From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:50652 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752619AbcGXXE6 (ORCPT ); Sun, 24 Jul 2016 19:04:58 -0400 Subject: Patch "arm64: kernel: Save and restore UAO and addr_limit on exception entry" has been added to the 4.6-stable tree To: james.morse@arm.com, gregkh@linuxfoundation.org, mark.rutland@arm.com, will.deacon@arm.com Cc: , From: Date: Sun, 24 Jul 2016 16:05:12 -0700 Message-ID: <146940151219071@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 arm64: kernel: Save and restore UAO and addr_limit on exception entry to the 4.6-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: arm64-kernel-save-and-restore-uao-and-addr_limit-on-exception-entry.patch and it can be found in the queue-4.6 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From e19a6ee2460bdd0d0055a6029383422773f9999a Mon Sep 17 00:00:00 2001 From: James Morse Date: Mon, 20 Jun 2016 18:28:01 +0100 Subject: arm64: kernel: Save and restore UAO and addr_limit on exception entry From: James Morse commit e19a6ee2460bdd0d0055a6029383422773f9999a upstream. If we take an exception while at EL1, the exception handler inherits the original context's addr_limit and PSTATE.UAO values. To be consistent always reset addr_limit and PSTATE.UAO on (re-)entry to EL1. This prevents accidental re-use of the original context's addr_limit. Based on a similar patch for arm from Russell King. Acked-by: Will Deacon Reviewed-by: Mark Rutland Signed-off-by: James Morse Signed-off-by: Will Deacon Signed-off-by: Greg Kroah-Hartman --- arch/arm64/include/asm/ptrace.h | 2 ++ arch/arm64/kernel/asm-offsets.c | 1 + arch/arm64/kernel/entry.S | 19 +++++++++++++++++-- arch/arm64/mm/fault.c | 3 ++- 4 files changed, 22 insertions(+), 3 deletions(-) --- a/arch/arm64/include/asm/ptrace.h +++ b/arch/arm64/include/asm/ptrace.h @@ -117,6 +117,8 @@ struct pt_regs { }; u64 orig_x0; u64 syscallno; + u64 orig_addr_limit; + u64 unused; // maintain 16 byte alignment }; #define arch_has_single_step() (1) --- a/arch/arm64/kernel/asm-offsets.c +++ b/arch/arm64/kernel/asm-offsets.c @@ -59,6 +59,7 @@ int main(void) DEFINE(S_PC, offsetof(struct pt_regs, pc)); DEFINE(S_ORIG_X0, offsetof(struct pt_regs, orig_x0)); DEFINE(S_SYSCALLNO, offsetof(struct pt_regs, syscallno)); + DEFINE(S_ORIG_ADDR_LIMIT, offsetof(struct pt_regs, orig_addr_limit)); DEFINE(S_FRAME_SIZE, sizeof(struct pt_regs)); BLANK(); DEFINE(MM_CONTEXT_ID, offsetof(struct mm_struct, context.id.counter)); --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -28,6 +28,7 @@ #include #include #include +#include #include #include @@ -97,7 +98,14 @@ mov x29, xzr // fp pointed to user-space .else add x21, sp, #S_FRAME_SIZE - .endif + get_thread_info tsk + /* Save the task's original addr_limit and set USER_DS (TASK_SIZE_64) */ + ldr x20, [tsk, #TI_ADDR_LIMIT] + str x20, [sp, #S_ORIG_ADDR_LIMIT] + mov x20, #TASK_SIZE_64 + str x20, [tsk, #TI_ADDR_LIMIT] + ALTERNATIVE(nop, SET_PSTATE_UAO(0), ARM64_HAS_UAO, CONFIG_ARM64_UAO) + .endif /* \el == 0 */ mrs x22, elr_el1 mrs x23, spsr_el1 stp lr, x21, [sp, #S_LR] @@ -128,6 +136,14 @@ .endm .macro kernel_exit, el + .if \el != 0 + /* Restore the task's original addr_limit. */ + ldr x20, [sp, #S_ORIG_ADDR_LIMIT] + str x20, [tsk, #TI_ADDR_LIMIT] + + /* No need to restore UAO, it will be restored from SPSR_EL1 */ + .endif + ldp x21, x22, [sp, #S_PC] // load ELR, SPSR .if \el == 0 ct_user_enter @@ -406,7 +422,6 @@ el1_irq: bl trace_hardirqs_off #endif - get_thread_info tsk irq_handler #ifdef CONFIG_PREEMPT --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -284,7 +284,8 @@ static int __kprobes do_page_fault(unsig } if (permission_fault(esr) && (addr < USER_DS)) { - if (get_fs() == KERNEL_DS) + /* regs->orig_addr_limit may be 0 if we entered from EL0 */ + if (regs->orig_addr_limit == KERNEL_DS) die("Accessing user space memory with fs=KERNEL_DS", regs, esr); if (!search_exception_tables(regs->pc)) Patches currently in stable-queue which might be from james.morse@arm.com are queue-4.6/arm64-kernel-save-and-restore-uao-and-addr_limit-on-exception-entry.patch queue-4.6/kvm-arm-arm64-stop-leaking-vcpu-pid-references.patch queue-4.6/arm64-fix-dump_instr-when-pan-and-uao-are-in-use.patch