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authorMiklos Szeredi <mszeredi@redhat.com>2016-07-04 16:49:48 +0200
committerMiklos Szeredi <mszeredi@redhat.com>2016-07-04 16:49:48 +0200
commitb99c2d913810e56682a538c9f2394d76fca808f8 (patch)
tree01c7236cc00eafd5a9f72481ef31c5e17d34783a
parenta99cde438de0c4c0cecc1d1af1a55a75b10bfdef (diff)
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ovl: handle ATTR_KILL*
Before 4bacc9c9234c ("overlayfs: Make f_path...") file->f_path pointed to the underlying file, hence suid/sgid removal on write worked fine. After that patch file->f_path pointed to the overlay file, and the file mode bits weren't copied to overlay_inode->i_mode. So the suid/sgid removal simply stopped working. The fix is to copy the mode bits, but then ovl_setattr() needs to clear ATTR_MODE to avoid the BUG() in notify_change(). So do this first, then in the next patch copy the mode. Reported-by: Eryu Guan <eguan@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Fixes: 4bacc9c9234c ("overlayfs: Make f_path always point to the overlay and f_inode to the underlay") Cc: <stable@vger.kernel.org>
-rw-r--r--fs/overlayfs/inode.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index c831c2e5f803..1233992a7c47 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -80,6 +80,9 @@ int ovl_setattr(struct dentry *dentry, struct iattr *attr)
goto out_drop_write;
}
+ if (attr->ia_valid & (ATTR_KILL_SUID|ATTR_KILL_SGID))
+ attr->ia_valid &= ~ATTR_MODE;
+
inode_lock(upperdentry->d_inode);
err = notify_change(upperdentry, attr, NULL);
if (!err)