[PATCH] ethoc: fix null dereference in ethoc_probe

From: Thomas Chou
Date: Sun May 23 2010 - 23:18:57 EST


Dan reported the patch 0baa080c75c: "ethoc: use system memory
as buffer" introduced a potential null dereference.

1060 free:
1061 if (priv->dma_alloc)
^^^^^^^^^^^^^^^
priv can be null here.

He also suggested that the error handling is not complete.

This patch fixes the null priv issue and improves resources
releasing in ethoc_probe() and ethoc_remove().

Reported-by: Dan Carpenter <error27@xxxxxxxxx>
Signed-off-by: Thomas Chou <thomas@xxxxxxxxxxxxx>
---
drivers/net/ethoc.c | 34 ++++++++++++++++++++++++++++++----
1 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethoc.c b/drivers/net/ethoc.c
index a8d9250..fddd5f5 100644
--- a/drivers/net/ethoc.c
+++ b/drivers/net/ethoc.c
@@ -174,6 +174,7 @@ MODULE_PARM_DESC(buffer_size, "DMA buffer allocation size");
* @iobase: pointer to I/O memory region
* @membase: pointer to buffer memory region
* @dma_alloc: dma allocated buffer size
+ * @io_region_size: I/O memory region size
* @num_tx: number of send buffers
* @cur_tx: last send buffer written
* @dty_tx: last buffer actually sent
@@ -193,6 +194,7 @@ struct ethoc {
void __iomem *iobase;
void __iomem *membase;
int dma_alloc;
+ resource_size_t io_region_size;

unsigned int num_tx;
unsigned int cur_tx;
@@ -944,6 +946,7 @@ static int ethoc_probe(struct platform_device *pdev)
priv = netdev_priv(netdev);
priv->netdev = netdev;
priv->dma_alloc = 0;
+ priv->io_region_size = mmio->end - mmio->start + 1;

priv->iobase = devm_ioremap_nocache(&pdev->dev, netdev->base_addr,
resource_size(mmio));
@@ -1049,20 +1052,34 @@ static int ethoc_probe(struct platform_device *pdev)
ret = register_netdev(netdev);
if (ret < 0) {
dev_err(&netdev->dev, "failed to register interface\n");
- goto error;
+ goto error2;
}

goto out;

+error2:
+ netif_napi_del(&priv->napi);
error:
mdiobus_unregister(priv->mdio);
free_mdio:
kfree(priv->mdio->irq);
mdiobus_free(priv->mdio);
free:
- if (priv->dma_alloc)
- dma_free_coherent(NULL, priv->dma_alloc, priv->membase,
- netdev->mem_start);
+ if (priv) {
+ if (priv->dma_alloc)
+ dma_free_coherent(NULL, priv->dma_alloc, priv->membase,
+ netdev->mem_start);
+ else if (priv->membase)
+ devm_iounmap(&pdev->dev, priv->membase);
+ if (priv->iobase)
+ devm_iounmap(&pdev->dev, priv->iobase);
+ }
+ if (mem)
+ devm_release_mem_region(&pdev->dev, mem->start,
+ mem->end - mem->start + 1);
+ if (mmio)
+ devm_release_mem_region(&pdev->dev, mmio->start,
+ mmio->end - mmio->start + 1);
free_netdev(netdev);
out:
return ret;
@@ -1080,6 +1097,7 @@ static int ethoc_remove(struct platform_device *pdev)
platform_set_drvdata(pdev, NULL);

if (netdev) {
+ netif_napi_del(&priv->napi);
phy_disconnect(priv->phy);
priv->phy = NULL;

@@ -1091,6 +1109,14 @@ static int ethoc_remove(struct platform_device *pdev)
if (priv->dma_alloc)
dma_free_coherent(NULL, priv->dma_alloc, priv->membase,
netdev->mem_start);
+ else {
+ devm_iounmap(&pdev->dev, priv->membase);
+ devm_release_mem_region(&pdev->dev, netdev->mem_start,
+ netdev->mem_end - netdev->mem_start + 1);
+ }
+ devm_iounmap(&pdev->dev, priv->iobase);
+ devm_release_mem_region(&pdev->dev, netdev->base_addr,
+ priv->io_region_size);
unregister_netdev(netdev);
free_netdev(netdev);
}
--
1.7.1.86.g0e460

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