diff options
Diffstat (limited to 'pkg/tcpip/network')
| -rw-r--r-- | pkg/tcpip/network/ipv4/ipv4.go | 18 | ||||
| -rw-r--r-- | pkg/tcpip/network/ipv6/ipv6.go | 10 |
2 files changed, 15 insertions, 13 deletions
diff --git a/pkg/tcpip/network/ipv4/ipv4.go b/pkg/tcpip/network/ipv4/ipv4.go index fa4ae2012..f4394749d 100644 --- a/pkg/tcpip/network/ipv4/ipv4.go +++ b/pkg/tcpip/network/ipv4/ipv4.go @@ -404,11 +404,15 @@ func (e *endpoint) HandlePacket(r *stack.Route, pkt *stack.PacketBuffer) { return } // The packet is a fragment, let's try to reassemble it. - last := h.FragmentOffset() + uint16(pkt.Data.Size()) - 1 - // Drop the packet if the fragmentOffset is incorrect. i.e the - // combination of fragmentOffset and pkt.Data.size() causes a - // wrap around resulting in last being less than the offset. - if last < h.FragmentOffset() { + start := h.FragmentOffset() + // Drop the fragment if the size of the reassembled payload would exceed the + // maximum payload size. + // + // Note that this addition doesn't overflow even on 32bit architecture + // because pkt.Data.Size() should not exceed 65535 (the max IP datagram + // size). Otherwise the packet would've been rejected as invalid before + // reaching here. + if int(start)+pkt.Data.Size() > header.IPv4MaximumPayloadSize { r.Stats().IP.MalformedPacketsReceived.Increment() r.Stats().IP.MalformedFragmentsReceived.Increment() return @@ -425,8 +429,8 @@ func (e *endpoint) HandlePacket(r *stack.Route, pkt *stack.PacketBuffer) { ID: uint32(h.ID()), Protocol: proto, }, - h.FragmentOffset(), - last, + start, + start+uint16(pkt.Data.Size())-1, h.More(), proto, pkt.Data, diff --git a/pkg/tcpip/network/ipv6/ipv6.go b/pkg/tcpip/network/ipv6/ipv6.go index af3cd91c6..e821a8bff 100644 --- a/pkg/tcpip/network/ipv6/ipv6.go +++ b/pkg/tcpip/network/ipv6/ipv6.go @@ -311,12 +311,10 @@ func (e *endpoint) HandlePacket(r *stack.Route, pkt *stack.PacketBuffer) { // The packet is a fragment, let's try to reassemble it. start := extHdr.FragmentOffset() * header.IPv6FragmentExtHdrFragmentOffsetBytesPerUnit - last := start + uint16(fragmentPayloadLen) - 1 - // Drop the packet if the fragmentOffset is incorrect. i.e the - // combination of fragmentOffset and pkt.Data.size() causes a - // wrap around resulting in last being less than the offset. - if last < start { + // Drop the fragment if the size of the reassembled payload would exceed + // the maximum payload size. + if int(start)+fragmentPayloadLen > header.IPv6MaximumPayloadSize { r.Stats().IP.MalformedPacketsReceived.Increment() r.Stats().IP.MalformedFragmentsReceived.Increment() return @@ -333,7 +331,7 @@ func (e *endpoint) HandlePacket(r *stack.Route, pkt *stack.PacketBuffer) { ID: extHdr.ID(), }, start, - last, + start+uint16(fragmentPayloadLen)-1, extHdr.More(), uint8(rawPayload.Identifier), rawPayload.Buf, |