From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934942AbcKNCZO (ORCPT ); Sun, 13 Nov 2016 21:25:14 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:47094 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753150AbcKNCZH (ORCPT ); Sun, 13 Nov 2016 21:25:07 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Al Viro" , "Vineet Gupta" , "Al Viro" , linux-snps-arc@lists.infradead.org, "Vineet Gupta" , "Linus Torvalds" Date: Mon, 14 Nov 2016 00:14:20 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 278/346] ARC: uaccess: get_user to zero out dest in cause of fault In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.39-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Vineet Gupta commit 05d9d0b96e53c52a113fd783c0c97c830c8dc7af upstream. Al reported potential issue with ARC get_user() as it wasn't clearing out destination pointer in case of fault due to bad address etc. Verified using following | { | u32 bogus1 = 0xdeadbeef; | u64 bogus2 = 0xdead; | int rc1, rc2; | | pr_info("Orig values %x %llx\n", bogus1, bogus2); | rc1 = get_user(bogus1, (u32 __user *)0x40000000); | rc2 = get_user(bogus2, (u64 __user *)0x50000000); | pr_info("access %d %d, new values %x %llx\n", | rc1, rc2, bogus1, bogus2); | } | [ARCLinux]# insmod /mnt/kernel-module/qtn.ko | Orig values deadbeef dead | access -14 -14, new values 0 0 Reported-by: Al Viro Cc: Linus Torvalds Cc: linux-snps-arc@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Vineet Gupta Signed-off-by: Al Viro Signed-off-by: Ben Hutchings --- arch/arc/include/asm/uaccess.h | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) --- a/arch/arc/include/asm/uaccess.h +++ b/arch/arc/include/asm/uaccess.h @@ -83,7 +83,10 @@ "2: ;nop\n" \ " .section .fixup, \"ax\"\n" \ " .align 4\n" \ - "3: mov %0, %3\n" \ + "3: # return -EFAULT\n" \ + " mov %0, %3\n" \ + " # zero out dst ptr\n" \ + " mov %1, 0\n" \ " j 2b\n" \ " .previous\n" \ " .section __ex_table, \"a\"\n" \ @@ -101,7 +104,11 @@ "2: ;nop\n" \ " .section .fixup, \"ax\"\n" \ " .align 4\n" \ - "3: mov %0, %3\n" \ + "3: # return -EFAULT\n" \ + " mov %0, %3\n" \ + " # zero out dst ptr\n" \ + " mov %1, 0\n" \ + " mov %R1, 0\n" \ " j 2b\n" \ " .previous\n" \ " .section __ex_table, \"a\"\n" \ From mboxrd@z Thu Jan 1 00:00:00 1970 From: ben@decadent.org.uk (Ben Hutchings) Date: Mon, 14 Nov 2016 00:14:20 +0000 Subject: [PATCH 3.16 278/346] ARC: uaccess: get_user to zero out dest in cause of fault In-Reply-To: List-ID: Message-ID: To: linux-snps-arc@lists.infradead.org 3.16.39-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Vineet Gupta commit 05d9d0b96e53c52a113fd783c0c97c830c8dc7af upstream. Al reported potential issue with ARC get_user() as it wasn't clearing out destination pointer in case of fault due to bad address etc. Verified using following | { | u32 bogus1 = 0xdeadbeef; | u64 bogus2 = 0xdead; | int rc1, rc2; | | pr_info("Orig values %x %llx\n", bogus1, bogus2); | rc1 = get_user(bogus1, (u32 __user *)0x40000000); | rc2 = get_user(bogus2, (u64 __user *)0x50000000); | pr_info("access %d %d, new values %x %llx\n", | rc1, rc2, bogus1, bogus2); | } | [ARCLinux]# insmod /mnt/kernel-module/qtn.ko | Orig values deadbeef dead | access -14 -14, new values 0 0 Reported-by: Al Viro Cc: Linus Torvalds Cc: linux-snps-arc at lists.infradead.org Cc: linux-kernel at vger.kernel.org Signed-off-by: Vineet Gupta Signed-off-by: Al Viro Signed-off-by: Ben Hutchings --- arch/arc/include/asm/uaccess.h | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) --- a/arch/arc/include/asm/uaccess.h +++ b/arch/arc/include/asm/uaccess.h @@ -83,7 +83,10 @@ "2: ;nop\n" \ " .section .fixup, \"ax\"\n" \ " .align 4\n" \ - "3: mov %0, %3\n" \ + "3: # return -EFAULT\n" \ + " mov %0, %3\n" \ + " # zero out dst ptr\n" \ + " mov %1, 0\n" \ " j 2b\n" \ " .previous\n" \ " .section __ex_table, \"a\"\n" \ @@ -101,7 +104,11 @@ "2: ;nop\n" \ " .section .fixup, \"ax\"\n" \ " .align 4\n" \ - "3: mov %0, %3\n" \ + "3: # return -EFAULT\n" \ + " mov %0, %3\n" \ + " # zero out dst ptr\n" \ + " mov %1, 0\n" \ + " mov %R1, 0\n" \ " j 2b\n" \ " .previous\n" \ " .section __ex_table, \"a\"\n" \