On Thu, May 11, 2023 at 03:25:06PM +0200, Alexander Mikhalitsyn wrote: > Implement ->bpf_bypass_getsockopt proto callback and filter out > SCTP_SOCKOPT_PEELOFF, SCTP_SOCKOPT_PEELOFF_FLAGS and SCTP_SOCKOPT_CONNECTX3 > socket options from running eBPF hook on them. > > SCTP_SOCKOPT_PEELOFF and SCTP_SOCKOPT_PEELOFF_FLAGS options do fd_install(), > and if BPF_CGROUP_RUN_PROG_GETSOCKOPT hook returns an error after success of > the original handler sctp_getsockopt(...), userspace will receive an error > from getsockopt syscall and will be not aware that fd was successfully > installed into a fdtable. > > As pointed by Marcelo Ricardo Leitner it seems reasonable to skip > bpf getsockopt hook for SCTP_SOCKOPT_CONNECTX3 sockopt too. > Because internaly, it triggers connect() and if error is masked > then userspace will be confused. > > This patch was born as a result of discussion around a new SCM_PIDFD interface: > https://lore.kernel.org/all/20230413133355.350571-3-aleksandr.mikhalitsyn@xxxxxxxxxxxxx/ > > Fixes: 0d01da6afc54 ("bpf: implement getsockopt and setsockopt hooks") > Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx> > Cc: Christian Brauner <brauner@xxxxxxxxxx> > Cc: Stanislav Fomichev <sdf@xxxxxxxxxx> > Cc: Neil Horman <nhorman@xxxxxxxxxxxxx> > Cc: Marcelo Ricardo Leitner <marcelo.leitner@xxxxxxxxx> > Cc: Xin Long <lucien.xin@xxxxxxxxx> > Cc: linux-sctp@xxxxxxxxxxxxxxx > Cc: linux-kernel@xxxxxxxxxxxxxxx > Cc: netdev@xxxxxxxxxxxxxxx > Suggested-by: Stanislav Fomichev <sdf@xxxxxxxxxx> > Acked-by: Stanislav Fomichev <sdf@xxxxxxxxxx> > Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@xxxxxxxxxxxxx> > --- Reviewed-by: Christian Brauner <brauner@xxxxxxxxxx>
