From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752891AbZJZP0c (ORCPT ); Mon, 26 Oct 2009 11:26:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751827AbZJZP0c (ORCPT ); Mon, 26 Oct 2009 11:26:32 -0400 Received: from hera.kernel.org ([140.211.167.34]:32778 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752599AbZJZP0b (ORCPT ); Mon, 26 Oct 2009 11:26:31 -0400 Date: Mon, 26 Oct 2009 15:24:51 GMT From: tip-bot for Jan Beulich Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, roland@redhat.com, jbeulich@novell.com, stable@kernel.org, JBeulich@novell.com, tglx@linutronix.de, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, roland@redhat.com, jbeulich@novell.com, stable@kernel.org, JBeulich@novell.com, tglx@linutronix.de, mingo@elte.hu In-Reply-To: <4AE5CC4D020000780001BD13@vpn.id2.novell.com> References: <4AE5CC4D020000780001BD13@vpn.id2.novell.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/urgent] x86-64: Fix register leak in 32-bit syscall audting Message-ID: Git-Commit-ID: 81766741fe1eee3884219e8daaf03f466f2ed52f X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 81766741fe1eee3884219e8daaf03f466f2ed52f Gitweb: http://git.kernel.org/tip/81766741fe1eee3884219e8daaf03f466f2ed52f Author: Jan Beulich AuthorDate: Mon, 26 Oct 2009 15:20:29 +0000 Committer: Ingo Molnar CommitDate: Mon, 26 Oct 2009 16:23:26 +0100 x86-64: Fix register leak in 32-bit syscall audting Restoring %ebp after the call to audit_syscall_exit() is not only unnecessary (because the register didn't get clobbered), but in the sysenter case wasn't even doing the right thing: It loaded %ebp from a location below the top of stack (RBP < ARGOFFSET), i.e. arbitrary kernel data got passed back to user mode in the register. Signed-off-by: Jan Beulich Acked-by: Roland McGrath Cc: LKML-Reference: <4AE5CC4D020000780001BD13@vpn.id2.novell.com> Signed-off-by: Ingo Molnar --- arch/x86/ia32/ia32entry.S | 5 ++--- 1 files changed, 2 insertions(+), 3 deletions(-) diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S index 1733f9f..581b056 100644 --- a/arch/x86/ia32/ia32entry.S +++ b/arch/x86/ia32/ia32entry.S @@ -204,7 +204,7 @@ sysexit_from_sys_call: movl RDI-ARGOFFSET(%rsp),%r8d /* reload 5th syscall arg */ .endm - .macro auditsys_exit exit,ebpsave=RBP + .macro auditsys_exit exit testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),TI_flags(%r10) jnz ia32_ret_from_sys_call TRACE_IRQS_ON @@ -217,7 +217,6 @@ sysexit_from_sys_call: call audit_syscall_exit GET_THREAD_INFO(%r10) movl RAX-ARGOFFSET(%rsp),%eax /* reload syscall return value */ - movl \ebpsave-ARGOFFSET(%rsp),%ebp /* reload user register value */ movl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),%edi cli TRACE_IRQS_OFF @@ -351,7 +350,7 @@ cstar_auditsys: jmp cstar_dispatch sysretl_audit: - auditsys_exit sysretl_from_sys_call, RCX /* user %ebp in RCX slot */ + auditsys_exit sysretl_from_sys_call #endif cstar_tracesys: