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Message-ID: <d75a16de-ea8e-842f-1bb6-b8d776d345a6@gmail.com>
Date: Sun, 1 Apr 2018 10:42:02 +0800
From: Jia-Ju Bai <baijiaju1990@...il.com>
To: Ji-Hun Kim <ji_hun.kim@...sung.com>, gregkh@...uxfoundation.org,
forest@...ttletooquiet.net
Cc: dartnorris@...il.com, santhameena13@...il.com,
julia.lawall@...6.fr, y.k.oh@...sung.com,
devel@...verdev.osuosl.org, linux-kernel@...r.kernel.org,
kernel-janitors@...r.kernel.org
Subject: Re: [PATCH v4 1/2] staging: vt6655: check for memory allocation
failures
On 2018/3/30 13:51, Ji-Hun Kim wrote:
> 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@...sung.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)
It looks okay now :)
Best wishes,
Jia-Ju Bai
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