Patch "NFSD: Update the NFSv2 GETATTR argument decoder to use struct xdr_stream" has been added to the 5.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    NFSD: Update the NFSv2 GETATTR argument decoder to use struct xdr_stream

to the 5.10-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-update-the-nfsv2-getattr-argument-decoder-to-us.patch
and it can be found in the queue-5.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 1e265741e8e5554e2fd1e4a42aa49e827a518da2
Author: Chuck Lever <chuck.lever@xxxxxxxxxx>
Date:   Wed Oct 21 12:14:23 2020 -0400

    NFSD: Update the NFSv2 GETATTR argument decoder to use struct xdr_stream
    
    [ Upstream commit ebcd8e8b28535b643a4c06685bd363b3b73a96af ]
    
    Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
    Stable-dep-of: 401bc1f90874 ("NFSD: Protect against send buffer overflow in NFSv2 READ")
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c
index dbd8d3604653..5c187d3bcb57 100644
--- a/fs/nfsd/nfsproc.c
+++ b/fs/nfsd/nfsproc.c
@@ -626,7 +626,7 @@ static const struct svc_procedure nfsd_procedures2[18] = {
 	},
 	[NFSPROC_GETATTR] = {
 		.pc_func = nfsd_proc_getattr,
-		.pc_decode = nfssvc_decode_fhandle,
+		.pc_decode = nfssvc_decode_fhandleargs,
 		.pc_encode = nfssvc_encode_attrstat,
 		.pc_release = nfssvc_release_attrstat,
 		.pc_argsize = sizeof(struct nfsd_fhandle),
@@ -776,7 +776,7 @@ static const struct svc_procedure nfsd_procedures2[18] = {
 	},
 	[NFSPROC_STATFS] = {
 		.pc_func = nfsd_proc_statfs,
-		.pc_decode = nfssvc_decode_fhandle,
+		.pc_decode = nfssvc_decode_fhandleargs,
 		.pc_encode = nfssvc_encode_statfsres,
 		.pc_argsize = sizeof(struct nfsd_fhandle),
 		.pc_ressize = sizeof(struct nfsd_statfsres),
diff --git a/fs/nfsd/nfsxdr.c b/fs/nfsd/nfsxdr.c
index 13df5464a087..45d980d624f4 100644
--- a/fs/nfsd/nfsxdr.c
+++ b/fs/nfsd/nfsxdr.c
@@ -23,8 +23,9 @@ static u32	nfs_ftypes[] = {
 
 
 /*
- * XDR functions for basic NFS types
+ * Basic NFSv2 data types (RFC 1094 Section 2.3)
  */
+
 static __be32 *
 decode_fh(__be32 *p, struct svc_fh *fhp)
 {
@@ -37,6 +38,21 @@ decode_fh(__be32 *p, struct svc_fh *fhp)
 	return p + (NFS_FHSIZE >> 2);
 }
 
+static bool
+svcxdr_decode_fhandle(struct xdr_stream *xdr, struct svc_fh *fhp)
+{
+	__be32 *p;
+
+	p = xdr_inline_decode(xdr, NFS_FHSIZE);
+	if (!p)
+		return false;
+	fh_init(fhp, NFS_FHSIZE);
+	memcpy(&fhp->fh_handle.fh_base, p, NFS_FHSIZE);
+	fhp->fh_handle.fh_size = NFS_FHSIZE;
+
+	return true;
+}
+
 /* Helper function for NFSv2 ACL code */
 __be32 *nfs2svc_decode_fh(__be32 *p, struct svc_fh *fhp)
 {
@@ -194,14 +210,12 @@ __be32 *nfs2svc_encode_fattr(struct svc_rqst *rqstp, __be32 *p, struct svc_fh *f
  */
 
 int
-nfssvc_decode_fhandle(struct svc_rqst *rqstp, __be32 *p)
+nfssvc_decode_fhandleargs(struct svc_rqst *rqstp, __be32 *p)
 {
+	struct xdr_stream *xdr = &rqstp->rq_arg_stream;
 	struct nfsd_fhandle *args = rqstp->rq_argp;
 
-	p = decode_fh(p, &args->fh);
-	if (!p)
-		return 0;
-	return xdr_argsize_check(rqstp, p);
+	return svcxdr_decode_fhandle(xdr, &args->fh);
 }
 
 int
diff --git a/fs/nfsd/xdr.h b/fs/nfsd/xdr.h
index edd87688ff86..50466ac6200c 100644
--- a/fs/nfsd/xdr.h
+++ b/fs/nfsd/xdr.h
@@ -144,7 +144,7 @@ union nfsd_xdrstore {
 #define NFS2_SVC_XDRSIZE	sizeof(union nfsd_xdrstore)
 
 
-int nfssvc_decode_fhandle(struct svc_rqst *, __be32 *);
+int nfssvc_decode_fhandleargs(struct svc_rqst *, __be32 *);
 int nfssvc_decode_sattrargs(struct svc_rqst *, __be32 *);
 int nfssvc_decode_diropargs(struct svc_rqst *, __be32 *);
 int nfssvc_decode_readargs(struct svc_rqst *, __be32 *);