From 40a14deaf411592b57cb0720f0e8004293ab9865 Mon Sep 17 00:00:00 2001 From: Jesse Brandeburg Date: Tue, 19 Jan 2010 14:15:38 +0000 Subject: [PATCH] e1000: enhance frame fragment detection Originally From: Neil Horman Modified by: Jesse Brandeburg Hey all- A security discussion was recently given: http://events.ccc.de/congress/2009/Fahrplan//events/3596.en.html And a patch that I submitted awhile back was brought up. Apparently some of their testing revealed that they were able to force a buffer fragment in e1000 in which the trailing fragment was greater than 4 bytes. As a result the fragment check I introduced failed to detect the fragement and a partial invalid frame was passed up into the network stack. I've written this patch to correct it. I'm in the process of testing it now, but it makes good logical sense to me. Effectively it maintains a per-adapter state variable which detects a non-EOP frame, and discards it and subsequent non-EOP frames leading up to _and_ _including_ the next positive-EOP frame (as it is by definition the last fragment). This should prevent any and all partial frames from entering the network stack from e1000. Signed-off-by: Jesse Brandeburg Acked-by: Neil Horman Signed-off-by: Jeff Kirsher Signed-off-by: David S. Miller --- drivers/net/e1000/e1000.h | 2 ++ drivers/net/e1000/e1000_main.c | 13 +++++++++++-- 2 files changed, 13 insertions(+), 2 deletions(-) diff --git a/drivers/net/e1000/e1000.h b/drivers/net/e1000/e1000.h index 2a567df..e8932db 100644 --- a/drivers/net/e1000/e1000.h +++ b/drivers/net/e1000/e1000.h @@ -326,6 +326,8 @@ struct e1000_adapter { /* for ioport free */ int bars; int need_ioport; + + bool discarding; }; enum e1000_state_t { diff --git a/drivers/net/e1000/e1000_main.c b/drivers/net/e1000/e1000_main.c index b3f67b4..a53a201 100644 --- a/drivers/net/e1000/e1000_main.c +++ b/drivers/net/e1000/e1000_main.c @@ -3850,13 +3850,22 @@ 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 (unlikely(!(status & E1000_RXD_STAT_EOP) || (length <= 4))) { + * packet, if thats the case we need to toss it. In fact, we + * 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->discarding = true; + + if (adapter->discarding) { /* All receives must fit into a single buffer */ E1000_DBG("%s: Receive packet consumed multiple" " buffers\n", netdev->name); /* recycle */ buffer_info->skb = skb; + if (status & E1000_RXD_STAT_EOP) + adapter->discarding = false; goto next_desc; } -- 1.8.2.3