Patch "parisc: Fix kernel crash with reversed copy_from_user()" has been added to the 4.4-stable tree

Patch "parisc: Fix kernel crash with reversed copy_from_user()" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    parisc: Fix kernel crash with reversed copy_from_user()

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     parisc-fix-kernel-crash-with-reversed-copy_from_user.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From ef72f3110d8b19f4c098a0bff7ed7d11945e70c6 Mon Sep 17 00:00:00 2001
From: Helge Deller <deller@gmx.de>
Date: Fri, 8 Apr 2016 18:18:48 +0200
Subject: parisc: Fix kernel crash with reversed copy_from_user()

From: Helge Deller <deller@gmx.de>

commit ef72f3110d8b19f4c098a0bff7ed7d11945e70c6 upstream.

The kernel module testcase (lib/test_user_copy.c) exhibited a kernel
crash on parisc if the parameters for copy_from_user were reversed
("illegal reversed copy_to_user" testcase).

Fix this potential crash by checking the fault handler if the faulting
address is in the exception table.

Signed-off-by: Helge Deller <deller@gmx.de>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/parisc/kernel/traps.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/arch/parisc/kernel/traps.c
+++ b/arch/parisc/kernel/traps.c
@@ -798,6 +798,9 @@ void notrace handle_interruption(int cod
 
 	    if (fault_space == 0 && !faulthandler_disabled())
 	    {
+		/* Clean up and return if in exception table. */
+		if (fixup_exception(regs))
+			return;
 		pdc_chassis_send_status(PDC_CHASSIS_DIRECT_PANIC);
 		parisc_terminate("Kernel Fault", regs, code, fault_address);
 	    }


Patches currently in stable-queue which might be from deller@gmx.de are

queue-4.4/parisc-fix-kernel-crash-with-reversed-copy_from_user.patch
queue-4.4/parisc-unbreak-handling-exceptions-from-kernel-modules.patch
queue-4.4/parisc-avoid-function-pointers-for-kernel-exception-routines.patch