From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Sandeen Subject: Re: [PATCH] added sanity check for xattr validation Date: Thu, 21 Jun 2007 15:50:37 -0500 Message-ID: <467AE49D.6030207@redhat.com> References: <20070226223322.GA30215@schatzie.adilger.int> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: "Theodore Ts'o" , linux-ext4@vger.kernel.org, Jim Garlick To: Andreas Dilger Return-path: Received: from mx1.redhat.com ([66.187.233.31]:46679 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755758AbXFUUu4 (ORCPT ); Thu, 21 Jun 2007 16:50:56 -0400 In-Reply-To: <20070226223322.GA30215@schatzie.adilger.int> Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org Andreas Dilger wrote: > Ted, > the attached patch adds an extra validity test in check_ext_attr(). If > an attribute's e_value_size is zero the current code does not allocate > a region for it and as a result the e_value_offs value is not verified. > However, if e_value_offs is very large then the later call to > ext2fs_ext_attr_hash_entry() can dereference bad memory and crash e2fsck. Did this patch get lost? Don't see it in Hg... Thanks, -Eric > Signed-off-by: Andreas Dilger > Signed-off-by: Jim Garlick > > =========================== e_value_offs.patch ============================ > > Index: e2fsprogs-1.39/e2fsck/pass1.c > =================================================================== > --- e2fsprogs-1.39.orig/e2fsck/pass1.c 2007-02-10 15:43:36.000000000 +0530 > +++ e2fsprogs-1.39/e2fsck/pass1.c 2007-02-10 15:45:36.000000000 +0530 > @@ -1346,6 +1347,11 @@ > if (fix_problem(ctx, PR_1_EA_BAD_VALUE, pctx)) > goto clear_extattr; > } > + if (entry->e_value_offs + entry->e_value_size > fs->blocksize) { > + if (fix_problem(ctx, PR_1_EA_BAD_VALUE, pctx)) > + goto clear_extattr; > + break; > + } > if (entry->e_value_size && > region_allocate(region, entry->e_value_offs, > EXT2_EXT_ATTR_SIZE(entry->e_value_size))) { > =========================== e_value_offs.patch ============================ > > Cheers, Andreas > -- > Andreas Dilger > Principal Software Engineer > Cluster File Systems, Inc. > > - > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html