Patch "x86/mpx: Correctly report do_mpx_bt_fault() failures to user-space" has been added to the 4.9-stable tree

Patch "x86/mpx: Correctly report do_mpx_bt_fault() failures to user-space" has been added to the 4.9-stable tree

[gregkh]

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

    x86/mpx: Correctly report do_mpx_bt_fault() failures to user-space

to the 4.9-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:
     x86-mpx-correctly-report-do_mpx_bt_fault-failures-to-user-space.patch
and it can be found in the queue-4.9 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 5ed386ec09a5d75bcf073967e55e895c2607a5c3 Mon Sep 17 00:00:00 2001
From: Joerg Roedel <jroedel@suse.de>
Date: Thu, 6 Apr 2017 16:19:22 +0200
Subject: x86/mpx: Correctly report do_mpx_bt_fault() failures to user-space

From: Joerg Roedel <jroedel@suse.de>

commit 5ed386ec09a5d75bcf073967e55e895c2607a5c3 upstream.

When this function fails it just sends a SIGSEGV signal to
user-space using force_sig(). This signal is missing
essential information about the cause, e.g. the trap_nr or
an error code.

Fix this by propagating the error to the only caller of
mpx_handle_bd_fault(), do_bounds(), which sends the correct
SIGSEGV signal to the process.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: fe3d197f84319 ('x86, mpx: On-demand kernel allocation of bounds tables')
Link: http://lkml.kernel.org/r/1491488362-27198-1-git-send-email-joro@8bytes.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/x86/mm/mpx.c |   10 +---------
 1 file changed, 1 insertion(+), 9 deletions(-)

--- a/arch/x86/mm/mpx.c
+++ b/arch/x86/mm/mpx.c
@@ -525,15 +525,7 @@ int mpx_handle_bd_fault(void)
 	if (!kernel_managing_mpx_tables(current->mm))
 		return -EINVAL;
 
-	if (do_mpx_bt_fault()) {
-		force_sig(SIGSEGV, current);
-		/*
-		 * The force_sig() is essentially "handling" this
-		 * exception, so we do not pass up the error
-		 * from do_mpx_bt_fault().
-		 */
-	}
-	return 0;
+	return do_mpx_bt_fault();
 }
 
 /*


Patches currently in stable-queue which might be from jroedel@suse.de are

queue-4.9/x86-mpx-correctly-report-do_mpx_bt_fault-failures-to-user-space.patch