e1000e: enhance frame fragment detection
Originally patched by Neil Horman <nhorman@tuxdriver.com>
e1000e could with a jumbo frame enabled interface, and packet split disabled,
receive a packet that would overflow a single rx buffer. While in practice
very hard to craft a packet that could abuse this, it is possible.
this is related to CVE-2009-4538
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
CC: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/e1000e/netdev.c b/drivers/net/e1000e/netdev.c
index f91f247..1ea395b 100644
--- a/drivers/net/e1000e/netdev.c
+++ b/drivers/net/e1000e/netdev.c
@@ -450,13 +450,23 @@
length = le16_to_cpu(rx_desc->length);
- /* !EOP means multiple descriptors were used to store a single
- * packet, also make sure the frame isn't just CRC only */
- if (!(status & E1000_RXD_STAT_EOP) || (length <= 4)) {
+ /*
+ * !EOP means multiple descriptors were used to store a single
+ * packet, if that's the case we need to toss it. In fact, we
+ * need to toss every packet with the EOP bit clear and the
+ * next frame that _does_ have the EOP bit set, as it is by
+ * definition only a frame fragment
+ */
+ if (unlikely(!(status & E1000_RXD_STAT_EOP)))
+ adapter->flags2 |= FLAG2_IS_DISCARDING;
+
+ if (adapter->flags2 & FLAG2_IS_DISCARDING) {
/* All receives must fit into a single buffer */
e_dbg("Receive packet consumed multiple buffers\n");
/* recycle */
buffer_info->skb = skb;
+ if (status & E1000_RXD_STAT_EOP)
+ adapter->flags2 &= ~FLAG2_IS_DISCARDING;
goto next_desc;
}
@@ -745,10 +755,16 @@
PCI_DMA_FROMDEVICE);
buffer_info->dma = 0;
- if (!(staterr & E1000_RXD_STAT_EOP)) {
+ /* see !EOP comment in other rx routine */
+ if (!(staterr & E1000_RXD_STAT_EOP))
+ adapter->flags2 |= FLAG2_IS_DISCARDING;
+
+ if (adapter->flags2 & FLAG2_IS_DISCARDING) {
e_dbg("Packet Split buffers didn't pick up the full "
"packet\n");
dev_kfree_skb_irq(skb);
+ if (staterr & E1000_RXD_STAT_EOP)
+ adapter->flags2 &= ~FLAG2_IS_DISCARDING;
goto next_desc;
}
@@ -1118,6 +1134,7 @@
rx_ring->next_to_clean = 0;
rx_ring->next_to_use = 0;
+ adapter->flags2 &= ~FLAG2_IS_DISCARDING;
writel(0, adapter->hw.hw_addr + rx_ring->head);
writel(0, adapter->hw.hw_addr + rx_ring->tail);