This is a note to let you know that I've just added the patch titled
NFSD: Fix handling of oversized NFSv4 COMPOUND requests
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nfsd-fix-handling-of-oversized-nfsv4-compound-reques.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 1234a1013aa5254ff21c722d47d02eb28c7de6a0
Author: Chuck Lever <chuck.lever@xxxxxxxxxx>
Date: Mon Sep 5 15:33:32 2022 -0400
NFSD: Fix handling of oversized NFSv4 COMPOUND requests
[ Upstream commit 7518a3dc5ea249d4112156ce71b8b184eb786151 ]
If an NFS server returns NFS4ERR_RESOURCE on the first operation in
an NFSv4 COMPOUND, there's no way for a client to know where the
problem is and then simplify the compound to make forward progress.
So instead, make NFSD process as many operations in an oversized
COMPOUND as it can and then return NFS4ERR_RESOURCE on the first
operation it did not process.
pynfs NFSv4.0 COMP6 exercises this case, but checks only for the
COMPOUND status code, not whether the server has processed any
of the operations.
pynfs NFSv4.1 SEQ6 and SEQ7 exercise the NFSv4.1 case, which detects
too many operations per COMPOUND by checking against the limits
negotiated when the session was created.
Suggested-by: Bruce Fields <bfields@xxxxxxxxxxxx>
Fixes: 0078117c6d91 ("nfsd: return RESOURCE not GARBAGE_ARGS on too many ops")
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index f7584787dab2..09dd70f79158 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -2493,9 +2493,6 @@ nfsd4_proc_compound(struct svc_rqst *rqstp)
status = nfserr_minor_vers_mismatch;
if (nfsd_minorversion(nn, 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) {
@@ -2508,10 +2505,20 @@ nfsd4_proc_compound(struct svc_rqst *rqstp)
rqstp->rq_lease_breaker = (void **)&cstate->clp;
- trace_nfsd_compound(rqstp, args->opcnt);
+ trace_nfsd_compound(rqstp, args->client_opcnt);
while (!status && resp->opcnt < args->opcnt) {
op = &args->ops[resp->opcnt++];
+ if (unlikely(resp->opcnt == NFSD_MAX_OPS_PER_COMPOUND)) {
+ /* If there are still more operations to process,
+ * stop here and report NFS4ERR_RESOURCE. */
+ if (cstate->minorversion == 0 &&
+ args->client_opcnt > resp->opcnt) {
+ op->status = nfserr_resource;
+ goto encode_op;
+ }
+ }
+
/*
* The XDR decode routines may have pre-set op->status;
* for example, if there is a miscellaneous XDR error
@@ -2587,8 +2594,8 @@ nfsd4_proc_compound(struct svc_rqst *rqstp)
status = op->status;
}
- trace_nfsd_compound_status(args->opcnt, resp->opcnt, status,
- nfsd4_op_name(op->opnum));
+ trace_nfsd_compound_status(args->client_opcnt, resp->opcnt,
+ status, nfsd4_op_name(op->opnum));
nfsd4_cstate_clear_replay(cstate);
nfsd4_increment_op_stats(op->opnum);
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 4504d1246d14..3c66517a6f0f 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -2349,16 +2349,10 @@ nfsd4_decode_compound(struct nfsd4_compoundargs *argp)
if (xdr_stream_decode_u32(argp->xdr, &argp->minorversion) < 0)
return false;
- if (xdr_stream_decode_u32(argp->xdr, &argp->opcnt) < 0)
+ if (xdr_stream_decode_u32(argp->xdr, &argp->client_opcnt) < 0)
return false;
-
- /*
- * 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 true;
+ argp->opcnt = min_t(u32, argp->client_opcnt,
+ NFSD_MAX_OPS_PER_COMPOUND);
if (argp->opcnt > ARRAY_SIZE(argp->iops)) {
argp->ops = kzalloc(argp->opcnt * sizeof(*argp->ops), GFP_KERNEL);
diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
index 8812256cd520..50242d8cd09e 100644
--- a/fs/nfsd/xdr4.h
+++ b/fs/nfsd/xdr4.h
@@ -688,9 +688,10 @@ struct nfsd4_compoundargs {
struct svcxdr_tmpbuf *to_free;
struct svc_rqst *rqstp;
- u32 taglen;
char * tag;
+ u32 taglen;
u32 minorversion;
+ u32 client_opcnt;
u32 opcnt;
struct nfsd4_op *ops;
struct nfsd4_op iops[8];
