2022-03-31 10:13:49

by Xiaoke Wang

Subject: [PATCH] staging: r8188eu: change the allocation type of pdata_attr

From: Xiaoke Wang <[email protected]>

`pdata_attr` was allocated by kzalloc() in go_add_group_info_attr(), but
there is a lack of error handlers along the call chain it lies and the
lifetime of `pdata_attr` is only in go_add_group_info_attr().
Therefore, changing it to a local variable on stack like the other
functions in rtw_p2p.c is a possible choice, such as
`u8 p2pie[MAX_P2P_IE_LEN] = { 0x00 };` in build_probe_resp_p2p_ie()
which is the caller of go_add_group_info_attr().

Signed-off-by: Xiaoke Wang <[email protected]>
---
drivers/staging/r8188eu/core/rtw_p2p.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/r8188eu/core/rtw_p2p.c b/drivers/staging/r8188eu/core/rtw_p2p.c
index e2b6cf2..f1a5df8 100644
--- a/drivers/staging/r8188eu/core/rtw_p2p.c
+++ b/drivers/staging/r8188eu/core/rtw_p2p.c
@@ -27,15 +27,14 @@ static u32 go_add_group_info_attr(struct wifidirect_info *pwdinfo, u8 *pbuf)
struct list_head *phead, *plist;
u32 len = 0;
u16 attr_len = 0;
- u8 tmplen, *pdata_attr, *pstart, *pcur;
+ u8 pdata_attr[MAX_P2P_IE_LEN] = { 0x00 };
+ u8 tmplen, *pstart, *pcur;
struct sta_info *psta = NULL;
struct adapter *padapter = pwdinfo->padapter;
struct sta_priv *pstapriv = &padapter->stapriv;

DBG_88E("%s\n", __func__);

- pdata_attr = kzalloc(MAX_P2P_IE_LEN, GFP_KERNEL);
-
pstart = pdata_attr;
pcur = pdata_attr;

@@ -106,7 +105,6 @@ static u32 go_add_group_info_attr(struct wifidirect_info *pwdinfo, u8 *pbuf)
if (attr_len > 0)
len = rtw_set_p2p_attr_content(pbuf, P2P_ATTR_GROUP_INFO, attr_len, pdata_attr);

- kfree(pdata_attr);
return len;
}

--

2022-03-31 19:39:17

by Greg Kroah-Hartman

Subject: Re: [PATCH] staging: r8188eu: change the allocation type of pdata_attr

On Thu, Mar 31, 2022 at 03:37:00PM +0800, [email protected] wrote:
> From: Xiaoke Wang <[email protected]>
>
> `pdata_attr` was allocated by kzalloc() in go_add_group_info_attr(), but
> there is a lack of error handlers along the call chain it lies and the
> lifetime of `pdata_attr` is only in go_add_group_info_attr().
> Therefore, changing it to a local variable on stack like the other
> functions in rtw_p2p.c is a possible choice, such as
> `u8 p2pie[MAX_P2P_IE_LEN] = { 0x00 };` in build_probe_resp_p2p_ie()
> which is the caller of go_add_group_info_attr().
>
> Signed-off-by: Xiaoke Wang <[email protected]>
> ---
> drivers/staging/r8188eu/core/rtw_p2p.c | 6 ++----
> 1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/staging/r8188eu/core/rtw_p2p.c b/drivers/staging/r8188eu/core/rtw_p2p.c
> index e2b6cf2..f1a5df8 100644
> --- a/drivers/staging/r8188eu/core/rtw_p2p.c
> +++ b/drivers/staging/r8188eu/core/rtw_p2p.c
> @@ -27,15 +27,14 @@ static u32 go_add_group_info_attr(struct wifidirect_info *pwdinfo, u8 *pbuf)
> struct list_head *phead, *plist;
> u32 len = 0;
> u16 attr_len = 0;
> - u8 tmplen, *pdata_attr, *pstart, *pcur;
> + u8 pdata_attr[MAX_P2P_IE_LEN] = { 0x00 };

As I said before, this is way too big to put on the stack.