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Subject[PATCH v4 1/2] staging: vt6655: check for memory allocation failures
Date
There are no null pointer checking on rd_info and td_info values which
are allocated by kzalloc. It has potential null pointer dereferencing
issues. Implement error handling code on device_init_rd*, device_init_td*
and vnt_start for the allocation failures.

Signed-off-by: Ji-Hun Kim <ji_hun.kim@samsung.com>
---
Changes v2:
- Delete WARN_ON which can makes crashes on some machines.
- Instead of return directly, goto freeing function for freeing previously
allocated memory in the for loop after kzalloc() failed.
- In the freeing function, add if statement for freeing to only allocated
values.

Changes v3:
- Modify return type of device_init_rd*, device_init_td*. Then add returns
error code at those functions and vnt_start as well.

Changes v4:
- Fix potential memory leaks from error handling code of device init
functions in vnt_start().

drivers/staging/vt6655/device_main.c | 121 ++++++++++++++++++++++++++---------
1 file changed, 89 insertions(+), 32 deletions(-)

diff --git a/drivers/staging/vt6655/device_main.c b/drivers/staging/vt6655/device_main.c
index fbc4bc6..c9752df 100644
--- a/drivers/staging/vt6655/device_main.c
+++ b/drivers/staging/vt6655/device_main.c
@@ -124,10 +124,10 @@
static void device_free_info(struct vnt_private *priv);
static void device_print_info(struct vnt_private *priv);

-static void device_init_rd0_ring(struct vnt_private *priv);
-static void device_init_rd1_ring(struct vnt_private *priv);
-static void device_init_td0_ring(struct vnt_private *priv);
-static void device_init_td1_ring(struct vnt_private *priv);
+static int device_init_rd0_ring(struct vnt_private *priv);
+static int device_init_rd1_ring(struct vnt_private *priv);
+static int device_init_td0_ring(struct vnt_private *priv);
+static int device_init_td1_ring(struct vnt_private *priv);

static int device_rx_srv(struct vnt_private *priv, unsigned int idx);
static int device_tx_srv(struct vnt_private *priv, unsigned int idx);
@@ -528,18 +528,22 @@ static void device_free_rings(struct vnt_private *priv)
priv->tx0_bufs, priv->tx_bufs_dma0);
}

-static void device_init_rd0_ring(struct vnt_private *priv)
+static int device_init_rd0_ring(struct vnt_private *priv)
{
int i;
dma_addr_t curr = priv->rd0_pool_dma;
struct vnt_rx_desc *desc;
+ int ret = 0;

/* Init the RD0 ring entries */
for (i = 0; i < priv->opts.rx_descs0;
i ++, curr += sizeof(struct vnt_rx_desc)) {
desc = &priv->aRD0Ring[i];
desc->rd_info = kzalloc(sizeof(*desc->rd_info), GFP_KERNEL);
-
+ if (!desc->rd_info) {
+ ret = -ENOMEM;
+ goto error;
+ }
if (!device_alloc_rx_buf(priv, desc))
dev_err(&priv->pcid->dev, "can not alloc rx bufs\n");

@@ -550,20 +554,29 @@ static void device_init_rd0_ring(struct vnt_private *priv)
if (i > 0)
priv->aRD0Ring[i-1].next_desc = cpu_to_le32(priv->rd0_pool_dma);
priv->pCurrRD[0] = &priv->aRD0Ring[0];
+
+ return 0;
+error:
+ device_free_rd0_ring(priv);
+ return ret;
}

-static void device_init_rd1_ring(struct vnt_private *priv)
+static int device_init_rd1_ring(struct vnt_private *priv)
{
int i;
dma_addr_t curr = priv->rd1_pool_dma;
struct vnt_rx_desc *desc;
+ int ret = 0;

/* Init the RD1 ring entries */
for (i = 0; i < priv->opts.rx_descs1;
i ++, curr += sizeof(struct vnt_rx_desc)) {
desc = &priv->aRD1Ring[i];
desc->rd_info = kzalloc(sizeof(*desc->rd_info), GFP_KERNEL);
-
+ if (!desc->rd_info) {
+ ret = -ENOMEM;
+ goto error;
+ }
if (!device_alloc_rx_buf(priv, desc))
dev_err(&priv->pcid->dev, "can not alloc rx bufs\n");

@@ -574,6 +587,11 @@ static void device_init_rd1_ring(struct vnt_private *priv)
if (i > 0)
priv->aRD1Ring[i-1].next_desc = cpu_to_le32(priv->rd1_pool_dma);
priv->pCurrRD[1] = &priv->aRD1Ring[0];
+
+ return 0;
+error:
+ device_free_rd1_ring(priv);
+ return ret;
}

static void device_free_rd0_ring(struct vnt_private *priv)
@@ -584,12 +602,12 @@ static void device_free_rd0_ring(struct vnt_private *priv)
struct vnt_rx_desc *desc = &priv->aRD0Ring[i];
struct vnt_rd_info *rd_info = desc->rd_info;

- dma_unmap_single(&priv->pcid->dev, rd_info->skb_dma,
- priv->rx_buf_sz, DMA_FROM_DEVICE);
-
- dev_kfree_skb(rd_info->skb);
-
- kfree(desc->rd_info);
+ if (rd_info) {
+ dma_unmap_single(&priv->pcid->dev, rd_info->skb_dma,
+ priv->rx_buf_sz, DMA_FROM_DEVICE);
+ dev_kfree_skb(rd_info->skb);
+ kfree(desc->rd_info);
+ }
}
}

@@ -601,27 +619,31 @@ static void device_free_rd1_ring(struct vnt_private *priv)
struct vnt_rx_desc *desc = &priv->aRD1Ring[i];
struct vnt_rd_info *rd_info = desc->rd_info;

- dma_unmap_single(&priv->pcid->dev, rd_info->skb_dma,
- priv->rx_buf_sz, DMA_FROM_DEVICE);
-
- dev_kfree_skb(rd_info->skb);
-
- kfree(desc->rd_info);
+ if (rd_info) {
+ dma_unmap_single(&priv->pcid->dev, rd_info->skb_dma,
+ priv->rx_buf_sz, DMA_FROM_DEVICE);
+ dev_kfree_skb(rd_info->skb);
+ kfree(desc->rd_info);
+ }
}
}

-static void device_init_td0_ring(struct vnt_private *priv)
+static int device_init_td0_ring(struct vnt_private *priv)
{
int i;
dma_addr_t curr;
struct vnt_tx_desc *desc;
+ int ret = 0;

curr = priv->td0_pool_dma;
for (i = 0; i < priv->opts.tx_descs[0];
i++, curr += sizeof(struct vnt_tx_desc)) {
desc = &priv->apTD0Rings[i];
desc->td_info = kzalloc(sizeof(*desc->td_info), GFP_KERNEL);
-
+ if (!desc->td_info) {
+ ret = -ENOMEM;
+ goto error;
+ }
desc->td_info->buf = priv->tx0_bufs + i * PKT_BUF_SZ;
desc->td_info->buf_dma = priv->tx_bufs_dma0 + i * PKT_BUF_SZ;

@@ -632,13 +654,19 @@ static void device_init_td0_ring(struct vnt_private *priv)
if (i > 0)
priv->apTD0Rings[i-1].next_desc = cpu_to_le32(priv->td0_pool_dma);
priv->apTailTD[0] = priv->apCurrTD[0] = &priv->apTD0Rings[0];
+
+ return 0;
+error:
+ device_free_td0_ring(priv);
+ return ret;
}

-static void device_init_td1_ring(struct vnt_private *priv)
+static int device_init_td1_ring(struct vnt_private *priv)
{
int i;
dma_addr_t curr;
struct vnt_tx_desc *desc;
+ int ret = 0;

/* Init the TD ring entries */
curr = priv->td1_pool_dma;
@@ -646,7 +674,10 @@ static void device_init_td1_ring(struct vnt_private *priv)
i++, curr += sizeof(struct vnt_tx_desc)) {
desc = &priv->apTD1Rings[i];
desc->td_info = kzalloc(sizeof(*desc->td_info), GFP_KERNEL);
-
+ if (!desc->td_info) {
+ ret = -ENOMEM;
+ goto error;
+ }
desc->td_info->buf = priv->tx1_bufs + i * PKT_BUF_SZ;
desc->td_info->buf_dma = priv->tx_bufs_dma1 + i * PKT_BUF_SZ;

@@ -657,6 +688,11 @@ static void device_init_td1_ring(struct vnt_private *priv)
if (i > 0)
priv->apTD1Rings[i-1].next_desc = cpu_to_le32(priv->td1_pool_dma);
priv->apTailTD[1] = priv->apCurrTD[1] = &priv->apTD1Rings[0];
+
+ return 0;
+error:
+ device_free_td1_ring(priv);
+ return ret;
}

static void device_free_td0_ring(struct vnt_private *priv)
@@ -667,8 +703,10 @@ static void device_free_td0_ring(struct vnt_private *priv)
struct vnt_tx_desc *desc = &priv->apTD0Rings[i];
struct vnt_td_info *td_info = desc->td_info;

- dev_kfree_skb(td_info->skb);
- kfree(desc->td_info);
+ if (td_info) {
+ dev_kfree_skb(td_info->skb);
+ kfree(desc->td_info);
+ }
}
}

@@ -680,8 +718,10 @@ static void device_free_td1_ring(struct vnt_private *priv)
struct vnt_tx_desc *desc = &priv->apTD1Rings[i];
struct vnt_td_info *td_info = desc->td_info;

- dev_kfree_skb(td_info->skb);
- kfree(desc->td_info);
+ if (td_info) {
+ dev_kfree_skb(td_info->skb);
+ kfree(desc->td_info);
+ }
}
}

@@ -1165,10 +1205,18 @@ static int vnt_start(struct ieee80211_hw *hw)
}

dev_dbg(&priv->pcid->dev, "call device init rd0 ring\n");
- device_init_rd0_ring(priv);
- device_init_rd1_ring(priv);
- device_init_td0_ring(priv);
- device_init_td1_ring(priv);
+ ret = device_init_rd0_ring(priv);
+ if (ret)
+ goto err_init_rd0_ring;
+ ret = device_init_rd1_ring(priv);
+ if (ret)
+ goto err_init_rd1_ring;
+ ret = device_init_td0_ring(priv);
+ if (ret)
+ goto err_init_td0_ring;
+ ret = device_init_td1_ring(priv);
+ if (ret)
+ goto err_init_td1_ring;

device_init_registers(priv);

@@ -1178,6 +1226,15 @@ static int vnt_start(struct ieee80211_hw *hw)
ieee80211_wake_queues(hw);

return 0;
+
+err_init_td1_ring:
+ device_free_td0_ring(priv);
+err_init_td0_ring:
+ device_free_rd1_ring(priv);
+err_init_rd1_ring:
+ device_free_rd0_ring(priv);
+err_init_rd0_ring:
+ return ret;
}

static void vnt_stop(struct ieee80211_hw *hw)
--
1.9.1
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