[v2,12/20] sgi-xp: Use designated initializers

Commit Message

Kees Cook May 26, 2017, 8:17 p.m. UTC

Prepare to mark sensitive kernel structures for randomization by making
sure they're using designated initializers. These were identified during
allyesconfig builds of x86, arm, and arm64, with most initializer fixes
extracted from grsecurity.

To avoid casting, this implements dummy functions with full function
prototypes.

Signed-off-by: Kees Cook <[e-mail]>
Acked-by: Robin Holt <[e-mail]>
---
 drivers/misc/sgi-xp/xp_main.c | 59 ++++++++++++++++++++++++++++---------------
 1 file changed, 39 insertions(+), 20 deletions(-)

Comments

Christoph Hellwig May 27, 2017, 8:44 a.m. UTC | #1

On Fri, May 26, 2017 at 01:17:16PM -0700, Kees Cook wrote:
> Prepare to mark sensitive kernel structures for randomization by making
> sure they're using designated initializers. These were identified during
> allyesconfig builds of x86, arm, and arm64, with most initializer fixes
> extracted from grsecurity.
> 
> To avoid casting, this implements dummy functions with full function
> prototypes.

Can we get this in ASAP?

> +static void xpc_notloaded_connect(int ch_number)
> +{ }
> +
> +static void xpc_notloaded_disconnect(int ch_number)
> +{ }

Also it might be a good idea to just check in the caller if the
methods are defined instead of having all these dummys.  A branch
is usually cheaper than an indirect call, AND it leads to less code,
AND is is less fragile.

Patch

diff --git a/drivers/misc/sgi-xp/xp_main.c b/drivers/misc/sgi-xp/xp_main.c
index 01be66d02ca8..bb47f9d9b68a 100644
--- a/drivers/misc/sgi-xp/xp_main.c
+++ b/drivers/misc/sgi-xp/xp_main.c
@@ -71,20 +71,44 @@  EXPORT_SYMBOL_GPL(xpc_registrations);
 /*
  * Initialize the XPC interface to indicate that XPC isn't loaded.
  */
-static enum xp_retval
-xpc_notloaded(void)
+static void xpc_notloaded_connect(int ch_number)
+{ }
+
+static void xpc_notloaded_disconnect(int ch_number)
+{ }
+
+static enum xp_retval xpc_notloaded_send(short partid, int ch_number,
+					 u32 flags, void *payload,
+					 u16 payload_size)
+{
+	return xpNotLoaded;
+}
+
+static enum xp_retval xpc_notloaded_send_notify(short partid, int ch_number,
+						u32 flags, void *payload,
+						u16 payload_size,
+						xpc_notify_func func,
+						void *key)
+{
+	return xpNotLoaded;
+}
+
+static void xpc_notloaded_received(short partid, int ch_number, void *payload)
+{ }
+
+static enum xp_retval xpc_notloaded_partid_to_nasids(short partid,
+						     void *nasid_mask)
 {
 	return xpNotLoaded;
 }
 
 struct xpc_interface xpc_interface = {
-	(void (*)(int))xpc_notloaded,
-	(void (*)(int))xpc_notloaded,
-	(enum xp_retval(*)(short, int, u32, void *, u16))xpc_notloaded,
-	(enum xp_retval(*)(short, int, u32, void *, u16, xpc_notify_func,
-			   void *))xpc_notloaded,
-	(void (*)(short, int, void *))xpc_notloaded,
-	(enum xp_retval(*)(short, void *))xpc_notloaded
+	.connect = xpc_notloaded_connect,
+	.disconnect = xpc_notloaded_disconnect,
+	.send = xpc_notloaded_send,
+	.send_notify = xpc_notloaded_send_notify,
+	.received = xpc_notloaded_received,
+	.partid_to_nasids = xpc_notloaded_partid_to_nasids
 };
 EXPORT_SYMBOL_GPL(xpc_interface);
 
@@ -115,17 +139,12 @@  EXPORT_SYMBOL_GPL(xpc_set_interface);
 void
 xpc_clear_interface(void)
 {
-	xpc_interface.connect = (void (*)(int))xpc_notloaded;
-	xpc_interface.disconnect = (void (*)(int))xpc_notloaded;
-	xpc_interface.send = (enum xp_retval(*)(short, int, u32, void *, u16))
-	    xpc_notloaded;
-	xpc_interface.send_notify = (enum xp_retval(*)(short, int, u32, void *,
-						       u16, xpc_notify_func,
-						       void *))xpc_notloaded;
-	xpc_interface.received = (void (*)(short, int, void *))
-	    xpc_notloaded;
-	xpc_interface.partid_to_nasids = (enum xp_retval(*)(short, void *))
-	    xpc_notloaded;
+	xpc_interface.connect = xpc_notloaded_connect;
+	xpc_interface.disconnect = xpc_notloaded_disconnect;
+	xpc_interface.send = xpc_notloaded_send;
+	xpc_interface.send_notify = xpc_notloaded_send_notify;
+	xpc_interface.received = xpc_notloaded_received;
+	xpc_interface.partid_to_nasids = xpc_notloaded_partid_to_nasids;
 }
 EXPORT_SYMBOL_GPL(xpc_clear_interface);