virtio-9p: Security model for chmod

Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
diff --git a/hw/file-op-9p.h b/hw/file-op-9p.h
index 307bd1e..1c8d89b 100644
--- a/hw/file-op-9p.h
+++ b/hw/file-op-9p.h
@@ -49,7 +49,7 @@
 {
     int (*lstat)(FsContext *, const char *, struct stat *);
     ssize_t (*readlink)(FsContext *, const char *, char *, size_t);
-    int (*chmod)(FsContext *, const char *, mode_t);
+    int (*chmod)(FsContext *, const char *, FsCred *);
     int (*chown)(FsContext *, const char *, uid_t, gid_t);
     int (*mknod)(FsContext *, const char *, mode_t, dev_t);
     int (*mksock)(FsContext *, const char *);
diff --git a/hw/virtio-9p-local.c b/hw/virtio-9p-local.c
index 056b4ba..9bdcf02 100644
--- a/hw/virtio-9p-local.c
+++ b/hw/virtio-9p-local.c
@@ -129,9 +129,14 @@
     return writev(fd, iov, iovcnt);
 }
 
-static int local_chmod(FsContext *ctx, const char *path, mode_t mode)
+static int local_chmod(FsContext *fs_ctx, const char *path, FsCred *credp)
 {
-    return chmod(rpath(ctx, path), mode);
+    if (fs_ctx->fs_sm == SM_MAPPED) {
+        return local_set_xattr(rpath(fs_ctx, path), credp);
+    } else if (fs_ctx->fs_sm == SM_PASSTHROUGH) {
+        return chmod(rpath(fs_ctx, path), credp->fc_mode);
+    }
+    return -1;
 }
 
 static int local_mknod(FsContext *ctx, const char *path, mode_t mode, dev_t dev)
@@ -253,8 +258,6 @@
 
 static int local_fsync(FsContext *ctx, int fd)
 {
-    if (0) /* Just to supress the warning. Will be removed in next patch. */
-        (void)local_set_xattr(NULL, NULL);
     return fsync(fd);
 }
 
diff --git a/hw/virtio-9p.c b/hw/virtio-9p.c
index a7ba4b6..24291f4 100644
--- a/hw/virtio-9p.c
+++ b/hw/virtio-9p.c
@@ -154,7 +154,10 @@
 
 static int v9fs_do_chmod(V9fsState *s, V9fsString *path, mode_t mode)
 {
-    return s->ops->chmod(&s->ctx, path->data, mode);
+    FsCred cred;
+    cred_init(&cred);
+    cred.fc_mode = mode;
+    return s->ops->chmod(&s->ctx, path->data, &cred);
 }
 
 static int v9fs_do_mknod(V9fsState *s, V9fsString *path, mode_t mode, dev_t dev)