Commit 27b0fcae authored by Chuck Lever's avatar Chuck Lever
Browse files

xdrgen: Initialize data pointer for zero-length items 



The xdrgen decoders for strings and opaque data had an
optimization that skipped calling xdr_inline_decode() when the
item length was zero. This left the data pointer uninitialized,
which could lead to unpredictable behavior when callers access
it.

Remove the zero-length check and always call xdr_inline_decode().
When passed a length of zero, xdr_inline_decode() returns the
current buffer position, which is valid and matches the behavior
of hand-coded XDR decoders throughout the kernel.

Fixes: 4b132aac ("tools: Add xdrgen")
Reviewed-by: default avatarJeff Layton <jlayton@kernel.org>
Reviewed-by: default avatarNeilBrown <neil@brown.name>
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
parent 41b0a87b

include/linux/sunrpc/xdrgen/_builtins.h

+8 −12
Original line number Diff line number Diff line
@@ -248,12 +248,10 @@ xdrgen_decode_string(struct xdr_stream *xdr, string *ptr, u32 maxlen) 
		return false;

	if (unlikely(maxlen && len > maxlen))

		return false;

	if (len != 0) {

	p = xdr_inline_decode(xdr, len);

	if (unlikely(!p))

		return false;

	ptr->data = (unsigned char *)p;

	}

	ptr->len = len;

	return true;

}
@@ -279,12 +277,10 @@ xdrgen_decode_opaque(struct xdr_stream *xdr, opaque *ptr, u32 maxlen) 
		return false;

	if (unlikely(maxlen && len > maxlen))

		return false;

	if (len != 0) {

	p = xdr_inline_decode(xdr, len);

	if (unlikely(!p))

		return false;

	ptr->data = (u8 *)p;

	}

	ptr->len = len;

	return true;

}