[PATCH stable] b43: Fix possible NULL pointer dereference in DMA code

[PATCH stable] b43: Fix possible NULL pointer dereference in DMA code

[Michael Buesch]

This fixes a possible NULL pointer dereference in an error path of the
DMA allocation error checking code. In case the DMA allocation address is invalid,
the dev pointer is dereferenced for unmapping of the buffer.

This is a cut-down version of 3ab4b64c46784ed83f213bf4e1b51d9c55858600
which is upstream in John Linville's wireless-testing.git tree.

Signed-off-by: Michael Buesch <mb@bu3sch.de>


Index: linux-2.6.25.6/drivers/net/wireless/b43/dma.c
===================================================================
--- linux-2.6.25.6.orig/drivers/net/wireless/b43/dma.c	2008-06-14 22:43:28.000000000 +0200
+++ linux-2.6.25.6/drivers/net/wireless/b43/dma.c	2008-06-14 22:45:30.000000000 +0200
@@ -847,12 +847,13 @@ struct b43_dmaring *b43_setup_dmaring(st
 	dma_addr_t dma_test;
 
 	ring = kzalloc(sizeof(*ring), GFP_KERNEL);
 	if (!ring)
 		goto out;
 	ring->type = type;
+	ring->dev = dev;
 
 	nr_slots = B43_RXRING_SLOTS;
 	if (for_tx)
 		nr_slots = B43_TXRING_SLOTS;
 
 	ring->meta = kcalloc(nr_slots, sizeof(struct b43_dmadesc_meta),
@@ -898,13 +899,12 @@ struct b43_dmaring *b43_setup_dmaring(st
 
 		dma_unmap_single(dev->dev->dma_dev,
 				 dma_test, b43_txhdr_size(dev),
 				 DMA_TO_DEVICE);
 	}
 
-	ring->dev = dev;
 	ring->nr_slots = nr_slots;
 	ring->mmio_base = b43_dmacontroller_base(type, controller_index);
 	ring->index = controller_index;
 	if (type == B43_DMA_64BIT)
 		ring->ops = &dma64_ops;
 	else

Re: [PATCH stable] b43: Fix possible NULL pointer dereference in DMA code

[John W. Linville]

On Sat, Jun 14, 2008 at 10:57:55PM +0200, Michael Buesch wrote:
> This fixes a possible NULL pointer dereference in an error path of the
> DMA allocation error checking code. In case the DMA allocation address is invalid,
> the dev pointer is dereferenced for unmapping of the buffer.
> 
> This is a cut-down version of 3ab4b64c46784ed83f213bf4e1b51d9c55858600
> which is upstream in John Linville's wireless-testing.git tree.

...which will probably be 028118a5f09a9c807e6b43e2231efdff9f224c74
in linux-2.6.git

John
-- 
John W. Linville
linville@tuxdriver.com