Giters

google / gvisor

Application Kernel for Containers

Home Page:https://gvisor.dev

Geek Repo:Geek Repo

Github PK Tool:Github PK Tool

Incorrect address added to IP options

nhurley3 opened this issue · comments

commented

Description

The record route and timestamp options sometimes require that an address be inserted. The relevant RFCs state that the address of the output interface should be used:

Currently, the input interface is used:

gvisor/pkg/tcpip/network/ipv4/ipv4.go

Line 644 in 47b5915

newOpts, _, optProblem := e.processIPOptions(pkt, opts, &optionUsageForward{})

When making this change, the author should also consider making this logic more efficient. For example, an approach that is similar to the Linux implementation and better aligns with RFC 1812 5.2.1.1 [1] should be considered:

  • Validate the options once before branching into local delivery, unicast forwarding, or multicast forwarding. Set the timestamp only if a timestamp (no address) is requested.
  • Maintain the unrecognized options instead of sometimes dropping them. Unrecognized options should be ignored [2].
  • Before writing the packet to the output interface, update the relevant options with the output interface address. This shouldn't need to revalidate the options.

[1] https://datatracker.ietf.org/doc/html/rfc1812#section-5.2.1.1
[2] https://datatracker.ietf.org/doc/html/rfc1812#section-4.2.2.6

Is this feature related to a specific bug?

No response

Do you have a specific solution in mind?

No response

commented

A friendly reminder that this issue had no activity for 120 days.