From: Chuck Lever <chuck.lever@xxxxxxxxxx>
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@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Anna Schumaker <Anna.Schumaker@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/sunrpc/xdr.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
index 6f7d82fb1eb0a..be11d672b5b97 100644
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -1118,6 +1118,7 @@ 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;
}
@@ -1130,6 +1131,8 @@ 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;
}
@@ -1141,6 +1144,7 @@ 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;
}
--
2.25.1
