[PATCH v1 12/27] SUNRPC: Add XDR encoding helper for opaque_auth
From: Chuck Lever <cel@kernel.org>
Date: 2023-01-08 16:29:45
Subsystem:
kernel nfsd, sunrpc, and lockd servers, networking [general], nfs, sunrpc, and lockd clients, the rest · Maintainers:
Chuck Lever, Jeff Layton, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Trond Myklebust, Anna Schumaker, Linus Torvalds
From: Chuck Lever <redacted>
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.
Signed-off-by: Chuck Lever <redacted>
---
include/linux/sunrpc/xdr.h | 2 ++
net/sunrpc/xdr.c | 29 +++++++++++++++++++++++++++++
2 files changed, 31 insertions(+)
diff --git a/include/linux/sunrpc/xdr.h b/include/linux/sunrpc/xdr.h
index 884df67009f4..f3b6eb9accd7 100644
--- a/include/linux/sunrpc/xdr.h
+++ b/include/linux/sunrpc/xdr.h@@ -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
diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
index 56d87c784c9e..6b2ec24ec62d 100644
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c@@ -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);