[48/64] drbd: Use struct_group() to zero algs

Message ID	20210727205855.411487-49-keescook@chromium.org
State	New
Headers	show Return-Path: <linux-wireless-owner@kernel.org> From: Kees Cook <keescook@chromium.org> To: linux-hardening@vger.kernel.org Cc: Kees Cook <keescook@chromium.org>, "Gustavo A. R. Silva" <gustavoars@kernel.org>, Keith Packard <keithpac@amazon.com>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Andrew Morton <akpm@linux-foundation.org>, linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-staging@lists.linux.dev, linux-block@vger.kernel.org, linux-kbuild@vger.kernel.org, clang-built-linux@googlegroups.com Subject: [PATCH 48/64] drbd: Use struct_group() to zero algs Date: Tue, 27 Jul 2021 13:58:39 -0700 Message-Id: <20210727205855.411487-49-keescook@chromium.org> In-Reply-To: <20210727205855.411487-1-keescook@chromium.org> References: <20210727205855.411487-1-keescook@chromium.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	Introduce strict memcpy() bounds checking \| expand [00/64] Introduce strict memcpy() bounds checking [01/64] media: omap3isp: Extract struct group for memcpy() region [02/64] mac80211: Use flex-array for radiotap header bitmap [03/64] rpmsg: glink: Replace strncpy() with strscpy_pad() [04/64] stddef: Introduce struct_group() helper macro [05/64] skbuff: Switch structure bounds to struct_group() [06/64] bnxt_en: Use struct_group_attr() for memcpy() region [07/64] staging: rtl8192e: Use struct_group() for memcpy() region [08/64] staging: rtl8192u: Use struct_group() for memcpy() region [09/64] staging: rtl8723bs: Avoid field-overflowing memcpy() [10/64] lib80211: Use struct_group() for memcpy() region [11/64] net/mlx5e: Avoid field-overflowing memcpy() [12/64] mwl8k: Use struct_group() for memcpy() region [13/64] libertas: Use struct_group() for memcpy() region [14/64] libertas_tf: Use struct_group() for memcpy() region [15/64] ipw2x00: Use struct_group() for memcpy() region [16/64] thermal: intel: int340x_thermal: Use struct_group() for memcpy() region [17/64] iommu/amd: Use struct_group() for memcpy() region [18/64] cxgb3: Use struct_group() for memcpy() region [19/64] ip: Use struct_group() for memcpy() regions [20/64] intersil: Use struct_group() for memcpy() region [21/64] cxgb4: Use struct_group() for memcpy() region [22/64] bnx2x: Use struct_group() for memcpy() region [23/64] drm/amd/pm: Use struct_group() for memcpy() region [24/64] staging: wlan-ng: Use struct_group() for memcpy() region [25/64] drm/mga/mga_ioc32: Use struct_group() for memcpy() region [26/64] net/mlx5e: Use struct_group() for memcpy() region [27/64] HID: cp2112: Use struct_group() for memcpy() region [28/64] compiler_types.h: Remove __compiletime_object_size() [29/64] lib/string: Move helper functions out of string.c [30/64] fortify: Move remaining fortify helpers into fortify-string.h [31/64] fortify: Explicitly disable Clang support [32/64] fortify: Add compile-time FORTIFY_SOURCE tests [33/64] lib: Introduce CONFIG_TEST_MEMCPY [34/64] fortify: Detect struct member overflows in memcpy() at compile-time [35/64] fortify: Detect struct member overflows in memmove() at compile-time [36/64] scsi: ibmvscsi: Avoid multi-field memset() overflow by aiming at srp [37/64] string.h: Introduce memset_after() for wiping trailing members/padding [38/64] xfrm: Use memset_after() to clear padding [39/64] mac80211: Use memset_after() to clear tx status [40/64] net: 802: Use memset_after() to clear struct fields [41/64] net: dccp: Use memset_after() for TP zeroing [42/64] net: qede: Use memset_after() for counters [43/64] ath11k: Use memset_after() for clearing queue descriptors [44/64] iw_cxgb4: Use memset_after() for cpl_t5_pass_accept_rpl [45/64] intel_th: msu: Use memset_after() for clearing hw header [46/64] IB/mthca: Use memset_after() for clearing mpt_entry [47/64] btrfs: Use memset_after() to clear end of struct [48/64] drbd: Use struct_group() to zero algs [49/64] cm4000_cs: Use struct_group() to zero struct cm4000_dev region [50/64] KVM: x86: Use struct_group() to zero decode cache [51/64] tracing: Use struct_group() to zero struct trace_iterator [52/64] dm integrity: Use struct_group() to zero struct journal_sector [53/64] HID: roccat: Use struct_group() to zero kone_mouse_event [54/64] ipv6: Use struct_group() to zero rt6_info [55/64] RDMA/mlx5: Use struct_group() to zero struct mlx5_ib_mr [56/64] ethtool: stats: Use struct_group() to clear all stats at once [57/64] netfilter: conntrack: Use struct_group() to zero struct nf_conn [58/64] powerpc: Split memset() to avoid multi-field overflow [59/64] fortify: Detect struct member overflows in memset() at compile-time [60/64] fortify: Work around Clang inlining bugs [61/64] Makefile: Enable -Warray-bounds [62/64] netlink: Avoid false-positive memcpy() warning [63/64] iwlwifi: dbg_ini: Split memcpy() to avoid multi-field write [64/64] fortify: Add run-time WARN for cross-field memcpy()

Message ID

20210727205855.411487-49-keescook@chromium.org

State

New

Headers

From: Kees Cook <keescook@chromium.org>
To: linux-hardening@vger.kernel.org
Cc: Kees Cook <keescook@chromium.org>,
	"Gustavo A. R. Silva" <gustavoars@kernel.org>,
	Keith Packard <keithpac@amazon.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org,
	netdev@vger.kernel.org, dri-devel@lists.freedesktop.org,
	linux-staging@lists.linux.dev, linux-block@vger.kernel.org,
	linux-kbuild@vger.kernel.org, clang-built-linux@googlegroups.com
Subject: [PATCH 48/64] drbd: Use struct_group() to zero algs
Date: Tue, 27 Jul 2021 13:58:39 -0700
Message-Id: <20210727205855.411487-49-keescook@chromium.org>
In-Reply-To: <20210727205855.411487-1-keescook@chromium.org>
References: <20210727205855.411487-1-keescook@chromium.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Series

Introduce strict memcpy() bounds checking | expand

Commit Message

Kees Cook July 27, 2021, 8:58 p.m. UTC

In preparation for FORTIFY_SOURCE performing compile-time and run-time
field bounds checking for memset(), avoid intentionally writing across
neighboring fields.

Add a struct_group() for the algs so that memset() can correctly reason
about the size.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/block/drbd/drbd_main.c     | 3 ++-
 drivers/block/drbd/drbd_protocol.h | 6 ++++--
 drivers/block/drbd/drbd_receiver.c | 3 ++-
 3 files changed, 8 insertions(+), 4 deletions(-)

Comments

Bart Van Assche July 28, 2021, 9:45 p.m. UTC | #1

On 7/27/21 1:58 PM, Kees Cook wrote:
> In preparation for FORTIFY_SOURCE performing compile-time and run-time
> field bounds checking for memset(), avoid intentionally writing across
> neighboring fields.
> 
> Add a struct_group() for the algs so that memset() can correctly reason
> about the size.
> 
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
>   drivers/block/drbd/drbd_main.c     | 3 ++-
>   drivers/block/drbd/drbd_protocol.h | 6 ++++--
>   drivers/block/drbd/drbd_receiver.c | 3 ++-
>   3 files changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
> index 55234a558e98..b824679cfcb2 100644
> --- a/drivers/block/drbd/drbd_main.c
> +++ b/drivers/block/drbd/drbd_main.c
> @@ -729,7 +729,8 @@ int drbd_send_sync_param(struct drbd_peer_device *peer_device)
>   	cmd = apv >= 89 ? P_SYNC_PARAM89 : P_SYNC_PARAM;
>   
>   	/* initialize verify_alg and csums_alg */
> -	memset(p->verify_alg, 0, 2 * SHARED_SECRET_MAX);
> +	BUILD_BUG_ON(sizeof(p->algs) != 2 * SHARED_SECRET_MAX);
> +	memset(&p->algs, 0, sizeof(p->algs));
>   
>   	if (get_ldev(peer_device->device)) {
>   		dc = rcu_dereference(peer_device->device->ldev->disk_conf);
> diff --git a/drivers/block/drbd/drbd_protocol.h b/drivers/block/drbd/drbd_protocol.h
> index dea59c92ecc1..a882b65ab5d2 100644
> --- a/drivers/block/drbd/drbd_protocol.h
> +++ b/drivers/block/drbd/drbd_protocol.h
> @@ -283,8 +283,10 @@ struct p_rs_param_89 {
>   
>   struct p_rs_param_95 {
>   	u32 resync_rate;
> -	char verify_alg[SHARED_SECRET_MAX];
> -	char csums_alg[SHARED_SECRET_MAX];
> +	struct_group(algs,
> +		char verify_alg[SHARED_SECRET_MAX];
> +		char csums_alg[SHARED_SECRET_MAX];
> +	);
>   	u32 c_plan_ahead;
>   	u32 c_delay_target;
>   	u32 c_fill_target;
> diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
> index 1f740e42e457..6df2539e215b 100644
> --- a/drivers/block/drbd/drbd_receiver.c
> +++ b/drivers/block/drbd/drbd_receiver.c
> @@ -3921,7 +3921,8 @@ static int receive_SyncParam(struct drbd_connection *connection, struct packet_i
>   
>   	/* initialize verify_alg and csums_alg */
>   	p = pi->data;
> -	memset(p->verify_alg, 0, 2 * SHARED_SECRET_MAX);
> +	BUILD_BUG_ON(sizeof(p->algs) != 2 * SHARED_SECRET_MAX);
> +	memset(&p->algs, 0, sizeof(p->algs));

Using struct_group() introduces complexity. Has it been considered not 
to modify struct p_rs_param_95 and instead to use two memset() calls 
instead of one (one memset() call per member)?

Thanks,

Bart.

Bart Van Assche July 30, 2021, 2:57 a.m. UTC | #2

On 7/29/21 7:31 PM, Kees Cook wrote:
> On Wed, Jul 28, 2021 at 02:45:55PM -0700, Bart Van Assche wrote:

>> On 7/27/21 1:58 PM, Kees Cook wrote:

>>> In preparation for FORTIFY_SOURCE performing compile-time and run-time

>>> field bounds checking for memset(), avoid intentionally writing across

>>> neighboring fields.

>>>

>>> Add a struct_group() for the algs so that memset() can correctly reason

>>> about the size.

>>>

>>> Signed-off-by: Kees Cook <keescook@chromium.org>

>>> ---

>>>   drivers/block/drbd/drbd_main.c     | 3 ++-

>>>   drivers/block/drbd/drbd_protocol.h | 6 ++++--

>>>   drivers/block/drbd/drbd_receiver.c | 3 ++-

>>>   3 files changed, 8 insertions(+), 4 deletions(-)

>>>

>>> diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c

>>> index 55234a558e98..b824679cfcb2 100644

>>> --- a/drivers/block/drbd/drbd_main.c

>>> +++ b/drivers/block/drbd/drbd_main.c

>>> @@ -729,7 +729,8 @@ int drbd_send_sync_param(struct drbd_peer_device *peer_device)

>>>   	cmd = apv >= 89 ? P_SYNC_PARAM89 : P_SYNC_PARAM;

>>>   	/* initialize verify_alg and csums_alg */

>>> -	memset(p->verify_alg, 0, 2 * SHARED_SECRET_MAX);

>>> +	BUILD_BUG_ON(sizeof(p->algs) != 2 * SHARED_SECRET_MAX);

>>> +	memset(&p->algs, 0, sizeof(p->algs));

>>>   	if (get_ldev(peer_device->device)) {

>>>   		dc = rcu_dereference(peer_device->device->ldev->disk_conf);

>>> diff --git a/drivers/block/drbd/drbd_protocol.h b/drivers/block/drbd/drbd_protocol.h

>>> index dea59c92ecc1..a882b65ab5d2 100644

>>> --- a/drivers/block/drbd/drbd_protocol.h

>>> +++ b/drivers/block/drbd/drbd_protocol.h

>>> @@ -283,8 +283,10 @@ struct p_rs_param_89 {

>>>   struct p_rs_param_95 {

>>>   	u32 resync_rate;

>>> -	char verify_alg[SHARED_SECRET_MAX];

>>> -	char csums_alg[SHARED_SECRET_MAX];

>>> +	struct_group(algs,

>>> +		char verify_alg[SHARED_SECRET_MAX];

>>> +		char csums_alg[SHARED_SECRET_MAX];

>>> +	);

>>>   	u32 c_plan_ahead;

>>>   	u32 c_delay_target;

>>>   	u32 c_fill_target;

>>> diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c

>>> index 1f740e42e457..6df2539e215b 100644

>>> --- a/drivers/block/drbd/drbd_receiver.c

>>> +++ b/drivers/block/drbd/drbd_receiver.c

>>> @@ -3921,7 +3921,8 @@ static int receive_SyncParam(struct drbd_connection *connection, struct packet_i

>>>   	/* initialize verify_alg and csums_alg */

>>>   	p = pi->data;

>>> -	memset(p->verify_alg, 0, 2 * SHARED_SECRET_MAX);

>>> +	BUILD_BUG_ON(sizeof(p->algs) != 2 * SHARED_SECRET_MAX);

>>> +	memset(&p->algs, 0, sizeof(p->algs));

>>

>> Using struct_group() introduces complexity. Has it been considered not to

>> modify struct p_rs_param_95 and instead to use two memset() calls instead of

>> one (one memset() call per member)?

> 

> I went this direction because using two memset()s (or memcpy()s in other

> patches) changes the machine code. It's not much of a change, but it

> seems easier to justify "no binary changes" via the use of struct_group().

> 

> If splitting the memset() is preferred, I can totally do that instead.

> :)


I don't have a strong opinion about this. Lars, do you want to comment
on this patch?

Thanks,

Bart.

Lars Ellenberg July 30, 2021, 9:25 a.m. UTC | #3

On Thu, Jul 29, 2021 at 07:57:47PM -0700, Bart Van Assche wrote:
> On 7/29/21 7:31 PM, Kees Cook wrote:
> > On Wed, Jul 28, 2021 at 02:45:55PM -0700, Bart Van Assche wrote:
> >> On 7/27/21 1:58 PM, Kees Cook wrote:
> >>> In preparation for FORTIFY_SOURCE performing compile-time and run-time
> >>> field bounds checking for memset(), avoid intentionally writing across
> >>> neighboring fields.
> >>>
> >>> Add a struct_group() for the algs so that memset() can correctly reason
> >>> about the size.
> >>>
> >>> Signed-off-by: Kees Cook <keescook@chromium.org>
> >>> ---
> >>>   drivers/block/drbd/drbd_main.c     | 3 ++-
> >>>   drivers/block/drbd/drbd_protocol.h | 6 ++++--
> >>>   drivers/block/drbd/drbd_receiver.c | 3 ++-
> >>>   3 files changed, 8 insertions(+), 4 deletions(-)
> >>>
> >>> diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
> >>> index 55234a558e98..b824679cfcb2 100644
> >>> --- a/drivers/block/drbd/drbd_main.c
> >>> +++ b/drivers/block/drbd/drbd_main.c
> >>> @@ -729,7 +729,8 @@ int drbd_send_sync_param(struct drbd_peer_device *peer_device)
> >>>   	cmd = apv >= 89 ? P_SYNC_PARAM89 : P_SYNC_PARAM;
> >>>   	/* initialize verify_alg and csums_alg */
> >>> -	memset(p->verify_alg, 0, 2 * SHARED_SECRET_MAX);
> >>> +	BUILD_BUG_ON(sizeof(p->algs) != 2 * SHARED_SECRET_MAX);
> >>> +	memset(&p->algs, 0, sizeof(p->algs));
> >>>   	if (get_ldev(peer_device->device)) {
> >>>   		dc = rcu_dereference(peer_device->device->ldev->disk_conf);
> >>> diff --git a/drivers/block/drbd/drbd_protocol.h b/drivers/block/drbd/drbd_protocol.h
> >>> index dea59c92ecc1..a882b65ab5d2 100644
> >>> --- a/drivers/block/drbd/drbd_protocol.h
> >>> +++ b/drivers/block/drbd/drbd_protocol.h
> >>> @@ -283,8 +283,10 @@ struct p_rs_param_89 {
> >>>   struct p_rs_param_95 {
> >>>   	u32 resync_rate;
> >>> -	char verify_alg[SHARED_SECRET_MAX];
> >>> -	char csums_alg[SHARED_SECRET_MAX];
> >>> +	struct_group(algs,
> >>> +		char verify_alg[SHARED_SECRET_MAX];
> >>> +		char csums_alg[SHARED_SECRET_MAX];
> >>> +	);
> >>>   	u32 c_plan_ahead;
> >>>   	u32 c_delay_target;
> >>>   	u32 c_fill_target;
> >>> diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
> >>> index 1f740e42e457..6df2539e215b 100644
> >>> --- a/drivers/block/drbd/drbd_receiver.c
> >>> +++ b/drivers/block/drbd/drbd_receiver.c
> >>> @@ -3921,7 +3921,8 @@ static int receive_SyncParam(struct drbd_connection *connection, struct packet_i
> >>>   	/* initialize verify_alg and csums_alg */
> >>>   	p = pi->data;
> >>> -	memset(p->verify_alg, 0, 2 * SHARED_SECRET_MAX);
> >>> +	BUILD_BUG_ON(sizeof(p->algs) != 2 * SHARED_SECRET_MAX);
> >>> +	memset(&p->algs, 0, sizeof(p->algs));
> >>
> >> Using struct_group() introduces complexity. Has it been considered not to
> >> modify struct p_rs_param_95 and instead to use two memset() calls instead of
> >> one (one memset() call per member)?
> > 
> > I went this direction because using two memset()s (or memcpy()s in other
> > patches) changes the machine code. It's not much of a change, but it
> > seems easier to justify "no binary changes" via the use of struct_group().
> > 
> > If splitting the memset() is preferred, I can totally do that instead.
> > :)
> 
> I don't have a strong opinion about this. Lars, do you want to comment
> on this patch?


Fine either way. "no binary changes" sounds good ;-)

Thanks,
    Lars

diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 55234a558e98..b824679cfcb2 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -729,7 +729,8 @@  int drbd_send_sync_param(struct drbd_peer_device *peer_device)
 	cmd = apv >= 89 ? P_SYNC_PARAM89 : P_SYNC_PARAM;
 
 	/* initialize verify_alg and csums_alg */
-	memset(p->verify_alg, 0, 2 * SHARED_SECRET_MAX);
+	BUILD_BUG_ON(sizeof(p->algs) != 2 * SHARED_SECRET_MAX);
+	memset(&p->algs, 0, sizeof(p->algs));
 
 	if (get_ldev(peer_device->device)) {
 		dc = rcu_dereference(peer_device->device->ldev->disk_conf);
diff --git a/drivers/block/drbd/drbd_protocol.h b/drivers/block/drbd/drbd_protocol.h
index dea59c92ecc1..a882b65ab5d2 100644
--- a/drivers/block/drbd/drbd_protocol.h
+++ b/drivers/block/drbd/drbd_protocol.h
@@ -283,8 +283,10 @@  struct p_rs_param_89 {
 
 struct p_rs_param_95 {
 	u32 resync_rate;
-	char verify_alg[SHARED_SECRET_MAX];
-	char csums_alg[SHARED_SECRET_MAX];
+	struct_group(algs,
+		char verify_alg[SHARED_SECRET_MAX];
+		char csums_alg[SHARED_SECRET_MAX];
+	);
 	u32 c_plan_ahead;
 	u32 c_delay_target;
 	u32 c_fill_target;
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 1f740e42e457..6df2539e215b 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -3921,7 +3921,8 @@  static int receive_SyncParam(struct drbd_connection *connection, struct packet_i
 
 	/* initialize verify_alg and csums_alg */
 	p = pi->data;
-	memset(p->verify_alg, 0, 2 * SHARED_SECRET_MAX);
+	BUILD_BUG_ON(sizeof(p->algs) != 2 * SHARED_SECRET_MAX);
+	memset(&p->algs, 0, sizeof(p->algs));
 
 	err = drbd_recv_all(peer_device->connection, p, header_size);
 	if (err)

[48/64] drbd: Use struct_group() to zero algs

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