linux-kernel - [PATCH 1/2] itimers: fix racy writes to cpu

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-next>] [day] [month] [year] [list]

Message-Id: <1253802903-979-1-git-send-email-sgruszka@redhat.com>
Date:	Thu, 24 Sep 2009 16:35:02 +0200
From:	Stanislaw Gruszka <sgruszka@...hat.com>
To:	Thomas Gleixner <tglx@...utronix.de>
Cc:	Ingo Molnar <mingo@...e.hu>, Oleg Nesterov <oleg@...hat.com>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	linux-kernel@...r.kernel.org,
	Stanislaw Gruszka <sgruszka@...hat.com>
Subject: [PATCH 1/2] itimers: fix racy writes to cpu_itimer fields

incr_error and error fields of struct cpu_itimer are used when calculating
next timer tick in check_cpu_itimers() and should not be modified without
tsk->sighand->siglock taken.

Signed-off-by: Stanislaw Gruszka <sgruszka@...hat.com>
---
 kernel/itimer.c |    7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/kernel/itimer.c b/kernel/itimer.c
index b03451e..d802883 100644
--- a/kernel/itimer.c
+++ b/kernel/itimer.c
@@ -146,6 +146,7 @@ static void set_cpu_itimer(struct task_struct *tsk, unsigned int clock_id,
 {
 	cputime_t cval, nval, cinterval, ninterval;
 	s64 ns_ninterval, ns_nval;
+	u32 error, incr_error;
 	struct cpu_itimer *it = &tsk->signal->it[clock_id];
 
 	nval = timeval_to_cputime(&value->it_value);
@@ -153,8 +154,8 @@ static void set_cpu_itimer(struct task_struct *tsk, unsigned int clock_id,
 	ninterval = timeval_to_cputime(&value->it_interval);
 	ns_ninterval = timeval_to_ns(&value->it_interval);
 
-	it->incr_error = cputime_sub_ns(ninterval, ns_ninterval);
-	it->error = cputime_sub_ns(nval, ns_nval);
+	error = cputime_sub_ns(nval, ns_nval);
+	incr_error = cputime_sub_ns(ninterval, ns_ninterval);
 
 	spin_lock_irq(&tsk->sighand->siglock);
 
@@ -168,6 +169,8 @@ static void set_cpu_itimer(struct task_struct *tsk, unsigned int clock_id,
 	}
 	it->expires = nval;
 	it->incr = ninterval;
+	it->error = error;
+	it->incr_error = incr_error;
 	trace_itimer_state(clock_id == CPUCLOCK_VIRT ?
 			   ITIMER_VIRTUAL : ITIMER_PROF, value, nval);
 
-- 
1.6.2.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/