On Tue, 2020-11-17 at 15:36 -0800, Linus Torvalds wrote: > Another alternative is to change the policy and say "any write-only > open gets turned into a read-write open". > > But it needs to be done at *OPEN* time, not randomly afterwards by > just lying to the 'struct file'.
The ima_file_check hook is at open, but it is immediately after vfs_open(). Only after the file is opened can we determine if the file is in policy. If the file was originally opened without read permission, a new file instance (dentry_open) with read permission is opened. Would limiting opening a new file instance with read permission to just the ima_file_check hook be acceptable? thanks, Mimi
