout >= 0) {
             virBufferAddLit(&query, MSVM_CONCRETEJOB_WQL_SELECT);
-            virBufferAsprintf(&query, "where InstanceID = \"%s\"", instanceID);
+            virBufferEscapeSQL(&query, "where InstanceID = \"%s\"", instanceID);
 
             if (hypervGetMsvmConcreteJobList(priv, &query, &job) < 0
                     || job == NULL)

src/libvirt_private.syms

@@ -1384,6 +1384,7 @@ virBufferEscapeN;
 virBufferEscapeRegex;
 virBufferEscapeSexpr;
 virBufferEscapeShell;
+virBufferEscapeSQL;
 virBufferEscapeString;
 virBufferFreeAndReset;
 virBufferGetIndent;

src/util/virbuffer.c

@@ -574,6 +574,26 @@ virBufferEscapeRegex(virBufferPtr buf,
     virBufferEscape(buf, '\\', "^$.|?*+()[]{}\\", format, str);
 }
 
+
+/**
+ * virBufferEscapeSQL:
+ * @buf: the buffer to append to
+ * @format: a printf like format string but with only one %s parameter
+ * @str: the string argument which needs to be escaped
+ *
+ * Do a formatted print with a single string to a buffer.  The @str is
+ * escaped to prevent SQL injection (format is expected to contain \"%s\").
+ * Auto indentation may be applied.
+ */
+void
+virBufferEscapeSQL(virBufferPtr buf,
+                   const char *format,
+                   const char *str)
+{
+    virBufferEscape(buf, '\\', "'\"\\", format, str);
+}
+
+
 /**
  * virBufferEscape:
  * @buf: the buffer to append to

src/util/virbuffer.h

@@ -93,6 +93,9 @@ void virBufferEscapeSexpr(virBufferPtr buf, const char *format,
 void virBufferEscapeRegex(virBufferPtr buf,
                           const char *format,
                           const char *str);
+void virBufferEscapeSQL(virBufferPtr buf,
+                        const char *format,
+                        const char *str);
 void virBufferEscapeShell(virBufferPtr buf, const char *str);
 void virBufferURIEncodeString(virBufferPtr buf, const char *str);