| Message ID | 20230511132506.379102-1-aleksandr.mikhalitsyn@canonical.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 2598619e012cee5273a2821441b9a051ad931249 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net-next,v3] sctp: add bpf_bypass_getsockopt proto callback | expand |
On Thu, May 11, 2023 at 9:33 AM Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> wrote: > > 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@canonical.com/ > > > > Fixes: 0d01da6afc54 ("bpf: implement getsockopt and setsockopt hooks") > > Cc: Daniel Borkmann <daniel@iogearbox.net> > > Cc: Christian Brauner <brauner@kernel.org> > > Cc: Stanislav Fomichev <sdf@google.com> > > Cc: Neil Horman <nhorman@tuxdriver.com> > > Cc: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> > > Cc: Xin Long <lucien.xin@gmail.com> > > Cc: linux-sctp@vger.kernel.org > > Cc: linux-kernel@vger.kernel.org > > Cc: netdev@vger.kernel.org > > Suggested-by: Stanislav Fomichev <sdf@google.com> > > Acked-by: Stanislav Fomichev <sdf@google.com> > > Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com> > > Thx! > > Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Acked-by: Xin Long <lucien.xin@gmail.com>
Hello: This patch was applied to netdev/net-next.git (main) by David S. Miller <davem@davemloft.net>: On Thu, 11 May 2023 15:25:06 +0200 you 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. > > [...] Here is the summary with links: - [net-next,v3] sctp: add bpf_bypass_getsockopt proto callback https://git.kernel.org/netdev/net-next/c/2598619e012c You are awesome, thank you!
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@canonical.com/ > > Fixes: 0d01da6afc54 ("bpf: implement getsockopt and setsockopt hooks") > Cc: Daniel Borkmann <daniel@iogearbox.net> > Cc: Christian Brauner <brauner@kernel.org> > Cc: Stanislav Fomichev <sdf@google.com> > Cc: Neil Horman <nhorman@tuxdriver.com> > Cc: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> > Cc: Xin Long <lucien.xin@gmail.com> > Cc: linux-sctp@vger.kernel.org > Cc: linux-kernel@vger.kernel.org > Cc: netdev@vger.kernel.org > Suggested-by: Stanislav Fomichev <sdf@google.com> > Acked-by: Stanislav Fomichev <sdf@google.com> > Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com> > --- Reviewed-by: Christian Brauner <brauner@kernel.org>
diff --git a/net/sctp/socket.c b/net/sctp/socket.c index cda8c2874691..a68e1d541b12 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -8281,6 +8281,22 @@ static int sctp_getsockopt(struct sock *sk, int level, int optname, return retval; } +static bool sctp_bpf_bypass_getsockopt(int level, int optname) +{ + if (level == SOL_SCTP) { + switch (optname) { + case SCTP_SOCKOPT_PEELOFF: + case SCTP_SOCKOPT_PEELOFF_FLAGS: + case SCTP_SOCKOPT_CONNECTX3: + return true; + default: + return false; + } + } + + return false; +} + static int sctp_hash(struct sock *sk) { /* STUB */ @@ -9650,6 +9666,7 @@ struct proto sctp_prot = { .shutdown = sctp_shutdown, .setsockopt = sctp_setsockopt, .getsockopt = sctp_getsockopt, + .bpf_bypass_getsockopt = sctp_bpf_bypass_getsockopt, .sendmsg = sctp_sendmsg, .recvmsg = sctp_recvmsg, .bind = sctp_bind, @@ -9705,6 +9722,7 @@ struct proto sctpv6_prot = { .shutdown = sctp_shutdown, .setsockopt = sctp_setsockopt, .getsockopt = sctp_getsockopt, + .bpf_bypass_getsockopt = sctp_bpf_bypass_getsockopt, .sendmsg = sctp_sendmsg, .recvmsg = sctp_recvmsg, .bind = sctp_bind,
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@canonical.com/ Fixes: 0d01da6afc54 ("bpf: implement getsockopt and setsockopt hooks") Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Christian Brauner <brauner@kernel.org> Cc: Stanislav Fomichev <sdf@google.com> Cc: Neil Horman <nhorman@tuxdriver.com> Cc: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Cc: Xin Long <lucien.xin@gmail.com> Cc: linux-sctp@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: netdev@vger.kernel.org Suggested-by: Stanislav Fomichev <sdf@google.com> Acked-by: Stanislav Fomichev <sdf@google.com> Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com> --- v3: fix commit description and remove comments v2: filter out SCTP_SOCKOPT_CONNECTX3 --- net/sctp/socket.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+)