Re: /proc/pid/fd && anon_inode_fops

[Oleg Nesterov <oleg@redhat.com>]

On 08/26, Oleg Nesterov wrote:
>
> Not sure we really want this in this case but
>
> 	$ ./ls /proc/self/fd
> 	0  1  2  3
>
> still works, I guess thanks to proc_fd_permission().

And btw. Whatever we do, shouldn't we change proc_fd_permission()?

/proc/self is actually /proc/tgid, this means that the task_pid()
check can't help if a sub-thread uses /proc/self.

Oleg.

--- x/fs/proc/fd.c
+++ x/fs/proc/fd.c
@@ -288,7 +288,7 @@ int proc_fd_permission(struct inode *ino
 	int rv = generic_permission(inode, mask);
 	if (rv == 0)
 		return 0;
-	if (task_pid(current) == proc_pid(inode))
+	if (task_tgid(current) == proc_pid(inode))
 		rv = 0;
 	return rv;
 }