diff options
Diffstat (limited to 'main/linux-pae/net-git-c0cd88-r8169-offical-fix-for-CVE-2009-4537-overlength-frame-DMAs.patch')
| -rw-r--r-- | main/linux-pae/net-git-c0cd88-r8169-offical-fix-for-CVE-2009-4537-overlength-frame-DMAs.patch | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/main/linux-pae/net-git-c0cd88-r8169-offical-fix-for-CVE-2009-4537-overlength-frame-DMAs.patch b/main/linux-pae/net-git-c0cd88-r8169-offical-fix-for-CVE-2009-4537-overlength-frame-DMAs.patch new file mode 100644 index 0000000000..250c85d678 --- /dev/null +++ b/main/linux-pae/net-git-c0cd88-r8169-offical-fix-for-CVE-2009-4537-overlength-frame-DMAs.patch @@ -0,0 +1,119 @@ +From c0cd884af045338476b8e69a61fceb3f34ff22f1 Mon Sep 17 00:00:00 2001 +From: Neil Horman <nhorman@redhat.com> +Date: Mon, 29 Mar 2010 13:16:02 -0700 +Subject: [PATCH] r8169: offical fix for CVE-2009-4537 (overlength frame DMAs) + +Official patch to fix the r8169 frame length check error. + +Based on this initial thread: +http://marc.info/?l=linux-netdev&m=126202972828626&w=1 +This is the official patch to fix the frame length problems in the r8169 +driver. As noted in the previous thread, while this patch incurs a performance +hit on the driver, its possible to improve performance dynamically by updating +the mtu and rx_copybreak values at runtime to return performance to what it was +for those NICS which are unaffected by the ideosyncracy (if there are any). + +Summary: + + A while back Eric submitted a patch for r8169 in which the proper +allocated frame size was written to RXMaxSize to prevent the NIC from dmaing too +much data. This was done in commit fdd7b4c3302c93f6833e338903ea77245eb510b4. A +long time prior to that however, Francois posted +126fa4b9ca5d9d7cb7d46f779ad3bd3631ca387c, which expiclitly disabled the MaxSize +setting due to the fact that the hardware behaved in odd ways when overlong +frames were received on NIC's supported by this driver. This was mentioned in a +security conference recently: +http://events.ccc.de/congress/2009/Fahrplan//events/3596.en.html + +It seems that if we can't enable frame size filtering, then, as Eric correctly +noticed, we can find ourselves DMA-ing too much data to a buffer, causing +corruption. As a result is seems that we are forced to allocate a frame which +is ready to handle a maximally sized receive. + +This obviously has performance issues with it, so to mitigate that issue, this +patch does two things: + +1) Raises the copybreak value to the frame allocation size, which should force +appropriately sized packets to get allocated on rx, rather than a full new 16k +buffer. + +2) This patch only disables frame filtering initially (i.e., during the NIC +open), changing the MTU results in ring buffer allocation of a size in relation +to the new mtu (along with a warning indicating that this is dangerous). + +Because of item (2), individuals who can't cope with the performance hit (or can +otherwise filter frames to prevent the bug), or who have hardware they are sure +is unaffected by this issue, can manually lower the copybreak and reset the mtu +such that performance is restored easily. + +Signed-off-by: Neil Horman <nhorman@redhat.com> +Signed-off-by: David S. Miller <davem@davemloft.net> +--- + drivers/net/r8169.c | 29 ++++++++++++++++++++++++----- + 1 files changed, 24 insertions(+), 5 deletions(-) + +diff --git a/drivers/net/r8169.c b/drivers/net/r8169.c +index 7193afc..9674005 100644 +--- a/drivers/net/r8169.c ++++ b/drivers/net/r8169.c +@@ -186,7 +186,12 @@ static DEFINE_PCI_DEVICE_TABLE(rtl8169_pci_tbl) = { + + MODULE_DEVICE_TABLE(pci, rtl8169_pci_tbl); + +-static int rx_copybreak = 200; ++/* ++ * we set our copybreak very high so that we don't have ++ * to allocate 16k frames all the time (see note in ++ * rtl8169_open() ++ */ ++static int rx_copybreak = 16383; + static int use_dac; + static struct { + u32 msg_enable; +@@ -3217,9 +3222,13 @@ static void __devexit rtl8169_remove_one(struct pci_dev *pdev) + } + + static void rtl8169_set_rxbufsize(struct rtl8169_private *tp, +- struct net_device *dev) ++ unsigned int mtu) + { +- unsigned int max_frame = dev->mtu + VLAN_ETH_HLEN + ETH_FCS_LEN; ++ unsigned int max_frame = mtu + VLAN_ETH_HLEN + ETH_FCS_LEN; ++ ++ if (max_frame != 16383) ++ printk(KERN_WARNING "WARNING! Changing of MTU on this NIC" ++ "May lead to frame reception errors!\n"); + + tp->rx_buf_sz = (max_frame > RX_BUF_SIZE) ? max_frame : RX_BUF_SIZE; + } +@@ -3231,7 +3240,17 @@ static int rtl8169_open(struct net_device *dev) + int retval = -ENOMEM; + + +- rtl8169_set_rxbufsize(tp, dev); ++ /* ++ * Note that we use a magic value here, its wierd I know ++ * its done because, some subset of rtl8169 hardware suffers from ++ * a problem in which frames received that are longer than ++ * the size set in RxMaxSize register return garbage sizes ++ * when received. To avoid this we need to turn off filtering, ++ * which is done by setting a value of 16383 in the RxMaxSize register ++ * and allocating 16k frames to handle the largest possible rx value ++ * thats what the magic math below does. ++ */ ++ rtl8169_set_rxbufsize(tp, 16383 - VLAN_ETH_HLEN - ETH_FCS_LEN); + + /* + * Rx and Tx desscriptors needs 256 bytes alignment. +@@ -3884,7 +3903,7 @@ static int rtl8169_change_mtu(struct net_device *dev, int new_mtu) + + rtl8169_down(dev); + +- rtl8169_set_rxbufsize(tp, dev); ++ rtl8169_set_rxbufsize(tp, dev->mtu); + + ret = rtl8169_init_ring(dev); + if (ret < 0) +-- +1.7.0.3 + |