From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jarkko Sakkinen Subject: Re: [PATCH 1/1] efi/libstub: tpm: zero initialize pointer variables for mixed mode Date: Fri, 16 Mar 2018 15:02:50 +0200 Message-ID: <20180316130250.GD5035@linux.intel.com> References: <20180313140922.17266-1-ard.biesheuvel@linaro.org> <20180313140922.17266-2-ard.biesheuvel@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20180313140922.17266-2-ard.biesheuvel@linaro.org> Sender: linux-kernel-owner@vger.kernel.org To: Ard Biesheuvel Cc: linux-efi@vger.kernel.org, Ingo Molnar , Thomas Gleixner , hdegoede@redhat.com, tweek@google.com, javierm@redhat.com, linux-kernel@vger.kernel.org List-Id: linux-efi@vger.kernel.org On Tue, Mar 13, 2018 at 02:09:21PM +0000, Ard Biesheuvel wrote: > As reported by Jeremy, running the new TPM libstub code in mixed mode > (i.e., 64-bit kernel on 32-bit UEFI) results in hangs when invoking > the TCG2 protocol, or when accessing the log_tbl pool allocation. > > The reason turns out to be that in both cases, the 64-bit pointer > variables are not fully initialized by the 32-bit EFI code, and so > we should take care to zero initialize these variables beforehand, > or we'll end up dereferencing bogus pointers. > > Reported-by: Jeremy Cline > Signed-off-by: Ard Biesheuvel Reviewed-by: Jarkko Sakkinen /Jarkko