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Subject[PATCH v2] farsync: fix invalid memory accesses in fst_add_one() and fst_init_card()
Date
There are several issues in fst_add_one() and fst_init_card():
- invalid pointer dereference at card->ports[card->nports - 1] if
register_hdlc_device() fails for the first port in fst_init_card();
- fst_card_array overflow at fst_card_array[no_of_cards_added]
because there is no checks for array overflow;
- use after free because pointer to deallocated card is left in fst_card_array
if something fails after fst_card_array[no_of_cards_added] = card;
- several leaks on failure paths in fst_add_one().

The patch fixes all the issues and makes code more readable.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
---
drivers/net/wan/farsync.c | 112 ++++++++++++++++++++++++----------------------
1 file changed, 58 insertions(+), 54 deletions(-)

diff --git a/drivers/net/wan/farsync.c b/drivers/net/wan/farsync.c
index 93ace042d0aa..1f041271f7fe 100644
--- a/drivers/net/wan/farsync.c
+++ b/drivers/net/wan/farsync.c
@@ -2363,7 +2363,7 @@ static char *type_strings[] = {
"FarSync TE1"
};

-static void
+static int
fst_init_card(struct fst_card_info *card)
{
int i;
@@ -2374,24 +2374,21 @@ fst_init_card(struct fst_card_info *card)
* we'll have to revise it in some way then.
*/
for (i = 0; i < card->nports; i++) {
- err = register_hdlc_device(card->ports[i].dev);
- if (err < 0) {
- int j;
+ err = register_hdlc_device(card->ports[i].dev);
+ if (err < 0) {
pr_err("Cannot register HDLC device for port %d (errno %d)\n",
- i, -err);
- for (j = i; j < card->nports; j++) {
- free_netdev(card->ports[j].dev);
- card->ports[j].dev = NULL;
- }
- card->nports = i;
- break;
- }
+ i, -err);
+ while (i--)
+ unregister_hdlc_device(card->ports[i].dev);
+ return err;
+ }
}

pr_info("%s-%s: %s IRQ%d, %d ports\n",
port_to_dev(&card->ports[0])->name,
port_to_dev(&card->ports[card->nports - 1])->name,
type_strings[card->type], card->irq, card->nports);
+ return 0;
}

static const struct net_device_ops fst_ops = {
@@ -2447,15 +2444,12 @@ fst_add_one(struct pci_dev *pdev, const struct pci_device_id *ent)
/* Try to enable the device */
if ((err = pci_enable_device(pdev)) != 0) {
pr_err("Failed to enable card. Err %d\n", -err);
- kfree(card);
- return err;
+ goto enable_fail;
}

if ((err = pci_request_regions(pdev, "FarSync")) !=0) {
pr_err("Failed to allocate regions. Err %d\n", -err);
- pci_disable_device(pdev);
- kfree(card);
- return err;
+ goto regions_fail;
}

/* Get virtual addresses of memory regions */
@@ -2464,30 +2458,21 @@ fst_add_one(struct pci_dev *pdev, const struct pci_device_id *ent)
card->phys_ctlmem = pci_resource_start(pdev, 3);
if ((card->mem = ioremap(card->phys_mem, FST_MEMSIZE)) == NULL) {
pr_err("Physical memory remap failed\n");
- pci_release_regions(pdev);
- pci_disable_device(pdev);
- kfree(card);
- return -ENODEV;
+ err = -ENODEV;
+ goto ioremap_physmem_fail;
}
if ((card->ctlmem = ioremap(card->phys_ctlmem, 0x10)) == NULL) {
pr_err("Control memory remap failed\n");
- pci_release_regions(pdev);
- pci_disable_device(pdev);
- iounmap(card->mem);
- kfree(card);
- return -ENODEV;
+ err = -ENODEV;
+ goto ioremap_ctlmem_fail;
}
dbg(DBG_PCI, "kernel mem %p, ctlmem %p\n", card->mem, card->ctlmem);

/* Register the interrupt handler */
if (request_irq(pdev->irq, fst_intr, IRQF_SHARED, FST_DEV_NAME, card)) {
pr_err("Unable to register interrupt %d\n", card->irq);
- pci_release_regions(pdev);
- pci_disable_device(pdev);
- iounmap(card->ctlmem);
- iounmap(card->mem);
- kfree(card);
- return -ENODEV;
+ err = -ENODEV;
+ goto irq_fail;
}

/* Record info we need */
@@ -2513,13 +2498,8 @@ fst_add_one(struct pci_dev *pdev, const struct pci_device_id *ent)
while (i--)
free_netdev(card->ports[i].dev);
pr_err("FarSync: out of memory\n");
- free_irq(card->irq, card);
- pci_release_regions(pdev);
- pci_disable_device(pdev);
- iounmap(card->ctlmem);
- iounmap(card->mem);
- kfree(card);
- return -ENODEV;
+ err = -ENOMEM;
+ goto hdlcdev_fail;
}
card->ports[i].dev = dev;
card->ports[i].card = card;
@@ -2565,9 +2545,16 @@ fst_add_one(struct pci_dev *pdev, const struct pci_device_id *ent)
pci_set_drvdata(pdev, card);

/* Remainder of card setup */
+ if (no_of_cards_added >= FST_MAX_CARDS) {
+ pr_err("FarSync: too many cards\n");
+ err = -ENOMEM;
+ goto card_array_fail;
+ }
fst_card_array[no_of_cards_added] = card;
card->card_no = no_of_cards_added++; /* Record instance and bump it */
- fst_init_card(card);
+ err = fst_init_card(card);
+ if (err)
+ goto init_card_fail;
if (card->family == FST_FAMILY_TXU) {
/*
* Allocate a dma buffer for transmit and receives
@@ -2577,29 +2564,46 @@ fst_add_one(struct pci_dev *pdev, const struct pci_device_id *ent)
&card->rx_dma_handle_card);
if (card->rx_dma_handle_host == NULL) {
pr_err("Could not allocate rx dma buffer\n");
- fst_disable_intr(card);
- pci_release_regions(pdev);
- pci_disable_device(pdev);
- iounmap(card->ctlmem);
- iounmap(card->mem);
- kfree(card);
- return -ENOMEM;
+ err = -ENOMEM;
+ goto rx_dma_fail;
}
card->tx_dma_handle_host =
pci_alloc_consistent(card->device, FST_MAX_MTU,
&card->tx_dma_handle_card);
if (card->tx_dma_handle_host == NULL) {
pr_err("Could not allocate tx dma buffer\n");
- fst_disable_intr(card);
- pci_release_regions(pdev);
- pci_disable_device(pdev);
- iounmap(card->ctlmem);
- iounmap(card->mem);
- kfree(card);
- return -ENOMEM;
+ err = -ENOMEM;
+ goto tx_dma_fail;
}
}
return 0; /* Success */
+
+tx_dma_fail:
+ pci_free_consistent(card->device, FST_MAX_MTU,
+ card->rx_dma_handle_host,
+ card->rx_dma_handle_card);
+rx_dma_fail:
+ fst_disable_intr(card);
+ for (i = 0 ; i < card->nports ; i++)
+ unregister_hdlc_device(card->ports[i].dev);
+init_card_fail:
+ fst_card_array[card->card_no] = NULL;
+card_array_fail:
+ for (i = 0 ; i < card->nports ; i++)
+ free_netdev(card->ports[i].dev);
+hdlcdev_fail:
+ free_irq(card->irq, card);
+irq_fail:
+ iounmap(card->ctlmem);
+ioremap_ctlmem_fail:
+ iounmap(card->mem);
+ioremap_physmem_fail:
+ pci_release_regions(pdev);
+regions_fail:
+ pci_disable_device(pdev);
+enable_fail:
+ kfree(card);
+ return err;
}

/*
--
1.9.1


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