[PATCH 3.2 101/126] can: raw: raw_setsockopt: limit number of can_filter that can be set

[Ben Hutchings]

3.2.85-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>

commit 332b05ca7a438f857c61a3c21a88489a21532364 upstream.

This patch adds a check to limit the number of can_filters that can be
set via setsockopt on CAN_RAW sockets. Otherwise allocations > MAX_ORDER
are not prevented resulting in a warning.

Reference: https://lkml.org/lkml/2016/12/2/230

Reported-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Tested-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
[bwh: Backported to 3.2: adjust filename]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 include/linux/can.h | 1 +
 net/can/raw.c       | 3 +++
 2 files changed, 4 insertions(+)

--- a/include/linux/can.h
+++ b/include/linux/can.h
@@ -105,5 +105,6 @@ struct can_filter {
 };
 
 #define CAN_INV_FILTER 0x20000000U /* to be set in can_filter.can_id */
+#define CAN_RAW_FILTER_MAX 512 /* maximum number of can_filter set via setsockopt() */
 
 #endif /* CAN_H */
--- a/net/can/raw.c
+++ b/net/can/raw.c
@@ -459,6 +459,9 @@ static int raw_setsockopt(struct socket
 		if (optlen % sizeof(struct can_filter) != 0)
 			return -EINVAL;
 
+		if (optlen > CAN_RAW_FILTER_MAX * sizeof(struct can_filter))
+			return -EINVAL;
+
 		count = optlen / sizeof(struct can_filter);
 
 		if (count > 1) {