IP_RECVORIGDSTADDR not working

[ghost]

Unknown channel option 'IP_RECVORIGDSTADDR' for channel '[id: 0x8d4431fe]'

[normanmaurer]

Yep I think we not support this one atm... PRs welcome :)

[igor-lukyanov]

Tried the commit #13 in our real app.
At first sight, it seems to work (no errors occur anymore during the setOption(...) call), but it's hard to judge if it's actually fixing things (i.e. if after setting up the option local address 0.0.0.0 starts to get substituted with tproxy remote address like 10.xx.xx.xx) apparently because of the other bug #10 which causes remote addr to be always 0.0.0.0.

[igor-lukyanov]

Due to a CVE related to io_uring and AF_LOCAL sockets https://bugs.chromium.org/p/project-zero/issues/detail?id=1975 sending of ancillary data (which is used by IP_RECVORIGDSTADDR) was completely disabled in io_uring stack.
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d69e07793f89
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=181e448d8709

It was partially fixed in 5.10 release candidates, but only for TCP sockets.
torvalds/linux@583bbf0

We'll post a patch to LKML and ask to enable cmsg for io_uring+UDP as well. Until it's done this task can't be implemented.

[normanmaurer]

Sounds good... thanks for keep us posted

[normanmaurer]

This is fixed in 5.12 ... We may want to pick this up again