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Commit 7a9619e3 authored by Benjamin Coddington's avatar Benjamin Coddington Committed by Greg Kroah-Hartman
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NFS: Guard against READDIR loop when entry names exceed MAXNAMELEN 



[ Upstream commit f67b55b6588bcf9316a1e6e8d529100a5aa3ebe6 ]

Commit 64cfca85bacd asserts the only valid return values for
nfs2/3_decode_dirent should not include -ENAMETOOLONG, but for a server
that sends a filename3 which exceeds MAXNAMELEN in a READDIR response the
client's behavior will be to endlessly retry the operation.

We could map -ENAMETOOLONG into -EBADCOOKIE, but that would produce
truncated listings without any error.  The client should return an error
for this case to clearly assert that the server implementation must be
corrected.

Fixes: 64cfca85bacd ("NFS: Return valid errors from nfs2/3_decode_dirent()")
Signed-off-by: default avatarBenjamin Coddington <bcodding@redhat.com>
Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 16282aec

fs/nfs/nfs2xdr.c

+1 −1
Original line number Diff line number Diff line
@@ -953,7 +953,7 @@ int nfs2_decode_dirent(struct xdr_stream *xdr, struct nfs_entry *entry, 


	error = decode_filename_inline(xdr, &entry->name, &entry->len);

	if (unlikely(error))

		return -EAGAIN;

		return error == -ENAMETOOLONG ? -ENAMETOOLONG : -EAGAIN;



	/*

	 * The type (size and byte order) of nfscookie isn't defined in

fs/nfs/nfs3xdr.c

+1 −1
Original line number Diff line number Diff line
@@ -1991,7 +1991,7 @@ int nfs3_decode_dirent(struct xdr_stream *xdr, struct nfs_entry *entry, 


	error = decode_inline_filename3(xdr, &entry->name, &entry->len);

	if (unlikely(error))

		return -EAGAIN;

		return error == -ENAMETOOLONG ? -ENAMETOOLONG : -EAGAIN;



	error = decode_cookie3(xdr, &new_cookie);

	if (unlikely(error))