From: Dominik Brodowski Date: Tue, 3 Aug 2010 07:33:45 +0000 (+0200) Subject: pcmcia: avoid buffer overflow in pcmcia_setup_isa_irq X-Git-Tag: v2.6.34.6~28 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=e9237ad37ea237e7d84581d72650d69701559f65;p=thirdparty%2Fkernel%2Fstable.git pcmcia: avoid buffer overflow in pcmcia_setup_isa_irq commit 127c03cdbad9bd5af5d7f33bd31a1015a90cb77f upstream. 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 Signed-off-by: Dominik Brodowski Signed-off-by: Christoph Fritz Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/pcmcia/pcmcia_resource.c b/drivers/pcmcia/pcmcia_resource.c index 7c3d03bb4f304..cfcf868a9ffcb 100644 --- a/drivers/pcmcia/pcmcia_resource.c +++ b/drivers/pcmcia/pcmcia_resource.c @@ -41,7 +41,7 @@ module_param(io_speed, int, 0444); #ifdef CONFIG_PCMCIA_PROBE #include /* 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]; #endif static int pcmcia_adjust_io_region(struct resource *res, unsigned long start, @@ -768,6 +768,9 @@ int pcmcia_request_irq(struct pcmcia_device *p_dev, irq_req_t *req) for (try = 0; try < 64; try++) { irq = try % 32; + if (irq > NR_IRQS) + continue; + /* marked as available by driver, and not blocked by userspace? */ if (!((mask >> irq) & 1)) continue;