[PATCH] staging: rtl8723au: fix potential leak in update_bcn_wps_ie()

[PATCH] staging: rtl8723au: fix potential leak in update_bcn_wps_ie()

[Christian Engelmayer]

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Fix a potential leak in the error path of function update_bcn_wps_ie().
Make sure that allocated memory for 'pbackup_remainder_ie' is freed
upon return. Detected by Coverity - CID 1077718.

Signed-off-by: Christian Engelmayer <cengelma@gmx.at>
---
Compile tested and applies against branch staging-next of tree
git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git
---
 drivers/staging/rtl8723au/core/rtw_ap.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/staging/rtl8723au/core/rtw_ap.c b/drivers/staging/rtl8723au/core/rtw_ap.c
index 9b31412..f2c78a7 100644
--- a/drivers/staging/rtl8723au/core/rtw_ap.c
+++ b/drivers/staging/rtl8723au/core/rtw_ap.c
@@ -1276,7 +1276,7 @@ static void update_bcn_wps_ie(struct rtw_adapter *padapter)
 
 	pwps_ie_src = pmlmepriv->wps_beacon_ie;
 	if (pwps_ie_src == NULL)
-		return;
+		goto exit;
 
 	wps_ielen = (uint)pwps_ie_src[1];/* to get ie data len */
 	if ((wps_offset+wps_ielen+2+remainder_ielen)<= MAX_IE_SZ)
@@ -1291,8 +1291,8 @@ static void update_bcn_wps_ie(struct rtw_adapter *padapter)
 		pnetwork->IELength = wps_offset + (wps_ielen+2) + remainder_ielen;
 	}
 
-	if (pbackup_remainder_ie)
-		kfree(pbackup_remainder_ie);
+exit:
+	kfree(pbackup_remainder_ie);
 }
 
 static void update_bcn_p2p_ie(struct rtw_adapter *padapter)
-- 
1.9.1

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Re: [PATCH] staging: rtl8723au: fix potential leak in update_bcn_wps_ie()

[Mateusz Guzik]

On Thu, May 01, 2014 at 01:57:27PM +0200, Christian Engelmayer wrote:
> Fix a potential leak in the error path of function update_bcn_wps_ie().
> Make sure that allocated memory for 'pbackup_remainder_ie' is freed
> upon return. Detected by Coverity - CID 1077718.
> 

        if (remainder_ielen > 0) {
                pbackup_remainder_ie = kmalloc(remainder_ielen, GFP_ATOMIC);
                if (pbackup_remainder_ie)
                        memcpy(pbackup_remainder_ie, premainder_ie,
                               remainder_ielen);
        }

        pwps_ie_src = pmlmepriv->wps_beacon_ie;
        if (pwps_ie_src == NULL)
                return;


Maybe just check pwps_ie_src earlier?

-- 
Mateusz Guzik

Re: [PATCH] staging: rtl8723au: fix potential leak in update_bcn_wps_ie()

[Christian Engelmayer]

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On Thu, 1 May 2014 14:22:17 +0200, Mateusz Guzik <mguzik@redhat.com> wrote:
> On Thu, May 01, 2014 at 01:57:27PM +0200, Christian Engelmayer wrote:
> > Fix a potential leak in the error path of function update_bcn_wps_ie().
> > Make sure that allocated memory for 'pbackup_remainder_ie' is freed
> > upon return. Detected by Coverity - CID 1077718.
> > 
> 
>         if (remainder_ielen > 0) {
>                 pbackup_remainder_ie = kmalloc(remainder_ielen, GFP_ATOMIC);
>                 if (pbackup_remainder_ie)
>                         memcpy(pbackup_remainder_ie, premainder_ie,
>                                remainder_ielen);
>         }
> 
>         pwps_ie_src = pmlmepriv->wps_beacon_ie;
>         if (pwps_ie_src == NULL)
>                 return;
> 
> 
> Maybe just check pwps_ie_src earlier?
> 

You are right, I see no reason why this cannot be done early in the function.


diff --git a/drivers/staging/rtl8723au/core/rtw_ap.c b/drivers/staging/rtl8723au/core/rtw_ap.c
index 9b31412..da028c535 100644
--- a/drivers/staging/rtl8723au/core/rtw_ap.c
+++ b/drivers/staging/rtl8723au/core/rtw_ap.c
@@ -1256,6 +1256,10 @@ static void update_bcn_wps_ie(struct rtw_adapter *padapter)
 
 	DBG_8723A("%s\n", __func__);
 
+	pwps_ie_src = pmlmepriv->wps_beacon_ie;
+	if (pwps_ie_src == NULL)
+		return;
+
 	pwps_ie = rtw_get_wps_ie23a(ie+_FIXED_IE_LENGTH_, ielen-_FIXED_IE_LENGTH_, NULL, &wps_ielen);
 
 	if (pwps_ie == NULL || wps_ielen == 0)
@@ -1274,10 +1278,6 @@ static void update_bcn_wps_ie(struct rtw_adapter *padapter)
 			       remainder_ielen);
 	}
 
-	pwps_ie_src = pmlmepriv->wps_beacon_ie;
-	if (pwps_ie_src == NULL)
-		return;
-
 	wps_ielen = (uint)pwps_ie_src[1];/* to get ie data len */
 	if ((wps_offset+wps_ielen+2+remainder_ielen)<= MAX_IE_SZ)
 	{


Regards,
Christian

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Re: [PATCH] staging: rtl8723au: fix potential leak in update_bcn_wps_ie()

[Jes Sorensen]

Christian Engelmayer <cengelma@gmx.at> writes:
> On Thu, 1 May 2014 14:22:17 +0200, Mateusz Guzik <mguzik@redhat.com> wrote:
>> On Thu, May 01, 2014 at 01:57:27PM +0200, Christian Engelmayer wrote:
>> > Fix a potential leak in the error path of function update_bcn_wps_ie().
>> > Make sure that allocated memory for 'pbackup_remainder_ie' is freed
>> > upon return. Detected by Coverity - CID 1077718.
>> > 
>> 
>>         if (remainder_ielen > 0) {
>>                 pbackup_remainder_ie = kmalloc(remainder_ielen, GFP_ATOMIC);
>>                 if (pbackup_remainder_ie)
>>                         memcpy(pbackup_remainder_ie, premainder_ie,
>>                                remainder_ielen);
>>         }
>> 
>>         pwps_ie_src = pmlmepriv->wps_beacon_ie;
>>         if (pwps_ie_src == NULL)
>>                 return;
>> 
>> 
>> Maybe just check pwps_ie_src earlier?
>> 
>
> You are right, I see no reason why this cannot be done early in the function.

Looks good to me - if you send me a patch with a commit message and a
Signed-off-by, I'll add it to the rtl8723au driver tree and push it to
Greg with my next set of changes.

Cheers,
Jes