From: Chuck Lever chuck.lever@oracle.com
commit 89a3c9f5b9f0bcaa9aea3e8b2a616fcaea9aad78 upstream.
@subbuf is an output parameter of xdr_buf_subsegment(). A survey of call sites shows that @subbuf is always uninitialized before xdr_buf_segment() is invoked by callers.
There are some execution paths through xdr_buf_subsegment() that do not set all of the fields in @subbuf, leaving some pointer fields containing garbage addresses. Subsequent processing of that buffer then results in a page fault.
Signed-off-by: Chuck Lever chuck.lever@oracle.com Cc: stable@vger.kernel.org Signed-off-by: Anna Schumaker Anna.Schumaker@Netapp.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/sunrpc/xdr.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c index ed9bbd383f7d3..df7ecf9584f68 100644 --- a/net/sunrpc/xdr.c +++ b/net/sunrpc/xdr.c @@ -1031,6 +1031,7 @@ xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf, base = 0; } else { base -= buf->head[0].iov_len; + subbuf->head[0].iov_base = buf->head[0].iov_base; subbuf->head[0].iov_len = 0; }
@@ -1043,6 +1044,8 @@ xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf, base = 0; } else { base -= buf->page_len; + subbuf->pages = buf->pages; + subbuf->page_base = 0; subbuf->page_len = 0; }
@@ -1054,6 +1057,7 @@ xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf, base = 0; } else { base -= buf->tail[0].iov_len; + subbuf->tail[0].iov_base = buf->tail[0].iov_base; subbuf->tail[0].iov_len = 0; }