[v2,0/4,next] net: Avoid thousands of -Wflex-array-member-not-at-end warnings

Message

Gustavo A. R. Silva Oct. 24, 2024, 9:07 p.m. UTC

This series aims to resolve thousands of -Wflex-array-member-not-at-end
warnings by introducing `struct sockaddr_legacy`. The intention is to use
it to replace the type of several struct members in the middle of composite
structures, currently of type `struct sockaddr`.

These middle struct members are currently causing thousands of warnings
because `struct sockaddr` contains a flexible-array member, introduced
by commit b5f0de6df6dce ("net: dev: Convert sa_data to flexible array in
struct sockaddR").

The new `struct sockaddr_legacy` doesn't include a flexible-array
member, making it suitable for use as the type of middle members
in composite structs that don't really require the flexible-array
member in `struct sockaddr`, thus avoiding -Wflex-array-member-not-at-end
warnings.

As this new struct will live in UAPI, to avoid breaking user-space code
that expects `struct sockaddr`, the `__kernel_sockaddr_legacy` macro is
introduced. This macro allows us to use either `struct sockaddr` or
`struct sockaddr_legacy` depending on the context in which the code is
used: kernel-space or user-space.

Changes in v2
 - Drop nfsd patch.
 - Move `struct sockaddr_legacy` to include/uapi/linux/socket.h
 - Introduce `__kernel_sockaddr_legacy` macro (Kees)

v1:
 Link: https://lore.kernel.org/linux-hardening/[e-mail]/

Gustavo A. R. Silva (4):
  uapi: socket: Introduce struct sockaddr_legacy
  uapi: wireless: Avoid -Wflex-array-member-not-at-end warnings
  uapi: net: arp: Avoid -Wflex-array-member-not-at-end warnings
  uapi: net: Avoid -Wflex-array-member-not-at-end warnings

 include/net/compat.h          | 30 +++++++++----------
 include/uapi/linux/if_arp.h   | 18 +++++------
 include/uapi/linux/route.h    | 28 +++++++++---------
 include/uapi/linux/socket.h   | 28 ++++++++++++++++++
 include/uapi/linux/wireless.h | 56 +++++++++++++++++------------------
 net/appletalk/ddp.c           |  2 +-
 net/ipv4/af_inet.c            |  2 +-
 net/ipv4/arp.c                |  2 +-
 net/ipv4/fib_frontend.c       |  2 +-
 9 files changed, 98 insertions(+), 70 deletions(-)