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@xxxxxxxxxxxx> Signed-off-by: Ping-Ke Shih <pkshih@xxxxxxxxxxx> --- 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