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authorJ. Bruce Fields <bfields@redhat.com>2017-11-15 12:30:27 -0500
committerJ. Bruce Fields <bfields@redhat.com>2018-02-08 13:40:16 -0500
commit0078117c6d9160031b866cfa1853514d4f6865d2 (patch)
tree284b86e03244fca4e73f872fb32c42e08987590c /fs/nfsd
parent2502072058b35e2297f4ad7b211a45ad95a6a3d5 (diff)
downloadlinux-0078117c6d9160031b866cfa1853514d4f6865d2.tar.bz2
nfsd: return RESOURCE not GARBAGE_ARGS on too many ops
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.fnst@cn.fujitsu.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Diffstat (limited to 'fs/nfsd')
-rw-r--r--fs/nfsd/nfs4proc.c3
-rw-r--r--fs/nfsd/nfs4xdr.c9
2 files changed, 10 insertions, 2 deletions
diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index effeeb4f556f..a0bed2b2004d 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1703,6 +1703,9 @@ 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 2c61c6b8ae09..5dcd7cb45b2d 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -1918,8 +1918,13 @@ 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);