linux-kernel - [tip: timers/urgent] ntp: Remove invalid cast in time offset math

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <173271786637.412.11744400812569588652.tip-bot2@tip-bot2>
Date: Wed, 27 Nov 2024 14:31:06 -0000
From: "tip-bot2 for Marcelo Dalmas" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Marcelo Dalmas <marcelo.dalmas@...com>,
 Thomas Gleixner <tglx@...utronix.de>, stable@...r.kernel.org, x86@...nel.org,
 linux-kernel@...r.kernel.org
Subject: [tip: timers/urgent] ntp: Remove invalid cast in time offset math

The following commit has been merged into the timers/urgent branch of tip:

Commit-ID:     299130166e70124956c865a66a3669a61db1c212
Gitweb:        https://git.kernel.org/tip/299130166e70124956c865a66a3669a61db1c212
Author:        Marcelo Dalmas <marcelo.dalmas@...com>
AuthorDate:    Mon, 25 Nov 2024 12:16:09 
Committer:     Thomas Gleixner <tglx@...utronix.de>
CommitterDate: Wed, 27 Nov 2024 15:18:45 +01:00

ntp: Remove invalid cast in time offset math

Due to an unsigned cast, adjtimex() returns the wrong offest when using
ADJ_MICRO and the offset is negative. In this case a small negative offset
returns approximately 4.29 seconds (~ 2^32/1000 milliseconds) due to the
unsigned cast of the negative offset.

Remove the cast and restore the signed division to cure that issue.

Fixes: ead25417f82e ("timex: use __kernel_timex internally")
Signed-off-by: Marcelo Dalmas <marcelo.dalmas@...com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: stable@...r.kernel.org
Link: https://lore.kernel.org/all/SJ0P101MB03687BF7D5A10FD3C49C51E5F42E2@SJ0P101MB0368.NAMP101.PROD.OUTLOOK.COM
---
 kernel/time/ntp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index b550ebe..02e7fe6 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -798,7 +798,7 @@ int __do_adjtimex(struct __kernel_timex *txc, const struct timespec64 *ts,
 
 		txc->offset = shift_right(ntpdata->time_offset * NTP_INTERVAL_FREQ, NTP_SCALE_SHIFT);
 		if (!(ntpdata->time_status & STA_NANO))
-			txc->offset = (u32)txc->offset / NSEC_PER_USEC;
+			txc->offset /= NSEC_PER_USEC;
 	}
 
 	result = ntpdata->time_state;