[03/64] rpmsg: glink: Replace strncpy() with strscpy_pad()

Message ID	20210727205855.411487-4-keescook@chromium.org (mailing list archive)
State	Not Applicable
Delegated to:	Johannes Berg
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 03/64] rpmsg: glink: Replace strncpy() with strscpy_pad() Date: Tue, 27 Jul 2021 13:57:54 -0700 Message-Id: <20210727205855.411487-4-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

20210727205855.411487-4-keescook@chromium.org (mailing list archive)

State

Not Applicable

Delegated to:

Johannes Berg

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 03/64] rpmsg: glink: Replace strncpy() with strscpy_pad()
Date: Tue, 27 Jul 2021 13:57:54 -0700
Message-Id: <20210727205855.411487-4-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, 8:57 p.m. UTC

The use of strncpy() is considered deprecated for NUL-terminated
strings[1]. Replace strncpy() with strscpy_pad() (as it seems this case
expects the NUL padding to fill the allocation following the flexible
array). This additionally silences a warning seen when building under
-Warray-bounds:

./include/linux/fortify-string.h:38:30: warning: '__builtin_strncpy' offset 24 from the object at '__mptr' is out of the bounds of referenced subobject 'data' with type 'u8[]' {aka 'unsigned char[]'} at offset 24 [-Warray-bounds]
   38 | #define __underlying_strncpy __builtin_strncpy
      |                              ^
./include/linux/fortify-string.h:50:9: note: in expansion of macro '__underlying_strncpy'
   50 |  return __underlying_strncpy(p, q, size);
      |         ^~~~~~~~~~~~~~~~~~~~
drivers/rpmsg/qcom_glink_native.c: In function 'qcom_glink_work':
drivers/rpmsg/qcom_glink_native.c:36:5: note: subobject 'data' declared here
   36 |  u8 data[];
      |     ^~~~

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/rpmsg/qcom_glink_native.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Gustavo A. R. Silva July 28, 2021, 2:07 a.m. UTC | #1

On Tue, Jul 27, 2021 at 01:57:54PM -0700, Kees Cook wrote:
> The use of strncpy() is considered deprecated for NUL-terminated
> strings[1]. Replace strncpy() with strscpy_pad() (as it seems this case
> expects the NUL padding to fill the allocation following the flexible
> array). This additionally silences a warning seen when building under
> -Warray-bounds:
> 
> ./include/linux/fortify-string.h:38:30: warning: '__builtin_strncpy' offset 24 from the object at '__mptr' is out of the bounds of referenced subobject 'data' with type 'u8[]' {aka 'unsigned char[]'} at offset 24 [-Warray-bounds]
>    38 | #define __underlying_strncpy __builtin_strncpy
>       |                              ^
> ./include/linux/fortify-string.h:50:9: note: in expansion of macro '__underlying_strncpy'
>    50 |  return __underlying_strncpy(p, q, size);
>       |         ^~~~~~~~~~~~~~~~~~~~
> drivers/rpmsg/qcom_glink_native.c: In function 'qcom_glink_work':
> drivers/rpmsg/qcom_glink_native.c:36:5: note: subobject 'data' declared here
>    36 |  u8 data[];
>       |     ^~~~
> 
> [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings
> 
> Signed-off-by: Kees Cook <keescook@chromium.org>

Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Thanks
--
Gustavo

> ---
>  drivers/rpmsg/qcom_glink_native.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c
> index 05533c71b10e..c7b9de655080 100644
> --- a/drivers/rpmsg/qcom_glink_native.c
> +++ b/drivers/rpmsg/qcom_glink_native.c
> @@ -1440,7 +1440,7 @@ static int qcom_glink_rx_open(struct qcom_glink *glink, unsigned int rcid,
>  		}
>  
>  		rpdev->ept = &channel->ept;
> -		strncpy(rpdev->id.name, name, RPMSG_NAME_SIZE);
> +		strscpy_pad(rpdev->id.name, name, RPMSG_NAME_SIZE);
>  		rpdev->src = RPMSG_ADDR_ANY;
>  		rpdev->dst = RPMSG_ADDR_ANY;
>  		rpdev->ops = &glink_device_ops;
> -- 
> 2.30.2
>

diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c
index 05533c71b10e..c7b9de655080 100644
--- a/drivers/rpmsg/qcom_glink_native.c
+++ b/drivers/rpmsg/qcom_glink_native.c
@@ -1440,7 +1440,7 @@  static int qcom_glink_rx_open(struct qcom_glink *glink, unsigned int rcid,
 		}
 
 		rpdev->ept = &channel->ept;
-		strncpy(rpdev->id.name, name, RPMSG_NAME_SIZE);
+		strscpy_pad(rpdev->id.name, name, RPMSG_NAME_SIZE);
 		rpdev->src = RPMSG_ADDR_ANY;
 		rpdev->dst = RPMSG_ADDR_ANY;
 		rpdev->ops = &glink_device_ops;

[03/64] rpmsg: glink: Replace strncpy() with strscpy_pad()

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