Commit 7b402c8d authored by Chuck Lever's avatar Chuck Lever
Browse files

SUNRPC: Add XDR encoding helper for opaque_auth 



RFC 5531 defines an MSG_ACCEPTED Reply message like this:

	struct accepted_reply {
		opaque_auth verf;
		union switch (accept_stat stat) {
		case SUCCESS:
		   ...

In the current server code, struct opaque_auth encoding is open-
coded. Introduce a helper that encodes an opaque_auth data item
within the context of a xdr_stream.

Done as part of hardening the server-side RPC header decoding and
encoding paths.

Reviewed-by: default avatarJeff Layton <jlayton@kernel.org>
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
parent 6d037b15

include/linux/sunrpc/xdr.h

+2 −0
Original line number Diff line number Diff line
@@ -348,6 +348,8 @@ ssize_t xdr_stream_decode_string_dup(struct xdr_stream *xdr, char **str, 
		size_t maxlen, gfp_t gfp_flags);

ssize_t xdr_stream_decode_opaque_auth(struct xdr_stream *xdr, u32 *flavor,

		void **body, unsigned int *body_len);

ssize_t xdr_stream_encode_opaque_auth(struct xdr_stream *xdr, u32 flavor,

		void *body, unsigned int body_len);



/**

 * xdr_align_size - Calculate padded size of an object

net/sunrpc/xdr.c

+29 −0
Original line number Diff line number Diff line
@@ -2310,3 +2310,32 @@ ssize_t xdr_stream_decode_opaque_auth(struct xdr_stream *xdr, u32 *flavor, 
	return len + ret;

}

EXPORT_SYMBOL_GPL(xdr_stream_decode_opaque_auth);



/**

 * xdr_stream_encode_opaque_auth - Encode struct opaque_auth (RFC5531 S8.2)

 * @xdr: pointer to xdr_stream

 * @flavor: verifier flavor to encode

 * @body: content of body to encode

 * @body_len: length of body to encode

 *

 * Return values:

 *   On success, returns length in bytes of XDR buffer consumed

 *   %-EBADMSG on XDR buffer overflow

 *   %-EMSGSIZE if the size of @body exceeds 400 octets

 */

ssize_t xdr_stream_encode_opaque_auth(struct xdr_stream *xdr, u32 flavor,

				      void *body, unsigned int body_len)

{

	ssize_t ret, len;



	if (unlikely(body_len > RPC_MAX_AUTH_SIZE))

		return -EMSGSIZE;

	len = xdr_stream_encode_u32(xdr, flavor);

	if (unlikely(len < 0))

		return len;

	ret = xdr_stream_encode_opaque(xdr, body, body_len);

	if (unlikely(ret < 0))

		return ret;

	return len + ret;

}

EXPORT_SYMBOL_GPL(xdr_stream_encode_opaque_auth);