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Commit e0b057b4 authored by Tetsuo Handa's avatar Tetsuo Handa Committed by James Morris
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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: default avatarTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: default avatarJames Morris <jmorris@namei.org>
parent 6afcb3b7

security/tomoyo/common.c

+1 −0
Original line number Diff line number Diff line
@@ -2591,6 +2591,7 @@ ssize_t tomoyo_write_control(struct tomoyo_io_buffer *head, 
		return -EFAULT;

	if (mutex_lock_interruptible(&head->io_sem))

		return -EINTR;

	head->read_user_buf_avail = 0;

	idx = tomoyo_read_lock();

	/* Read a line and dispatch it to the policy handler. */

	while (avail_len > 0) {