--- /dev/null
+This patch adds poisoning and sanity checking to the RX DMA buffers.
+This is used for protection against buggy hardware/firmware that raises
+RX interrupts without doing an actual DMA transfer.
+
+This mechanism protects against rare "bad packets" (due to uninitialized skb data)
+and rare kernel crashes due to uninitialized RX headers.
+
+The poison is selected to not match on valid frames and to be cheap for checking.
+
+The poison check mechanism _might_ trigger incorrectly, if we are voluntarily
+receiving frames with bad PLCP headers. However, this is nonfatal, because the
+chance of such a match is basically zero and in case it happens it just results
+in dropping the packet.
+Bad-PLCP RX defaults to off, and you should leave it off unless you want to listen
+to the latest news broadcasted by your microwave oven.
+
+This patch also moves the initialization of the RX-header "length" field in front of
+the mapping of the DMA buffer. The CPU should not touch the buffer after we mapped it.
+
+Cc: stable@kernel.org
+Reported-by: Francesco Gringoli <francesco.gringoli@ing.unibs.it>
+Signed-off-by: Michael Buesch <mb@bu3sch.de>
+
+---
+
+Index: compat-wireless-2009-03-31/drivers/net/wireless/b43/dma.c
+===================================================================
+--- compat-wireless-2009-03-31.orig/drivers/net/wireless/b43/dma.c 2009-04-06 18:52:25.000000000 +0200
++++ compat-wireless-2009-03-31/drivers/net/wireless/b43/dma.c 2009-04-06 18:52:30.000000000 +0200
+@@ -555,11 +555,32 @@ address_error:
+ return 1;
+ }
+
++static bool b43_rx_buffer_is_poisoned(struct b43_dmaring *ring, struct sk_buff *skb)
++{
++ unsigned char *f = skb->data + ring->frameoffset;
++
++ return ((f[0] & f[1] & f[2] & f[3] & f[4] & f[5] & f[6] & f[7]) == 0xFF);
++}
++
++static void b43_poison_rx_buffer(struct b43_dmaring *ring, struct sk_buff *skb)
++{
++ struct b43_rxhdr_fw4 *rxhdr;
++ unsigned char *frame;
++
++ /* This poisons the RX buffer to detect DMA failures. */
++
++ rxhdr = (struct b43_rxhdr_fw4 *)(skb->data);
++ rxhdr->frame_len = 0;
++
++ B43_WARN_ON(ring->rx_buffersize < ring->frameoffset + sizeof(struct b43_plcp_hdr6) + 2);
++ frame = skb->data + ring->frameoffset;
++ memset(frame, 0xFF, sizeof(struct b43_plcp_hdr6) + 2 /* padding */);
++}
++
+ static int setup_rx_descbuffer(struct b43_dmaring *ring,
+ struct b43_dmadesc_generic *desc,
+ struct b43_dmadesc_meta *meta, gfp_t gfp_flags)
+ {
+- struct b43_rxhdr_fw4 *rxhdr;
+ dma_addr_t dmaaddr;
+ struct sk_buff *skb;
+
+@@ -568,6 +589,7 @@ static int setup_rx_descbuffer(struct b4
+ skb = __dev_alloc_skb(ring->rx_buffersize, gfp_flags);
+ if (unlikely(!skb))
+ return -ENOMEM;
++ b43_poison_rx_buffer(ring, skb);
+ dmaaddr = map_descbuffer(ring, skb->data, ring->rx_buffersize, 0);
+ if (b43_dma_mapping_error(ring, dmaaddr, ring->rx_buffersize, 0)) {
+ /* ugh. try to realloc in zone_dma */
+@@ -578,6 +600,7 @@ static int setup_rx_descbuffer(struct b4
+ skb = __dev_alloc_skb(ring->rx_buffersize, gfp_flags);
+ if (unlikely(!skb))
+ return -ENOMEM;
++ b43_poison_rx_buffer(ring, skb);
+ dmaaddr = map_descbuffer(ring, skb->data,
+ ring->rx_buffersize, 0);
+ if (b43_dma_mapping_error(ring, dmaaddr, ring->rx_buffersize, 0)) {
+@@ -592,9 +615,6 @@ static int setup_rx_descbuffer(struct b4
+ ring->ops->fill_descriptor(ring, desc, dmaaddr,
+ ring->rx_buffersize, 0, 0, 0);
+
+- rxhdr = (struct b43_rxhdr_fw4 *)(skb->data);
+- rxhdr->frame_len = 0;
+-
+ return 0;
+ }
+
+@@ -1489,6 +1509,15 @@ static void dma_rx(struct b43_dmaring *r
+ goto drop;
+ }
+ }
++ if (unlikely(b43_rx_buffer_is_poisoned(ring, skb))) {
++ /* Something went wrong with the DMA.
++ * The device did not touch the buffer and did not overwrite the poison. */
++ b43dbg(ring->dev->wl, "DMA RX: Dropping poisoned buffer.\n");
++ /* recycle the descriptor buffer. */
++ sync_descbuffer_for_device(ring, meta->dmaaddr,
++ ring->rx_buffersize);
++ goto drop;
++ }
+ if (unlikely(len > ring->rx_buffersize)) {
+ /* The data did not fit into one descriptor buffer
+ * and is split over multiple buffers.
--- /dev/null
+The RX buffer poison needs to be refreshed, if we recycle an RX buffer,
+because it might be (partially) overwritten by some DMA operations.
+
+Cc: stable@kernel.org
+Cc: Francesco Gringoli <francesco.gringoli@ing.unibs.it>
+Signed-off-by: Michael Buesch <mb@bu3sch.de>
+
+---
+
+Index: compat-wireless-2009-03-31/drivers/net/wireless/b43/dma.c
+===================================================================
+--- compat-wireless-2009-03-31.orig/drivers/net/wireless/b43/dma.c 2009-04-06 18:52:30.000000000 +0200
++++ compat-wireless-2009-03-31/drivers/net/wireless/b43/dma.c 2009-04-06 18:53:04.000000000 +0200
+@@ -1503,20 +1503,16 @@ static void dma_rx(struct b43_dmaring *r
+ len = le16_to_cpu(rxhdr->frame_len);
+ } while (len == 0 && i++ < 5);
+ if (unlikely(len == 0)) {
+- /* recycle the descriptor buffer. */
+- sync_descbuffer_for_device(ring, meta->dmaaddr,
+- ring->rx_buffersize);
+- goto drop;
++ dmaaddr = meta->dmaaddr;
++ goto drop_recycle_buffer;
+ }
+ }
+ if (unlikely(b43_rx_buffer_is_poisoned(ring, skb))) {
+ /* Something went wrong with the DMA.
+ * The device did not touch the buffer and did not overwrite the poison. */
+ b43dbg(ring->dev->wl, "DMA RX: Dropping poisoned buffer.\n");
+- /* recycle the descriptor buffer. */
+- sync_descbuffer_for_device(ring, meta->dmaaddr,
+- ring->rx_buffersize);
+- goto drop;
++ dmaaddr = meta->dmaaddr;
++ goto drop_recycle_buffer;
+ }
+ if (unlikely(len > ring->rx_buffersize)) {
+ /* The data did not fit into one descriptor buffer
+@@ -1530,6 +1526,7 @@ static void dma_rx(struct b43_dmaring *r
+ while (1) {
+ desc = ops->idx2desc(ring, *slot, &meta);
+ /* recycle the descriptor buffer. */
++ b43_poison_rx_buffer(ring, meta->skb);
+ sync_descbuffer_for_device(ring, meta->dmaaddr,
+ ring->rx_buffersize);
+ *slot = next_slot(ring, *slot);
+@@ -1548,8 +1545,7 @@ static void dma_rx(struct b43_dmaring *r
+ err = setup_rx_descbuffer(ring, desc, meta, GFP_ATOMIC);
+ if (unlikely(err)) {
+ b43dbg(ring->dev->wl, "DMA RX: setup_rx_descbuffer() failed\n");
+- sync_descbuffer_for_device(ring, dmaaddr, ring->rx_buffersize);
+- goto drop;
++ goto drop_recycle_buffer;
+ }
+
+ unmap_descbuffer(ring, dmaaddr, ring->rx_buffersize, 0);
+@@ -1559,6 +1555,11 @@ static void dma_rx(struct b43_dmaring *r
+ b43_rx(ring->dev, skb, rxhdr);
+ drop:
+ return;
++
++drop_recycle_buffer:
++ /* Poison and recycle the RX buffer. */
++ b43_poison_rx_buffer(ring, skb);
++ sync_descbuffer_for_device(ring, dmaaddr, ring->rx_buffersize);
+ }
+
+ void b43_dma_rx(struct b43_dmaring *ring)
---- a/drivers/net/wireless/b43/b43.h
-+++ b/drivers/net/wireless/b43/b43.h
-@@ -624,9 +624,11 @@ struct b43_wl {
+Index: compat-wireless-2009-03-31/drivers/net/wireless/b43/b43.h
+===================================================================
+--- compat-wireless-2009-03-31.orig/drivers/net/wireless/b43/b43.h 2009-04-06 18:52:21.000000000 +0200
++++ compat-wireless-2009-03-31/drivers/net/wireless/b43/b43.h 2009-04-06 18:53:19.000000000 +0200
+@@ -625,9 +625,11 @@ struct b43_wl {
/* Stats about the wireless interface */
struct ieee80211_low_level_stats ieee_stats;
/* The RF-kill button */
struct b43_rfkill rfkill;
---- a/drivers/net/wireless/b43/main.c
-+++ b/drivers/net/wireless/b43/main.c
+Index: compat-wireless-2009-03-31/drivers/net/wireless/b43/main.c
+===================================================================
+--- compat-wireless-2009-03-31.orig/drivers/net/wireless/b43/main.c 2009-04-06 18:52:28.000000000 +0200
++++ compat-wireless-2009-03-31/drivers/net/wireless/b43/main.c 2009-04-06 18:53:19.000000000 +0200
@@ -2982,6 +2982,7 @@ static void b43_security_init(struct b43
b43_clear_keys(dev);
}
return err;
}
---- a/config.mk
-+++ b/config.mk
+Index: compat-wireless-2009-03-31/config.mk
+===================================================================
+--- compat-wireless-2009-03-31.orig/config.mk 2009-04-06 18:52:21.000000000 +0200
++++ compat-wireless-2009-03-31/config.mk 2009-04-06 18:53:19.000000000 +0200
@@ -148,6 +148,7 @@ CONFIG_ATH9K_DEBUG=y
# CONFIG_B43_PIO=y
# CONFIG_B43_LEDS=y
projects / openwrt / staging / dedeckeh.git / commitdiff