[PATCH 0/2][next] wifi: brcmfmac: common: Replace one-element array with flexible-array member

[PATCH 0/2][next] wifi: brcmfmac: common: Replace one-element array with flexible-array member

[Gustavo A. R. Silva]

Hi!

This series aims to replace a one-element array with flexible-array
member in drivers/net/wireless/broadcom/brcm80211/brcmfmac/fwil_types.h
(in struct brcmf_dload_data_le) and use the struct_size() helper.

This helps with the ongoing efforts to tighten the FORTIFY_SOURCE
routines on memcpy() and help us make progress towards globally
enabling -fstrict-flex-arrays=3 [1].

Link: https://www.kernel.org/doc/html/v5.10/process/deprecated.html#zero-length-and-one-element-arrays
Link: https://github.com/KSPP/linux/issues/230
Link: https://github.com/KSPP/linux/issues/79
Link: https://gcc.gnu.org/pipermail/gcc-patches/2022-October/602902.html [1]

Gustavo A. R. Silva (2):
  wifi: brcmfmac: replace one-element array with flexible-array member
    in struct brcmf_dload_data_le
  wifi: brcmfmac: Use struct_size() in code ralated to struct
    brcmf_dload_data_le

 drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c  | 7 ++++---
 .../net/wireless/broadcom/brcm80211/brcmfmac/fwil_types.h  | 2 +-
 2 files changed, 5 insertions(+), 4 deletions(-)

-- 
2.34.1

[PATCH 1/2][next] wifi: brcmfmac: replace one-element array with flexible-array member in struct brcmf_dload_data_le

[Gustavo A. R. Silva]

One-element arrays are deprecated, and we are replacing them with flexible
array members instead. So, replace one-element array with flexible-array
member in struct brcmf_dload_data_le.

Important to mention is that doing a build before/after this patch results
in no binary output differences.

This helps with the ongoing efforts to tighten the FORTIFY_SOURCE routines
on memcpy() and help us make progress towards globally enabling
-fstrict-flex-arrays=3 [1].

Link: https://github.com/KSPP/linux/issues/230
Link: https://github.com/KSPP/linux/issues/79
Link: https://gcc.gnu.org/pipermail/gcc-patches/2022-October/602902.html [1]
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
 drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c     | 4 ++--
 drivers/net/wireless/broadcom/brcm80211/brcmfmac/fwil_types.h | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c
index 22344e68fd59..2e836566e218 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c
@@ -110,7 +110,7 @@ static int brcmf_c_download(struct brcmf_if *ifp, u16 flag,
 	dload_buf->dload_type = cpu_to_le16(DL_TYPE_CLM);
 	dload_buf->len = cpu_to_le32(len);
 	dload_buf->crc = cpu_to_le32(0);
-	len = sizeof(*dload_buf) + len - 1;
+	len = sizeof(*dload_buf) + len;
 
 	err = brcmf_fil_iovar_data_set(ifp, "clmload", dload_buf, len);
 
@@ -139,7 +139,7 @@ static int brcmf_c_process_clm_blob(struct brcmf_if *ifp)
 		return 0;
 	}
 
-	chunk_buf = kzalloc(sizeof(*chunk_buf) + MAX_CHUNK_LEN - 1, GFP_KERNEL);
+	chunk_buf = kzalloc(sizeof(*chunk_buf) + MAX_CHUNK_LEN, GFP_KERNEL);
 	if (!chunk_buf) {
 		err = -ENOMEM;
 		goto done;
diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fwil_types.h b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fwil_types.h
index f518e025d6e4..a69339f72c66 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fwil_types.h
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fwil_types.h
@@ -943,7 +943,7 @@ struct brcmf_dload_data_le {
 	__le16 dload_type;
 	__le32 len;
 	__le32 crc;
-	u8 data[1];
+	u8 data[];
 };
 
 /**
-- 
2.34.1

Re: [PATCH 1/2][next] wifi: brcmfmac: replace one-element array with flexible-array member in struct brcmf_dload_data_le

[Kees Cook]

On Tue, Nov 15, 2022 at 03:53:27PM -0600, Gustavo A. R. Silva wrote:
> One-element arrays are deprecated, and we are replacing them with flexible
> array members instead. So, replace one-element array with flexible-array
> member in struct brcmf_dload_data_le.
> 
> Important to mention is that doing a build before/after this patch results
> in no binary output differences.
> 
> This helps with the ongoing efforts to tighten the FORTIFY_SOURCE routines
> on memcpy() and help us make progress towards globally enabling
> -fstrict-flex-arrays=3 [1].
> 
> Link: https://github.com/KSPP/linux/issues/230
> Link: https://github.com/KSPP/linux/issues/79
> Link: https://gcc.gnu.org/pipermail/gcc-patches/2022-October/602902.html [1]
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

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

-- 
Kees Cook

Re: [PATCH 1/2][next] wifi: brcmfmac: replace one-element array with flexible-array member in struct brcmf_dload_data_le

[Kalle Valo]

"Gustavo A. R. Silva" <gustavoars@kernel.org> wrote:

> One-element arrays are deprecated, and we are replacing them with flexible
> array members instead. So, replace one-element array with flexible-array
> member in struct brcmf_dload_data_le.
> 
> Important to mention is that doing a build before/after this patch results
> in no binary output differences.
> 
> This helps with the ongoing efforts to tighten the FORTIFY_SOURCE routines
> on memcpy() and help us make progress towards globally enabling
> -fstrict-flex-arrays=3 [1].
> 
> Link: https://github.com/KSPP/linux/issues/230
> Link: https://github.com/KSPP/linux/issues/79
> Link: https://gcc.gnu.org/pipermail/gcc-patches/2022-October/602902.html [1]
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
> Reviewed-by: Kees Cook <keescook@chromium.org>

2 patches applied to wireless-next.git, thanks.

0001650b3d89 wifi: brcmfmac: replace one-element array with flexible-array member in struct brcmf_dload_data_le
633a9b6f514c wifi: brcmfmac: Use struct_size() in code ralated to struct brcmf_dload_data_le

-- 
https://patchwork.kernel.org/project/linux-wireless/patch/905f5b68cf93c812360d081caae5b15221db09b6.1668548907.git.gustavoars@kernel.org/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches

[PATCH 2/2][next] wifi: brcmfmac: Use struct_size() in code ralated to struct brcmf_dload_data_le

[Gustavo A. R. Silva]

Prefer struct_size() over open-coded versions of idiom:

sizeof(struct-with-flex-array) + sizeof(typeof-flex-array-elements) * count

where count is the max number of items the flexible array is supposed to
contain.

In this particular case, in the open-coded version sizeof(typeof-flex-array-elements)
is implicit in _count_ because the type of the flex array data is u8:

drivers/net/wireless/broadcom/brcm80211/brcmfmac/fwil_types.h:941:
 941 struct brcmf_dload_data_le {
 942         __le16 flag;
 943         __le16 dload_type;
 944         __le32 len;
 945         __le32 crc;
 946         u8 data[];
 947 };

Link: https://github.com/KSPP/linux/issues/160
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
 drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c
index 2e836566e218..4a309e5a5707 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c
@@ -110,9 +110,9 @@ static int brcmf_c_download(struct brcmf_if *ifp, u16 flag,
 	dload_buf->dload_type = cpu_to_le16(DL_TYPE_CLM);
 	dload_buf->len = cpu_to_le32(len);
 	dload_buf->crc = cpu_to_le32(0);
-	len = sizeof(*dload_buf) + len;
 
-	err = brcmf_fil_iovar_data_set(ifp, "clmload", dload_buf, len);
+	err = brcmf_fil_iovar_data_set(ifp, "clmload", dload_buf,
+				       struct_size(dload_buf, data, len));
 
 	return err;
 }
@@ -139,7 +139,8 @@ static int brcmf_c_process_clm_blob(struct brcmf_if *ifp)
 		return 0;
 	}
 
-	chunk_buf = kzalloc(sizeof(*chunk_buf) + MAX_CHUNK_LEN, GFP_KERNEL);
+	chunk_buf = kzalloc(struct_size(chunk_buf, data, MAX_CHUNK_LEN),
+			    GFP_KERNEL);
 	if (!chunk_buf) {
 		err = -ENOMEM;
 		goto done;
-- 
2.34.1

Re: [PATCH 2/2][next] wifi: brcmfmac: Use struct_size() in code ralated to struct brcmf_dload_data_le

[Kees Cook]

On Tue, Nov 15, 2022 at 03:55:34PM -0600, Gustavo A. R. Silva wrote:
> Prefer struct_size() over open-coded versions of idiom:
> 
> sizeof(struct-with-flex-array) + sizeof(typeof-flex-array-elements) * count
> 
> where count is the max number of items the flexible array is supposed to
> contain.
> 
> In this particular case, in the open-coded version sizeof(typeof-flex-array-elements)
> is implicit in _count_ because the type of the flex array data is u8:
> 
> drivers/net/wireless/broadcom/brcm80211/brcmfmac/fwil_types.h:941:
>  941 struct brcmf_dload_data_le {
>  942         __le16 flag;
>  943         __le16 dload_type;
>  944         __le32 len;
>  945         __le32 crc;
>  946         u8 data[];
>  947 };
> 
> Link: https://github.com/KSPP/linux/issues/160
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

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

-- 
Kees Cook

Re: [PATCH 2/2][next] wifi: brcmfmac: Use struct_size() in code ralated to struct brcmf_dload_data_le

[Gustavo A. R. Silva]

On 11/16/22 16:23, Kees Cook wrote:
> On Tue, Nov 15, 2022 at 03:55:34PM -0600, Gustavo A. R. Silva wrote:
>> Prefer struct_size() over open-coded versions of idiom:
>>
>> sizeof(struct-with-flex-array) + sizeof(typeof-flex-array-elements) * count
>>
>> where count is the max number of items the flexible array is supposed to
>> contain.
>>
>> In this particular case, in the open-coded version sizeof(typeof-flex-array-elements)
>> is implicit in _count_ because the type of the flex array data is u8:
>>
>> drivers/net/wireless/broadcom/brcm80211/brcmfmac/fwil_types.h:941:
>>   941 struct brcmf_dload_data_le {
>>   942         __le16 flag;
>>   943         __le16 dload_type;
>>   944         __le32 len;
>>   945         __le32 crc;
>>   946         u8 data[];
>>   947 };
>>
>> Link: https://github.com/KSPP/linux/issues/160
>> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
> 
> Reviewed-by: Kees Cook <keescook@chromium.org>
> 

Thanks for the reviews! :)

--
Gustavo