linux.git/fs/nfs/flexfilelayout, branch v6.5

cred: Do not default to init_cred in prepare_kernel_cred()

2022-11-01T17:04:52+00:00

A common exploit pattern for ROP attacks is to abuse prepare_kernel_cred()
in order to construct escalated privileges[1]. Instead of providing a
short-hand argument (NULL) to the "daemon" argument to indicate using
init_cred as the base cred, require that "daemon" is always set to
an actual task. Replace all existing callers that were passing NULL
with &init_task.

Future attacks will need to have sufficiently powerful read/write
primitives to have found an appropriately privileged task and written it
to the ROP stack as an argument to succeed, which is similarly difficult
to the prior effort needed to escalate privileges before struct cred
existed: locate the current cred and overwrite the uid member.

This has the added benefit of meaning that prepare_kernel_cred() can no
longer exceed the privileges of the init task, which may have changed from
the original init_cred (e.g. dropping capabilities from the bounding set).

[1] https://google.com/search?q=commit_creds(prepare_kernel_cred(0))

Cc: "Eric W. Biederman" 
Cc: David Howells 
Cc: "Rafael J. Wysocki" 
Cc: Steve French 
Cc: Ronnie Sahlberg 
Cc: Shyam Prasad N 
Cc: Tom Talpey 
Cc: Namjae Jeon 
Cc: Trond Myklebust 
Cc: Anna Schumaker 
Cc: Chuck Lever 
Cc: Jeff Layton 
Cc: "David S. Miller" 
Cc: Eric Dumazet 
Cc: Jakub Kicinski 
Cc: Paolo Abeni 
Cc: "Michal Koutný" 
Cc: Peter Zijlstra 
Cc: linux-cifs@vger.kernel.org
Cc: samba-technical@lists.samba.org
Cc: linux-nfs@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: Kees Cook 
Acked-by: Luis Chamberlain 
Reviewed-by: Sergey Senozhatsky 
Acked-by: Russ Weight 
Acked-by: Greg Kroah-Hartman 
Acked-by: Paulo Alcantara (SUSE) 
Link: https://lore.kernel.org/r/20221026232943.never.775-kees@kernel.org

NFSv4/flexfiles: Cancel I/O if the layout is recalled or revoked

2022-10-06T13:52:09+00:00

If the layout is recalled or revoked, we want to cancel I/O as quickly
as possible so that we can return the layout.

Signed-off-by: Trond Myklebust 
Signed-off-by: Anna Schumaker

NFSv4/pNFS: Always return layout stats on layout return for flexfiles

2022-10-03T15:26:37+00:00

We want to ensure that the server never misses the layout stats when
we're closing the file, so that it knows whether or not to update its
internal state. Otherwise, if we were racing with a layout stat, we
might cause the server to invalidate its layout before the layout stat
got processed.

Fixes: 06946c6a3d8b ("pNFS/flexfiles: Only send layoutstats updates for mirrors that were updated")
Signed-off-by: Trond Myklebust 
Signed-off-by: Anna Schumaker

NFS: Allow setting rsize / wsize to a multiple of PAGE_SIZE

2022-07-12T14:53:10+00:00

Previously, we required this to value to be a power of 2 for UDP related
reasons. This patch keeps the power of 2 rule for UDP but allows more
flexibility for TCP and RDMA.

Signed-off-by: Anna Schumaker 
Signed-off-by: Trond Myklebust

pNFS/flexfiles: Report RDMA connection errors to the server

2022-07-10T23:00:53+00:00

The RPC/RDMA driver will return -EPROTO and -ENODEV as connection errors
under certain circumstances. Make sure that we handle them and report
them to the server. If not, we can end up cycling forever in a
LAYOUTGET/LAYOUTRETURN loop.

Fixes: a12f996d3413 ("NFSv4/pNFS: Use connections to a DS that are all of the same protocol family")
Cc: stable@vger.kernel.org # 5.11.x
Signed-off-by: Trond Myklebust

pNFS/flexfiles: Ensure pNFS allocation modes are consistent with nfsiod

2022-03-22T19:52:56+00:00

Ensure that pNFS flexfile allocations in rpciod/nfsiod callbacks can
fail in low memory mode, so that the threads don't block and loop
forever.

Signed-off-by: Trond Myklebust

NFSv4/flexfiles: Convert GFP_NOFS to GFP_KERNEL

2022-02-25T23:50:12+00:00

Assume that the higher layers will have set memalloc_nofs_save/restore
as appropriate.

Signed-off-by: Trond Myklebust

SUNRPC: Trace calls to .rpc_call_done

2021-10-20T22:09:54+00:00

Introduce a single tracepoint that can replace simple dprintk call
sites in upper layer "rpc_call_done" callbacks. Example:

   kworker/u24:2-1254  [001]   771.026677: rpc_stats_latency:    task:00000001@00000002 xid=0x16a6f3c0 rpcbindv2 GETPORT backlog=446 rtt=101 execute=555
   kworker/u24:2-1254  [001]   771.026677: rpc_task_call_done:   task:00000001@00000002 flags=ASYNC|DYNAMIC|SOFT|SOFTCONN|SENT runstate=RUNNING|ACTIVE status=0 action=rpcb_getport_done
   kworker/u24:2-1254  [001]   771.026678: rpcb_setport:         task:00000001@00000002 status=0 port=20048

Signed-off-by: Chuck Lever 
Signed-off-by: Trond Myklebust

pnfs/flexfiles: Fix misplaced barrier in nfs4_ff_layout_prepare_ds

2021-10-04T03:00:50+00:00

_nfs4_pnfs_v3/v4_ds_connect do
   some work
   smp_wmb
   ds->ds_clp = clp;

And nfs4_ff_layout_prepare_ds currently does
   smp_rmb
   if(ds->ds_clp)
      ...

This patch places the smp_rmb after the if. This ensures that following
reads only happen once nfs4_ff_layout_prepare_ds has checked that data
has been properly initialized.

Fixes: d67ae825a59d6 ("pnfs/flexfiles: Add the FlexFile Layout Driver")
Signed-off-by: Baptiste Lepers 
Signed-off-by: Trond Myklebust

pNFS/flexfiles: fix incorrect size check in decode_nfs_fh()

2021-04-14T13:36:29+00:00

We (adam zabrocki, alexander matrosov, alexander tereshkin, maksym
bazalii) observed the check:

	if (fh->size > sizeof(struct nfs_fh))

should not use the size of the nfs_fh struct which includes an extra two
bytes from the size field.

struct nfs_fh {
	unsigned short         size;
	unsigned char          data[NFS_MAXFHSIZE];
}

but should determine the size from data[NFS_MAXFHSIZE] so the memcpy
will not write 2 bytes beyond destination.  The proposed fix is to
compare against the NFS_MAXFHSIZE directly, as is done elsewhere in fs
code base.

Fixes: d67ae825a59d ("pnfs/flexfiles: Add the FlexFile Layout Driver")
Signed-off-by: Nikola Livic 
Signed-off-by: Dan Carpenter 
Signed-off-by: Trond Myklebust