From b94b50289622e816adc9f94111cfc2679c80177c Mon Sep 17 00:00:00 2001 From: Jesse Brandeburg Date: Tue, 19 Jan 2010 14:15:59 +0000 Subject: [PATCH] e1000e: enhance frame fragment detection Originally patched by Neil Horman 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 CC: Neil Horman Signed-off-by: Jeff Kirsher Signed-off-by: David S. Miller --- drivers/net/e1000e/e1000.h | 1 + drivers/net/e1000e/netdev.c | 25 +++++++++++++++++++++---- 2 files changed, 22 insertions(+), 4 deletions(-) diff --git a/drivers/net/e1000e/e1000.h b/drivers/net/e1000e/e1000.h index d6ee28f6ea08..d236efaf7478 100644 --- 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])) diff --git a/drivers/net/e1000e/netdev.c b/drivers/net/e1000e/netdev.c index f91f247ed6af..1ea395b6c992 100644 --- a/drivers/net/e1000e/netdev.c +++ b/drivers/net/e1000e/netdev.c @@ -450,13 +450,23 @@ 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("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 @@ 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("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 @@ 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);