[libvirt] [PATCH] qemu: Forbid slashes in shmem name

Martin Kletzander mkletzan at redhat.com
Thu Feb 2 13:14:14 UTC 2017


With that users could access files outside /dev/shm.  That itself
isn't a security problem, but might cause some errors we want to
avoid.  So let's forbid slashes as we do with domain and volume names
and also mention that in the schema.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1395496

Signed-off-by: Martin Kletzander <mkletzan at redhat.com>
---
 docs/schemas/domaincommon.rng |  6 +++++-
 src/qemu/qemu_process.c       | 23 +++++++++++++++++++++++
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
index cc6e0d0c0d65..00cdc93bca59 100644
--- a/docs/schemas/domaincommon.rng
+++ b/docs/schemas/domaincommon.rng
@@ -3598,7 +3598,11 @@

   <define name="shmem">
     <element name="shmem">
-      <attribute name="name"/>
+      <attribute name="name">
+        <data type="string">
+          <param name="pattern">[^/]*</param>
+        </data>
+      </attribute>
       <interleave>
         <optional>
           <element name="model">
diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index 184440dc1af6..0f63668100a6 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -4586,6 +4586,26 @@ qemuProcessStartValidateVideo(virDomainObjPtr vm,


 static int
+qemuProcessStartValidateShmem(virDomainObjPtr vm)
+{
+    size_t i;
+
+    for (i = 0; i < vm->def->nshmems; i++) {
+        virDomainShmemDefPtr shmem = vm->def->shmems[i];
+
+        if (strchr(shmem->name, '/')) {
+            virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                           _("shmem name '%s' must not contain '/'"),
+                           shmem->name);
+            return -1;
+        }
+    }
+
+    return 0;
+}
+
+
+static int
 qemuProcessStartValidateXML(virQEMUDriverPtr driver,
                             virDomainObjPtr vm,
                             virQEMUCapsPtr qemuCaps,
@@ -4661,6 +4681,9 @@ qemuProcessStartValidate(virQEMUDriverPtr driver,
     if (qemuProcessStartValidateVideo(vm, qemuCaps) < 0)
         return -1;

+    if (qemuProcessStartValidateShmem(vm) < 0)
+        return -1;
+
     VIR_DEBUG("Checking for any possible (non-fatal) issues");

     qemuProcessStartWarnShmem(vm);
-- 
2.11.0




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