[PATCH mptcp-next v2 0/7] mptcp: add bpf_setsockopt support

From: Gang Yan <[email protected]>

Changelog:
v2:
  - Patches 1 and 2 are new in this series; they address TCP_MAXSEG
    handling in the bpf_setsockopt() path [1].
  - Patch 4 adds an early return to fix msk->sk_rcvlowat being
    unexpectedly modified, an issue seen in v1.
  - Patch 5 makes the hook safe for the non-tcp master socket: it guards
    bpf_sock_ops_cb_flags_set() with sk_is_tcp() to prevent out-of-bounds
    heap reads/writes through tcp_sk(sk)->bpf_sock_ops_cb_flags, and does
    not set is_locked_tcp_sock for the msk (unlike tcp_call_bpf()). That
    flag authorizes the verifier's direct tcp_sock-offset field accesses;
    since the msk is not a tcp_sock, leaving it at the default 0 is safe.

v1:
  Link: https://patchwork.kernel.org/project/mptcp/cover/[email protected]/

Gang Yan (7):
  mptcp: drop unused @max arg of __mptcp_setsockopt_set_val
  mptcp: take TCP_MAXSEG handling into __mptcp_setsockopt_set_val
  mptcp: use sockopt_lock/release_sock in sockopt
  mptcp: reject sockopt requiring ssks' lock in BPF context
  mptcp: enable bpf_setsockopt on the master socket
  mptcp: add TCP_CONNECT_CB sock_ops hook
  selftests: bpf: verify mptcp bpf_setsockopt from TCP_CONNECT_CB

 include/net/mptcp.h                           |   9 ++
 net/core/filter.c                             |  10 ++
 net/ipv4/tcp.c                                |   1 +
 net/mptcp/protocol.c                          |   6 +
 net/mptcp/protocol.h                          |  29 ++++
 net/mptcp/sockopt.c                           | 149 +++++++++---------
 .../testing/selftests/bpf/prog_tests/mptcp.c  |  61 +++++++
 .../selftests/bpf/progs/mptcp_setsockopt.c    |  32 ++++
 8 files changed, 223 insertions(+), 74 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/progs/mptcp_setsockopt.c

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2.43.0