Thanks for the review.
MIN_FRAGMENT_SIZE is used to determine maximum number of fragments that are
allowed for an IP datagram.
I will update the macro MAX_FRAGMENTS to compute the value based on
MIN_FRAGMENT_SIZE.
Regards,
Anand Kumar
On 3/6/18, 5:43 AM, "aserd...@ovn.org" <aserd...@ovn.org> wrote:
I guess you can also remove the define
(https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_openvswitch_ovs_blob_master_datapath-2Dwindows_ovsext_IpFr&d=DwIFBA&c=uilaK90D4TOVoH58JNXRgQ&r=Q5z9tBe-nAOpE7LIHSPV8uy5-437agMXvkeHHMkR8Us&m=IO3JXN8xQplOxWRufcsmrjAad9LTMz362Yoy7M5ydI0&s=FWfFKSKtm6492BHmJ_HpEwBo_iYESHGduKFqDgo4ZOU&e=
agment.c#L30)
since it is not used anywhere else.
Thanks,
Alin.
-----Mesaj original-----
De la: ovs-dev-boun...@openvswitch.org <ovs-dev-boun...@openvswitch.org> În
numele Anand Kumar
Trimis: Tuesday, March 6, 2018 1:21 AM
Către: d...@openvswitch.org
Subiect: [ovs-dev] [PATCH] datapath-windows: Do not drop Ip fragments less
than MIN_FRAGMENT_SIZE
Previously ipfragment module would drop any fragments less than
MIN_FRAGMENT_SIZE (400 bytes), which was added to safeguard against the
vulnerability CVE-2000-0305. This check is incorrect, since minimum size of
the Ipfragment is 68 bytes (i.e. max length of Ip Header + 8 bytes of
L4 header). So Ip fragments less than MIN_FRAGMENT_SIZE (400 bytes) is not
guranted to be malformed or illegal.
To guard against security vulnerability CVE-2000-0305, for a given ip
datagram, ipfragments should be dropped only when number of smallest
fragments recieved reaches a certain threshold.
Signed-off-by: Anand Kumar <kumaran...@vmware.com>
---
datapath-windows/ovsext/IpFragment.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/datapath-windows/ovsext/IpFragment.c
b/datapath-windows/ovsext/IpFragment.c
index 3d5277a..da9d33a 100644
--- a/datapath-windows/ovsext/IpFragment.c
+++ b/datapath-windows/ovsext/IpFragment.c
@@ -275,10 +275,7 @@ OvsProcessIpv4Fragment(POVS_SWITCH_CONTEXT
switchContext,
offset = ntohs(ipHdr->frag_off) & IP_OFFSET;
offset <<= 3;
flags = ntohs(ipHdr->frag_off) & IP_MF;
- /* Only the last fragment can be of smaller size.*/
- if (flags && ntohs(ipHdr->tot_len) < MIN_FRAGMENT_SIZE) {
- return NDIS_STATUS_INVALID_LENGTH;
- }
+
/*Copy fragment specific fields. */
fragKey.protocol = ipHdr->protocol;
fragKey.id = ipHdr->id;
--
2.9.3.windows.1
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