9pfs: fix memory leak in v9fs_xattrcreate

The 'fs.xattr.value' field in V9fsFidState object doesn't consider the
situation that this field has been allocated previously. Every time, it
will be allocated directly. This leads to a host memory leak issue if
the client sends another Txattrcreate message with the same fid number
before the fid from the previous time got clunked.

Signed-off-by: Li Qiang <liqiang6-s@360.cn>
Reviewed-by: Greg Kurz <groug@kaod.org>
[groug, updated the changelog to indicate how the leak can occur]
Signed-off-by: Greg Kurz <groug@kaod.org>

diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
index bf23b01..66135cf 100644 (file)
--- a/hw/9pfs/9p.c
+++ b/hw/9pfs/9p.c
@@ -3282,6 +3282,7 @@ static void coroutine_fn v9fs_xattrcreate(void *opaque)
     xattr_fidp->fs.xattr.flags = flags;
     v9fs_string_init(&xattr_fidp->fs.xattr.name);
     v9fs_string_copy(&xattr_fidp->fs.xattr.name, &name);
+    g_free(xattr_fidp->fs.xattr.value);
     xattr_fidp->fs.xattr.value = g_malloc0(size);
     err = offset;
     put_fid(pdu, file_fidp);