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Sender: Chuck Lever <chucklever@gmail.com>
Subject: [PATCH v2 109/118] NFSD: Remove argument length checking in
 nfsd_dispatch()
From:   Chuck Lever <chuck.lever@oracle.com>
To:     linux-nfs@vger.kernel.org
Date:   Fri, 20 Nov 2020 15:43:26 -0500
Message-ID: <160590500604.1340.6630770609567437600.stgit@klimt.1015granger.net>
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Now that the decoders for NFSv2, NFSv3, and NFSACL all use the
xdr_stream mechanism, the special length checking logic in
nfsd_dispatch() is no longer necessary.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 fs/nfsd/nfssvc.c |   39 ---------------------------------------
 1 file changed, 39 deletions(-)

diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index cae6fbf10514..c51287de9a8d 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -961,37 +961,6 @@ nfsd(void *vrqstp)
 	return 0;
 }
 
-/*
- * A write procedure can have a large argument, and a read procedure can
- * have a large reply, but no NFSv2 or NFSv3 procedure has argument and
- * reply that can both be larger than a page.  The xdr code has taken
- * advantage of this assumption to be a sloppy about bounds checking in
- * some cases.  Pending a rewrite of the NFSv2/v3 xdr code to fix that
- * problem, we enforce these assumptions here:
- */
-static bool nfs_request_too_big(struct svc_rqst *rqstp,
-				const struct svc_procedure *proc)
-{
-	/*
-	 * The ACL code has more careful bounds-checking and is not
-	 * susceptible to this problem:
-	 */
-	if (rqstp->rq_prog != NFS_PROGRAM)
-		return false;
-	/*
-	 * Ditto NFSv4 (which can in theory have argument and reply both
-	 * more than a page):
-	 */
-	if (rqstp->rq_vers >= 4)
-		return false;
-	/* The reply will be small, we're OK: */
-	if (proc->pc_xdrressize > 0 &&
-	    proc->pc_xdrressize < XDR_QUADLEN(PAGE_SIZE))
-		return false;
-
-	return rqstp->rq_arg.len > PAGE_SIZE;
-}
-
 /**
  * nfsd_dispatch - Process an NFS or NFSACL Request
  * @rqstp: incoming request
@@ -1013,9 +982,6 @@ int nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp)
 	dprintk("nfsd_dispatch: vers %d proc %d\n",
 				rqstp->rq_vers, rqstp->rq_proc);
 
-	if (nfs_request_too_big(rqstp, proc))
-		goto out_too_large;
-
 	/*
 	 * Give the xdr decoder a chance to change this if it wants
 	 * (necessary in the NFSv4.0 compound case)
@@ -1053,11 +1019,6 @@ int nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp)
 out_cached_reply:
 	return 1;
 
-out_too_large:
-	dprintk("nfsd: NFSv%d argument too large\n", rqstp->rq_vers);
-	*statp = rpc_garbage_args;
-	return 1;
-
 out_decode_err:
 	dprintk("nfsd: failed to decode arguments!\n");
 	*statp = rpc_garbage_args;