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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Andre Przywara <andre.przywara@arm.com>,
	Jernej Skrabec <jernej.skrabec@gmail.com>,
	Alexandre Belloni <alexandre.belloni@bootlin.com>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 15/97] rtc: sun6i: Fix time overflow handling
Date: Mon, 23 May 2022 19:05:19 +0200	[thread overview]
Message-ID: <20220523165814.759854261@linuxfoundation.org> (raw)
In-Reply-To: <20220523165812.244140613@linuxfoundation.org>

From: Andre Przywara <andre.przywara@arm.com>

[ Upstream commit 9f6cd82eca7e91a0d0311242a87c6aa3c2737968 ]

Using "unsigned long" for UNIX timestamps is never a good idea, and
comparing the value of such a variable against U32_MAX does not do
anything useful on 32-bit systems.

Use the proper time64_t type when dealing with timestamps, and avoid
cutting down the time range unnecessarily. This also fixes the flawed
check for the alarm time being too far into the future.

The check for this condition is actually somewhat theoretical, as the
RTC counts till 2033 only anyways, and 2^32 seconds from now is not
before the year 2157 - at which point I hope nobody will be using this
hardware anymore.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220211122643.1343315-4-andre.przywara@arm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/rtc/rtc-sun6i.c | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/drivers/rtc/rtc-sun6i.c b/drivers/rtc/rtc-sun6i.c
index f2818cdd11d8..52b36b7c6129 100644
--- a/drivers/rtc/rtc-sun6i.c
+++ b/drivers/rtc/rtc-sun6i.c
@@ -138,7 +138,7 @@ struct sun6i_rtc_dev {
 	const struct sun6i_rtc_clk_data *data;
 	void __iomem *base;
 	int irq;
-	unsigned long alarm;
+	time64_t alarm;
 
 	struct clk_hw hw;
 	struct clk_hw *int_osc;
@@ -510,10 +510,8 @@ static int sun6i_rtc_setalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
 	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
 	struct rtc_time *alrm_tm = &wkalrm->time;
 	struct rtc_time tm_now;
-	unsigned long time_now = 0;
-	unsigned long time_set = 0;
-	unsigned long time_gap = 0;
-	int ret = 0;
+	time64_t time_now, time_set;
+	int ret;
 
 	ret = sun6i_rtc_gettime(dev, &tm_now);
 	if (ret < 0) {
@@ -528,9 +526,7 @@ static int sun6i_rtc_setalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
 		return -EINVAL;
 	}
 
-	time_gap = time_set - time_now;
-
-	if (time_gap > U32_MAX) {
+	if ((time_set - time_now) > U32_MAX) {
 		dev_err(dev, "Date too far in the future\n");
 		return -EINVAL;
 	}
@@ -539,7 +535,7 @@ static int sun6i_rtc_setalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
 	writel(0, chip->base + SUN6I_ALRM_COUNTER);
 	usleep_range(100, 300);
 
-	writel(time_gap, chip->base + SUN6I_ALRM_COUNTER);
+	writel(time_set - time_now, chip->base + SUN6I_ALRM_COUNTER);
 	chip->alarm = time_set;
 
 	sun6i_rtc_setaie(wkalrm->enabled, chip);
-- 
2.35.1




  parent reply	other threads:[~2022-05-23 17:18 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-23 17:05 [PATCH 5.10 00/97] 5.10.118-rc1 review Greg Kroah-Hartman
2022-05-23 17:05 ` [PATCH 5.10 01/97] usb: gadget: fix race when gadget driver register via ioctl Greg Kroah-Hartman
2022-05-23 17:05 ` [PATCH 5.10 02/97] io_uring: always grab file table for deferred statx Greg Kroah-Hartman
2022-05-23 17:05 ` [PATCH 5.10 03/97] floppy: use a statically allocated error counter Greg Kroah-Hartman
2022-05-23 17:05 ` [PATCH 5.10 04/97] Revert "drm/i915/opregion: check port number bounds for SWSCI display power state" Greg Kroah-Hartman
2022-05-23 17:05 ` [PATCH 5.10 05/97] igc: Remove _I_PHY_ID checking Greg Kroah-Hartman
2022-05-23 17:05 ` [PATCH 5.10 06/97] igc: Remove phy->type checking Greg Kroah-Hartman
2022-05-23 17:05 ` [PATCH 5.10 07/97] igc: Update I226_K device ID Greg Kroah-Hartman
2022-05-25 10:45   ` Pavel Machek
2022-05-26  4:02     ` Neftin, Sasha
2022-05-23 17:05 ` [PATCH 5.10 08/97] rtc: fix use-after-free on device removal Greg Kroah-Hartman
2022-05-23 17:05 ` [PATCH 5.10 09/97] rtc: pcf2127: fix bug when reading alarm registers Greg Kroah-Hartman
2022-05-23 17:05 ` [PATCH 5.10 10/97] um: Cleanup syscall_handler_t definition/cast, fix warning Greg Kroah-Hartman
2022-05-23 17:05 ` [PATCH 5.10 11/97] Input: add bounds checking to input_set_capability() Greg Kroah-Hartman
2022-05-23 17:05 ` [PATCH 5.10 12/97] Input: stmfts - fix reference leak in stmfts_input_open Greg Kroah-Hartman
2022-05-23 17:05 ` [PATCH 5.10 13/97] nvme-pci: add quirks for Samsung X5 SSDs Greg Kroah-Hartman
2022-05-23 17:05 ` [PATCH 5.10 14/97] gfs2: Disable page faults during lockless buffered reads Greg Kroah-Hartman
2022-05-23 17:05 ` Greg Kroah-Hartman [this message]
2022-05-23 17:05 ` [PATCH 5.10 16/97] crypto: stm32 - fix reference leak in stm32_crc_remove Greg Kroah-Hartman
2022-05-23 17:05 ` [PATCH 5.10 17/97] crypto: x86/chacha20 - Avoid spurious jumps to other functions Greg Kroah-Hartman
2022-05-23 17:05 ` [PATCH 5.10 18/97] ALSA: hda/realtek: Enable headset mic on Lenovo P360 Greg Kroah-Hartman
2022-05-23 17:05 ` [PATCH 5.10 19/97] s390/pci: improve zpci_dev reference counting Greg Kroah-Hartman
2022-05-23 17:05 ` [PATCH 5.10 20/97] vhost_vdpa: dont setup irq offloading when irq_num < 0 Greg Kroah-Hartman
2022-05-23 17:05 ` [PATCH 5.10 21/97] tools/virtio: compile with -pthread Greg Kroah-Hartman
2022-05-23 17:05 ` [PATCH 5.10 22/97] nvme-multipath: fix hang when disk goes live over reconnect Greg Kroah-Hartman
2022-05-23 17:05 ` [PATCH 5.10 23/97] rtc: mc146818-lib: Fix the AltCentury for AMD platforms Greg Kroah-Hartman
2022-05-23 17:05 ` [PATCH 5.10 24/97] fs: fix an infinite loop in iomap_fiemap Greg Kroah-Hartman
2022-05-23 17:05 ` [PATCH 5.10 25/97] MIPS: lantiq: check the return value of kzalloc() Greg Kroah-Hartman
2022-05-23 17:05 ` [PATCH 5.10 26/97] drbd: remove usage of list iterator variable after loop Greg Kroah-Hartman
2022-05-23 17:05 ` [PATCH 5.10 27/97] platform/chrome: cros_ec_debugfs: detach log reader wq from devm Greg Kroah-Hartman
2022-05-23 17:05 ` [PATCH 5.10 28/97] ARM: 9191/1: arm/stacktrace, kasan: Silence KASAN warnings in unwind_frame() Greg Kroah-Hartman
2022-05-23 17:05 ` [PATCH 5.10 29/97] nilfs2: fix lockdep warnings in page operations for btree nodes Greg Kroah-Hartman
2022-05-23 17:05 ` [PATCH 5.10 30/97] nilfs2: fix lockdep warnings during disk space reclamation Greg Kroah-Hartman
2022-05-23 17:05 ` [PATCH 5.10 31/97] Revert "swiotlb: fix info leak with DMA_FROM_DEVICE" Greg Kroah-Hartman
2022-05-23 18:25 ` [PATCH 5.10 00/97] 5.10.118-rc1 review Florian Fainelli
2022-05-23 21:36 ` Daniel Díaz
2022-05-25  7:16   ` Greg Kroah-Hartman
2022-05-23 22:56 ` Shuah Khan
2022-05-24  9:24 ` Fox Chen
2022-05-24 14:49 ` Sudip Mukherjee
2022-05-24 15:25 ` Pavel Machek
2022-05-24 20:04 ` Guenter Roeck
2022-05-25  1:05 ` Samuel Zou

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