Commit e0b057b4 authored Oct 21, 2011 by Tetsuo Handa Committed by James Morris Oct 22, 2011

TOMOYO: Fix incomplete read after seek.



Commit f23571e8 "TOMOYO: Copy directly to userspace buffer." introduced
tomoyo_flush() that flushes data to be read as soon as possible.
tomoyo_select_domain() (which is called by write()) enqueues data which meant
to be read by next read(), but previous read()'s read buffer's size was not
cleared. As a result, since 2.6.36, sequence like

   char *cp = "select global-pid=1\n";
   read(fd, buf1, sizeof(buf1));
   write(fd, cp, strlen(cp));
   read(fd, buf2, sizeof(buf2));

causes enqueued data to be flushed to buf1 rather than buf2.
Fix this bug by clearing read buffer's size upon write() request.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>

parent 6afcb3b7

security/tomoyo/common.c

+1 −0

Original line number	Original line	Diff line number	Diff line
	@@ -2591,6 +2591,7 @@ ssize_t tomoyo_write_control(struct tomoyo_io_buffer *head,
	return -EFAULT;		return -EFAULT;
	if (mutex_lock_interruptible(&head->io_sem))		if (mutex_lock_interruptible(&head->io_sem))
	return -EINTR;		return -EINTR;
			head->read_user_buf_avail = 0;
	idx = tomoyo_read_lock();		idx = tomoyo_read_lock();
	/* Read a line and dispatch it to the policy handler. */		/* Read a line and dispatch it to the policy handler. */
	while (avail_len > 0) {		while (avail_len > 0) {

Admin message