HID: Bluetooth: hidp: make sure input buffers are big enough

HID core expects the input buffers to be at least of size 4096
(HID_MAX_BUFFER_SIZE). Other sizes will result in buffer-overflows if an
input-report is smaller than advertised. We could, like i2c, compute the
biggest report-size instead of using HID_MAX_BUFFER_SIZE, but this will
blow up if report-descriptors are changed after ->start() has been called.
So lets be safe and just use the biggest buffer we have.

Note that this adds an additional copy to the HIDP input path. If there is
a way to make sure the skb-buf is big enough, we should use that instead.

The best way would be to make hid-core honor the @size argument, though,
that sounds easier than it is. So lets just fix the buffer-overflows for
now and afterwards look for a faster way for all transport drivers.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

diff --git a/net/bluetooth/hidp/core.c b/net/bluetooth/hidp/core.c
index 292e619db8961c82e7c3aa7f3280cb4236176ab8..d9fb9345144238f61372fdb21ca57c08b9471efd 100644 (file)
--- a/net/bluetooth/hidp/core.c
+++ b/net/bluetooth/hidp/core.c
@@ -430,6 +430,16 @@ static void hidp_del_timer(struct hidp_session *session)
                del_timer(&session->timer);
 }
 
+static void hidp_process_report(struct hidp_session *session,
+                               int type, const u8 *data, int len, int intr)
+{
+       if (len > HID_MAX_BUFFER_SIZE)
+               len = HID_MAX_BUFFER_SIZE;
+
+       memcpy(session->input_buf, data, len);
+       hid_input_report(session->hid, type, session->input_buf, len, intr);
+}
+
 static void hidp_process_handshake(struct hidp_session *session,
                                        unsigned char param)
 {
@@ -502,7 +512,8 @@ static int hidp_process_data(struct hidp_session *session, struct sk_buff *skb,
                        hidp_input_report(session, skb);
 
                if (session->hid)
-                       hid_input_report(session->hid, HID_INPUT_REPORT, skb->data, skb->len, 0);
+                       hidp_process_report(session, HID_INPUT_REPORT,
+                                           skb->data, skb->len, 0);
                break;
 
        case HIDP_DATA_RTYPE_OTHER:
@@ -584,7 +595,8 @@ static void hidp_recv_intr_frame(struct hidp_session *session,
                        hidp_input_report(session, skb);
 
                if (session->hid) {
-                       hid_input_report(session->hid, HID_INPUT_REPORT, skb->data, skb->len, 1);
+                       hidp_process_report(session, HID_INPUT_REPORT,
+                                           skb->data, skb->len, 1);
                        BT_DBG("report len %d", skb->len);
                }
        } else {

diff --git a/net/bluetooth/hidp/hidp.h b/net/bluetooth/hidp/hidp.h
index ab5241400cf78a9d7371d7a866d58aeba0d8043a..8798492a6e9971fff198344b580fa5ec3f17b8be 100644 (file)
--- a/net/bluetooth/hidp/hidp.h
+++ b/net/bluetooth/hidp/hidp.h
@@ -24,6 +24,7 @@
 #define __HIDP_H
 
 #include <linux/types.h>
+#include <linux/hid.h>
 #include <linux/kref.h>
 #include <net/bluetooth/bluetooth.h>
 #include <net/bluetooth/l2cap.h>
@@ -179,6 +180,9 @@ struct hidp_session {
 
        /* Used in hidp_output_raw_report() */
        int output_report_success; /* boolean */
+
+       /* temporary input buffer */
+       u8 input_buf[HID_MAX_BUFFER_SIZE];
 };
 
 /* HIDP init defines */