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[3.11.y.z,extended,stable] Patch "target/tcm_fc: Fix use-after-free of ft_tpg" has been added to staging queue

Message ID 1398072798-18071-1-git-send-email-luis.henriques@canonical.com
State New
Headers show

Commit Message

Luis Henriques April 21, 2014, 9:33 a.m. UTC
This is a note to let you know that I have just added a patch titled

    target/tcm_fc: Fix use-after-free of ft_tpg

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

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From a25396406013b92aa236ad7372409d060567fa64 Mon Sep 17 00:00:00 2001
From: Andy Grover <agrover@redhat.com>
Date: Fri, 4 Apr 2014 16:44:37 -0700
Subject: target/tcm_fc: Fix use-after-free of ft_tpg

commit 2c42be2dd4f6586728dba5c4e197afd5cfaded78 upstream.

ft_del_tpg checks tpg->tport is set before unlinking the tpg from the
tport when the tpg is being removed. Set this pointer in ft_tport_create,
or the unlinking won't happen in ft_del_tpg and tport->tpg will reference
a deleted object.

This patch sets tpg->tport in ft_tport_create, because that's what
ft_del_tpg checks, and is the only way to get back to the tport to
clear tport->tpg.

The bug was occuring when:

- lport created, tport (our per-lport, per-provider context) is
  allocated.
  tport->tpg = NULL
- tpg created
- a PRLI is received. ft_tport_create is called, tpg is found and
  tport->tpg is set
- tpg removed. ft_tpg is freed in ft_del_tpg. Since tpg->tport was not
  set, tport->tpg is not cleared and points at freed memory
- Future calls to ft_tport_create return tport via first conditional,
  instead of searching for new tpg by calling ft_lport_find_tpg.
  tport->tpg is still invalid, and will access freed memory.

see https://bugzilla.redhat.com/show_bug.cgi?id=1071340

Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---
 drivers/target/tcm_fc/tfc_sess.c | 1 +
 1 file changed, 1 insertion(+)

--
1.9.1
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Patch

diff --git a/drivers/target/tcm_fc/tfc_sess.c b/drivers/target/tcm_fc/tfc_sess.c
index 4859505..639fdb3 100644
--- a/drivers/target/tcm_fc/tfc_sess.c
+++ b/drivers/target/tcm_fc/tfc_sess.c
@@ -68,6 +68,7 @@  static struct ft_tport *ft_tport_create(struct fc_lport *lport)

 	if (tport) {
 		tport->tpg = tpg;
+		tpg->tport = tport;
 		return tport;
 	}