[SRU][F/E/B/X][PATCH v2 0/2] ipsec interfaces: fix sending with bpf_redirect() / AF_PACKET sockets

[Kelsey Skunberg]

BugLink: https://bugs.launchpad.net/bugs/1860969

SRU Justification:

[Impact]
Packets sent to a vti[6]/xfrm interface via bpf_redirect() or via an AF_PACKET
socket are dropped (no carrier). 

The bug exists since the beginning of each driver.

[Fix]
This has been fixed in v5.5 by the following upstream commits
 - 95224166a903 ("vti[6]: fix packet tx through bpf_redirect()")
 - f042365dbffe ("xfrm interface: fix packet tx through bpf_redirect()")

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=95224166a903
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f042365dbffe

Backport the requested patches to Eoan (5.3), Bionic (4.15) and
Xenial (4.4).

Patches have already been applied to 5.4 focal tree through upstream stable
updates.

[Testcase]
Can be reproduced and tested with an AF_PACKET socket and python script which
is included in both mentioned patches.

[Risk of Regression]
This patch affects only the cases described above (when no dst is attached
to the skb), thus the risk should be low.

Changes in v2:
  - organize SRU Justification information to be listed under proper
    catergories 
  - limit lines to 80 characters 

Nicolas Dichtel (2):
  vti[6]: fix packet tx through bpf_redirect()
  xfrm interface: fix packet tx through bpf_redirect()

 net/ipv4/ip_vti.c         | 13 +++++++++++--
 net/ipv6/ip6_vti.c        | 13 +++++++++++--
 net/xfrm/xfrm_interface.c | 32 +++++++++++++++++++++++++-------
 3 files changed, 47 insertions(+), 11 deletions(-)

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2.20.1