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 5b31170..0389981 100644
--- a/fs/sdcardfs/inode.c
+++ b/fs/sdcardfs/inode.c
@@ -745,6 +745,11 @@
* 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) {
@@ -770,8 +775,6 @@
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);