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

[ Upstream commit 0078117c6d9160031b866cfa1853514d4f6865d2 ]

A client that sends more than a hundred ops in a single compound
currently gets an rpc-level GARBAGE_ARGS error.

It would be more helpful to return NFS4ERR_RESOURCE, since that gives
the client a better idea how to recover (for example by splitting up the
compound into smaller compounds).

This is all a bit academic since we've never actually seen a reason for
clients to send such long compounds, but we may as well fix it.

While we're there, just use NFSD4_MAX_OPS_PER_COMPOUND == 16, the
constant we already use in the 4.1 case, instead of hard-coding 100.
Chances anyone actually uses even 16 ops per compound are small enough
that I think there's a neglible risk or any regression.

This fixes pynfs test COMP6.

Reported-by: "Lu, Xinyu" <luxy.f...@cn.fujitsu.com>
Signed-off-by: J. Bruce Fields <bfie...@redhat.com>
Signed-off-by: Sasha Levin <alexander.le...@microsoft.com>
---
 fs/nfsd/nfs4proc.c | 3 +++
 fs/nfsd/nfs4xdr.c  | 9 +++++++--
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index bfbee8ddf978..8f35f0a15bfa 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1627,6 +1627,9 @@ nfsd4_proc_compound(struct svc_rqst *rqstp,
        status = nfserr_minor_vers_mismatch;
        if (nfsd_minorversion(args->minorversion, NFSD_TEST) <= 0)
                goto out;
+       status = nfserr_resource;
+       if (args->opcnt > NFSD_MAX_OPS_PER_COMPOUND)
+               goto out;
 
        status = nfs41_check_op_ordering(args);
        if (status) {
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 544672b440de..5ad02bdb62a3 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -1824,8 +1824,13 @@ nfsd4_decode_compound(struct nfsd4_compoundargs *argp)
 
        if (argp->taglen > NFSD4_MAX_TAGLEN)
                goto xdr_error;
-       if (argp->opcnt > 100)
-               goto xdr_error;
+       /*
+        * NFS4ERR_RESOURCE is a more helpful error than GARBAGE_ARGS
+        * here, so we return success at the xdr level so that
+        * nfsd4_proc can handle this is an NFS-level error.
+        */
+       if (argp->opcnt > NFSD_MAX_OPS_PER_COMPOUND)
+               return 0;
 
        if (argp->opcnt > ARRAY_SIZE(argp->iops)) {
                argp->ops = kzalloc(argp->opcnt * sizeof(*argp->ops), 
GFP_KERNEL);
-- 
2.15.1

Reply via email to