tree 92a0b49d9fa8d672517d4554a7b1dd5a16ff36eb
parent ccc543e1920dd02b5d283b4e69abff44ab7e5999
author Yongliang Gao <leonylgao@tencent.com> 1728621113 +0800
committer Kevin Berry <kpberry@google.com> 1736551627 -0800

rtc: check if __rtc_read_time was successful in rtc_timer_do_work()

[ Upstream commit e8ba8a2bc4f60a1065f23d6a0e7cbea945a0f40d ]

If the __rtc_read_time call fails,, the struct rtc_time tm; may contain
uninitialized data, or an illegal date/time read from the RTC hardware.

When calling rtc_tm_to_ktime later, the result may be a very large value
(possibly KTIME_MAX). If there are periodic timers in rtc->timerqueue,
they will continually expire, may causing kernel softlockup.

BUG=b/388469199
TEST=presubmit
RELEASE_NOTE=Fixed CVE-2024-56739 in the Linux kernel.

cos-patch: security-moderate
Fixes: 6610e0893b8b ("RTC: Rework RTC code to use timerqueue for events")
Change-Id: I593b7806d457d49c0a33c2497b0bc87c24b7a1ef
Signed-off-by: Yongliang Gao <leonylgao@tencent.com>
Acked-by: Jingqun Li <jingqunli@tencent.com>
Link: https://lore.kernel.org/r/20241011043153.3788112-1-leonylgao@gmail.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kernel CVE Triage Automation <cloud-image-kernel-cve-triage-automation@prod.google.com>
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/89861
Reviewed-by: Kevin Berry <kpberry@google.com>
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Reviewed-by: Arnav Kansal <rnv@google.com>