From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:49064 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751643AbeDIMHH (ORCPT ); Mon, 9 Apr 2018 08:07:07 -0400 Subject: Patch "signal/arm: Document conflicts with SI_USER and SIGFPE" has been added to the 4.14-stable tree To: ebiederm@xmission.com, alexander.levin@microsoft.com, gregkh@linuxfoundation.org, rmk@flint.arm.linux.org.uk Cc: , From: Date: Mon, 09 Apr 2018 14:04:35 +0200 Message-ID: <152327547534244@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled signal/arm: Document conflicts with SI_USER and SIGFPE to the 4.14-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: signal-arm-document-conflicts-with-si_user-and-sigfpe.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From foo@baz Mon Apr 9 13:58:16 CEST 2018 From: "Eric W. Biederman" Date: Thu, 17 Aug 2017 17:07:46 -0500 Subject: signal/arm: Document conflicts with SI_USER and SIGFPE From: "Eric W. Biederman" [ Upstream commit 7771c66457004977b616bab785209f49d164f527 ] Setting si_code to 0 results in a userspace seeing an si_code of 0. This is the same si_code as SI_USER. Posix and common sense requires that SI_USER not be a signal specific si_code. As such this use of 0 for the si_code is a pretty horribly broken ABI. Further use of si_code == 0 guaranteed that copy_siginfo_to_user saw a value of __SI_KILL and now sees a value of SIL_KILL with the result that uid and pid fields are copied and which might copying the si_addr field by accident but certainly not by design. Making this a very flakey implementation. Utilizing FPE_FIXME, siginfo_layout will now return SIL_FAULT and the appropriate fields will be reliably copied. Possible ABI fixes includee: - Send the signal without siginfo - Don't generate a signal - Possibly assign and use an appropriate si_code - Don't handle cases which can't happen Cc: Russell King Cc: linux-arm-kernel@lists.infradead.org Ref: 451436b7bbb2 ("[ARM] Add support code for ARM hardware vector floating point") History Tree: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git Signed-off-by: "Eric W. Biederman" Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- arch/arm/include/uapi/asm/siginfo.h | 13 +++++++++++++ arch/arm/vfp/vfpmodule.c | 2 +- 2 files changed, 14 insertions(+), 1 deletion(-) create mode 100644 arch/arm/include/uapi/asm/siginfo.h --- /dev/null +++ b/arch/arm/include/uapi/asm/siginfo.h @@ -0,0 +1,13 @@ +#ifndef __ASM_SIGINFO_H +#define __ASM_SIGINFO_H + +#include + +/* + * SIGFPE si_codes + */ +#ifdef __KERNEL__ +#define FPE_FIXME 0 /* Broken dup of SI_USER */ +#endif /* __KERNEL__ */ + +#endif --- a/arch/arm/vfp/vfpmodule.c +++ b/arch/arm/vfp/vfpmodule.c @@ -257,7 +257,7 @@ static void vfp_raise_exceptions(u32 exc if (exceptions == VFP_EXCEPTION_ERROR) { vfp_panic("unhandled bounce", inst); - vfp_raise_sigfpe(0, regs); + vfp_raise_sigfpe(FPE_FIXME, regs); return; } Patches currently in stable-queue which might be from ebiederm@xmission.com are queue-4.14/signal-metag-document-a-conflict-with-si_user-with-sigfpe.patch queue-4.14/signal-arm-document-conflicts-with-si_user-and-sigfpe.patch queue-4.14/signal-powerpc-document-conflicts-with-si_user-and-sigfpe-and-sigtrap.patch