linux/debian/patches/bugfix/all/e1000e-enhance-fragment-det...

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Subject: [net-2.6,2/2] e1000e: enhance frame fragment detection
Date: Tue, 19 Jan 2010 14:15:59 -0000
From: Jesse Brandeburg <jesse.brandeburg@intel.com>
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
--- a/drivers/net/e1000e/e1000.h
+++ b/drivers/net/e1000e/e1000.h
@@ -421,6 +421,7 @@ struct e1000_info {
/* CRC Stripping defines */
#define FLAG2_CRC_STRIPPING (1 << 0)
#define FLAG2_HAS_PHY_WAKEUP (1 << 1)
+#define FLAG2_IS_DISCARDING (1 << 2)
#define E1000_RX_DESC_PS(R, i) \
(&(((union e1000_rx_desc_packet_split *)((R).desc))[i]))
--- a/drivers/net/e1000e/netdev.c
+++ b/drivers/net/e1000e/netdev.c
@@ -450,14 +450,24 @@ static bool e1000_clean_rx_irq(struct e1000_adapter *adapter,
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("%s: Receive packet consumed multiple buffers\n",
netdev->name);
/* recycle */
buffer_info->skb = skb;
+ if (status & E1000_RXD_STAT_EOP)
+ adapter->flags2 &= ~FLAG2_IS_DISCARDING;
goto next_desc;
}
@@ -745,10 +755,16 @@ static bool e1000_clean_rx_irq_ps(struct e1000_adapter *adapter,
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("%s: Packet Split buffers didn't pick up the "
"full packet\n", netdev->name);
dev_kfree_skb_irq(skb);
+ if (staterr & E1000_RXD_STAT_EOP)
+ adapter->flags2 &= ~FLAG2_IS_DISCARDING;
goto next_desc;
}
@@ -1118,6 +1134,7 @@ static void e1000_clean_rx_ring(struct e1000_adapter *adapter)
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);