From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7780CEB64D8 for ; Thu, 22 Jun 2023 17:32:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231140AbjFVRc2 (ORCPT ); Thu, 22 Jun 2023 13:32:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59710 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230072AbjFVRc1 (ORCPT ); Thu, 22 Jun 2023 13:32:27 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DEB952111 for ; Thu, 22 Jun 2023 10:31:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1687455094; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=3A/9MXgBBjsOiJR7aN+jD3J+Q2qngmB+feAsrMbXy+w=; b=HjT/g6WCMyyUN8UuSLua0gMYMWDTsY720NuWa6QhBpHt+ginsofeElSCh5WZyZTpMIg7hs TbZt9x9scd43eHP+tUIayIED9pDSgBv57QN6QTCUEJIedzgT1DputyPxLF5M+rtZUkFHFJ 3pMVDGfPQNQHS6/uQXjzEaLjFCJf6KY= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-252-UyN40HpJMXeYe_nUBtgVVA-1; Thu, 22 Jun 2023 13:31:31 -0400 X-MC-Unique: UyN40HpJMXeYe_nUBtgVVA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 1F2C11C08781; Thu, 22 Jun 2023 17:31:28 +0000 (UTC) Received: from file1-rdu.file-001.prod.rdu2.dc.redhat.com (unknown [10.11.5.21]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 11C002166B25; Thu, 22 Jun 2023 17:31:28 +0000 (UTC) Received: by file1-rdu.file-001.prod.rdu2.dc.redhat.com (Postfix, from userid 12668) id 0BC4130C0457; Thu, 22 Jun 2023 17:31:28 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by file1-rdu.file-001.prod.rdu2.dc.redhat.com (Postfix) with ESMTP id 0ACF83F7CF; Thu, 22 Jun 2023 19:31:28 +0200 (CEST) Date: Thu, 22 Jun 2023 19:31:28 +0200 (CEST) From: Mikulas Patocka To: Demi Marie Obenour cc: Alasdair Kergon , Mike Snitzer , dm-devel@redhat.com, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [dm-devel] [PATCH v2 3/6] device-mapper: structs and parameter strings must not overlap In-Reply-To: <20230603145244.1538-4-demi@invisiblethingslab.com> Message-ID: References: <20230601212456.1533-1-demi@invisiblethingslab.com> <20230603145244.1538-1-demi@invisiblethingslab.com> <20230603145244.1538-4-demi@invisiblethingslab.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Sat, 3 Jun 2023, Demi Marie Obenour wrote: > The NUL terminator for each target parameter string must precede the > following 'struct dm_target_spec'. Otherwise, dm_split_args() might > corrupt this struct. Furthermore, the first 'struct dm_target_spec' > must come after the 'struct dm_ioctl', as if it overlaps too much > dm_split_args() could corrupt the 'struct dm_ioctl'. > > Signed-off-by: Demi Marie Obenour > Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") > Cc: stable@vger.kernel.org Reviewed-by: Mikulas Patocka > --- > drivers/md/dm-ioctl.c | 28 +++++++++++++++++++++------- > 1 file changed, 21 insertions(+), 7 deletions(-) > > diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c > index 64e8f16d344c47057de5e2d29e3d63202197dca0..da6ca26b51d0953df380582bb3a51c2ec22c27cb 100644 > --- a/drivers/md/dm-ioctl.c > +++ b/drivers/md/dm-ioctl.c > @@ -1391,7 +1391,7 @@ static inline fmode_t get_mode(struct dm_ioctl *param) > return mode; > } > > -static int next_target(struct dm_target_spec *last, uint32_t next, void *end, > +static int next_target(struct dm_target_spec *last, uint32_t next, const char *end, > struct dm_target_spec **spec, char **target_params) > { > static_assert(_Alignof(struct dm_target_spec) <= 8, > @@ -1404,7 +1404,7 @@ static int next_target(struct dm_target_spec *last, uint32_t next, void *end, > * sizeof(struct dm_target_spec) or more, as otherwise *last was > * out of bounds already. > */ > - size_t remaining = (char *)end - (char *)last; > + size_t remaining = end - (char *)last; > > /* > * There must be room for both the next target spec and the > @@ -1423,10 +1423,7 @@ static int next_target(struct dm_target_spec *last, uint32_t next, void *end, > *spec = (struct dm_target_spec *) ((unsigned char *) last + next); > *target_params = (char *) (*spec + 1); > > - if (*spec < (last + 1)) > - return -EINVAL; > - > - return invalid_str(*target_params, end); > + return 0; > } > > static int populate_table(struct dm_table *table, > @@ -1436,8 +1433,9 @@ static int populate_table(struct dm_table *table, > unsigned int i = 0; > struct dm_target_spec *spec = (struct dm_target_spec *) param; > uint32_t next = param->data_start; > - void *end = (void *) param + param_size; > + const char *const end = (const char *) param + param_size; > char *target_params; > + size_t min_size = sizeof(struct dm_ioctl); > > if (!param->target_count) { > DMERR("%s: no targets specified", __func__); > @@ -1445,6 +1443,13 @@ static int populate_table(struct dm_table *table, > } > > for (i = 0; i < param->target_count; i++) { > + const char *nul_terminator; > + > + if (next < min_size) { > + DMERR("%s: next target spec (offset %u) overlaps %s", > + __func__, next, i ? "previous target" : "'struct dm_ioctl'"); > + return -EINVAL; > + } > > r = next_target(spec, next, end, &spec, &target_params); > if (r) { > @@ -1452,6 +1457,15 @@ static int populate_table(struct dm_table *table, > return r; > } > > + nul_terminator = memchr(target_params, 0, (size_t)(end - target_params)); > + if (nul_terminator == NULL) { > + DMERR("%s: target parameters not NUL-terminated", __func__); > + return -EINVAL; > + } > + > + /* Add 1 for NUL terminator */ > + min_size = (size_t)(nul_terminator - (const char *)spec) + 1; > + > r = dm_table_add_target(table, spec->target_type, > (sector_t) spec->sector_start, > (sector_t) spec->length, > -- > Sincerely, > Demi Marie Obenour (she/her/hers) > Invisible Things Lab > > -- > dm-devel mailing list > dm-devel@redhat.com > https://listman.redhat.com/mailman/listinfo/dm-devel >