[PATCH AUTOSEL 4.9 002/141] nfsd4: avoid NULL deference on strange COPY compounds

[PATCH AUTOSEL 4.9 002/141] nfsd4: avoid NULL deference on strange COPY compounds

[Sasha Levin]

From: "J. Bruce Fields" <bfields@redhat.com>

[ Upstream commit d781e3df710745fbbaee4eb07fd5b64331a1b175 ]

With cross-server COPY we've introduced the possibility that the current
or saved filehandle might not have fh_dentry/fh_export filled in, but we
missed a place that assumed it was.  I think this could be triggered by
a compound like:

	PUTFH(foreign filehandle)
	GETATTR
	SAVEFH
	COPY

First, check_if_stalefh_allowed sets no_verify on the first (PUTFH) op.
Then op_func = nfsd4_putfh runs and leaves current_fh->fh_export NULL.
need_wrongsec_check returns true, since this PUTFH has OP_IS_PUTFH_LIKE
set and GETATTR does not have OP_HANDLES_WRONGSEC set.

We should probably also consider tightening the checks in
check_if_stalefh_allowed and double-checking that we don't assume the
filehandle is verified elsewhere in the compound.  But I think this
fixes the immediate issue.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: 4e48f1cccab3 "NFSD: allow inter server COPY to have... "
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/nfsd/nfs4proc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 66985a6a7047b..33537bbb70b36 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1800,7 +1800,8 @@ nfsd4_proc_compound(struct svc_rqst *rqstp,
 			if (opdesc->op_flags & OP_CLEAR_STATEID)
 				clear_current_stateid(cstate);
 
-			if (need_wrongsec_check(rqstp))
+			if (current_fh->fh_export &&
+					need_wrongsec_check(rqstp))
 				op->status = check_nfsd_access(current_fh->fh_export, rqstp);
 		}
 encode_op:
-- 
2.20.1

[PATCH AUTOSEL 4.9 021/141] nfs: NFS_SWAP should depend on SWAP

[Sasha Levin]

From: Geert Uytterhoeven <geert+renesas@glider.be>

[ Upstream commit 474c4f306eefbb21b67ebd1de802d005c7d7ecdc ]

If CONFIG_SWAP=n, it does not make much sense to offer the user the
option to enable support for swapping over NFS, as that will still fail
at run time:

    # swapon /swap
    swapon: /swap: swapon failed: Function not implemented

Fix this by adding a dependency on CONFIG_SWAP.

Fixes: a564b8f0398636ba ("nfs: enable swap on NFS")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/nfs/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/nfs/Kconfig b/fs/nfs/Kconfig
index b1daeafbea920..c3428767332c2 100644
--- a/fs/nfs/Kconfig
+++ b/fs/nfs/Kconfig
@@ -89,7 +89,7 @@ config NFS_V4
 config NFS_SWAP
 	bool "Provide swap over NFS support"
 	default n
-	depends on NFS_FS
+	depends on NFS_FS && SWAP
 	select SUNRPC_SWAP
 	help
 	  This option enables swapon to work on files located on NFS mounts.
-- 
2.20.1

[PATCH AUTOSEL 4.9 140/141] NFSv4: try lease recovery on NFS4ERR_EXPIRED

[Sasha Levin]

From: Robert Milkowski <rmilkowski@gmail.com>

[ Upstream commit 924491f2e476f7234d722b24171a4daff61bbe13 ]

Currently, if an nfs server returns NFS4ERR_EXPIRED to open(),
we return EIO to applications without even trying to recover.

Fixes: 272289a3df72 ("NFSv4: nfs4_do_handle_exception() handle revoke/expiry of a single stateid")
Signed-off-by: Robert Milkowski <rmilkowski@gmail.com>
Reviewed-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/nfs/nfs4proc.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index ca4249ae644f2..632d3c3f8dfb3 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2916,6 +2916,11 @@ static struct nfs4_state *nfs4_do_open(struct inode *dir,
 			exception.retry = 1;
 			continue;
 		}
+		if (status == -NFS4ERR_EXPIRED) {
+			nfs4_schedule_lease_recovery(server->nfs_client);
+			exception.retry = 1;
+			continue;
+		}
 		if (status == -EAGAIN) {
 			/* We must have found a delegation */
 			exception.retry = 1;
-- 
2.20.1