[PATCH AUTOSEL 5.4 09/28] watchdog: Fix possible use-after-free in wdt_startup()

[PATCH AUTOSEL 5.4 09/28] watchdog: Fix possible use-after-free in wdt_startup()

[Sasha Levin]

From: Zou Wei <zou_wei@huawei.com>

[ Upstream commit c08a6b31e4917034f0ed0cb457c3bb209576f542 ]

This module's remove path calls del_timer(). However, that function
does not wait until the timer handler finishes. This means that the
timer handler may still be running after the driver's remove function
has finished, which would result in a use-after-free.

Fix by calling del_timer_sync(), which makes sure the timer handler
has finished, and unable to re-schedule itself.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zou Wei <zou_wei@huawei.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/1620716495-108352-1-git-send-email-zou_wei@huawei.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/watchdog/sbc60xxwdt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/watchdog/sbc60xxwdt.c b/drivers/watchdog/sbc60xxwdt.c
index c3151642694c..de1f7add05c3 100644
--- a/drivers/watchdog/sbc60xxwdt.c
+++ b/drivers/watchdog/sbc60xxwdt.c
@@ -146,7 +146,7 @@ static void wdt_startup(void)
 static void wdt_turnoff(void)
 {
 	/* Stop the timer */
-	del_timer(&timer);
+	del_timer_sync(&timer);
 	inb_p(wdt_stop);
 	pr_info("Watchdog timer is now disabled...\n");
 }
-- 
2.30.2

[PATCH AUTOSEL 5.4 10/28] watchdog: sc520_wdt: Fix possible use-after-free in wdt_turnoff()

[Sasha Levin]

From: Zou Wei <zou_wei@huawei.com>

[ Upstream commit 90b7c141132244e8e49a34a4c1e445cce33e07f4 ]

This module's remove path calls del_timer(). However, that function
does not wait until the timer handler finishes. This means that the
timer handler may still be running after the driver's remove function
has finished, which would result in a use-after-free.

Fix by calling del_timer_sync(), which makes sure the timer handler
has finished, and unable to re-schedule itself.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zou Wei <zou_wei@huawei.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/1620716691-108460-1-git-send-email-zou_wei@huawei.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/watchdog/sc520_wdt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/watchdog/sc520_wdt.c b/drivers/watchdog/sc520_wdt.c
index a612128c5f80..57969564c7f9 100644
--- a/drivers/watchdog/sc520_wdt.c
+++ b/drivers/watchdog/sc520_wdt.c
@@ -186,7 +186,7 @@ static int wdt_startup(void)
 static int wdt_turnoff(void)
 {
 	/* Stop the timer */
-	del_timer(&timer);
+	del_timer_sync(&timer);
 
 	/* Stop the watchdog */
 	wdt_config(0);
-- 
2.30.2

[PATCH AUTOSEL 5.4 11/28] watchdog: Fix possible use-after-free by calling del_timer_sync()

[Sasha Levin]

From: Zou Wei <zou_wei@huawei.com>

[ Upstream commit d0212f095ab56672f6f36aabc605bda205e1e0bf ]

This driver's remove path calls del_timer(). However, that function
does not wait until the timer handler finishes. This means that the
timer handler may still be running after the driver's remove function
has finished, which would result in a use-after-free.

Fix by calling del_timer_sync(), which makes sure the timer handler
has finished, and unable to re-schedule itself.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zou Wei <zou_wei@huawei.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Vladimir Zapolskiy <vz@mleia.com>
Link: https://lore.kernel.org/r/1620802676-19701-1-git-send-email-zou_wei@huawei.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/watchdog/lpc18xx_wdt.c | 2 +-
 drivers/watchdog/w83877f_wdt.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/watchdog/lpc18xx_wdt.c b/drivers/watchdog/lpc18xx_wdt.c
index 78cf11c94941..60b6d74f267d 100644
--- a/drivers/watchdog/lpc18xx_wdt.c
+++ b/drivers/watchdog/lpc18xx_wdt.c
@@ -292,7 +292,7 @@ static int lpc18xx_wdt_remove(struct platform_device *pdev)
 	struct lpc18xx_wdt_dev *lpc18xx_wdt = platform_get_drvdata(pdev);
 
 	dev_warn(&pdev->dev, "I quit now, hardware will probably reboot!\n");
-	del_timer(&lpc18xx_wdt->timer);
+	del_timer_sync(&lpc18xx_wdt->timer);
 
 	return 0;
 }
diff --git a/drivers/watchdog/w83877f_wdt.c b/drivers/watchdog/w83877f_wdt.c
index 6eb5185d6ea6..d9addf06b44d 100644
--- a/drivers/watchdog/w83877f_wdt.c
+++ b/drivers/watchdog/w83877f_wdt.c
@@ -166,7 +166,7 @@ static void wdt_startup(void)
 static void wdt_turnoff(void)
 {
 	/* Stop the timer */
-	del_timer(&timer);
+	del_timer_sync(&timer);
 
 	wdt_change(WDT_DISABLE);
 
-- 
2.30.2

[PATCH AUTOSEL 5.4 12/28] watchdog: imx_sc_wdt: fix pretimeout

[Sasha Levin]

From: Stefan Eichenberger <eichest@gmail.com>

[ Upstream commit 854478a381078ee86ae2a7908a934b1ded399130 ]

If the WDIOF_PRETIMEOUT flag is not set when registering the device the
driver will not show the sysfs entries or register the default governor.
By moving the registering after the decision whether pretimeout is
supported this gets fixed.

Signed-off-by: Stefan Eichenberger <eichest@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Dong Aisheng <aisheng.dong@nxp.com>
Link: https://lore.kernel.org/r/20210519080311.142928-1-eichest@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/watchdog/imx_sc_wdt.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/drivers/watchdog/imx_sc_wdt.c b/drivers/watchdog/imx_sc_wdt.c
index e0e62149a6f4..8c9936e78bee 100644
--- a/drivers/watchdog/imx_sc_wdt.c
+++ b/drivers/watchdog/imx_sc_wdt.c
@@ -185,16 +185,12 @@ static int imx_sc_wdt_probe(struct platform_device *pdev)
 	watchdog_stop_on_reboot(wdog);
 	watchdog_stop_on_unregister(wdog);
 
-	ret = devm_watchdog_register_device(dev, wdog);
-	if (ret)
-		return ret;
-
 	ret = imx_scu_irq_group_enable(SC_IRQ_GROUP_WDOG,
 				       SC_IRQ_WDOG,
 				       true);
 	if (ret) {
 		dev_warn(dev, "Enable irq failed, pretimeout NOT supported\n");
-		return 0;
+		goto register_device;
 	}
 
 	imx_sc_wdd->wdt_notifier.notifier_call = imx_sc_wdt_notify;
@@ -205,7 +201,7 @@ static int imx_sc_wdt_probe(struct platform_device *pdev)
 					 false);
 		dev_warn(dev,
 			 "Register irq notifier failed, pretimeout NOT supported\n");
-		return 0;
+		goto register_device;
 	}
 
 	ret = devm_add_action_or_reset(dev, imx_sc_wdt_action,
@@ -215,7 +211,8 @@ static int imx_sc_wdt_probe(struct platform_device *pdev)
 	else
 		dev_warn(dev, "Add action failed, pretimeout NOT supported\n");
 
-	return 0;
+register_device:
+	return devm_watchdog_register_device(dev, wdog);
 }
 
 static int __maybe_unused imx_sc_wdt_suspend(struct device *dev)
-- 
2.30.2

[PATCH AUTOSEL 5.4 13/28] watchdog: iTCO_wdt: Account for rebooting on second timeout

[Sasha Levin]

From: Jan Kiszka <jan.kiszka@siemens.com>

[ Upstream commit cb011044e34c293e139570ce5c01aed66a34345c ]

This was already attempted to fix via 1fccb73011ea: If the BIOS did not
enable TCO SMIs, the timer definitely needs to trigger twice in order to
cause a reboot. If TCO SMIs are on, as well as SMIs in general, we can
continue to assume that the BIOS will perform a reboot on the first
timeout.

QEMU with its ICH9 and related BIOS falls into the former category,
currently taking twice the configured timeout in order to reboot the
machine. For iTCO version that fall under turn_SMI_watchdog_clear_off,
this is also true and was currently only addressed for v1, irrespective
of the turn_SMI_watchdog_clear_off value.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/0b8bb307-d08b-41b5-696c-305cdac6789c@siemens.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/watchdog/iTCO_wdt.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/watchdog/iTCO_wdt.c b/drivers/watchdog/iTCO_wdt.c
index e707c4797f76..08e534fba1bf 100644
--- a/drivers/watchdog/iTCO_wdt.c
+++ b/drivers/watchdog/iTCO_wdt.c
@@ -72,6 +72,8 @@
 #define TCOBASE(p)	((p)->tco_res->start)
 /* SMI Control and Enable Register */
 #define SMI_EN(p)	((p)->smi_res->start)
+#define TCO_EN		(1 << 13)
+#define GBL_SMI_EN	(1 << 0)
 
 #define TCO_RLD(p)	(TCOBASE(p) + 0x00) /* TCO Timer Reload/Curr. Value */
 #define TCOv1_TMR(p)	(TCOBASE(p) + 0x01) /* TCOv1 Timer Initial Value*/
@@ -344,8 +346,12 @@ static int iTCO_wdt_set_timeout(struct watchdog_device *wd_dev, unsigned int t)
 
 	tmrval = seconds_to_ticks(p, t);
 
-	/* For TCO v1 the timer counts down twice before rebooting */
-	if (p->iTCO_version == 1)
+	/*
+	 * If TCO SMIs are off, the timer counts down twice before rebooting.
+	 * Otherwise, the BIOS generally reboots when the SMI triggers.
+	 */
+	if (p->smi_res &&
+	    (SMI_EN(p) & (TCO_EN | GBL_SMI_EN)) != (TCO_EN | GBL_SMI_EN))
 		tmrval /= 2;
 
 	/* from the specs: */
@@ -510,7 +516,7 @@ static int iTCO_wdt_probe(struct platform_device *pdev)
 		 * Disables TCO logic generating an SMI#
 		 */
 		val32 = inl(SMI_EN(p));
-		val32 &= 0xffffdfff;	/* Turn off SMI clearing watchdog */
+		val32 &= ~TCO_EN;	/* Turn off SMI clearing watchdog */
 		outl(val32, SMI_EN(p));
 	}
 
-- 
2.30.2