[PATCH 1/2] wifi: rtw89: coex: add annotation __counted_by() for struct rtw89_btc_btf_set_slot_table

[PATCH 1/2] wifi: rtw89: coex: add annotation __counted_by() for struct rtw89_btc_btf_set_slot_table

[Ping-Ke Shih]

Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for
array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

Use struct_size() and flex_array_size() helpers to calculate proper sizes
for allocation and memcpy().

Don't change logic at all, and result is identical as before.

Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
---
 drivers/net/wireless/realtek/rtw89/coex.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/net/wireless/realtek/rtw89/coex.c b/drivers/net/wireless/realtek/rtw89/coex.c
index 4ba8b3df70ae..9f9da122f3f8 100644
--- a/drivers/net/wireless/realtek/rtw89/coex.c
+++ b/drivers/net/wireless/realtek/rtw89/coex.c
@@ -237,7 +237,7 @@ struct rtw89_btc_btf_set_report {
 struct rtw89_btc_btf_set_slot_table {
 	u8 fver;
 	u8 tbl_num;
-	u8 buf[];
+	struct rtw89_btc_fbtc_slot tbls[] __counted_by(tbl_num);
 } __packed;
 
 struct rtw89_btc_btf_set_mon_reg {
@@ -1821,19 +1821,17 @@ static void rtw89_btc_fw_en_rpt(struct rtw89_dev *rtwdev,
 static void rtw89_btc_fw_set_slots(struct rtw89_dev *rtwdev, u8 num,
 				   struct rtw89_btc_fbtc_slot *s)
 {
-	struct rtw89_btc_btf_set_slot_table *tbl = NULL;
-	u8 *ptr = NULL;
-	u16 n = 0;
+	struct rtw89_btc_btf_set_slot_table *tbl;
+	u16 n;
 
-	n = sizeof(*s) * num + sizeof(*tbl);
+	n = struct_size(tbl, tbls, num);
 	tbl = kmalloc(n, GFP_KERNEL);
 	if (!tbl)
 		return;
 
 	tbl->fver = BTF_SET_SLOT_TABLE_VER;
 	tbl->tbl_num = num;
-	ptr = &tbl->buf[0];
-	memcpy(ptr, s, num * sizeof(*s));
+	memcpy(tbl->tbls, s, flex_array_size(tbl, tbls, num));
 
 	_send_fw_cmd(rtwdev, BTFC_SET, SET_SLOT_TABLE, tbl, n);
 
-- 
2.25.1

[PATCH 2/2] wifi: rtw89: coex: add annotation __counted_by() to struct rtw89_btc_btf_set_mon_reg

[Ping-Ke Shih]

Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for
array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

Use struct_size() and flex_array_size() helpers to calculate proper sizes
for allocation and memcpy().

Don't change logic at all, and result is identical as before.

Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
---
 drivers/net/wireless/realtek/rtw89/coex.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/net/wireless/realtek/rtw89/coex.c b/drivers/net/wireless/realtek/rtw89/coex.c
index 9f9da122f3f8..207218cdf2c4 100644
--- a/drivers/net/wireless/realtek/rtw89/coex.c
+++ b/drivers/net/wireless/realtek/rtw89/coex.c
@@ -243,7 +243,7 @@ struct rtw89_btc_btf_set_slot_table {
 struct rtw89_btc_btf_set_mon_reg {
 	u8 fver;
 	u8 reg_num;
-	u8 buf[];
+	struct rtw89_btc_fbtc_mreg regs[] __counted_by(reg_num);
 } __packed;
 
 enum btc_btf_set_cx_policy {
@@ -1843,7 +1843,7 @@ static void btc_fw_set_monreg(struct rtw89_dev *rtwdev)
 	const struct rtw89_chip_info *chip = rtwdev->chip;
 	const struct rtw89_btc_ver *ver = rtwdev->btc.ver;
 	struct rtw89_btc_btf_set_mon_reg *monreg = NULL;
-	u8 n, *ptr = NULL, ulen, cxmreg_max;
+	u8 n, ulen, cxmreg_max;
 	u16 sz = 0;
 
 	n = chip->mon_reg_num;
@@ -1864,16 +1864,15 @@ static void btc_fw_set_monreg(struct rtw89_dev *rtwdev)
 		return;
 	}
 
-	ulen = sizeof(struct rtw89_btc_fbtc_mreg);
-	sz = (ulen * n) + sizeof(*monreg);
+	ulen = sizeof(monreg->regs[0]);
+	sz = struct_size(monreg, regs, n);
 	monreg = kmalloc(sz, GFP_KERNEL);
 	if (!monreg)
 		return;
 
 	monreg->fver = ver->fcxmreg;
 	monreg->reg_num = n;
-	ptr = &monreg->buf[0];
-	memcpy(ptr, chip->mon_reg, n * ulen);
+	memcpy(monreg->regs, chip->mon_reg, flex_array_size(monreg, regs, n));
 	rtw89_debug(rtwdev, RTW89_DBG_BTC,
 		    "[BTC], %s(): sz=%d ulen=%d n=%d\n",
 		    __func__, sz, ulen, n);
-- 
2.25.1

Re: [PATCH 2/2] wifi: rtw89: coex: add annotation __counted_by() to struct rtw89_btc_btf_set_mon_reg

[Kees Cook]

On Wed, Oct 11, 2023 at 02:37:25PM +0800, Ping-Ke Shih wrote:
> Prepare for the coming implementation by GCC and Clang of the __counted_by
> attribute. Flexible array members annotated with __counted_by can have
> their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for
> array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
> 
> Use struct_size() and flex_array_size() helpers to calculate proper sizes
> for allocation and memcpy().
> 
> Don't change logic at all, and result is identical as before.
> 
> Cc: Kees Cook <keescook@chromium.org>
> Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>

Looks good too. Thanks!

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

-- 
Kees Cook

Re: [PATCH 1/2] wifi: rtw89: coex: add annotation __counted_by() for struct rtw89_btc_btf_set_slot_table

[Kees Cook]

On Wed, Oct 11, 2023 at 02:37:24PM +0800, Ping-Ke Shih wrote:
> Prepare for the coming implementation by GCC and Clang of the __counted_by
> attribute. Flexible array members annotated with __counted_by can have
> their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for
> array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
> 
> Use struct_size() and flex_array_size() helpers to calculate proper sizes
> for allocation and memcpy().
> 
> Don't change logic at all, and result is identical as before.
> 
> Cc: Kees Cook <keescook@chromium.org>
> Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>

Thanks for this!

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

> ---
>  drivers/net/wireless/realtek/rtw89/coex.c | 12 +++++-------
>  1 file changed, 5 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/net/wireless/realtek/rtw89/coex.c b/drivers/net/wireless/realtek/rtw89/coex.c
> index 4ba8b3df70ae..9f9da122f3f8 100644
> --- a/drivers/net/wireless/realtek/rtw89/coex.c
> +++ b/drivers/net/wireless/realtek/rtw89/coex.c
> @@ -237,7 +237,7 @@ struct rtw89_btc_btf_set_report {
>  struct rtw89_btc_btf_set_slot_table {
>  	u8 fver;
>  	u8 tbl_num;
> -	u8 buf[];
> +	struct rtw89_btc_fbtc_slot tbls[] __counted_by(tbl_num);
>  } __packed;
>  
>  struct rtw89_btc_btf_set_mon_reg {
> @@ -1821,19 +1821,17 @@ static void rtw89_btc_fw_en_rpt(struct rtw89_dev *rtwdev,
>  static void rtw89_btc_fw_set_slots(struct rtw89_dev *rtwdev, u8 num,
>  				   struct rtw89_btc_fbtc_slot *s)
>  {
> -	struct rtw89_btc_btf_set_slot_table *tbl = NULL;
> -	u8 *ptr = NULL;
> -	u16 n = 0;
> +	struct rtw89_btc_btf_set_slot_table *tbl;
> +	u16 n;

Using u16 instead of size_t here makes me nervous, but since "num" is
u8, wrap-around isn't possible. :P

-- 
Kees Cook

Re: [PATCH 1/2] wifi: rtw89: coex: add annotation __counted_by() for struct rtw89_btc_btf_set_slot_table

[Kalle Valo]

Ping-Ke Shih <pkshih@realtek.com> wrote:

> Prepare for the coming implementation by GCC and Clang of the __counted_by
> attribute. Flexible array members annotated with __counted_by can have
> their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for
> array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
> 
> Use struct_size() and flex_array_size() helpers to calculate proper sizes
> for allocation and memcpy().
> 
> Don't change logic at all, and result is identical as before.
> 
> Cc: Kees Cook <keescook@chromium.org>
> Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
> Reviewed-by: Kees Cook <keescook@chromium.org>

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

07202dc12b53 wifi: rtw89: coex: add annotation __counted_by() for struct rtw89_btc_btf_set_slot_table
618071ae0f7e wifi: rtw89: coex: add annotation __counted_by() to struct rtw89_btc_btf_set_mon_reg

-- 
https://patchwork.kernel.org/project/linux-wireless/patch/20231011063725.25276-1-pkshih@realtek.com/

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