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pcmcia: avoid buffer overflow in pcmcia_setup_isa_irq

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NR_IRQS may be as low as 16, causing a (harmless?) buffer overflow in
pcmcia_setup_isa_irq():

static u8 pcmcia_used_irq[NR_IRQS];

...

		if ((try < 32) && pcmcia_used_irq[irq])
			continue;

This is read-only, so if this address would be non-zero, it would just
mean we would not attempt an IRQ >= NR_IRQS -- which would fail anyway!
And as request_irq() fails for an irq >= NR_IRQS, the setting code path:

			pcmcia_used_irq[irq]++;

is never reached as well.

Reported-by: Christoph Fritz <chf.fritz@googlemail.com>
CC: stable@kernel.org
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Christoph Fritz <chf.fritz@googlemail.com>
This commit is contained in:
Dominik Brodowski 2010-08-03 09:33:45 +02:00
parent 0f52e86ded
commit 127c03cdba
1 changed files with 4 additions and 1 deletions
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5
drivers/pcmcia/pcmcia_resource.c
View File

@ -677,7 +677,7 @@ EXPORT_SYMBOL(__pcmcia_request_exclusive_irq);
#ifdef CONFIG_PCMCIA_PROBE
/* mask of IRQs already reserved by other cards, we should avoid using them */
static u8 pcmcia_used_irq[NR_IRQS];
static u8 pcmcia_used_irq[32];
static irqreturn_t test_action(int cpl, void *dev_id)
{
@ -700,6 +700,9 @@ static int pcmcia_setup_isa_irq(struct pcmcia_device *p_dev, int type)
for (try = 0; try < 64; try++) {
irq = try % 32;
if (irq > NR_IRQS)
continue;
/* marked as available by driver, not blocked by userspace? */
if (!((mask >> irq) & 1))
continue;