linux-kernel - [PATCH 4.4 117/135] net: alx: fix race condition in alx

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20200629155309.2495516-118-sashal@kernel.org>
Date:   Mon, 29 Jun 2020 11:52:51 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Zekun Shen <bruceshenzk@...il.com>,
        "David S . Miller" <davem@...emloft.net>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.4 117/135] net: alx: fix race condition in alx_remove

From: Zekun Shen <bruceshenzk@...il.com>

[ Upstream commit e89df5c4322c1bf495f62d74745895b5fd2a4393 ]

There is a race condition exist during termination. The path is
alx_stop and then alx_remove. An alx_schedule_link_check could be called
before alx_stop by interrupt handler and invoke alx_link_check later.
Alx_stop frees the napis, and alx_remove cancels any pending works.
If any of the work is scheduled before termination and invoked before
alx_remove, a null-ptr-deref occurs because both expect alx->napis[i].

This patch fix the race condition by moving cancel_work_sync functions
before alx_free_napis inside alx_stop. Because interrupt handler can call
alx_schedule_link_check again, alx_free_irq is moved before
cancel_work_sync calls too.

Signed-off-by: Zekun Shen <bruceshenzk@...il.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/net/ethernet/atheros/alx/main.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/atheros/alx/main.c b/drivers/net/ethernet/atheros/alx/main.c
index df54475d163bf..43bcc19c90680 100644
--- a/drivers/net/ethernet/atheros/alx/main.c
+++ b/drivers/net/ethernet/atheros/alx/main.c
@@ -872,8 +872,12 @@ static int __alx_open(struct alx_priv *alx, bool resume)
 
 static void __alx_stop(struct alx_priv *alx)
 {
-	alx_halt(alx);
 	alx_free_irq(alx);
+
+	cancel_work_sync(&alx->link_check_wk);
+	cancel_work_sync(&alx->reset_wk);
+
+	alx_halt(alx);
 	alx_free_rings(alx);
 }
 
@@ -1406,9 +1410,6 @@ static void alx_remove(struct pci_dev *pdev)
 	struct alx_priv *alx = pci_get_drvdata(pdev);
 	struct alx_hw *hw = &alx->hw;
 
-	cancel_work_sync(&alx->link_check_wk);
-	cancel_work_sync(&alx->reset_wk);
-
 	/* restore permanent mac address */
 	alx_set_macaddr(hw, hw->perm_addr);
 
-- 
2.25.1