[PATCH v2] staging: r8188eu: add check for kzalloc

[PATCH v2] staging: r8188eu: add check for kzalloc

[Jiasheng Jiang]

As kzalloc() may return null pointer, it should be better to
check the return value and return error if fails in order
to avoid dereference of null pointer.
Moreover, the return value of rtw_alloc_hwxmits() should also
be dealt with.

Fixes: 15865124feed ("staging: r8188eu: introduce new core dir for RTL8188eu driver")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
---
Changelog

v1 -> v2:

*Change 1. Make rtw_alloc_hwxmits() return -ENOMEM on failure
and zero on success.
---
 drivers/staging/r8188eu/core/rtw_xmit.c    | 11 +++++++++--
 drivers/staging/r8188eu/include/rtw_xmit.h |  2 +-
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/staging/r8188eu/core/rtw_xmit.c b/drivers/staging/r8188eu/core/rtw_xmit.c
index c2a550e7250e..0b3bcfbf22f7 100644
--- a/drivers/staging/r8188eu/core/rtw_xmit.c
+++ b/drivers/staging/r8188eu/core/rtw_xmit.c
@@ -178,7 +178,10 @@ s32	_rtw_init_xmit_priv(struct xmit_priv *pxmitpriv, struct adapter *padapter)
 
 	pxmitpriv->free_xmit_extbuf_cnt = num_xmit_extbuf;
 
-	rtw_alloc_hwxmits(padapter);
+	res = rtw_alloc_hwxmits(padapter);
+	if (res)
+		goto exit;
+
 	rtw_init_hwxmits(pxmitpriv->hwxmits, pxmitpriv->hwxmit_entry);
 
 	for (i = 0; i < 4; i++)
@@ -1474,7 +1477,7 @@ s32 rtw_xmit_classifier(struct adapter *padapter, struct xmit_frame *pxmitframe)
 	return res;
 }
 
-void rtw_alloc_hwxmits(struct adapter *padapter)
+int rtw_alloc_hwxmits(struct adapter *padapter)
 {
 	struct hw_xmit *hwxmits;
 	struct xmit_priv *pxmitpriv = &padapter->xmitpriv;
@@ -1482,6 +1485,8 @@ void rtw_alloc_hwxmits(struct adapter *padapter)
 	pxmitpriv->hwxmit_entry = HWXMIT_ENTRY;
 
 	pxmitpriv->hwxmits = kzalloc(sizeof(struct hw_xmit) * pxmitpriv->hwxmit_entry, GFP_KERNEL);
+	if (!pxmitpriv->hwxmits)
+		return -ENOMEM;
 
 	hwxmits = pxmitpriv->hwxmits;
 
@@ -1498,6 +1503,8 @@ void rtw_alloc_hwxmits(struct adapter *padapter)
 		hwxmits[3] .sta_queue = &pxmitpriv->bk_pending;
 	} else {
 	}
+
+	return 0;
 }
 
 void rtw_free_hwxmits(struct adapter *padapter)
diff --git a/drivers/staging/r8188eu/include/rtw_xmit.h b/drivers/staging/r8188eu/include/rtw_xmit.h
index b2df1480d66b..e73632972900 100644
--- a/drivers/staging/r8188eu/include/rtw_xmit.h
+++ b/drivers/staging/r8188eu/include/rtw_xmit.h
@@ -341,7 +341,7 @@ s32 rtw_txframes_sta_ac_pending(struct adapter *padapter,
 void rtw_init_hwxmits(struct hw_xmit *phwxmit, int entry);
 s32 _rtw_init_xmit_priv(struct xmit_priv *pxmitpriv, struct adapter *padapter);
 void _rtw_free_xmit_priv(struct xmit_priv *pxmitpriv);
-void rtw_alloc_hwxmits(struct adapter *padapter);
+int rtw_alloc_hwxmits(struct adapter *padapter);
 void rtw_free_hwxmits(struct adapter *padapter);
 s32 rtw_xmit(struct adapter *padapter, struct sk_buff **pkt);
 
-- 
2.25.1

Re: [PATCH v2] staging: r8188eu: add check for kzalloc

[Dan Carpenter]

On Wed, May 18, 2022 at 02:30:24PM +0800, Jiasheng Jiang wrote:
> diff --git a/drivers/staging/r8188eu/core/rtw_xmit.c b/drivers/staging/r8188eu/core/rtw_xmit.c
> index c2a550e7250e..0b3bcfbf22f7 100644
> --- a/drivers/staging/r8188eu/core/rtw_xmit.c
> +++ b/drivers/staging/r8188eu/core/rtw_xmit.c
> @@ -178,7 +178,10 @@ s32	_rtw_init_xmit_priv(struct xmit_priv *pxmitpriv, struct adapter *padapter)
>  
>  	pxmitpriv->free_xmit_extbuf_cnt = num_xmit_extbuf;
>  
> -	rtw_alloc_hwxmits(padapter);
> +	res = rtw_alloc_hwxmits(padapter);
> +	if (res)
> +		goto exit;

Unfortunately this needs to be:

	if (res) {
		res = _FAIL;
		goto exit;
	}

Eventually someone will get rid of the _FAIL garbage but for now the
caller expects it.

regards,
dan carpenter