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69 lines
2.6 KiB
69 lines
2.6 KiB
From: Brandeburg, Jesse <jesse.brandeburg@intel.com>
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Subject: [PATCH] e1000: enhance frame fragment detection
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References: bnc#567376, CVE-2009-4536
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Patch-Mainline: Yes
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A security discussion was recently given:
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http://events.ccc.de/congress/2009/Fahrplan//events/3596.en.html And a patch
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that I submitted awhile back was brought up. Apparently some of their testing
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revealed that they were able to force a buffer fragment in e1000 in which the
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trailing fragment was greater than 4 bytes. As a result the fragment check I
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introduced failed to detect the fragement and a partial invalid frame was
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passed up into the network stack. I've written this patch to correct it. I'm
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in the process of testing it now, but it makes good logical sense to me.
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Effectively it maintains a per-adapter state variable which detects a non-EOP
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frame, and discards it and subsequent non-EOP frames leading up to _and_
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_including_ the next positive-EOP frame (as it is by definition the last
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fragment). This should prevent any and all partial frames from entering the
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network stack from e1000.
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Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
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Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
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Signed-off-by: Brandon Philips <bphilips@suse.de>
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---
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drivers/net/e1000/e1000.h | 2 ++
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drivers/net/e1000/e1000_main.c | 13 +++++++++++--
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2 files changed, 13 insertions(+), 2 deletions(-)
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--- a/drivers/net/e1000/e1000.h
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+++ b/drivers/net/e1000/e1000.h
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@@ -326,6 +326,8 @@ struct e1000_adapter {
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/* for ioport free */
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int bars;
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int need_ioport;
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+
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+ bool discarding;
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};
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enum e1000_state_t {
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--- a/drivers/net/e1000/e1000_main.c
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+++ b/drivers/net/e1000/e1000_main.c
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@@ -3834,13 +3834,22 @@ static bool e1000_clean_rx_irq(struct e1
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length = le16_to_cpu(rx_desc->length);
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/* !EOP means multiple descriptors were used to store a single
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- * packet, also make sure the frame isn't just CRC only */
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- if (unlikely(!(status & E1000_RXD_STAT_EOP) || (length <= 4))) {
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+ * packet, if thats the case we need to toss it. In fact, we
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+ * to toss every packet with the EOP bit clear and the next
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+ * frame that _does_ have the EOP bit set, as it is by
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+ * definition only a frame fragment
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+ */
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+ if (unlikely(!(status & E1000_RXD_STAT_EOP)))
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+ adapter->discarding = true;
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+
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+ if (adapter->discarding) {
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/* All receives must fit into a single buffer */
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E1000_DBG("%s: Receive packet consumed multiple"
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" buffers\n", netdev->name);
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/* recycle */
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buffer_info->skb = skb;
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+ if (status & E1000_RXD_STAT_EOP)
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+ adapter->discarding = false;
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goto next_desc;
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}
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