From 846b5756d7632523b5bfce78c163aa883aa9d587 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Mon, 2 Jan 2023 12:05:43 -0500 Subject: SUNRPC: Add an XDR decoding helper for struct opaque_auth RFC 5531 defines the body of an RPC Call message like this: struct call_body { unsigned int rpcvers; unsigned int prog; unsigned int vers; unsigned int proc; opaque_auth cred; opaque_auth verf; /* procedure-specific parameters start here */ }; In the current server code, decoding a struct opaque_auth type is open-coded in several places, and is thus difficult to harden everywhere. Introduce a helper for decoding an opaque_auth within the context of a xdr_stream. This helper can be shared with all authentication flavor implemenations, even on the client-side. Done as part of hardening the server-side RPC header decoding paths. Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever --- net/sunrpc/xdr.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) (limited to 'net/sunrpc/xdr.c') diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c index f7767bf22406..4845ba2113fd 100644 --- a/net/sunrpc/xdr.c +++ b/net/sunrpc/xdr.c @@ -2274,3 +2274,31 @@ ssize_t xdr_stream_decode_string_dup(struct xdr_stream *xdr, char **str, return ret; } EXPORT_SYMBOL_GPL(xdr_stream_decode_string_dup); + +/** + * xdr_stream_decode_opaque_auth - Decode struct opaque_auth (RFC5531 S8.2) + * @xdr: pointer to xdr_stream + * @flavor: location to store decoded flavor + * @body: location to store decode body + * @body_len: location to store length of decoded body + * + * Return values: + * On success, returns the number of buffer bytes consumed + * %-EBADMSG on XDR buffer overflow + * %-EMSGSIZE if the decoded size of the body field exceeds 400 octets + */ +ssize_t xdr_stream_decode_opaque_auth(struct xdr_stream *xdr, u32 *flavor, + void **body, unsigned int *body_len) +{ + ssize_t ret, len; + + len = xdr_stream_decode_u32(xdr, flavor); + if (unlikely(len < 0)) + return len; + ret = xdr_stream_decode_opaque_inline(xdr, body, RPC_MAX_AUTH_SIZE); + if (unlikely(ret < 0)) + return ret; + *body_len = ret; + return len + ret; +} +EXPORT_SYMBOL_GPL(xdr_stream_decode_opaque_auth); -- cgit v1.2.3