[PATCH v4] staging: r8188eu: fix potential memory leak in _rtw_init_xmit_priv()

[xkernel . wang]

From: Xiaoke Wang <xkernel.wang@xxxxxxxxxxx>

In _rtw_init_xmit_priv(), there are several error paths for allocation
failures just jump to the `exit` section. However, there is no action
will be performed, so the allocated resources are not properly released,
which leads to various memory leaks.

To properly release them, this patch unifies the error handling code and
several error handling paths are added.
According to the allocation sequence, if the validation fails, it will
jump to its corresponding error tag to release the resources.

Signed-off-by: Xiaoke Wang <xkernel.wang@xxxxxxxxxxx>
---
ChangeLog:
v1->v2 update the description and adjust the sequence of patches.
v2->v3 None to this patch, but some to another patch in this series.
v3->v4 rebase the original series and merge them due to the missing check
for kzalloc() in rtw_alloc_hwxmits() had been added.
 drivers/staging/r8188eu/core/rtw_xmit.c | 30 ++++++++++++++++++++-----
 1 file changed, 24 insertions(+), 6 deletions(-)

diff --git a/drivers/staging/r8188eu/core/rtw_xmit.c b/drivers/staging/r8188eu/core/rtw_xmit.c
index 9c39d08..9e70c79 100644
--- a/drivers/staging/r8188eu/core/rtw_xmit.c
+++ b/drivers/staging/r8188eu/core/rtw_xmit.c
@@ -134,7 +134,7 @@ s32	_rtw_init_xmit_priv(struct xmit_priv *pxmitpriv, struct adapter *padapter)
 
 	if (!pxmitpriv->pallocated_xmitbuf) {
 		res = _FAIL;
-		goto exit;
+		goto free_frame_buf;
 	}
 
 	pxmitpriv->pxmitbuf = (u8 *)ALIGN((size_t)(pxmitpriv->pallocated_xmitbuf), 4);
@@ -156,7 +156,7 @@ s32	_rtw_init_xmit_priv(struct xmit_priv *pxmitpriv, struct adapter *padapter)
 			msleep(10);
 			res = rtw_xmit_resource_alloc(padapter, pxmitbuf, (MAX_XMITBUF_SZ + XMITBUF_ALIGN_SZ));
 			if (res == _FAIL)
-				goto exit;
+				goto free_xmitbuf;
 		}
 
 		pxmitbuf->flags = XMIT_VO_QUEUE;
@@ -174,7 +174,7 @@ s32	_rtw_init_xmit_priv(struct xmit_priv *pxmitpriv, struct adapter *padapter)
 
 	if (!pxmitpriv->pallocated_xmit_extbuf) {
 		res = _FAIL;
-		goto exit;
+		goto free_xmitbuf;
 	}
 
 	pxmitpriv->pxmit_extbuf = (u8 *)ALIGN((size_t)(pxmitpriv->pallocated_xmit_extbuf), 4);
@@ -191,7 +191,7 @@ s32	_rtw_init_xmit_priv(struct xmit_priv *pxmitpriv, struct adapter *padapter)
 		res = rtw_xmit_resource_alloc(padapter, pxmitbuf, max_xmit_extbuf_size + XMITBUF_ALIGN_SZ);
 		if (res == _FAIL) {
 			res = _FAIL;
-			goto exit;
+			goto free_xmit_extbuf;
 		}
 
 		list_add_tail(&pxmitbuf->list, &pxmitpriv->free_xmit_extbuf_queue.queue);
@@ -202,7 +202,7 @@ s32	_rtw_init_xmit_priv(struct xmit_priv *pxmitpriv, struct adapter *padapter)
 
 	if (rtw_alloc_hwxmits(padapter)) {
 		res = _FAIL;
-		goto exit;
+		goto free_xmit_extbuf;
 	}
 
 	rtw_init_hwxmits(pxmitpriv->hwxmits, pxmitpriv->hwxmit_entry);
@@ -226,8 +226,26 @@ s32	_rtw_init_xmit_priv(struct xmit_priv *pxmitpriv, struct adapter *padapter)
 
 	rtl8188eu_init_xmit_priv(padapter);
 
-exit:
+	return _SUCCESS;
 
+free_xmit_extbuf:
+	pxmitbuf = (struct xmit_buf *)pxmitpriv->pxmit_extbuf;
+	while (i--) {
+		rtw_xmit_resource_free(padapter, pxmitbuf, (max_xmit_extbuf_size + XMITBUF_ALIGN_SZ));
+		pxmitbuf++;
+	}
+	vfree(pxmitpriv->pallocated_xmit_extbuf);
+	i = NR_XMITBUFF;
+free_xmitbuf:
+	pxmitbuf = (struct xmit_buf *)pxmitpriv->pxmitbuf;
+	while (i--) {
+		rtw_xmit_resource_free(padapter, pxmitbuf, (MAX_XMITBUF_SZ + XMITBUF_ALIGN_SZ));
+		pxmitbuf++;
+	}
+	vfree(pxmitpriv->pallocated_xmitbuf);
+free_frame_buf:
+	vfree(pxmitpriv->pallocated_frame_buf);
+exit:
 	return res;
 }
 
--