virtio-9p: Use layered xattr approach

We would need this to make sure we handle the mapped
security model correctly for different xattr names.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>

1 files changed, 101 insertions, 0 deletions

diff --git a/hw/virtio-9p-xattr-user.c b/hw/virtio-9p-xattr-user.c
new file mode 100644
index 0000000..b14dbb9
--- /dev/null
+++ b/hw/virtio-9p-xattr-user.c
@@ -0,0 +1,101 @@
+/*
+ * Virtio 9p user. xattr callback
+ *
+ * Copyright IBM, Corp. 2010
+ *
+ * Authors:
+ * Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ *
+ */
+
+#include <sys/types.h>
+#include "virtio.h"
+#include "virtio-9p.h"
+#include "file-op-9p.h"
+#include "virtio-9p-xattr.h"
+
+
+static ssize_t mp_user_getxattr(FsContext *ctx, const char *path,
+                                const char *name, void *value, size_t size)
+{
+    if (strncmp(name, "user.virtfs.", 12) == 0) {
+        /*
+         * Don't allow fetch of user.virtfs namesapce
+         * in case of mapped security
+         */
+        errno = ENOATTR;
+        return -1;
+    }
+    return lgetxattr(rpath(ctx, path), name, value, size);
+}
+
+static ssize_t mp_user_listxattr(FsContext *ctx, const char *path,
+                                 char *name, void *value, size_t size)
+{
+    int name_size = strlen(name) + 1;
+    if (strncmp(name, "user.virtfs.", 12) == 0) {
+        /*
+         * Don't allow fetch of user.virtfs namesapce
+         * in case of mapped security
+         */
+        return 0;
+    }
+    if (!value) {
+        return name_size;
+    }
+
+    if (size < name_size) {
+        errno = ERANGE;
+        return -1;
+    }
+
+    strncpy(value, name, name_size);
+    return name_size;
+}
+
+static int mp_user_setxattr(FsContext *ctx, const char *path, const char *name,
+                            void *value, size_t size, int flags)
+{
+    if (strncmp(name, "user.virtfs.", 12) == 0) {
+        /*
+         * Don't allow fetch of user.virtfs namesapce
+         * in case of mapped security
+         */
+        errno = EACCES;
+        return -1;
+    }
+    return lsetxattr(rpath(ctx, path), name, value, size, flags);
+}
+
+static int mp_user_removexattr(FsContext *ctx,
+                               const char *path, const char *name)
+{
+    if (strncmp(name, "user.virtfs.", 12) == 0) {
+        /*
+         * Don't allow fetch of user.virtfs namesapce
+         * in case of mapped security
+         */
+        errno = EACCES;
+        return -1;
+    }
+    return lremovexattr(rpath(ctx, path), name);
+}
+
+XattrOperations mapped_user_xattr = {
+    .name = "user.",
+    .getxattr = mp_user_getxattr,
+    .setxattr = mp_user_setxattr,
+    .listxattr = mp_user_listxattr,
+    .removexattr = mp_user_removexattr,
+};
+
+XattrOperations passthrough_user_xattr = {
+    .name = "user.",
+    .getxattr = pt_getxattr,
+    .setxattr = pt_setxattr,
+    .listxattr = pt_listxattr,
+    .removexattr = pt_removexattr,
+};