rtc: dev: zero-initialize struct rtc_wkalrm to prevent information leak

The struct rtc_wkalrm has padding holes after the 'pending' member.
When returned to userspace via the RTC_WKALRM_RD ioctl, uninitialized
kernel stack data residing in these holes may be leaked.

Zero-initialize the struct at declaration to eliminate this information
leak risk.

Fixes smatch warnings:
- drivers/rtc/dev.c:392 rtc_dev_ioctl() warn: check that 'alarm' doesn't
  leak information (struct has a hole after 'pending')

Fixes: 36e14f5fdf ("rtc: rename core files")
Assisted-by: smatch:2.0 [static analysis]
Signed-off-by: Liu Dalin <liudalin@kylinsec.com.cn>
Link: https://patch.msgid.link/B28B7DE18F3A9447+20260827015444.3314227-1-liudalin@kylinsec.com.cn
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
This commit is contained in:
Liu Dalin 2026-08-27 09:54:44 +08:00 • committed by Alexandre Belloni
commit 0ee5c5d804