ANDROID: sdcardfs: Allow non-owners to touch

This modifies the permission checks in setattr to
allow for non-owners to modify the timestamp of
files to things other than the current time.
This still requires write access, as enforced by
the permission call, but relaxes the requirement
that the caller must be the owner, allowing those
with group permissions to change it as well.

Signed-off-by: Daniel Rosenberg <drosen@google.com>
Bug: 11118565
Change-Id: Ied31f0cce2797675c7ef179eeb4e088185adcbad

diff --git a/fs/sdcardfs/inode.c b/fs/sdcardfs/inode.c
index b5a43c11a00c3cab34690fde48985b0d64db8a39..4bafdf78335484aae3ecae0cec64293bb5de81bc 100644 (file)
--- a/fs/sdcardfs/inode.c
+++ b/fs/sdcardfs/inode.c
@@ -748,6 +748,11 @@ static int sdcardfs_setattr(struct vfsmount *mnt, struct dentry *dentry, struct
         * this user can change the lower inode: that should happen when
         * calling notify_change on the lower inode.
         */
+       /* prepare our own lower struct iattr (with the lower file) */
+       memcpy(&lower_ia, ia, sizeof(lower_ia));
+       /* Allow touch updating timestamps. A previous permission check ensures
+        * we have write access. Changes to mode, owner, and group are ignored*/
+       ia->ia_valid |= ATTR_FORCE;
        err = setattr_prepare(&tmp_d, ia);
 
        if (!err) {
@@ -773,8 +778,6 @@ static int sdcardfs_setattr(struct vfsmount *mnt, struct dentry *dentry, struct
        lower_mnt = lower_path.mnt;
        lower_inode = sdcardfs_lower_inode(inode);
 
-       /* prepare our own lower struct iattr (with the lower file) */
-       memcpy(&lower_ia, ia, sizeof(lower_ia));
        if (ia->ia_valid & ATTR_FILE)
                lower_ia.ia_file = sdcardfs_lower_file(ia->ia_file);