Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755318AbeAOKcY (ORCPT + 1 other); Mon, 15 Jan 2018 05:32:24 -0500 Received: from mx2.suse.de ([195.135.220.15]:33990 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752343AbeAOKcX (ORCPT ); Mon, 15 Jan 2018 05:32:23 -0500 Date: Mon, 15 Jan 2018 11:32:20 +0100 From: Jan Kara To: Dan Williams Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, kernel-hardening@lists.openwall.com, Jan Kara , tglx@linutronix.de, torvalds@linux-foundation.org, akpm@linux-foundation.org, Elena Reshetova , alan@linux.intel.com Subject: Re: [PATCH v2 13/19] udf: prevent bounds-check bypass via speculative execution Message-ID: <20180115103220.g3xtdsybkfxqkapx@quack2.suse.cz> References: <151571798296.27429.7166552848688034184.stgit@dwillia2-desk3.amr.corp.intel.com> <151571805555.27429.728109914195885407.stgit@dwillia2-desk3.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <151571805555.27429.728109914195885407.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: NeoMutt/20170421 (1.8.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: On Thu 11-01-18 16:47:35, Dan Williams wrote: > Static analysis reports that 'eahd->appAttrLocation' and > 'eahd->impAttrLocation' may be a user controlled values that are used as > data dependencies for calculating source and destination buffers for > memmove operations. In order to avoid potential leaks of kernel memory > values, block speculative execution of the instruction stream that could > issue further reads based on invalid 'aal' or 'ial' values. > > Based on an original patch by Elena Reshetova. > > Cc: Jan Kara > Signed-off-by: Elena Reshetova > Signed-off-by: Dan Williams Dan, I've already emailed to you [1] why I don't think this patch is needed at all. Do you disagree or did my email just get lost? [1] https://marc.info/?l=linux-arch&m=151540683024125&w=2 Honza > --- > fs/udf/misc.c | 40 ++++++++++++++++++++++------------------ > 1 file changed, 22 insertions(+), 18 deletions(-) > > diff --git a/fs/udf/misc.c b/fs/udf/misc.c > index 401e64cde1be..693e24699928 100644 > --- a/fs/udf/misc.c > +++ b/fs/udf/misc.c > @@ -22,6 +22,7 @@ > #include "udfdecl.h" > > #include > +#include > #include > #include > > @@ -51,6 +52,8 @@ struct genericFormat *udf_add_extendedattr(struct inode *inode, uint32_t size, > int offset; > uint16_t crclen; > struct udf_inode_info *iinfo = UDF_I(inode); > + uint8_t *ea_dst, *ea_src; > + uint32_t aal, ial; > > ea = iinfo->i_ext.i_data; > if (iinfo->i_lenEAttr) { > @@ -100,33 +103,34 @@ struct genericFormat *udf_add_extendedattr(struct inode *inode, uint32_t size, > > offset = iinfo->i_lenEAttr; > if (type < 2048) { > - if (le32_to_cpu(eahd->appAttrLocation) < > - iinfo->i_lenEAttr) { > - uint32_t aal = > - le32_to_cpu(eahd->appAttrLocation); > - memmove(&ea[offset - aal + size], > - &ea[aal], offset - aal); > + aal = le32_to_cpu(eahd->appAttrLocation); > + ea_dst = array_ptr(ea, offset - aal + size, > + iinfo->i_lenEAttr); > + ea_src = array_ptr(ea, aal, iinfo->i_lenEAttr); > + if (ea_dst && ea_src) { > + memmove(ea_dst, ea_src, offset - aal); > offset -= aal; > eahd->appAttrLocation = > cpu_to_le32(aal + size); > } > - if (le32_to_cpu(eahd->impAttrLocation) < > - iinfo->i_lenEAttr) { > - uint32_t ial = > - le32_to_cpu(eahd->impAttrLocation); > - memmove(&ea[offset - ial + size], > - &ea[ial], offset - ial); > + > + ial = le32_to_cpu(eahd->impAttrLocation); > + ea_dst = array_ptr(ea, offset - ial + size, > + iinfo->i_lenEAttr); > + ea_src = array_ptr(ea, ial, iinfo->i_lenEAttr); > + if (ea_dst && ea_src) { > + memmove(ea_dst, ea_src, offset - ial); > offset -= ial; > eahd->impAttrLocation = > cpu_to_le32(ial + size); > } > } else if (type < 65536) { > - if (le32_to_cpu(eahd->appAttrLocation) < > - iinfo->i_lenEAttr) { > - uint32_t aal = > - le32_to_cpu(eahd->appAttrLocation); > - memmove(&ea[offset - aal + size], > - &ea[aal], offset - aal); > + aal = le32_to_cpu(eahd->appAttrLocation); > + ea_dst = array_ptr(ea, offset - aal + size, > + iinfo->i_lenEAttr); > + ea_src = array_ptr(ea, aal, iinfo->i_lenEAttr); > + if (ea_dst && ea_src) { > + memmove(ea_dst, ea_src, offset - aal); > offset -= aal; > eahd->appAttrLocation = > cpu_to_le32(aal + size); > > -- Jan Kara SUSE Labs, CR