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: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Benjamin Coddington 2023-08-22 14:22:38 -04:00 committed by Greg Kroah-Hartman
parent 16282aeca4
commit 7a9619e38c
2 changed files with 2 additions and 2 deletions

View File

@ -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); error = decode_filename_inline(xdr, &entry->name, &entry->len);
if (unlikely(error)) if (unlikely(error))
return -EAGAIN; return error == -ENAMETOOLONG ? -ENAMETOOLONG : -EAGAIN;
/* /*
* The type (size and byte order) of nfscookie isn't defined in * The type (size and byte order) of nfscookie isn't defined in

View File

@ -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); error = decode_inline_filename3(xdr, &entry->name, &entry->len);
if (unlikely(error)) if (unlikely(error))
return -EAGAIN; return error == -ENAMETOOLONG ? -ENAMETOOLONG : -EAGAIN;
error = decode_cookie3(xdr, &new_cookie); error = decode_cookie3(xdr, &new_cookie);
if (unlikely(error)) if (unlikely(error))