[PATCH 3.16 109/370] IB/mad: Fix an array index check

[Ben Hutchings]

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

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

From: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>

commit 2fe2f378dd45847d2643638c07a7658822087836 upstream.

The array ib_mad_mgmt_class_table.method_table has MAX_MGMT_CLASS
(80) elements. Hence compare the array index with that value instead
of with IB_MGMT_MAX_METHODS (128). This patch avoids that Coverity
reports the following:

Overrunning array class->method_table of 80 8-byte elements at element index 127 (byte offset 1016) using index convert_mgmt_class(mad_hdr->mgmt_class) (which evaluates to 127).

Fixes: commit b7ab0b19a85f ("IB/mad: Verify mgmt class in received MADs")
Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
Cc: Sean Hefty <sean.hefty@xxxxxxxxx>
Reviewed-by: Hal Rosenstock <hal@xxxxxxxxxxxx>
Signed-off-by: Doug Ledford <dledford@xxxxxxxxxx>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/infiniband/core/mad.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/infiniband/core/mad.c
+++ b/drivers/infiniband/core/mad.c
@@ -1607,7 +1607,7 @@ find_mad_agent(struct ib_mad_port_privat
 			if (!class)
 				goto out;
 			if (convert_mgmt_class(mad->mad_hdr.mgmt_class) >=
-			    IB_MGMT_MAX_METHODS)
+			    ARRAY_SIZE(class->method_table))
 				goto out;
 			method = class->method_table[convert_mgmt_class(
 							mad->mad_hdr.mgmt_class)];