--- /dev/null
+From 2f03fc340cac9ea1dc63cbf8c93dd2eb0f227815 Mon Sep 17 00:00:00 2001
+From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
+Date: Fri, 1 Mar 2024 22:04:06 +0900
+Subject: tomoyo: fix UAF write bug in tomoyo_write_control()
+
+From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
+
+commit 2f03fc340cac9ea1dc63cbf8c93dd2eb0f227815 upstream.
+
+Since tomoyo_write_control() updates head->write_buf when write()
+of long lines is requested, we need to fetch head->write_buf after
+head->io_sem is held. Otherwise, concurrent write() requests can
+cause use-after-free-write and double-free problems.
+
+Reported-by: Sam Sun <samsun1006219@gmail.com>
+Closes: https://lkml.kernel.org/r/CAEkJfYNDspuGxYx5kym8Lvp--D36CMDUErg4rxfWFJuPbbji8g@mail.gmail.com
+Fixes: bd03a3e4c9a9 ("TOMOYO: Add policy namespace support.")
+Cc: <stable@vger.kernel.org> # Linux 3.1+
+Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ security/tomoyo/common.c | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+--- a/security/tomoyo/common.c
++++ b/security/tomoyo/common.c
+@@ -2657,13 +2657,14 @@ ssize_t tomoyo_write_control(struct tomo
+ {
+ int error = buffer_len;
+ size_t avail_len = buffer_len;
+- char *cp0 = head->write_buf;
++ char *cp0;
+ int idx;
+
+ if (!head->write)
+ return -EINVAL;
+ if (mutex_lock_interruptible(&head->io_sem))
+ return -EINTR;
++ cp0 = head->write_buf;
+ head->read_user_buf_avail = 0;
+ idx = tomoyo_read_lock();
+ /* Read a line and dispatch it to the policy handler. */