[PATCH] RPC: Ensure XDR iovec length is initialized correctly in call_header

[deliverable/linux.git] / net / sunrpc / xdr.c

diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
index 67b9f035ba8606d1ee1f60bf7b2deb44a86f0e66..f86d1baa63029b38524c7ef0a1c225038f7a9b9a 100644 (file)
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -616,12 +616,24 @@ xdr_shift_buf(struct xdr_buf *buf, size_t len)
 void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, uint32_t *p)
 {
        struct kvec *iov = buf->head;
+       int scratch_len = buf->buflen - buf->page_len - buf->tail[0].iov_len;
 
+       BUG_ON(scratch_len < 0);
        xdr->buf = buf;
        xdr->iov = iov;
-       xdr->end = (uint32_t *)((char *)iov->iov_base + iov->iov_len);
-       buf->len = iov->iov_len = (char *)p - (char *)iov->iov_base;
-       xdr->p = p;
+       xdr->p = (uint32_t *)((char *)iov->iov_base + iov->iov_len);
+       xdr->end = (uint32_t *)((char *)iov->iov_base + scratch_len);
+       BUG_ON(iov->iov_len > scratch_len);
+
+       if (p != xdr->p && p != NULL) {
+               size_t len;
+
+               BUG_ON(p < xdr->p || p > xdr->end);
+               len = (char *)p - (char *)xdr->p;
+               xdr->p = p;
+               buf->len += len;
+               iov->iov_len += len;
+       }
 }
 EXPORT_SYMBOL(xdr_init_encode);