linux-kernel - Interrupt randomness in 3.14.10-rt

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: <1405045492.26540.67.camel@deadeye.wl.decadent.org.uk>
Date:	Fri, 11 Jul 2014 03:24:52 +0100
From:	Ben Hutchings <ben@...adent.org.uk>
To:	Thomas Gleixner <tglx@...utronix.de>
Cc:	LKML <linux-kernel@...r.kernel.org>, stable-rt@...r.kernel.org
Subject: Interrupt randomness in 3.14.10-rt

I noticed this change between 3.14.3-rt5 and 3.14.10-rt7:

--- debian/patches/features/all/rt/random-make-it-work-on-rt.patch      (revision 21522)
+++ debian/patches/features/all/rt/random-make-it-work-on-rt.patch      (working copy)
[...]
---- a/kernel/irq/manage.c
-+++ b/kernel/irq/manage.c
-@@ -942,6 +942,12 @@ static int irq_thread(void *data)
-               if (action_ret == IRQ_HANDLED)
-                       atomic_inc(&desc->threads_handled);
- 
-+#ifdef CONFIG_PREEMPT_RT_FULL
-+              migrate_disable();
-+              add_interrupt_randomness(action->irq, 0,
-+                               desc->random_ip ^ (unsigned long) action);
-+              migrate_enable();
-+#endif
-               wake_threads_waitq(desc);
-       }
- 

(I.e. old patch included these additions, new patch doesn't.)

Evidently this was made in the announced 3.14.10-rt6, not -rt7.  Was it
intentional?  Now irq_desc::random_ip is set but never used.

Ben.

-- 
Ben Hutchings
To err is human; to really foul things up requires a computer.

Download attachment "signature.asc" of type "application/pgp-signature" (812 bytes)