[PATCH 4.19 30/32] macintosh/adb: fix oob read in do_adb_query() function

[Greg Kroah-Hartman]

From: Ning Qiang <sohu0106@xxxxxxx>

commit fd97e4ad6d3b0c9fce3bca8ea8e6969d9ce7423b upstream.

In do_adb_query() function of drivers/macintosh/adb.c, req->data is copied
form userland. The parameter "req->data[2]" is missing check, the array
size of adb_handler[] is 16, so adb_handler[req->data[2]].original_address and
adb_handler[req->data[2]].handler_id will lead to oob read.

Cc: stable <stable@xxxxxxxxxx>
Signed-off-by: Ning Qiang <sohu0106@xxxxxxx>
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Acked-by: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20220713153734.2248-1-sohu0106@xxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/macintosh/adb.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/macintosh/adb.c
+++ b/drivers/macintosh/adb.c
@@ -645,7 +645,7 @@ do_adb_query(struct adb_request *req)
 
 	switch(req->data[1]) {
 	case ADB_QUERY_GETDEVINFO:
-		if (req->nbytes < 3)
+		if (req->nbytes < 3 || req->data[2] >= 16)
 			break;
 		mutex_lock(&adb_handler_mutex);
 		req->reply[0] = adb_handler[req->data[2]].original_address;