From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lingzhu Xiang Subject: Re: [PATCH] efivarfs: fix abnormal GUID in variable name by using strcpy to replace null with dash Date: Fri, 01 Mar 2013 17:31:43 +0800 Message-ID: <5130757F.4090702@redhat.com> References: <1362108018-13117-1-git-send-email-jlee@suse.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1362108018-13117-1-git-send-email-jlee@suse.com> Sender: linux-kernel-owner@vger.kernel.org To: "Lee, Chun-Yi" Cc: matt@console-pimps.org, linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, Michael Schroeder , Josh Boyer , Jeremy Kerr , "Lee, Chun-Yi" List-Id: linux-efi@vger.kernel.org On 03/01/2013 11:20 AM, Lee, Chun-Yi wrote: > From: Michael Schroeder > > On HP z220 system (firmware version 1.54), some EFI variables are incorrectly > named : > > ls -d /sys/firmware/efi/vars/*8be4d* | grep -v -- -8be returns > /sys/firmware/efi/vars/dbxDefault-pport8be4df61-93ca-11d2-aa0d-00e098032b8c > /sys/firmware/efi/vars/KEKDefault-pport8be4df61-93ca-11d2-aa0d-00e098032b8c > /sys/firmware/efi/vars/SecureBoot-pport8be4df61-93ca-11d2-aa0d-00e098032b8c > /sys/firmware/efi/vars/SetupMode-Information8be4df61-93ca-11d2-aa0d-00e098032b8c > > That causes by the following statement in efivar_create_sysfs_entry function: > > *(short_name + strlen(short_name)) = '-'; > efi_guid_unparse(vendor_guid, short_name + strlen(short_name)); > > The trailing \0 is overwritten with '-', but the next char doesn't seem to be a \0 > as well for HP. So, the second strlen return the point of next '\0', causes there > have garbage string attached before GUID. > > Tested on On HP z220. So short_name has trailing garbage, or rather, variable_name_size is larger than variable_name actually is, wouldn't new_efivar->var.VariableName also gets filled with trailing garbage? In efivar_store_raw the VariableName's trailing garbage can cause problem for comparison. You might want to also cover that or fix variable_name_size. Lingzhu Xiang