From: Dan Carpenter <dan.carpenter@oracle.com>
To: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
devel@driverdev.osuosl.org, linux-hardening@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH][next] staging: rtl8723bs: Replace one-element array with flexible-array member in struct ndis_80211_var_ie
Date: Thu, 11 Feb 2021 14:06:30 +0300 [thread overview]
Message-ID: <20210211110630.GG2696@kadam> (raw)
In-Reply-To: <20210210224937.GA11922@embeddedor>
On Wed, Feb 10, 2021 at 04:49:37PM -0600, Gustavo A. R. Silva wrote:
> There is a regular need in the kernel to provide a way to declare having
> a dynamically sized set of trailing elements in a structure. Kernel code
> should always use “flexible array members”[1] for these cases. The older
> style of one-element or zero-length arrays should no longer be used[2].
>
> Refactor the code according to the use of a flexible-array member in
> struct ndis_80211_var_ie, instead of a one-element array.
>
> Also, this helps with the ongoing efforts to enable -Warray-bounds and
> fix the following warnings:
>
> CC [M] drivers/staging/rtl8723bs/core/rtw_wlan_util.o
> In file included from ./drivers/staging/rtl8723bs/include/drv_types.h:20,
> from drivers/staging/rtl8723bs/core/rtw_wlan_util.c:9:
> drivers/staging/rtl8723bs/core/rtw_wlan_util.c: In function ‘HT_caps_handler’:
> ./drivers/staging/rtl8723bs/include/basic_types.h:108:11: warning: array subscript 1 is above array bounds of ‘u8[1]’ {aka ‘unsigned char[1]’} [-Warray-bounds]
> 108 | (EF1BYTE(*((u8 *)(__pstart))))
> | ^
> ./drivers/staging/rtl8723bs/include/basic_types.h:42:8: note: in definition of macro ‘EF1BYTE’
> 42 | ((u8)(_val))
> | ^~~~
> ./drivers/staging/rtl8723bs/include/basic_types.h:127:4: note: in expansion of macro ‘LE_P1BYTE_TO_HOST_1BYTE’
> 127 | (LE_P1BYTE_TO_HOST_1BYTE(__pstart) >> (__bitoffset)) & \
> | ^~~~~~~~~~~~~~~~~~~~~~~
> ./drivers/staging/rtl8723bs/include/rtw_ht.h:97:55: note: in expansion of macro ‘LE_BITS_TO_1BYTE’
> 97 | #define GET_HT_CAPABILITY_ELE_RX_STBC(_pEleStart) LE_BITS_TO_1BYTE((_pEleStart)+1, 0, 2)
> | ^~~~~~~~~~~~~~~~
> drivers/staging/rtl8723bs/core/rtw_wlan_util.c:1104:58: note: in expansion of macro ‘GET_HT_CAPABILITY_ELE_RX_STBC’
> 1104 | if (TEST_FLAG(phtpriv->stbc_cap, STBC_HT_ENABLE_TX) && GET_HT_CAPABILITY_ELE_RX_STBC(pIE->data)) {
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/staging/rtl8723bs/core/rtw_wlan_util.c:1051:75: warning: array subscript 2 is above array bounds of ‘u8[1]’ {aka ‘unsigned char[1]’} [-Warray-bounds]
> 1051 | if ((pmlmeinfo->HT_caps.u.HT_cap_element.AMPDU_para & 0x3) > (pIE->data[i] & 0x3))
> | ~~~~~~~~~^~~
> drivers/staging/rtl8723bs/core/rtw_wlan_util.c: In function ‘check_assoc_AP’:
> drivers/staging/rtl8723bs/core/rtw_wlan_util.c:1606:19: warning: array subscript 4 is above array bounds of ‘u8[1]’ {aka ‘unsigned char[1]’} [-Warray-bounds]
> 1606 | if (pIE->data[4] == 1)
> | ~~~~~~~~~^~~
> drivers/staging/rtl8723bs/core/rtw_wlan_util.c:1609:20: warning: array subscript 5 is above array bounds of ‘u8[1]’ {aka ‘unsigned char[1]’} [-Warray-bounds]
> 1609 | if (pIE->data[5] & RT_HT_CAP_USE_92SE)
> | ~~~~~~~~~^~~
> drivers/staging/rtl8723bs/core/rtw_wlan_util.c:1613:19: warning: array subscript 5 is above array bounds of ‘u8[1]’ {aka ‘unsigned char[1]’} [-Warray-bounds]
> 1613 | if (pIE->data[5] & RT_HT_CAP_USE_SOFTAP)
> | ~~~~~~~~~^~~
> drivers/staging/rtl8723bs/core/rtw_wlan_util.c:1617:20: warning: array subscript 6 is above array bounds of ‘u8[1]’ {aka ‘unsigned char[1]’} [-Warray-bounds]
> 1617 | if (pIE->data[6] & RT_HT_CAP_USE_JAGUAR_BCUT) {
> | ~~~~~~~~~^~~
>
> [1] https://en.wikipedia.org/wiki/Flexible_array_member
> [2] https://www.kernel.org/doc/html/v5.9/process/deprecated.html#zero-length-and-one-element-arrays
>
> Link: https://github.com/KSPP/linux/issues/79
> Link: https://github.com/KSPP/linux/issues/109
> Build-tested-by: kernel test robot <lkp@intel.com>
> Link: https://lore.kernel.org/lkml/602434b8.jc5DoXJ0bmHoxgIL%25lkp@intel.com/
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Looks okay to me. I looked for potential issues with changing the
sizeof the struct but couldn't find any.
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
regards,
dan carpenter
prev parent reply other threads:[~2021-02-11 11:38 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-10 22:49 [PATCH][next] staging: rtl8723bs: Replace one-element array with flexible-array member in struct ndis_80211_var_ie Gustavo A. R. Silva
2021-02-11 11:06 ` Dan Carpenter [this message]
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