linux/net/sunrpc
NeilBrown 626590ea4c SUNRPC: attempt to reach rpcbind with an abstract socket name
NFS is primarily name-spaced using network namespaces.  However it
contacts rpcbind (and gss_proxy) using AF_UNIX sockets which are
name-spaced using the mount namespaces.  This requires a container using
NFSv3 (the form that requires rpcbind) to manage both network and mount
namespaces, which can seem an unnecessary burden.

As NFS is primarily a network service it makes sense to use network
namespaces as much as possible, and to prefer to communicate with an
rpcbind running in the same network namespace.  This can be done, while
preserving the benefits of AF_UNIX sockets, by using an abstract socket
address.

An abstract address has a nul at the start of sun_path, and a length
that is exactly the complete size of the sockaddr_un up to the end of
the name, NOT including any trailing nul (which is not part of the
address).
Abstract addresses are local to a network namespace - regular AF_UNIX
path names a resolved in the mount namespace ignoring the network
namespace.

This patch causes rpcb to first try an abstract address before
continuing with regular AF_UNIX and then IP addresses.  This ensures
backwards compatibility.

Choosing the name needs some care as the same address will be configured
for rpcbind, and needs to be built in to libtirpc for this enhancement
to be fully successful.  There is no formal standard for choosing
abstract addresses.  The defacto standard appears to be to use a path
name similar to what would be used for a filesystem AF_UNIX address -
but with a leading nul.

In that case
   "\0/var/run/rpcbind.sock"
seems like the best choice.  However at this time /var/run is deprecated
in favour of /run, so
   "\0/run/rpcbind.sock"
might be better.
Though as we are deliberately moving away from using the filesystem it
might seem more sensible to explicitly break the connection and just
have
   "\0rpcbind.socket"
using the same name as the systemd unit file..

This patch chooses the second option, which seems least likely to raise
objections.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2023-06-19 12:12:22 -04:00
..
auth_gss SUNRPC: Avoid relying on crypto API to derive CBC-CTS output IV 2023-05-02 11:35:04 -04:00
xprtrdma nfsd-6.4 fixes: 2023-05-17 09:56:01 -07:00
.kunitconfig SUNRPC: Add KDF-HMAC-SHA2 Kunit tests 2023-02-20 09:20:51 -05:00
addr.c nfsd: don't alloc under spinlock in rpc_parse_scope_id 2021-09-21 17:51:47 -04:00
auth_null.c SUNRPC: Add rpc_auth::au_ralign field 2019-02-14 11:48:36 -05:00
auth_unix.c SUNRPC: Fix unx_lookup_cred() allocation 2022-03-22 15:52:55 -04:00
auth.c NFS client updates for Linux 5.20 2022-08-10 14:04:32 -07:00
backchannel_rqst.c NFS client updates for Linux 5.20 2022-08-10 14:04:32 -07:00
cache.c treewide: use get_random_u32_below() instead of deprecated function 2022-11-18 02:15:15 +01:00
clnt.c SUNRPC: support abstract unix socket addresses 2023-06-19 12:12:22 -04:00
debugfs.c SUNRPC: Cache deferral injection 2022-05-19 12:25:38 -04:00
fail.h SUNRPC: Cache deferral injection 2022-05-19 12:25:38 -04:00
Kconfig SUNRPC: Add KUnit tests for rpcsec_krb5.ko 2023-02-20 09:20:46 -05:00
Makefile sunrpc: Create a sunrpc directory under /sys/kernel/ 2021-07-08 14:03:23 -04:00
netns.h SUNRPC: Fix occasional warning when destroying gss_krb5_enctypes 2023-02-20 09:20:57 -05:00
rpc_pipe.c fs: allocate inode by using alloc_inode_sb() 2022-03-22 15:57:03 -07:00
rpcb_clnt.c SUNRPC: attempt to reach rpcbind with an abstract socket name 2023-06-19 12:12:22 -04:00
sched.c SUNRPC: Don't change task->tk_status after the call to rpc_exit_task 2023-05-19 16:50:05 -04:00
socklib.c use less confusing names for iov_iter direction initializers 2022-11-25 13:01:55 -05:00
socklib.h SUNRPC: Refactor xs_sendpages() 2020-03-16 12:04:33 -04:00
stats.c SUNRPC: Use per-CPU counters to tally server RPC counts 2023-02-20 09:20:32 -05:00
sunrpc_syms.c sunrpc: add IDs to multipath 2021-07-08 14:03:23 -04:00
sunrpc.h treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_149.RULE 2022-06-10 14:51:35 +02:00
svc_xprt.c SUNRPC: always free ctxt when freeing deferred request 2023-05-14 15:55:02 -04:00
svc.c SUNRPC: Fix trace_svc_register() call site 2023-05-14 15:58:14 -04:00
svcauth_unix.c SUNRPC: Support TLS handshake in the server-side TCP socket code 2023-04-27 18:49:24 -04:00
svcauth.c SUNRPC: Hoist init_decode out of svc_authenticate() 2023-02-20 09:20:19 -05:00
svcsock.c nfsd: fix double fget() bug in __write_ports_addfd() 2023-05-31 09:57:14 -04:00
sysctl.c sunrpc: simplify one-level sysctl registration for debug_table 2023-04-11 12:45:19 -04:00
sysfs.c SUNRPC: make kobj_type structures constant 2023-02-14 16:21:52 -05:00
sysfs.h SUNRPC: take a xprt offline using sysfs 2021-07-08 14:03:24 -04:00
timer.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
xdr.c NFSD 6.3 Release Notes 2023-02-22 14:21:40 -08:00
xprt.c timers: Get rid of del_singleshot_timer_sync() 2022-11-24 15:09:10 +01:00
xprtmultipath.c SUNRPC: Directly use ida_alloc()/free() 2022-10-03 11:26:36 -04:00
xprtsock.c SUNRPC: support abstract unix socket addresses 2023-06-19 12:12:22 -04:00