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: 4b132aacb0 ("tools: Add xdrgen")
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: NeilBrown <neil@brown.name>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
This commit is contained in:
Chuck Lever
2025-12-20 10:41:09 -05:00
parent 41b0a87bc6
commit 27b0fcae8f

View File

@@ -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;
}
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;
}
p = xdr_inline_decode(xdr, len);
if (unlikely(!p))
return false;
ptr->data = (u8 *)p;
ptr->len = len;
return true;
}