Commit e06cea11 authored Sep 27, 2019 by Fuqian Huang Committed by Greg Kroah-Hartman Oct 01, 2020

m68k: q40: Fix info-leak in rtc_ioctl



[ Upstream commit 7cf78b6b12fd5550545e4b73b35dca18bd46b44c ]

When the option is RTC_PLL_GET, pll will be copied to userland
via copy_to_user. pll is initialized using mach_get_rtc_pll indirect
call and mach_get_rtc_pll is only assigned with function
q40_get_rtc_pll in arch/m68k/q40/config.c.
In function q40_get_rtc_pll, the field pll_ctrl is not initialized.
This will leak uninitialized stack content to userland.
Fix this by zeroing the uninitialized field.

Signed-off-by: Fuqian Huang <huangfq.daxian@gmail.com>
Link: https://lore.kernel.org/r/20190927121544.7650-1-huangfq.daxian@gmail.com


Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 9b3416d1

arch/m68k/q40/config.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -303,6 +303,7 @@ static int q40_get_rtc_pll(struct rtc_pll_info *pll)
		{
		int tmp = Q40_RTC_CTRL;

		pll->pll_ctrl = 0;
		pll->pll_value = tmp & Q40_RTC_PLL_MASK;
		if (tmp & Q40_RTC_PLL_SIGN)
		pll->pll_value = -pll->pll_value;