Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756808Ab3DXO5N (ORCPT ); Wed, 24 Apr 2013 10:57:13 -0400 Received: from mail-wg0-f51.google.com ([74.125.82.51]:59471 "EHLO mail-wg0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755991Ab3DXO5L (ORCPT ); Wed, 24 Apr 2013 10:57:11 -0400 Message-ID: <5177F2C3.5080907@intel.com> Date: Wed, 24 Apr 2013 15:57:07 +0100 From: Matt Fleming Organization: Intel Corporation (UK) Ltd. - Registered No. 1134945 - Pipers Way, Swindon SN3 1RJ User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130329 Thunderbird/17.0.5 MIME-Version: 1.0 To: Josh Boyer CC: Matthew Garrett , linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] efi: Check EFI revision in setup_efi_vars References: <20130424143738.GB15272@hansolo.jdub.homelinux.org> <5177EFCE.80104@intel.com> <20130424145449.GC15272@hansolo.jdub.homelinux.org> In-Reply-To: <20130424145449.GC15272@hansolo.jdub.homelinux.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2328 Lines: 52 On 24/04/13 15:54, Josh Boyer wrote: > On Wed, Apr 24, 2013 at 03:44:30PM +0100, Matt Fleming wrote: >> On 24/04/13 15:37, Josh Boyer wrote: >>> We need to check the runtime sys_table for the EFI version the firmware >>> specifies instead of just checking for a NULL QueryVariableInfo. Older >>> implementations of EFI don't have QueryVariableInfo but the runtime is >>> a smaller structure, so the pointer to it may be pointing off into garbage. >>> >>> This is apparently the case with several Apple firmwares that support EFI >>> 1.10, and the current check causes them to no longer boot. Fix based on >>> a suggestion from Matthew Garrett. >>> >>> Signed-off-by: Josh Boyer >>> --- >>> arch/x86/boot/compressed/eboot.c | 4 +++- >>> 1 file changed, 3 insertions(+), 1 deletion(-) >>> >>> diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c >>> index 8615f75..b46efbf 100644 >>> --- a/arch/x86/boot/compressed/eboot.c >>> +++ b/arch/x86/boot/compressed/eboot.c >>> @@ -258,7 +258,9 @@ static efi_status_t setup_efi_vars(struct boot_params *params) >>> u64 store_size, remaining_size, var_size; >>> efi_status_t status; >>> >>> - if (!sys_table->runtime->query_variable_info) >>> + if (sys_table->runtime->hdr.revision < EFI_2_00_SYSTEM_TABLE_REVISION) >>> + return EFI_UNSUPPORTED; >>> + else if(!sys_table->runtime->query_variable_info) >>> return EFI_UNSUPPORTED; >>> >>> data = (struct setup_data *)(unsigned long)params->hdr.setup_data; >>> >> >> Thanks Josh, that looks correct. >> >> It's a small point, but does the check against NULL actually make sense? >> I don't think we ever check other system table pointers against NULL. > > That I'm not sure of. I was going off of the assumption that Matthew > put it there because someone's EFI 2.0 implementation was crappy and > didn't actually implement it. So I left that check in place for now. I presume that if that were true, virt_efi_query_variable_info() (which is called indirectly from the efivars code) would have exploded before now. Matthew? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/