Re: [syzbot] Re: [syzbot] [tomoyo?] WARNING in tomoyo_write_control

[syzbot <syzbot+7536f77535e5210a5c76@syzkaller.appspotmail.com>]

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***

Subject: Re: [syzbot] [tomoyo?] WARNING in tomoyo_write_control
Author: lizhi.xu@windriver.com

User input a too large avail length 0xfffffdeful.

#syz test

diff --git a/security/tomoyo/common.c b/security/tomoyo/common.c
index 5c7b059a332a..d25752eb8790 100644
--- a/security/tomoyo/common.c
+++ b/security/tomoyo/common.c
@@ -2656,6 +2656,9 @@ ssize_t tomoyo_write_control(struct tomoyo_io_buffer *head,
 		return -EINVAL;
 	if (mutex_lock_interruptible(&head->io_sem))
 		return -EINTR;
+	if (avail_len << PAGE_SHIFT > MAX_PAGE_ORDER)
+		return -EINVAL;
+
 	cp0 = head->write_buf;
 	head->read_user_buf_avail = 0;
 	idx = tomoyo_read_lock();